CONTRACTOR REPORT

SAND80-7171 Unlimited Release UC-63a

The Design of a Photovoltaic System for a Passive Design Northeast All-Electric Residence

E. M. Mehalick, G. F. Tully, J. Johnson, J. Parker, R. Felice Philadelphia, PA 19101

Prepared by Sandia National Laboratories Albuquerque, New Mexico 87185 and Livermore, California 94550 for the Uhited States Department of Energy under Contract DE-AC04-76DP00789

Printed January 1982

Issued by Sandia National Laboratories, operated for the United States Department of Energy by Sandia Corporation. NOTICE: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Govern· ment nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or pro­cess disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government, any agency thereof or any of their contractors or subcontractors. The views and opinions expressed herein do not necessarily state or reflect those of the United States Government, any agency thereof or any of their contractors or subcontractors.

Printed in the United States of America Available from National Technical Information Service U.S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161

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Distribution Category UC-63a

SAND80-7171 Unlimited Distribution Printed January 1982

THE DESIGN OF A PHOTOVOLTAIC SYSTEM FOR A PASSIVE DESIGN NORTHEAST ALL-ELECTRIC RESIDENCE

E. M. Mehalick, G. F. Tully, J. Johnson, J. Parker, R. Felice

General Electric Energy Systems and Technology Division General Electric

Advanced Energy Programs Department P. O. Box 8555

Philadelphia, Penn. 19101

ABSTRACT

A photovoltaic system has been developed and integrated into a passively designed, low energy consuming home suitable for the Northeast region of the country. The selected array size is 4.1 kW at NOCT conditions, and covers 51 sq.m. of roof area. The design addresses the residential market segment of low energy consuming houses with limited roof area avail­ability for photovoltaic arrays. A direct mount, next gen­eration, larger sized, PV shingle module is used to reduce installation costs over earlier generation shingle modules. A 4 kW line-commutated inverter is used in the power conver­sion subsystem, since it is representative of currently available equipment. This report describes the complete sys­tem and house design, including all the pertinent installa­tion and construction drawings. Specific performance results are presented for the Boston and Madison region. The system design presented in the report, coupled with previously com­pleted designs, provide a set of design options expected to be available to residential homeowners in the mid 1980's.

Prepared for Sandia National Laboratories under Contract No. 13-8779.

iii-iv

FOREWARD

This report presents the fourth of six detailed residential designs

developed on the Detailed Residential Photovoltaic System Preferred Designs

Study. The Advanced Energy Programs Department of the General Electric Company,

Energy Systems and Technology Division, performed the contract under Sandia

National Laboratories, Contract 13-8779. Mr. E. M. Mehalick served as the GE

Program Manager and Dr. G. Jones served as the Sandia Technical Monitor.

The choice of hardware for this design is made primarily based on

available data within the time constraints of this effort and should not be

considered an endorsement of the hardware. The set of designs consider the

implementation of various hardware components, including different flat PV

modules, selected roof mounting techniques and various power conditioning

equipment. The complete set of system designs, therefore, provide detailed

design information on several manufacturers' hardware options.

The intent of the detailed design is to provide sufficient detail for

obtaining a system installation cost estimate. A design package for this

installation can be formulated using the two appendices (Appendix A, Power

Conversion Subsystem Specification; and Appendix B, Electrical Installation

Specifications), along with a drawings package (architectural drawings AI-All

and electrical drawings E1-E9). These drawings are included as foldouts within

the report text and a full size set is delivered to Sandia.

The system design development and preparation of this report was

supported by contributions of the following individuals: Mr. G. Tully, of

Massdesign Architects and Planners, Inc., for the residential house design, and

photovoltaic array installation details; Mr. G. W. Johnson, of Johnson and

v

Stover, Inc., for the electrical system installation specification; General

Electric employees including Mr. R. Felice for overall system design and Mr. J.

Parker for system performance analysis.

vi

SECTION

1

2

3

4

5

6

7

TABLE OF CONTENTS

BACKGROUND

Application Description Design Criteria Project Team Report Format

SUMMARY

SYSTEM DESCRIPTION

Functional Description System Design Requirements Performance Characteristics Design Tradeoffs Design Performance

HOUSE DESIGN

Design Features House Plans Description of the Passive

Solar Heating System

SUBSYSTEM SPECIFICATIONS

Solar Array Power Conversion Subsystem PV Array Electrical Interface

To Conventional House System

SYSTEM DESIGN ALTERNATIVES

REFERENCES

APPENDICES

A

B

C

D

POWER CONVERSION SUBSYSTEM SPECIFICATION

ELECTRICAL SYSTEM INSTALLATION SPECIFICATION

INSTALLATION SAFETY NOTES

PERFORMANCE SIMULATION MODEL AND INPUT DATA

vii

PAGE

1-1

1-1 1-1 1-4 1-5

2-1

3-1

3-1 3-6 3-9 3-11 3-19

4-1

4-1 4-2 4-23

5-1

5-1 5-20 5-37

6-1

7-1

A-I

B-1

C-l

D-l

SECTION

E

F

TABLE OF CONTENTS

ECONOMIC MODEL AND ASSUMPTIONS

RECTANGULAR PV SHINGLE MODULE CONSTRUCTION

viii

PAGE

E-l

F-l

SECTION 1

BACKGROUND

Application Description

The photovoltaic (PV) system design described in this report is for a

residential two-story, passively heated house located in the Northeast region of

the country typified by the Boston/Madison weather environment. The house

design presents a minimum of south facing roof typical of this style. The house

is assumed newly constructed in 1986 with a living floor area of 157 sq.m. (1690

sq.ft.) and a rectangular south facing roof area of 57 sq.m. (614 sq.ft.). A

perspective of the house is shown in Figure 1-1. The design includes energy

conservation features projected for 1986 and additional passive design features

such as a greenhouse. An advanced performance 2 1/2 ton heat pump is used for

heating and cooling with an electric hot water heater. The garage is separate

from the house. The equipment area is located in the basement area.

The electrical energy derived from the PV system serves the normal

household electrical requirements including general appliances, lighting,

cooking, hot water heating and heat pump operation. When PV generated energy

exceeds the house requirements, excess energy is directed back to the utility

grid.

Design Criteria

The objective of the program is to develop designs of residential

photovoltaic systems which can be used as reference designs estimates. The

level of detail is sufficient to allow independent cost estimates for

installation of the system. Specifications for equipment are based on currently

1-1

..... I

to.)

Figure 1-1. Perspective of a Northeast Passive House

available components or similar currently available equipment if the component

is not available at present.

In general, the homeowner is considered the system user; therefore,

operation and maintenance requirements typical of conventional HVAC systems are

assumed. The system excludes instrumentation, since a mature system

installation is assumed.

To evaluate the performance of the system design, typical hourly

electrical load profiles and space conditioning demands for the house are used.

These load profiles were developed in the GE Regional Residential Study,

Reference 1, and updated in the Residential Load Center Program, Reference 2.

All the system performance analyses are completed based on these hourly loads

and using Typical Meteorological Year (TMY) weather data as developed by Sandia

National Laboratories. Life cycle cost analyses, based on system performance

results and system cost estimates, are used for system sizing and tradeoffs.

Previous designs, References 4, 15 and 16, have dealt with

applications having higher diversified electrical loads and higher space

conditioning loads. The system designs had array areas ranging from 74 sq.m. to

93 sq.m. Therefore, the design criteria used for this design requires a highly

passive house design, reducing thermal load requirements by approximatelY 50%

and improved efficiency appliances with an energy conscious family. The total

electrical load reduction is approximately 14% over the previous Northeast

residence designs. Consistent with the reduced loads is a house design having a

smaller south facing roof area. The smaller roof area requirement provides more

flexibility to the'architectural features of the house.

Furthermore, the Southwest design presented in Reference 4 used a

1-3

hexagonal shaped module with 0.196 sq.m. exposed module area. This small module

size may imply high installation costs. Therefore, the design considers a

larger shingle module (.916 sq.m. exposed module area) for comparison to the

previous design.

Project Team

The project team for the design effort consists of the participants

listed 1n Figure 1-2. General Electric Company, Advanced Energy Programs

Department, is the prime contractor with responsibility for system design and

integration and project management. Massdesign Architects and Planners, Inc.,

provides the details of the house design and analysis support related to the

solar array installation. Johnson and Stover, Inc., provides the installation

drawings for the electrical equipment associated with the photovoltaic system.

-PROJECT MANAGEMENT

GENERAL ELECTRIC COMPANY -SOLAR SYSTEM DEFINITION

ADVANCED ENERGY PROGRAMS .PERFORMANCE ESTIMATES

SPACE DIVISION -MAJOR EQUIPMENT SPECIFICATIONS

-DOCUMENTATION

MASS DESIGN ARCHITECTS JOHNSON & STOVER, INC. AND PLANNERS -ElECTRICAL ENGINEERS CAMBRIDGE, MASSACHUSETTS

-EQUIPMENT SPECIFICATION -ARCHITECTURAL DRAWINGS

-ELECTRICAL INSTALLATION -THERMAL INSTALLATION DRAWINGS DRAWINGS

Figure 1-2 Project Team

1-4

Report Format

The design details are presented in the main section of the report and

all background data and material 1n the Appendices. Section 2 is a concise

summary section presenting the design in bullet form. The next three sections

present all of the design details. Section 3 covers the system description.

Section 4 discusses the residential house design, and Section 5 provides the

subsystem specifications. The latter section includes most of the electrical

installation drawings and details and discusses the two primary subsystems, the

array and the power conversion subsystem (pes).

Finally, the Appendices provide design details such as the pes

specification and electrical system installation specification. Background

material on the cost assumptions and input data, several backup design

tradeoffs, and parametric variations are also discussed.

1-5

SECTION 2

SUMMARY

This section presents a brief overview of the key system design

elements and a synopsis of key design tradeoffs. Subsequent sections of the

report discuss the details of each of the topic areas.

A 4.1 kW grid-connected PV system with utility feedback is designed

for a passively heated house having low total electrical load requirements. The

major system elements are the photovoltaic array and the power conversion

subsystem. Marginal life cycle cost analysis is used for system sizing. The

analysis considers various array sizes and provides parametric performance

results. In general, under the assumed economic assumptions and with utility

sellback rates of 50% or greater, the results indicate a PV array size as large

as the available roof area. This design addresses the requirements of a low

energy consuming house with a m1n1mum of available roof area, and provides

installation details on a direct mounted shingle module significantly larger

than earlier designs.

2-1

House Description

o The house design 1S a TWO-STORY residence with a basement of NEW CONSTRUCTION for the NORTHEAST region of the country.

o The design includes PASSIVE SOLAR and ENERGY CONSERVATION projected in 1986.

FEATURES

o There is 157 sq.m. (1690 sq.ft.) of living area with a 9 sq.m. (96 sq.ft.) greenhouse and 57 sq.m. (614 sq.ft.) of south facing roof area.

o The house is ALL ELECTRIC with a 2 1/2-ton heat pump and electric hot water heater.

o The site layout has a detached garage with a lot area of 1/4 acre.

2-2

System Description

o The system is grid connected with a 4.1 kW NOCT array rating using a GE rectangular SHINGLE MODULE ARRAY. The array consists of a total of 52 FULL AND 8 HALF MODULES COVERING 51 sq.m. in a redundant parallel-series network.

o The power conversion subsystem uses TRACKING INVERTER to convert dc PHASE ISOLATION TRANSFORMER is used

a 4 kVA LINE COMMUTATED MAX POWER generated power to ac. A 5 kVA SINGLE

to match ac supply voltage to the load.

o The system operation is PARALLEL AND SYNCHRONIZED WITH THE UTILITY.

o Excess generated power is FED BACK to the utility.

o The system represents the SIMPLEST PHOTOVOLTAIC DESIGN with a minimum of components and controls.

rl UTILITY FEEDBACK SYSTEM :1-------, UTILITY BACK UP

I PV 1t-____ --1J DC/AC 11-+--11 GENERAL I ARRAY I rNVERTERj I LOADS

MAX, POWER TRACKER

2-3

H HEAT I PUMP

U HOT I I WATER

System Operation

o The system has AUTOMATIC STARTUP and SHUTDOWN control.

o The system automatically shuts down with loss of the utility power.

o System operation is summarized by the sequence below:

1. At sunrise, in the automatic "on" mode, the ac and dc contactors will close when the array bus voltage reaches a threshold of 156 Vdc.

2. During the daylight period, the inverter operates continuously if there is a net power output.

3. The inverter will track the maximum power operating point within +1 percent over the range of 156 to 180 Vdc.

4. The interruption of utility-supplied power opens the dc contact or and it remains open until the line voltage is restored.

5. At sunset, the inverter ac and dc contactors open when the net power output falls to zero. These contactors remain open throughout the night to eliminate the majority of the inverter parasitic losses.

urtUTY IERYICI.~ WIRE, S/NCiU PHAII. 24011. VAC

~OOF .-.ARAV

WALL

~~ POWEA CONVERSION rvSTeM

2-4

Photovoltaic Array

o The array consists of SHINGLE PV MODULES connected in an 8 series by 7 parallel network covering 51 sq.m. of roof area.

o The array orientation is due south with a roof pitch of 33.7 degrees. The overall cell packing efficiency is ~5% over the 51 sq.m.

o The modules are DIRECT MOUNTED on top of the roofing felt and plywood roof sheathing. They form a weather tight roof.

o The modules conventional Cables (FCC) the array.

... '!oIIk.

I

I

I

I

I

are installed by an overlapping procedure similar to shingles. Each shingle module requires two Flat Conductor

butt terminations to electrically interconnect the module to Standard roofing nails are used for attachment to the roof.

}7 I

I .. J I r~~I·;':!!

~eAIMer

I I I ~~

.. KTH ~l""

I I IJ\~_"" .-- C'.IIUI"o'Wr

.

I I~~~~I ~...,..

J ~Mrr~1 I t. ~,v _ ""~--~6. __

;nwo.. ~ . (M.S.' (4a7") . ",.,.. ..... 'MlriH') . 7 QJHMY'DHINI,Lb'b . L.6-,- _ 'J k.nvb' . .,....- -

2-5

f

Photovoltaic Modules

o The module is currently under development by General Electric Company.

o The module uses 95 mm SQUARE SILICON CELLS with 48 cells connected in series and 2 parallel circuits per module.

o A half-sized module with one series string of 48 cells is also used in the installation.

o For a NOCT of 65 degrees C, the MAXIMUM POWER OUTPUT is 74W and 16.6V at SOC conditions (1 kW/sq.m., 20 degrees C ambient, 1 m/s wind speed).

o A summary of the module characteristics are:

Full Module Half Module

- Module weight: 18 kg 9 kg

- Total Cell area: 0.866 sq.m. 0.433 sq.m.

- Exposed Module area: 0.916 sq.m. 0.458 sq.m.

- Module packing factor 0.945 0.945

0 .1 .. -

V"'~ 1.73 OJ

0.01

'~H ..- 0.15m

0.8 6m

L FULL SHINGLE

HALF

SHINGLE

-H (+l H (+)

e - -,-!J III • 25J;:

,

I

j ~ c==-+- 0.15 em TYP.==-]

.... 1. 54m • .

1. 55m)

2-6

Power Conversion Subsystem

o The PCS provides the interface between the PV array and the normal residential utility service and loads.

o The subsystem consists of three main components: the INVERTER, the DC FILTER and TRANSFORMER, along with the associated control circuitry.

o The subsystem is rated at 4.0 kW of power output with a 5 kVA transformer, sized to accommodate the out of phase ac voltage and current.

o The subsystem characteristics are summarized in the Table below.

o The Gemini Corporation of Mukwonago, Wisconsin, manufactures the subsystem components and Windworks, Inc., markets them.

Key Inverter Design Characteristics

Output Power Rating 4.0 kW Continuous

Output Voltage 240 Vac utility Residential

Input Voltage 168 +12 Vdc

Full Load Power Factor 60% Minimum

Full Load Efficiency 92% Minimum

Full Load Harmonic Distortion 30% Maximum

Operating Temperature o to 40 degrees C

POWER CONVERSION SYSTEM

MAXIMUM POWER

IOc----1L5.CO~N~T!!R~O~l..J

2-7

Service

PV Interface with Utility and House Service

o Interface arrangements employ CONVENTIONAL WIRING RUNS and EQUIPMENT as much as possible to facilitate acceptance by local regulatory authorities.

o The PV array output acts as a conventional utility service; therefore, its entrance to the residence is parallel to the utility line.

o An external switch provides a means to externally disconnect the array and the PCS equipment.

o An equipment area is located in the southwest corner of the basement level.

DO

2-8

Array Sizing

o The array sizing uses MARGINAL COSTS and BENEFITS.

o Energy sellback price the utility is willing to pay the homeowner affects the system sizing.

o The assumed energy escallation rate is 4% above inflation.

1.3 BOSTON 1.3 MADISON

1.2 1.2

1.1 1.1 0 SELL BACK .... RATIO

0

I-....

~ 1.0 ~ 1.0 I- 0.3 l-V> U') 0 <..J 0.5 0

0.9 <..J ... 0.9 .... 0.7 LLJ .... <..J <..J >-<..J 0.8 NOTES

>-<..J

0.8 NOTES LLJ "- I. PRICE OF ELECTRICITY

... .... "- 1. PRICE OF ELECTRICITY .... $0.0832/ KWH

.... 0.7

...J $0.0532/KWH 0.7

0.6 0.6

o o o 20 40 60 80 o 20 40 60

COLLECTOR AREA, ~ COLLECTOR AREA, II-

2-9

SELL BACK RATIO

80

Design Performance

o Total net system output for both Boston and Madison is approximately 40% of the total load requirements.

o Overall system efficiency based on incident isolation for gross array area is approximately 8.3% for the Northeast.

UTILITY MAKE-UP 10.6 MWH % OF LOAD SUPPLIED

DIRECTLY 25.3 2 INSOLATION ON ARRAY 1338 KWH/m

2-10

UTILITY MAKE-UP % OF LOAD SUPPLIED

DIRECTLY INSOLATION ON ARRAY

11.6 MWH

25.3 1456 KWH/m2

System

SECTION 3

SYSTEM DESCRIPTION

Functional Description

The grid connected residential PV system for the Northeast provides

the space conditioning requirements and all conventional electrical load

requirements for an all electric home. The system consists of two major

sUbsystems: The PY solar array and the power conversion subsystems. Figure 3-1

shows a system block diagram. The 51 sq.m. solar array uses a rectangular

shingle solar cell module being developed by General Electric. The module is

selected as a next generation to the Block IV module currently available. The

array 15 wired in a redundant series/parallel matrix with a 4.1 kW rated peak

output. The array Slze 1S based on the results of marginal life cycle cost

analysis consistent with the available roof area for a passively designed house.

The photovoltaic generated power is supplied to a 4 kVA PCS which is controlled

to track the solar array maximum power operating point. A line-commutated

Gemini unit is selected based on its current availability. The PCS feeds 240 Vac

power directly to the house loads or back to the utility when excess power is

generated. The PV power is isolated from the utility by a 5 kVA transformer.

The overall system connects in parallel with the utility service to

supply the residential load. Power generated by the array in excess of

residential loads is fed back into the utility grid. With this arrangement, all

house load demands are met, no electrical storage 15 required, and all net

energy output of the photovoltaic system is used.

3-1

UTILITY BACK UP

Figu~e 3-1 Solar System Block Diagram

Va~istors located at the positive dc line terminal and the ac service

panelboard p~ovide protection from lightning-induced voltage t~ansients. These

varistors p~otect the input and output pes circuitry f~om induced high voltage

surges. The ~emainder of the electrical equipment consists of disconnects and

fused ci~cuit breakers to isolate all the subsystems from each other and provide

an exterior disconnect switch to meet the code requirements for self-generating

power sources.

System operation is described below.

1. At sunrise in the automatic "on" mode, the ac and dc contactors will close when the array bus voltage reaches a threshold of 156 Vdc.

2. During the daylight period, the inverter operates continuously if there is a net power output.

3. The inverte~ will track the maximum powe~ operating point within +1 percent over the range of 156 to 180 Vdc.

4. The interruption of utility-supplied power opens the dc contact or and it remains open until the line voltage is restored.

5. At sunset, the inverter ac and dc· contactors open when the net power output falls to zero. These contactors remain open throughout the

3-2

night to eliminate the majority of the inverter parasitic losses.

The system represents the simplest photovoltaic design with a minimum

of components and controls. A key to the implementation of this design is the

acceptance of the feedback energy by the utility and the price the utility will

pay to the homeowner for this energy.

Components

A one line diagram of the system components is shown in Figure 3-2.

This section briefly describes the major functional elements of the system with

further details contained in Section 5.

Solar Array -- The solar array consists of 52 full and 8 .half shingle

modules connected electrically in a redundant series/parall.l circuit

arrangement. Eight modules are connected in series and with 7 parallei circui'ts.

The module electrical circuit terminates in positive and negativ. busbars which

are connected to cabling and run in conduit to the equipment room. The negative

busbar is grounded. The array output is 4.1 kW at NOCT conditions.

PCS -- The PCS provides the electrical interface between- the solar

array and the residential ac service. This subsystem consists of a dc input

filter, dc/ac inverter, a transformer and maximum power tracker and control

citcuits. This subsystem inverts the variable dc output of the solar array to

supply ac residential service in parallel with the utility electrical service.

Inverter The inverter is a Silicon Control Rectifier (SCR)

thyristor bridge circuit providing unidirectional current flow on the input dc

side and alternating current flow on the output ac side. It is sized at 4 kVA

and is line commutated.

3-3

V> I ~

UTlLlTV SERVICE-a WIRE, SINGLE PHASE, 240/120 VAC

ROOf ARRAV

UTlLlTV METER

'> ()

WALL

WALL

Figure 3-2

POWER CONVERSION SYSTEM SfRVIC[ PA'in

~;) MAIN SERVICE

:~II I 0 ...... 0--=--,

Residential Photovoltaic One Line Diagram

, TYPICAL ) BRANCH ? CIRCUIT

,1,

Transformer The 5 kVA transformer isolates the ac and dc circuits

and matches the output dc voltage of the array to the normal ac line voltage.

DC Filter -- This filter smooths the dc current flow which is subject

to high harmonics as a result of the switching action of the thyristors.

Inverter Controls These controls provide the timing signals for

firing of the thyristors and, in turn, control the level and direction of power

flow through the power conversion subsystem.

Maximum Power Control This control circuit modifies the inverter

timing control circuit fto operate the array at its dynamic maximum power point.

RFI Filter --- This filter attenuates high frequency output harmonics

to minimize radio and TV interference.

Exterior Array Fused Breaker This breaker provides a visible

exterior disconnect and is fused only if required by a strict National Electric

Code interpretation.

Varistors These devices provide lightning protection. They are

connected to the dc and ac residence input lines and provide induced transient

protection of the input and output PCS circuitry.

Interior Disconnects and Breakers -- An interior dc disconnect and a

service panelboard circuit breaker provide isolation of the PCS for installation

and service. The service panel board circuit breaker also isolates the utility

service from the solar array system.

3-5

System Design Requirements

A review of the environmental conditions applicable to the Northeast

region of the country, the goals for the implementation of residential PV

systems in 1986, and the specific constraints associated with residential house

designs have lead to the broad system design requirements listed in Table 3-1.

The environmental conditions listed are typical of the Northeast region. The

region has a moderate lightning environment which imposes only nominal

requirements on the design. The risk of hailstone damage in the Northeast 1S

also relatively moderate. The tempered glass cover of the rectangular shingle

module is the same as the Block IV Module which has passed hailstones tests

conducted by JPL.

regions.

The table also lists the average daily load requirements for the two

The heat pump average load requirements are based on the annual

electrical input to the heat pump required to satisfy both the space heating and

cooling requirements. Since no specific site is considered for the

installation, no specific local building, fire or electrical codes are imposed.

The design considers the general Model Code requirements appropriate for the

Northeast. The overall electrical design tries to assure safety in the normal

residential application.

The house is a new construction; therefore, the sile constraints do

not impose any significant design requirements. The house orientation is due

south and the south facing roof slopes at 33.7 degrees (8 to 12 pitch). The roof

slope is consistent with standard framing member sizes. The roof area covers 57

sq.m. and it is consistent with the aesthetic features of the house design. No

landscape shadowing or surrounding building shadowing is allowed.

3-6

System operating constraints require utility grid connection with the

PV system operating in parallel and synchronized with the utility. If utility

interruption occurs, the PV system disconnects.

3-7

Table 3-1

System Design Requirements

Environmental Conditions Boston Madison -

Ambient temperature: -20 to 39°C -34.4 to 36.7°C Module Thermal Cycle Test: - - - -40 to 90°C - - -Wind:

Extremes

Moderate Lightning Area: Isokeraunic Level Hail: Annual Horizontal Insolation:

Application Requirements • Electrical Load Summary:

27 m/s

20

Low 1341 kWh/m2

- Average Daily Base Electrical Load 18.4 kWh/day - Average Daily Hot Water Load 13.0 kWh/day - Average Daily Heat Pump Load 7.7 kWh/day - Annual Electrical Load 14272 kWh

e Load: Single Phase 240/120 Vac e Life: 20 Year Design Life • Meet Local Building and Electrical Codes e. Meet Local Fire District Regulations • Site Constraints (General Considerations)

- Roof Area Available - Roof Slope - House Orientation - Sun Rights

• System Operational Constraints - Disconnect Photovoltaic System if Utility is Interrupted - Operate in Parallel and Synchronized with the Utility

3-8

34.4 m/s

41

1472 kWh/m2

18.4 kWh/day 13.4 kWh/day 11. 0 kWh/day

15622 kWh

Performance Characteristics

The estimated residential photovoltaic system performance for Boston

is summarized in Table 3-2. The solar array consists of 56 rectangular shingle

modules in an 8 series by 7 parallel matrix. Each module has 96 9.5 cm, square

cells, or .866 sq.m. of cell area per module. The module has a cell packing

efficiency of 0.945. The total nominal solar cell area is 48.5 sq.m. The

exposed glass coverplate area of the shingles on the roof covers 51.3 sq.m. The

roof 1S 11.2 m. wide by 5.11 m. high, resulting in a total roof area of 57.1

sq.m. Thus, the overall roof packing efficiency of cells on the roof 1S 85%.

The calculated rated output of the solar array at Standard Operation Conditions

(including an NOCT of 65 degrees C) is 4.1 kW. On an annual basis, the ac

energy output for Boston is 5638 kWh with a total insolation of 1338 kWh/sq.m.

on the 33.7 degree sloped roof. Thus, the overall system conversion efficiency

is 8.2%. For Madison, the corresponding system efficiency is 8.31. with 0310 kWh

of ac energy output for an incident insolation level of 1486 kWh/sq.m. For both

locations, the solar array conversion efficiency varies between 9.3% in Boston

to 9.51. in Madison, with less than 11. annual energy loss due to the ser1es

resistance losses in the shingle module bus strips, the termination busbars, and

the cabling between the busbars and the inverter. The estimated annual PCS

efficiency is approximately 89.21. (89.91. in Boston and 88.41. in Madison)

resulting 1n the overall system efficiencies noted. The system output for each

location is greater than 501. of the diversified electrical baseload.

3-9

Table 3-2

Summary of System Performance

PARAMETER

Number of Modules (8 series x 7 parallel)

Total Solar Cell Area (m2)

1 d M 1 (m2) Tota Expose odu e Area

Module Packing Factor

Total Gross Roof Area (m2)

Array Output at SOC NOCT = 650 C (kW Peak)

Annual dc Energy Input to Inverter (kWh)

Annual ac Electrical Energy Output (kWh)

Annual Insolation on Array Surface (kWh/m2)

System Output Overall System Efficiency

Insolation x Array

dc Energy to Inverter Array Conversion Eff. =

Insolation x Array Area

3-10

Area

BOSTON

6272

5638

1338

8.2%

9.3%

VALUE

56

48.5

51. 3

0.95

57.1

4.1

MADISON

7131

6310

1486

8.3%

9.5%

VI LU

'" LU "-

'" <t:

...... ;:::: LU

'" '" :::> u

The I-V characteristics of the array at reference conditions are

summarized on Figure 3-3. The NOCT array output is 4.1 kWp at 132V and 31.2A. 40

30 /

20

10

o o

NOTES 1. IIRRAY CONFIGURATION

RECTANGULAR SHINGLE 8S X 7P

2. VALUES REFLECT BUS BAR AND CABLING LOSSES

3.

20

INSOLATION = 1 KW/t,(!

40 60 80

VOLTAGE. VOLTS DC

100 120

I

65°C (NOCT) _..-;<0'"\

I

I I I 132.8V

I

140

Figure 3-3 Solar Array I-V Characteristics at NOCT Conditions

Design Tradeoffs

160

System performance and economlC analyses provide the basis for

selecting the collector array size for both the Boston and Madison regions. ~ In

addition, the r-oof slope is selected based on sensitivity studies to maximize

output. The. models and input data used for all of these analyses are discussed

in Appendix D. The loads used in the analyses are reduced from previous

Northeast designs. The largest reduction occurs in the space conditioning loads.

which are reduced by 48%. The overall electrical load reduction is 14%.

Array Tilt Sensitivity

The sensitivity of collector tilt or roof slope angle to net system is

3-11

180

shown in Figure 3-4. The results indicate that the system output is maximized

at a roof slope of 34 degrees, or approximately 10 degrees less than the

latitude. The result is consistent with results for optimum array tilt angle

from previous studies. The actual design slope selected is 33.7 degrees., which

conforms to the use of standard framing techniques (8 to 12 pitch). The figure

shows that only small differences in net system output occur over the tilt angle

range of 20 degrees to 40 degrees •

. 5 Q.

~ 5500

it Iii > en

5000

o o

I~OPTIMUM TILT

I-LATITUDE

--1------I1----t1---1-t1----t1---I.--t1----11 20 25 30 35 40 45 50

COLLECTOR TILT ANGLE, DEG.

Figure 3-4 Array Tilt Angle Sensitivity in Boston

Collector Array Sizing

Array sizing is evaluated for both the Boston and Madison regions. The array

area is varied from 21 sq.m. to 64 sq.m. by maintaining 8 series modules along

the roof slant height, yielding the same system operating voltage, and adding

parallel circuits. The system performance as a function of array area is shown

i~ Figure 3-5 for each location. The performance is defined in terms of total

energy output and the energy delivered directly to the load. The effect of

array area on system performance in Boston and Madison is quite similar. Over

the range of area variation considered, the total system output increases in

3-12

direct proportion to array area; whereas, the amount of energy delivered

directly to the load approaches a limit dictated by the magnitude and shape of

the load profile during daylight hours. Since the PV system output is

proportional to array size, and the size of the array impacts the system cost,

the effect of array size is best evaluated by means of economic parameters such

as life cycle cost ratio (LCCR). The expression for LCCR in terms of levelized

annual costs is:

LCCR LEVELIZED COST OF PV SYSTEM + LEVELIZED COST OF BACKUP ENERGY

LEVELIZED COST OF CONVENTIONAL ENERGY

The LCCR ratio can also be written in terms of the levelized annual costs (LAC)

and levelized annual benefits (LAB) as

LCCR LACsolar + (LACconv - LAB)

LACconv

LACsolar represents the levelized annual costs of the total solar system and

LACconv represents the levelized annual costs of the conventional energy for the

all-electric house in this application. The minimum LCCR value represents the

optimized economic PV system size for the application. Photovoltaic systems and

energy systems typically follow the law of diminishing returns, that is, each

additional· unit of size or capacity contributes less benefit than the preceding

unit. Whenever an additional unit, for example a square meter of PV array, can

show levelized annual savings greater than levelized annual costs, the unit can

be economically added. The minimum LCCR value represents the point where the

marginal costs equal the marginal benefits. Appendix E describes the

calculation of the economic terms and lists all economic assumptions and cost

estimates.

3-13

10 10

8 I- 8 TOTAL

TOTAL / :::t:

~ 6 l BOSTON. MASS. / ~1ADISON. WISe. 6 ::::>

c.. I-::::> 0 / SELLBACK ::E: UJ l-

V) V') I

rr 4 -~ // DIRECT

TO LOAD «

2 ~ 2 DESIGN POINT

o o 60 70

O~I--~ ____ ~~~ __ ~ ____ L-__ ~ __ ~

70 10 20 30 40 50

ARRAY AREA - M2 o 10 20. 30 40 50

ARRAY AREA _ M2 60

Figure 3-5 Performance as a Function of Array Area in Boston and Madison

The LCCR 1S calculated for each system for three different utility

sellback energy ratios. Figure 3-6 shows these results which reflects the

regional differences of the cost of electricity and the weather between Boston

and Madison. For example, in Boston the PV system is economically viable

(LCCR<l) for array areas greater than 27 sq.m. for sellback ratios of 0.3 or

greater; whereas in Madison, sellback ratios of 0.7 or greater are required for

econom1C viability. These results assume an energy price escalation rate of 4%

above inflation.

The array area associated with the minimum LCCR also varies directly

with sellback ratio. For a sellback ratio of 0.3 in Boston, the area at minimum

LeCR is about 59 sq.m. At sellback ratios of 0.5 or greater, the area at

minimum LCCR is greater than 64 sq.m. Since the residence has an available roof

area of 57.1 sq.m., the largest rectangular shingle array configuration that the

roof can accommodate consists of 8 series by 7 parallel circuits covering 51.3

sq.m.

In Madison, the PV system is economically viable for array areas

greater than 60 sq.m. at a sellback ratio of 0.7. For smaller areas and lower

sellback ratios, the systems are not economical for the given set of costs,

energy prices and economic scenario assumed. Since the largest array which can

fit on the roof is 51.3 sq.m., a utility sellback ratio greater than 0.7 is

implied for economic viability. The assumed price of energy in each location is

the major factor contributing to the difference in economic conclusions between

Boston and Madison. In Boston, the assumed price of electricity is $.0832/kWp

(1980$); whereas in Madison, the assumed price is $0.532/kWp (Reference 3)·. The

selected system size demonstrates the economic viability of smaller-sized

systems for passively designed houses in the Northeast.

3-15

v.> I ......

0\

o -I-;:!2 l­V} o U

I.I.J ....I U >­U

I.I.J .1.1--....I.

1.1

o o

BOSTON

SELL BACK RATIO

~O.3 . 0.5

0.7

NOTES 1. PRICE OF ELECTRICITY

$0.0832/KWH

20 40 60

COLLECTOR AREA, M2 80

o -~ l­V} o U

I.I.J ....I U >­U

I.I.J 1.1-'...., ....I

NOTES 1.

o o

MADISON

SELL BACK RATIO

.~ 0.3

~ 0.5 0.7

PRICE OF ELECTRICITY $0.0532/KWH

20 40 60

COLLECTOR AREA, M2

Figure 3-6 Life Cycle Cost Ratio as a Function of

Collector Area for Boston and Madison

80

Load Sensitivity

The system performance evaluations are based on ,average residential

loads described in Appendix D. Variations in electrical loads from these

average values can exist, reflecting a range of energy conservation practices

within the home. The effects on the system by the change in loads is evaluated

for Boston. The space conditioning loads are not varied, since the design of

the houses represent tight, well-insulated construction with thermostats set at

relatively low settings. It is also noted that only the load levels are varied,

while the .load profile remains unchanged;

The resul ts of this load variation on annu,al energy cost are shown in

Figure 3-7. The' upper curve represents the levelized annual energy cost as a

function of electrical load for the residence without any PV system. The lower

curves define the levelized annual energy cost as a function of electrical load

and sellback ratio for the same residence incorporating the PV system. The

difference between the energy cost without a PV system and the energy cost with

a PV system represents the total energy savings associated with the PV system.

For sellback ratios less than unity, the savings accrued with the PV system

increase with increasing load. This is a direct result of the distribution of

the PV energy used directly in the house and that portion sold back to the

utility since the net system output is the same for all the cases. As the load

increases, more PV energy'can be directed to the load and less is sold back.

The energy used directly provides a greater benefit than if it were sold to the

utility at a reduced rate. As the load is reduced, the reverse is true less

PV energy is used directly in the house and more is sold back with the result

that savings are reduced. It is also noted in the figure that as the sellback

3-17

3000

2500

- 2000 .. l­V)

8 ~ 0:::

E5 1500

o

/ /

0.5

/ /

TOTAL ENERGY COST WITHOUT SOLAR ENERGY SYSTEM

/ /

/ /

NOTES 1.

2.

TOTAL ENERGY COST WITH SOLAR ENERGY SYSTEM FOR SELLBACK RATIO

ARRAY CONFIGURATION RECTANGULAR SHINGLE

8S x2

7P 51 m

PRICE OF ELECTRICITY $0.0832/KWH

- 0.5

1.0

1.0

ACTUAL LOAD/NOMINAL LOAD 1.5

Figure 3-7 Annual Energy Cost as a Function of Electric Load

price increases, the effect of load level on the savings is diminished. For a

sellback ratio of unity, the energy cost savings associated .with the PV system

are independent of load, since the value of the energy sold back to the utility

is equal to that purchased from the utility.

For the present analysis, with the nominal design load profile, 36% of

the system output exceeds the house load demand and is sold back to the utility.

When the actual load is reduced to 50% of nominal, 57% of the system output is

sold back; whereas, when the load is increased to 150% of nominal, only 21% is

3-18

sold back to the utility. Previous studies (Reference 4) have shown that the

load variations have very little effect on LCCR at sellback ratios of SOt. or

greater.

Design Performance

The monthly performance of the nominal design PV system is shown in

Figure 3-8 for Boston and Madison with the design collector area of 51.3 sq.m.

While the load curves represent total electrical demand, their shape clearly

reflects the difference in regional ct"imates between Boston and Madison, and the

resulting space conditioning loads. Despite the latitude similarity, Madison

generally experiences colder winters and milder summers than Boston; however,

Madison has higher levels of insolation than Boston has due to coastal cloud

cover. The overall effect of these conflicting regional factors tends to be

offsetting with respect to the percent of load supplied directly by the PV

system. In both locations, 25.3t. of the load is supplied directly by the PV

system.

3-19

w I .....

0

2.2 T BOSTON

2.0

1.8

1.6 ( LOAD

:I: 1. 4 .l.. \ 14.3 MWH ~ .; 1.2 1 \ I c.!:J a: w

t5 1.0 1 ~ ~ .8

.6 + ~ PV SYSTEM OUTPUT .4Y ~MWH

.2. ~ /"-..- C;r:IIRAr.1(

0 I I I I LLL~l I I

UTILITY MAKE-UP 10.6 MWH % OF LOAD SUPPLIED

DIRECTLY 25.3 INSOLATION ON ARRAY 1338 KWH/m2

2.2 V\ MADISON

2.0

1.8

1.6 + \ LOAD 15.6 MWH

1.4

1.2

1.0

.8

.6 Ii '\ .4

.2 + /

0

V"

"""

UTILITY MAKE-UP % OF LOAD SUPPLIED

DIRECTLY INSOLATION ON ARRAY

Figure 3-8 PV System Monthly Performance Summary

PV SYSTEM OUTPUT 6.3 MWH

SELLBACK 2.4 MWH

11.6 MWH

25.3 1456 KWH/m2

SECTION 4

HOUSE DESIGN CHARACTERISTICS

Design Features

A passively heated house has been designed by Hassdesign for the

Northeast region of the country. The house is configured to maximize the amount

of south glazing, while simultaneously providing a large rectangular roof for

the PV system and it incorporates energy conservation features.

The house has two stories and a full basement. On the first floor is

a large area containing the kitchen, dining room, staircase to the second floor,

and living room. Also on the first floor on the east end of the house is the

master bedroom suite, with a full bath, a dressing room, and a sliding glass

door facing south. On the second floor are two additional bedrooms and a bath.

Both bedrooms and the connecting hall are illuminated from clerestory windows

above the PV roof. The total floor area of the house is 157 sq.m. On the south

side of the living space is an 8.9 sq.m. greenhouse. A large brick fireplace

wall, which also provides massive storage for solar heating is located at the

core of the house, on the north side of the living room. The basement is not

subdivided, but is completely insulated around the walls and under the slab. All

of the electrical equipment for the PV array and the house panel is located in

the southwest corner of the basement. An airlock entry is provided on the north

side.

Although any of a number of energy conservation construction methods

are applicable to the building, it is designed around the innovative Acorn

Structures, Inc., building system. Hassdesign has been working for several

years with the Acorn systems, and has assisted Acorn in developing an effective

4-1

and economical method for providing a high level of energy conservation.

Because the system relies upon components trucked to the site, a

minimum of wood is used. The walls are 2 x 4 stud construction, at an average

spacing of 16 inches on center, with R-l1 insulation. On the inside of the

walls, an additional 3/4 inch of "Thermax" (trade name) foil-faced

polyisocyanurate insulation is used, yielding an extra R-factor of 6. The

combined wall section resistance value is 19. The combined cathedral ceiling R­

factor is 28. This total R value includes 7 inches of fiberglass in the ceiling

(limited by a 2 inch air space under the PV array), for an R-22 value, plus an

inside layer of Thermax for an additional R-6 value. Attic space ceilings are

insulated with R-30 insulation, and R-ll insulation is used between the attic

and the adjacent bedrooms. South windows are all double glazed and the

remainder of the windows are triple glazed. Motorized draperies are used across

the entire south facade in the living and dining spaces. These draperies

provide an additional R-factor of 5 when they are closed.

Infiltration is minimized as much as possible in the design. The

Thermax interior skin provides an excellent vapor barrier and a large measure of

infiltration control. In addition, a great deal of caulking is also used.

Because the Acorn house modular sections are made from kiln lumber and are built

to tolerances of 1/16 of an inch, the building is intrinsically sol·id and tight,

resulting in a low infiltration rate.

House Plans

Figure 4-1 shows two possible site plan arrangements of the house, one

with an entry from the west (or east, if the plan is reversed), and the other

4-2

GEN ERAL ELECTRIC ."ao. DIYI.ION

Detailed Residential P.V. System Preferred Designs Sandia Lab. Contract Doc.#13-8779

[\1 II

Johnson & Stover, Inc. Electrical Engineers 127 Taunton St. Middleborough. Mass. 02346 617-947-8464

. ~ ..... '&

. • ....".' •. 1<.:

Figure 4-1. Site Layout for Northeast Passive House

Sheel No.

4-3/4

with an entry from the south. By strategic location of the garage and the

addition of a trellis to mark the location of the entrance, both plans can

easily be accommodated and a third, north entry design, can be incorporated.

Flexible site plans are important, since a solar house has to face south

independent of the street location.

The basement floor plan (Figure 4-2) has not been subdivided, but

provides space for a shop, recreation area, or other non-habitable space which

is valuable to a homeowner. The entire basement 15 insulated with R-ll

insulation, and the underside of the slab is insulated with R-5 insulation. All

of the electrical equipment 1S located in the southwest corner of the basement

on both the west and south walls. Both the normal electrical service and PV

service enter on the west wall and penetrate diagonally through the wood

structure, coming out of the inside of the foundation wall. The heat pump

indoor section 1S located near the fireplace foundation, at the center of the

plan, minimizing duct runs.

The first floor plan (Figure 4-3) is organized around a large central

entry hall. The north airlock entry vestibule has ample closet space. Inside,

the entry hall floor has quarry tile, and another large storage closet is

located to the west. This hall opens to the kitchen/dining area, the living

room, the master bathroom or the master bedroom and the stairs to the second

floor. The

first floor.

master bath has two doors, making it accessible to visitors on the

The fireplace is located at the north end of the living room so

that the flue does not need to penetrate the roof area reserved for the PV

array. It is also partially free-standing in the middle of the plan. The

kitchen is located under the ordinary 2.4 m ceiling. It is open to the dining

room which has a cathedral ceiling rising up to the second floor under the PV

4-5

array. This cathedral ceiling continues along the south wall, interrupted by

the staircase, so that half of the living room is under the low ceiling, and the

other half is under the cathedral ceiling. Figure 4-4 shows that the landing of

the staircase has a railing looking down into both the dining room and into the

living room. This feature provides an element which is highly favored by buyers.

The staircase is located close to the windows, but leaves sufficient room for a

walkway. Both the dining room and the living room are accessible to the

greenhouse, which is centered to the south of the staircase by means of sliding

glass doors. The second floor plan (Figure 4-5) shows the layout of the

bedrooms and storage area.

Elevation views of the house are shown in Figures 4-6 through 4-9. In

cross-section, the house features a roof with a shortened slant height. This

permits the addition of a set of clerestory windows at the top of the PV roof.

By somewhat complicated framing, the second story is placed under the high part

of the section, and receives the benefit of the clerestory windows. The long

north roof returns back to the first level, forming a large attic over the

master bedroom, master bath, and entry areas. At the northwest corner of the

building, the long sloping north roof is cut away to expose a two-story high

section. The entry occurs at this point, and is designed for ready access from

the north and west (and from the east if the plan is reversed). By extending a

covered walkway, or trellis, out beyond the end of the plan, it is also possible

to enter the building from the south. These options are shown on the site plan.

4-6

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4-7/8

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Detailed Residential P.V. System Prefemld DesIgns SIndIa Lab. Contract Doc.#13-8779

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4-11/12

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4-13/14

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4-15/16

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4-17/18

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4-19/20

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4-21/22

Description of the Passive Solar Heating System

Figure 4-10 illustrates the four passive and auxilliary heating and

cooling air flow patterns.

1. Storing Heat from the Greenhouse Solar energy penetrating the glazing of the greenhouse can heat the greenhouse, and be stored or directed to the living space of the house. There is an insulated thermal storage slab, in the greenhouse proper, which provides part of the desirable storage. In addition, overheated air from the greenhouse is directed into the far side of the basement by a small supply fan whenever the greenhouse overheats. These fans are under the control of a high limit thermostat located near the top of the greenhouse. This design uses the existing mass in the insulated floor slab of the basement, the finished materials of the basement, and the chimney foundation to absorb any overheating from the greenhouse instead of providing massive construction between the house and the greenhouse. This provides two benefits: (1) a warm basement; and (2) heat gain to the main living space from the first floor (as opposed to a loss if the basement were cold). This approach appears cheaper than providing a dedicated storage device 1n the basement for the greenhouse.

2. Direct Gain with Intrinsic Storage -- The normal passive operating mode of the house involves direct gain through the south glass with distribution into all major spaces in the house. While no special storage mass is included in the living space, the chimney mass is available to receive indirect radiation; and the framing, gypsym board and flooring provide a modest amount of storage. Aside from the greenhouse (which can receive much more heat than it needs during a sunny day), the rest of the house is "sun tempered" rather than passively solar heated. This means that only a modest amount of south glazing is included, sized to the modest amount of storage available in the intrinsic construction of the building. Much of the direct gain in the living spaces comes, secondarily, through the greenhouse by way of the sliding glass doors between the greenhouse and the living spaces.

3. Auxiliary Heating from the Heat Pump Whenever passive gain is unavailable or inadequate to satisfy the heating demand for the house, the heat pump operates in a normal fashion. In addition, the heat pump can be run without the coil, using the fan to redistribute air throughout the building during periods of direct gain. This further extends the effectiveness of the direct gain solar heating, as it allows all of the intrinsic structure mass to store excess passive gain. This process is not as efficient as direct storage 1n massive interior walls or trombe walls, however, the high cost and construction difficulties involved in building with these massive walls offsets their advantages. This redistribution approach is a simple means of increasing the solar gain with no added cost since the distribution system for the heat pump is already in place.

4-23

4. Natural Cooling -- The house is designed to provide the maximum amount of natural cooling and minimize the operation of the heat pump during the summer. First, the sloping glass in the greenhouse is permanently covered during hot weather with an insulating cover, either outside (taking account of the high maintenance requirement) or inside the glazing. Inside the glazing, the cover will either have a white or reflective outer surface to avoid excess buildup of heat underneath the double glazing. In the house, the primary cooling device is the row of awning windows forming a clerestory. The high clerestory windows induce a substantial flow of air through the house, since the amount of thermal siphoning ventilation is proportional to the height differential between the intake and discharge of air. These windows are controlled manually by the owner. Typically, the windows are open all the time during the warm weather and closed only when it gets cool or is extremely hot and humid during the day. The basement is also included in the ventilation of the house. Operating the distribution system without the coil allows the mass in the basement to function as a heat sink and help absorb some of the excess heat during the day. This will keep the house comfortable until cool night air is introduced by thermal siphoned ventilation. Backup cooling 1S

provided by the heat pump.

Appendix D describes calculated estimates for the reduced heating

loads due to the passive house design features.

4-24

GENERAL. ELECTRIC ."aol DIYI.IOH

Detailed Residential P.V. System Preferred Designs SandIa Lab. Cootract Doc.#13-8779

Johnson & Stover, Inc. Electrical Engineers 127 Taunton 5t. Middleborough •. lllass.02346 617-947-8464

= • il'T!I=:!;r~,NOC';N~ ~ i ~:;-~--..;;;.;;;q~i1 ;; .......... "'--" ..... 138h1l._SLlc...or ........ D2138/1117 .. 1I1.e:.l

Sheel No.

Northeast Of'tiZf1iN0 Mo~ Passive House jf\. In/n ~P~.V~.~cm~I~~ __ ~ ________ ~ ~nn J~No, 9515 ' 0.,. l?/so 5,.,. He "'::<:AiL

Figure 4-10. Operating Modes for Passive and Auxiliary Heating

and Cooling

4-25/26

The fireplace is included in the design primarily because of the

intense market demand for fireplaces in a house of this price range. A wood

stove could be substituted for the fireplace with no change in the design. Most

of the chimney mass is interior to the house, with only the minimum chimney

extending above the roof. A gasketed flue top damper operated by solenoid 1S

included in the chimney to trap the air in the chimney and prevent the chimney

from being cooled by convected loss up the flue. The heat that has accumulated

in the chimney mass is then free to discharge into the space by radiation. By

covering the embers of a fire with a tight fitting metal hood, it is possible to

close the damper immediately after leaving th~ room, without having to leave the

flue open until all the embers are cooled. This strategy also greatly increases

the efficiency of an ordinary fireplace. If a wood stove were used, it would be

likely that the chimney would consist of a metal flue extending above the roof.

Masonry would be added around the flue on the inside of the building to provide

the desirable thermal mass. While the flue top damper is not an ideal solution

to the fireplace chimney problem, it does go a long way toward reducing

convected losses during cool-down periods.

4-27

Module

SECTION 5

SUBSYSTEM SPECIFICATIONS

Solar Array

The residential solar array design for this Northeast application uses

the GE rectangular shingle module in an 8 series by 7 parallel circuit

configuration. The modules are presently under development by GE. These

modules utilize a 9.4 cm. square silicon solar cell. The shingle modules are

shown in detail in Figure 5-1. There are two module types, a full size module

and a half size module. These physically different shingles are manufactured to

the same specifications, except that the full module is twice the power at the

same voltage as the palf module. The solar cell network of the full module

consists of 2 parallel connected rows of 48 cells wired in series. This

constitutes a total of 96 solar cells per full module. On the other hand, the

solar cell network of the half module, consists of 48 series connected cells.

The construction details of the shingle modules are discussed in appendix F.

This shi'ngle design is markedly different from the Block IV design

described in Reference 4. The current shingle interconnection scheme uses the

UL-approved AMP, Inc., flat-conductor cable (FCC) under carpet interconnecting

system. The use of this flat conductor cable and patented crimp connector (see

Figure 5-2) as the two output terminals of the module permits the reliable

series parallel interconnection of modules on the roof at a lower total

installed cost when compared to the original JPL Block IV design, which employed

copper foil conductors within each module. The four terminals of this previous

design were interconnected with machine screws to complete the series/parallel

5-1

0.1 m [- FCC

~ 1. 73

--0.04

m

.. I..f--- -- 0.15m

0.86m

L FULL SHINGLE

HALF

SHINGLE

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I -.-

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~ "",,,,41--+-__ 0 ._15_c~.~!. ~ I ~ ______ 1.55m) ______ ~

ILo'771.6.~1 ~.7748ml-J

Figure 5-1. GE Square Shingle Design

5-2

matrix on the roof surface. This AMP interconnection system also provides the

ability to accommodate relatively larger variations in the placement of the

modules on the roof and simplifies the module removal and placement procedure as

will be explained later in the Array Installation section.

The module design characteristics at standard operating conditions are

summarized in Table 5-1 for both the full and half shingles. The I-V trace for

the full sized shingle is shown in Figure 5-2 ••

Table 5-1

Summary of Design Characteristics

for the Rectangular Shingle Modules

PARAMETER

Configuration

Solar Cell Shape

Solar Cell Size (m)

Number of Solar Cells

2 Total Solar Cell Area (m )

2 Exposed Module Area (m )

Module Packing Factor

Average Maximum Power Point

at SOC (kWp) NOCT = 650 C

PMAX

(W)

VMP

(V)

Areal Specific Output

2 (Watts/m Module Area)

Module Weight (kgms)

VALUE

Full Shingle

Square

0.095

96

0.866

0.916

0.945

74

16.6

80.8

18

5-3

Half Shingle

48

0.433

0.458

37

9

I­z: UI

"" ""

4

13 2

o

NOTES 1.

CELL TEMP. = 65°C ) ~IAX. POWER = 74.0W -'-IN_O_CT...:.-__ --' AT 16.6V DC

CELL THIP. 0; 45°C MAX POWER = 84.9W AT 19.1V DC

INSOLATION = 1 KW/M2

2. CIRCUIT ARRANGEHENT 485 X 2P

3. CELL AREMf>1OD = .848 H2

CELL TEHP. = 25°C t1AX. POWER = 93.4W AT 21.0V DC

'-------+-----------b--------t------t--'--~-1--_t''------1_

o 5 10 15 20 25 30 VOLTAGE, VOLTS DC

Figure 5-2 Rectangular Shingle I-V Trace

Solar Array Characteristics

The solar array subsystem consists of an 8 series by 7 parallel module

network covering the 5.1 m by 11.1 m roof. The total active array area is 50.2

sq.m. The solar array consists of 52 full shingle and 8 half shingle modules.

The adjusted full shingle total is 56 modules. Eight modules are positioned

along the roof slant height while seven modules are placed along the roof's

horizontal dimension. The overall array layout is shown 1n Figure 5-3. The

module to module electrical interconnections between overlapping layers form the

series parallel matrix of shingles and are shown schematically in Figure 5-4.

The voltage increases as modules are added in the series direction along the

slant height of the roof from eave to ridge. The current increases as modules

5-4

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Figure 5-3. Overall Array Layout

5'-5/6

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Figure 5-4 Solar Array Module Interconnection Electrical Schematic

are added in the parallel direction across the length of the roof from gable to

gable. The negative terminations at the eave and the positive terminations at

the ridge for each solar cell circuit are attached to the FCC bus bars running

:he length of the roof.

Each module has a SOC average maximum power output of 74 W at 16.6 Vdc

at an NOCT of 65 degrees C. Thus, the total maximum power output for the array

subsystem is 4144 W. The array voltage at maximum power output 1S 132.8 Vdc.

The I-V characteristic curve for the array subsystem was previously shown 1n

Figure 3-3.

Solar Array Installation

The GE shingle module 1S classified as a direct mount system

5-7

installation. It is designed to serve as a weather-tight element and provide PV

dc power. A PV array constructed with these modules as building blocks becomes

the roof of the residence and displaces the need for conventional asphalt

shingles. Figure 5-5 shows the overlapping installation of the shingles in a

schematic diagram. Appendix C lists some general safety notes to follow during

system installation.

Before shingle installation, the plywood roof sheathing is prepared

with a Type 30 roofing felt, as in a typical residential asphalt shingled roof.

A horizontal and vertical network of #10 AWG FCC cable is placed on top of the

felt in accordance with the spacing requirements specified in Figures 5-6 and

5-7. The positive and negative buses each consist of three runs of FCC cable

connected at intermediate points developing a tapered busbar effect. The

negative busbar is folded and run up the left side of the roof to the roof ridge

as shown in Figure 5-6.

All the FCC cable rows can be secured to the roofing felt with duct

tape strips in their proper alignment prior to erection of the shingles; or they

can be placed sequentially as the installation progresses up the roof.

Dimensions of FCC cable rows detailed in Figure 5-6 are to the FCC center lines.

The placement of the cables does not have to be held exactly to the dimensions.

The cable row dimensions are identified as a guide so that shingle attaching

nails will clear the FCC cable.

5-8

~10UNTED SYSTHI

Figure 5-5 Installation of the

5-9

I I

i

I

DUCT TAPE SECURING ELECTRICAL BUSES

TO ROOF

INSULATING FILMS (SELF ADHERING)

AT ALL INTERCONNECTS

PRE-BONDED/PEEL-OFF SEALlNG l·!ATERIAL

HOUNTING HARm~ARE lG HD. ROOFING flAIL SLOTTED I~ASIlER ArID •

I Shingle Module GE Rectangu ar

The shingle installation begins with a dummy course of shingles placed

at the roof's eave in the manner shown in Figure 5-8. Dummy shingles are

electrically inactive shingles to complete a weather tight installation. They

are fabricated with the exact same dimensions as the full and half sized active

shingles. The dummy shingles are attached to the roof sheathing by nailing

through the substrate at two marked locations, per shingle, with roofing nails.

Following the dummy shingle course installation, seven full modules are overlaid

constituting the first active row.

The active shingles are attached to the roof sheathing by use of a

special split washer under the roofing nailhead as shown in the details of

Figure 5-9. Two through holes which are larger than the nailhead but smaller

than the washer diameter, are provided in the module substrate at specific

locations. The split in the washer must be oriented up the roof with the

removal slot positioned down the roof. The orientation of the washer is

important and must be maintained. Upon completion of shingle installation,

should it become necessary to replace a defective module, the washer can be

removed by using a slender hooked tool. The shingle can then be lifted over the

roofing nails allowing it to be slipped from under the overlapping shingle. The

fold in the FCC cable, as shown in Figure 5-9, can be extended and the FCC cut.

A replacement module can be reconnected with the AMP splice connector and the

module reinstalled.

5-10

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:..l.c:1

5-11/12

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5-13/14

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Figure 5-8. Installation Procedure

5-15/16

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Figure 5-9. Array Installation Details

5-17/18

The negative leads from the first active row of shingles are connected

to a single run of the triple layered negative FCC bus cable as indicated in the

second step shown on Figure 5-8. The positive leads from the first shingle row

are connected to FCC cable row B as shown in step three of Figure 5-8. The

positive and negative shingle leads are connected to the horizontal FCC cable

rows after nailing the shingles in place. All electrical connections and FCC

cable terminations are covered with a two-piece insulating patch, detailed 1n

Figure 5-9. The glass portions of the shingles are secured by an adhesive on

the back surface of the module to prevent module lifting during wind conditions.

Subsequent rows of shingles are attached in a similar manner. Figure

5-10 shows typical array connections on the roof. The positive leads of the

eighth active course of shingles terminate in a shingle run of the triple

layered positive busbar identical to the negative busbar connections. The

positive and negative buses are dressed through the roof to an AMP supplied

transition block shown in Figure 5-9. This block provides the transition from

FCC cable to the conventional cable. The remaining portion of the roof above

the eighth course is then covered with two courses of dummy shingles. Figure

5-11 shows additional details at the edges of the installation.

At the completion of shingle installation, gable edge strips are

applied to provide a weather-tight seal. The FCC electrical interconnection

system has been successfully installed at the Northeast and Southwest

Residential Experiment Stations with the GE Block IV-A shingle module.

5-19

Power Conversion Subsystem (PSC)

The power conversion subsystem, with the associated cabling ana

switchgear, provides the interface between the residential roof photovoltaic

array and the normal residential utility service and loads. Functionally, it

must convert the available array dc power to a usable and acceptable ac form. A

line commutated inverter manufactured by the Gemini Corporation and marketed by

Windworks, Inc., of Mukwonago, Wisconsin, is available in the 4 kVA range and

therefore selected for this application. It can be supplied according to the

sp~cification included as Appendix A to meet the preferred control options. The

pes is packaged in three units: the inverter, dc filter and transformer, along

with the control circuitry. Standard controls, filters and isolation

transformer options are provided by Gemini to encompass the requirements

specified for the residential design. Procurement of the basic inverter bridge,

desired controls, filter, and transformer from a single source is recommended to

assure compatible matching of PCS components.

Subsystem Requirements

The dc to ac conversion must be accomplished in a manner consistent

with residential electric practice. The conversion techniques should accommodate

the large range of solar array electrical parameter variations and residential

load and utility line voltage variations. The interface must provide safe

interconnections under all operational and failure modes and must provide

feedback of any excess array power to the utility. Equipment selection should

use proven technology to the extent available.

The requirements for converting the variable dc power and voltage of a

5-20

--- + Ihmnm::::::::::=~ I

GENERAL. ELECTRIC .PADS DIYI.IDH

Detailed Residential P.V. System Pre_AId Designs &ntIa lab. Contract Doc,#1:}-8779

!---- +

'Johnson & Stover, Inc. Electrical Engineers 127 Taunton St. Middleborough, Mass, 02346 617-947-8464

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Figure 5-10. Typical Electrical Array Connections

5-21/22

~~~~~~~~!i!i!!~~1FiIi""iii!t-- 'lAST! C- FLA'SHING>-RUNS uNDER PV. AR~Y

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Detailed Residential P. V. System Preferred Designs Sandia Lab. Contract Doc.:II:13-8779

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Johnson & Stover, Inc. Electrical Engineers 127 Taunton St. Middleborough,Mass.02346 617-947-8464

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Figure 5-11. PV Shingle Edge Installation Details

5-23/24

photovoltaic array to the utility residential fixed ac voltage low impedance

interface can be reliably and economically met by solid state electronic

inverter device, acting as a current source to transfer power. Although either

self- or line-commutated inverters can meet the requirements, the latter is

selected for this application. The line-commutated inverter, however, as

applied to this residential system has the inherent disadvantages of poor power

factor and high harmonics. On the other hand, it has a large technology

application base and has been applied and tested ln PV app.ications by several

installers.

Subsystem Sizing

Array IV characteristics are shown in Figure 3-3 at SOC conditions.

The characteristics indicate a maximum power rating of 4.1 kW and rated voltage

of 132.8 Vdc at NOCT. The array maximum power point and associated voltage

exhibits a dynamic variation with insolation, temperature and wind variations.

The array maXlmum power point and voltage is examined on an hourly basis for

Boston based on TMY weather data. Figures 5-12 and 5-13 illustrate the

distribution of the maximum power and maximum power voltage, respectively, as a

function of the array annual energy for Boston. These curves r~present the

array/PCS interface requirements.

Note that the array open circuit voltage under start-up conditions is

significantly higher than the maximum power point operating range limit of 188

Vdc. The initial high open circuit voltages during start-up has been a problem

for the prototype units under test at the Residential Experimenatal Station.

5-25

>-<.!l '" .<:: ...... '" z:: "-' -' c..

~" z: z -' CCLLl

:> >- LLI cc-' '" "'''' <LLI

"'~ cc c.. -' 01-V> "'"

7

6

>-<.!l:<:

"'''' 5 W 0;: Z "-' -' c.. ~v 4 z z -' cc LLI

> >- LLI 3 ;:1!-'

'" '" "",W

'" '" 0 2 <0. --' 01-(1')<

0

5.28 KW

7 I _6.44 MWh - --- -\.38 MWh 6

5 NOTES l. ARRAV CONFIGURAITON

4 56 RECTANGULAR SHINGLES 8 S x 7P

-- NO VOLTAGE RESTRICTION 3 VOLTAGE RESTRICTED 156-180 VDe

2

O~ ____ ~ ____ -+ ______ +-____ -r ____ ~ ____ ~

o

0

2 3 4 5

SOLAR ARRAY POI~ER OUTPUT"'" P, KW

Figure 5~12 Integral Power Distribution of the Solar Array for Boston

NOTES 1. ARRAY CONFIGURATION

6

188.4V 56 RECTANGULAR SHINGLES 8 S x 7 P 6.38 ~h. I l...

'._--'"~ - 6. 44-flWh NO VOLTAGE RESTRICTION

VOLTAGE RESTRICTED 156-180 VDC

VOLTAGE MINIMUM VOLTAGE .-4:-__ RESTRI CTEO ----i.~

RANGE 135V 156-180 VDC

150 160 170

SOLAR ARRAY VOLTAGE, VOLTS DC

Figure 5-13 Integral Voltage Distribution for the Solar Array in Boston

5-26

180 190

The annual distribution curves for maximum power and voltage in

Boston, Figures 5-12 and 5-13, can also be used for subsystem sizing

specification and operating voltage specification. The power distribution curve

of Figure 5-12 indicates that 6.30 MWh of annual energy is generated at a 4 kW

array rated level or below. The figure also shows a system peak power output of

5.28 kW. Only 2.2% additional energy is generated above the 4 kW power level.

This implies that selecting a standard size 4 kW output rated pes, captures

nearly all of the available energy. (A 4 kW output rated inverter, assuming an

average inverter efficiency of 87%, would accept input power levels up to 4.6

kW). The input power duration curve, Figure 5-14, indicates only 300 hours of

the total annual operation at a power level of 4 kW or greate~. This further

substantiates the selected inverter size.

Figure 5-13 shows a wide swing of the system maX1mum power point

voltage from 136 to 189 Vdc. The voltage can be expressed around the mid-point

of the range as 162 ~ 17% V. Accommodating the wide input voltage range usually

results in poorer efficiency, poorer power factor and higher harmonics in the

pes design. Since the curve 1S "s" shaped with relatively flat ends, the

maximum power voltage range can be limited with minimal loss of energy. Hourly

simUlation analyses, with excursion limits placed upon the maximum power voltage

of 168 ~ 7% V, are shown as the dotted curve 1n Figure 5-13. The annual energy

collection with these limits is 99.1% of the unrestricted case. Thus, a voltage

limit of 168 ~ 7% Vdc input to the inverter is selected to enhance inverter

performance with minimal annual energy collection losses.

These summary requirements have been analyzed for this Northeast

residential design and detailed in a specification as referenced in Appendix A.

Technical characteristics for the pes are summarized in Table 5-2.

5-27

Table 5-2

PCS Characteristics

RATINGS

Power Rating Output Voltage

Nominal Input Voltage Input Voltage Limits

Maximum Power Voltage

Full Load Efficiency

Range

Full Load Power Factor

Full Load Harmonic Distortion

Full Load Audible Noise

RFI

ENVIRONMENT

Ambient Operating Temperature

Relative Humidity

PHYSICAL SIZE

HEIGHT cm

DC Filter 40.6

Inverter 76.2

Transformer 61

WIDTH cm

40.6

61

30.5

5-28

4 KVA Continuous 240 ac Utility Line Control

168 Vdc Low 156 Vdc High 180 Vdc

156 - 180 Vdc

92% Minimum

60% Minimum

30% Maximum

50 dB @ 1 meter

200 pV Maximum From 5 kHz to 3 mHz

Up to 95%

DEPTH cm

40.6

35.6

30.5

WEIGHT kg

54.5

27.2

68.1

6

_5.28 KW 5

4

'" '" ~ " .

0.. 3 t

'" UJ 3: 0 0..

2

o o 500

'"

1000 1500

HOURS AT POWER > P

NOTES 1. ARRAY CONFIGURATION

56 RECTANGULAR SHINGLES 8 S x 7 P

2. POWER IN EXCESS OF TARE LOSS

-- NO VOLTAGE RESTRICTION

2000

VOLTAGE RESTRICTED 156-180 vac

3195 HOURS

2500 3000

Figure 5-14 Power Duration for PV Array for Boston

PCS Specification

The system schematic diagram, Figure 5-15, establishes the

interconnection of the PCS to its interfaces. The PCS consists of an inverter

with control circuits, a dc input filter and transformer.

Inverter Specification -- The major item within the inverter is the

conversion circuit. The inverter conversion circuit consists of a SCR thyristor

bridge with SCR phase angle firing control electronics and initial adjustments

for voltage and current limit settings. Commutation of the SCR's is accomplished

by the reversal of ac line voltage as seen by the bridge circuit through the

transformer, hence, line commutated. The phase angle firing control point is'

dynamically adjusted within limits to transfer the maximum available array

5-29

I.J1 I

W o

ur ~

{ -

11'( IN UTILITY I-

METfA

--!-o l-

'iOA

.!.-o I RI.' A,. I

I \fOA Ie 11"1 { -=--DISCONHECT

~OlJTSIDE WALl.

240/12.0 VAC, ~OH1!. $IH<OLE PHI\S~! ~ WIRE

I 1 I I

I START UP/ SHUTDOWN I

\" SURGE I I PROTEYOR ::- I

I I 9 I I TRANHORMER 1 1 \ I

I I ~ "- I + I I~

I ". I

0-1

I I DC l-I I 1 ~ - ~ n - .. - I II

I I

ISOLATION I FILTER INVERTER I I I I L _____________________ I

POWER CONVERSION SYSTE'M

Figure 5-15. Interconnection Diagram

» Ll

LI

SERvl'CE

PANEL V ZOOA ( (

GOA

-0--

GOA ;::--

.

I I I>

SUf/GE PROT[C DR

I-

,:IJ -

e

,

ISA :---

r '} TI'P,(AL

~R/'N(~ f-

WI p. P JJ"f -I

01

SE~I/ICE GRGUNO

I ROUNG ROL;

power. The initial adjustments provide for three set points: dc turn-on

voltage, IV load line slope, and current limit. These adjustments are described

below.

1. DC turn-on voltage -- This adjustment determines voltage input below which no power inversion takes place. This assures that the array source will have useful output before any loading takes place. Adjustment of this voltage is dependent upon the system characteristics and for this design it is set for 120 Vdc nominal.

2. Current limit -- This adjustment determines the maximum dc current that will be converted to ac and is essential for protection of both the power source and the inverter circuitry. Excessive current can be harmful to the components of the inverter or to the wiring or distribution equipment. Current limiting is accomplished by sensing the dc current and adjusting the switching action to avoid any excessive current.

3. IV Load Line Slope This adjustment determines the pattern of current rise that occurs as the voltage increases beyond turn-on voltage as described above. As the voltage increases, more and more current 1S converted to ac up to the point where current limiting action occurs. The amount of voltage increase from the turn-on voltage to the value at the current limit point is the current slope voltage.

Suitable fusing is also included on the dc input to the bridge circuit and the

ac output from the bridge circuit.

Start-up/Shutdown The control circuitry for daily operation is

shown in Figure 5-16. The inverter will operate in its normal mode when the

main on/off switch, Sl, 1S closed. The operation is illustrated by following

the sequence of circled numbers around the diagram. In the morn1ng when the sun

rises, the array dc voltage rises exponentially. It should be noted that the

array open circuit voltage 1S significantly higher than the maximum power

tracking range. A sensitive relay or solid state logic circuit, C, closes the

circuit for the ac input contractor B. AC line voltage, Ll and L2, will then

operate the dc input contractor, A, permitting the inverter to transfer power.

If either L1 or L2 should fail, contractor A opens, thus shutting the inverter

5-31

v­I

V> N

TO OC FILTCII

0t

r-~-I~

AUTOt.1ATIC OPERATION FOR voe; > MINIMUM AUTOMATIC SHUTDOWH ali AC LINE LO;,5 NO AC LOAD IN Off CONDITION

VOC)MIN LO"iC OR.

EQu IVALENT

--, I"

~,'" I

___ J

:---1 51 (ON/Off CONTROL) 0 • f2\ I C _J._ \V ,

-T-I .... ---- I 0

I I I

r~ {B

'---1 -0--0 -----co>----<r--'j .

A -I----U--- "\

AUTOMATIC

® ",

~ AUTOMATIC OPERATION WITH LII>!E CONNECTiOH

@t

I @~ '---y---'

120VAC SERVICE W~EN

VDe )MIN

r o-"'v--o I I 0

I

1--1-;>- ~--POWER INPUT

~ WITH liNe CONNECTION

AUTOMATIC LINE

CONNECT\ON -<

WITH VDe) MIN

~ ~ :~I~~l Q 1 1

o-j B La I '-----0---.;, ~ -- /

o 1 1 a I. I 10

INVERTE.R -----:-::~.--.I ~r?\.lu_

TRANSFORMER CONTACTOR fA!,,"

Figure 5-16. Power Conversion System Interface

down. Auxiliary logic and timing controls verify a net power output on start-

up. For no net power output, the inverter shuts down again for a preset short

period to avoid rapid cycling. When the sun sets, the inverter shuts down for

the night due to net power less than zero. This evening shutdown and opening of

the ac line contractor eliminates night-time no load losses on the transformer.

Maximum Power Control -- The operation of the maximum power tracking

controller is based upon the photovoltaic power-voltage characteristic shown In

Figure 5-17. A simplified block diagram for this tracking controller is' shown

in Figure 5-18. The basic elements include:

1. A wattmeter circuit that continuously measures the power level and provides a signal output proportional to actual power.

2. Two sample and hold circuits, controlled by a timer, that alternately sample the wattmeter signal output and hold it for comparison with the next sample.

3. A comparator that works in combination with a logic circuit to determine if a given sample represents a power level that is greater or smaller than the previous sample.

4. A flip-flop circuit that changes state whenever a new sample is smaller than the preceding one, but remains in the same state if a new sample is larger than the preceding one, thus representing an increase in power level.

5. An integrator circuit that provides a constantly changing output, whose direction of change is increasing for one state of the flip-flop and decreasing for the other state of the flip-flop.

5-33

VOLTS INPUT

WATT METER

v> +-' +-'

'" 3 . S-<lJ 3 0

c...

AMPERES

I-V

VI 0.. -<: . f-Z w "" 0:: ~ U

VOLTAGE, VOLTS

Figure 5-17 PV Power Characteristics

I I I ~---I LOGIC

I 2 1-'---,----' I COMPARATOR :

SAMPLE AND I I HOLD CIRCUITS I

FLIP FLOP

81 ___________ J

TIMER Fr:2 ~--- OUTPUT

INPUT INTEGRATOR

Figure 5-18 Simplified Block Diagram

of Gemini Maximum Power Tracking Controller

5-34

The output of the integrator is the signal which controls the input

voltage level to the Gemini. It has limits which are set so that it does not

attempt to control voltage beyond the tracking limit set-points. The integrator

constantly changes its output in a direction determined by the state of the

flip-flop. If, for example, the flip-flop 1S forced to remain in a state that

causes a constantly increasing output of the integrator, the Gemini will sweep

through its voltage range starting at a low level and increasing to maximum as

determined by its preset limit. If the state of the flip-flop is changed and

forced to remain in the opposite condition, the integrator signals the Gemini to

sweep down the curve toward zero.

In automatic operation, the flip-flop is not held in any particular

state, but is allowed to change as determined by the interpretation of

successive samples. The sample rate 1S adjusted so that many samples are taken

in the time it would take the Gemini to make a complete sweep from minimum to

maximum or from maximum to minimum.

If the Gemini starts at zero voltage and 1S moving in a direction

toward maximum voltage, as each sample is taken, the logic circuit and the

comparator compare it to the preceding one. On the short-circuit current side

of the maximum power point as the voltage increases, each sample of power is

larger than the one before it, and the flip-flop does not react. The voltage,

therefore, continues to rise. Eventually the voltage reaches the value

corresponding to maximum power point and passes through it. When this happens,

the next sample of power indicates to the logic circuit and the comparator that

the power has decreased from the preceding sample, and the flip-flop changes

state. This causes the voltage to stop rising, reverse movement to a downward

direction, and return toward the maximum power point.

5-35

From this time on, the voltage cycles back and forth around the

maximum power point, reversing direction each time it moves far enough to

indicate a decrease 1n power. If the source characteristics or output changes,

an automatic readjustment stores the Gemini voltage control to the new optimum

point. To provide minimum voltage swings in the area of maximum power and to

allow optimum stability, the rate of voltage change as well as the time between

samples, is adjustable.

De Input Filter and Transformer Specifications -- The remaining two

packages of the pes are the dc input filter and the transformer. The dc filter

inductor serves the function of maintaining current flow through the conduction

portion of each thyristor commutation cycle. This reduces the current harmonics

to levels acceptable for use or further filtering if required.

provides the filter package to match the inverter and power ratings.

Windworks

The third package of the pes is the transformer. The transformer

serves the dual function of providing isolation of dc array output and the ac

line and matching of the ac line voltage to the dc voltage for proper

commutation. Isolation of the sources is a mandatory circuit requirement when a

grounded dc bus is used in the array design. The negative bus is ground'ed ~in

this design, thus requiring an isolation transformer.

The transformer will be rated higher than the inverter bridge and pes

as a whole to accommodate the out of phase ac voltage and current. A nominal

rating of 5 kVA for the transformer 1S suitable for accommodating the

anticipated power factor of operation.

5-36

employ

PV Array Electrical Interface to Conventional

House System

The basic approach for design of the interface arrangements is to

conventional wiring runs and equipment in a manner to maximize safety in

accordance with the National Electric Code requirements. Since the PV system is

a self-generating source of electricity for the residence, it must be

interpreted as an electrical service and is treated in the same manner as the

utility service.

The array positive and negative FCC buses are brought down through the

roof approximately 2~.4 cm down from the peak between the rake and exterior wall

surface. The buses pass through a 2.5 cm raceway sleeve to the top of the

transition block (AMP, Incorporated Part No. 80-32273) and box enclosure.

Reference Figures 5-9 and 5-19 for transition block and roof rake details. The

transition block converts the FCC bus cables to #6 AWG positive and negative bus

conductors. These conductors pass through 2.5 cm PVC conduit and follow the ac

utility service entrance cable to the exterior PV array disconnect switch. The

PV service entrance is located at the same exterior wall as the utility service

as shown in Figure 5-19. This visually separates the residence from one having

only a normal overhead service and should alert emergency personnel that two

power systems are in use.

Since the equipment area is located at an exterior wall, the PV

disconnect could have been located inside the equipment room along with the

utility service disconnect. However, exterior disconnect capability is

preferable as it affords a visible break of the PV array supply. The disconnect

switch includes fuses for overcurrent protection required by code requirements

5-37

~

for electrical service devices. The PV array will generate a maximum of 110r. of

full load current, even if shorted.

The PV system schematic wiring diagram is shown in Figure 5-20. An

additional unfused disconnect is provided 1n the equipment room at the dc

service entrance location. This provides array isolation, and when used 1n

conjunction with the disconnect switch between the inverter and ac house

panelboard, allows safe maintenance on either the dc filter, inverter or

transformer. The positive leg of the dc system is surge suppressed with a

varistor connected to the array side of the interior disconnect switch. This

varistor provides surge protection of the array, even if the interior disconnect

switch 1S open. Beyond the indoor disconnect switch, all dc power is carried

through a raceway system to the inverter enclosure. Electrical connections

between the dc filter and inverter are conduit encased. Connections between the

transformer and inverter are through 3.8 cm Greenfield. All other power

connections from the inverter to the ac house panelboard are conduit encased.

The service pane I board is provided with residential type lightning arrestors to

provide output circuit protection to induced voltage surges.

An exposed copper house ground bus is located directly below the

service panelboard. This provides a visible and accessible means for

terminating all grounding conductors. The house ground bus is connected to the

incoming water service as prescribed by the National Electric Code. An

additional ground rod is provided should the water service ground be unsuitable.

5-38

I

I I !I

II I! J ,r-

GENERAL. ELECTRIC ."aa. DIYI.IDN

Detaied Residential P. V. System Prefemld DetiIgn& SandIa Lab. COntract Ooc.#13-8779

'I I

I

Johnson & Stover, Inc. Electrical Engineers 127 Taunton St. Middleborough. Man. 02346 617-941-8464

~ [;>e;r.bl L. ~L.Q\"'V

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theast PaSSive House P.V. On

.... tHo.

Figure 5-19. PV Interface Arrangement

5-39/40

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GEN ERAL. ELECTRIC Northeast Passive House P.V. Only

- .... .,.AG. IIIYI.'DN

Detailed Residential P.V. System Preferred Designs Sandia Lab. Contract Doc.#13-8779

Johnson & Stover, Inc. Electrical Engineers 127 TaunlonSt. Middieborough,Mass.02346 617-947-8464

n"l~~~~~"n~ ai~_;, _ ..................... 138 Me. AuIIunII!It. I ~ "--OZ"-/.,7 ..... ~'

pv, "JY":>-reM OHc L-1t1E. 1?1~

Figure 5-20. PV System Wiring Schematic

5-41/42

UL-Iabeled materials are used for all phases of the installation. All

equipment is labeled and a copy of the schematic diagram will be posted in the

equipment room. Appendix B lists the electrical system installation

specification.

Equipment Area Electrical Layout

The equipment area contains all the major equipment associated with

the power conditioning and distribution of the solar array power. This area is

located in the southwest corner of the basement level. There is no need for a

self-contained or enclosed equipment area.

Service entries to the equipment area from the outside disconnect

switch and utility service meter are via thru-wall nipples. Equipment placement

1S 1n accordance with the equipment area plan as shown in Figure 5-21. Wall

installed equipment is mounted on a 1.9 cm plywood backboard. This includes the

panel board disconnect switch, the house circuit breaker panel board and lightning

arrestors. The inverter and isolation transformer are floor mounted. A

tabulation of major equipment is listed in Table 5-3. Appendix B provides the

complete system installation specification.

5-43

Table 5-3 Major Electrical Equipment List

• Disconnect switch, fused, 2 pole, 60 Amp, 240 V, NEMA 3-R enclosure

• Varistor, GE Type V275LA40B

• Disconnect switch, non-fused, 2 pole, 60 Amp, 240 V, NEMA 1 enclosure

• Iron core swinging inductor, Gemini Corporation

• Inverter, 4 kVA, Gemini Corporation

• Isolation transformer, 5 kVA, Gemini Corporation

• Residence Circuit Breaker Panel board

• Varistors, GE Type TLP175

Lightning Protection

The lightning environment for the Boston area is shown in Table 5-4.

Due to the low isokeraunic level in the Northeast and the low probability of

residential building lightning strikes per year, nominal protection utilizing

surge arrestors will be installed on the positive array input terminal is

services with a GE Type V275LA40B varistor. The utility bus is surged suppressed

with GE Type TLP175 varistors. These varistor types provide inverter input and

output circuit protection due to high voltage surges.

5-44

,

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GENERAL. ELECTRIC .rAII. ItIYI.IIt"

Detailed ResIdential P.V. System Prefamlcl Detllgns SInIa Lab. COntract Doc.#13-8779

Johnson & Stover,lnc. Electrical Engineers 127 Tauntoo st. MIddleborough, Mesa. 02346 617-947-8464

o 1 2 " 4 ,

massw~sign ~"'''''''''k

13111t.''''*'"'lt.l~,~It'Z1.'1170411'''''

1~:House P.V. 'Only """No.9515 I ... • IO/eo

e.aulfi1t:1if ~Cl:>M f'LAH 4- eL..E.VAAON?

Figure 5-21. Equipment Room Layout

5-45/46

Table 5-4 Lightning Environment Summary

For the Northeast

Isokeraunic Level

Flashes/Yr/sq.km

Flashes to Ground/Yr/sq.km

Building Ground Plan Area (sq.m.)

Building Strikes/Yr

Equivalent to 1 Strike Every

100 m Radius Strikes/Yr

Equivalent to 1 Strike Every

5-47

BOSTON

20

3.3

1.0

130

1.30 x 10(E-4)

7692 Years

3.1 x 10(E-2)

32 Years

SECTION 6

SYSTEM DESIGN ALTERNATIVES

A logical extension to the present, highly energy conscious design is

a solar domestic hot water system. This system would further reduce the total

electrical load requirements on the house. This option was evaluated for a

Northeast residence in the side-by-side PV/Thermal design report, Reference 15.

In that design, approximately 8 sq.m. of thermal collectors reduced the hot

water demand by 651. in Boston. This results in an overall reduction of 221. in

the total electrical loads. The overall system economic viability and PV system

size remains unchanged with this option, and the total yearly energy bill of the

house is reduced. The amount of PV energy used directly in the house does

decrease as indicated in Figure 3-7. For this specific house design, however,

the roof area would have to be increased slightly or the PV array area would

have to be reduced to accommodate the solar thermal collector area.

Similar results would also be expected if a hot water recovery unit

was used to reduce the total electrical hot water requirements. This option was

evaluated in Reference 16. The net reduction in the hot water demand would not

be as significant as 1n the solar thermal hot water system, but no additional

ro~f area 1S required.

Since all potential options could not be addressed in each design, the

reader is directed to References 15 and 16 for more detailed discussions of

these design options.

6-1

SECTION 7

REFERENCES

1. "Final Report - Regional Conceptual Design and Analysis of Residential Photovoltaic Systems," SAND78-7039, General Electric Company, January 1979.

2. "Final Report Analysis and Design of Residential Load Centers," SAND80-7017, General Electric Company, October 1981.

3. Caskey, David, "Selected Residential Electric Rates and Rate Structures 1n the U.S.," July 1979, Sandia Laboratories, SAND79-2110, January 1980.

4. "The Design of a Photovoltaic System for a Southwest All-Electric Residence," SAND79-7056, General Electric Company, February 1980.

5. Personal Communication with R. Smiath, Sandia Laboratories, October 1979.

6. "Solar Energy Thermal Processes," J .A. Duffie and W.A. Beckman, Wiley 1974, Page 76.

7. "Residential Photovoltaic Module and Array Requirement Study," Report No.

8.

DOE/JPL-955149-79/1, Burt Hill Kosar Rittelmann Associates, June 1979.

Lee, Jr., "Future Residential and Commercial Demand in the Northeast," (Prepared for) Energy Research and Development Administration Under Contract No. E(30-1) 16, (Report No. BNL 50552.) Upton, New York: Brookhaven National Laboratory, March 1976.

9. Department of Energy, "Final Energy Efficiency Improvement Target," Federal Register, April and October 1978.

10. Balcomb, J.D., et aI, "Passive Solar DOE/CS-0127/2, January 1980.

11. "Typical Electrical Bills 1977," prepared Bureau of Power, U.S. Government 015-000-00364-2.

Design Handbook,"

by the Federal Power Printing Office,

Vol. 2,

Commission, Stock No.

12. "Photovoltaic System Sizing Analysis," G. Jones & E. Mehalick, Paper Presented at the Fourteenth IEEE Photovoltaic Specialists Conference, San Diego, CA, January 7-10, 1980.

13. "Heat Pump Applications," E.N. Kemler and S. Oglesby, Jr., McGraw-Hill Book Co., Inc., 1950.

14. "Thermal Performance Testing and Na tural Sunlight, " LSSA Proj ect Laboratory, California Institut~ of

Analysis of Photovoltaic Task Report 5101-31, Jet Technology, 29 July 1977.

Modules in Propulsion

15. "The Des ign of a Side-by-Side Photovoltaic Thermal Sys tem for a Northeas t All-Electric Residence," SAND80-7148, General Electric Company, November

7-1

1980.

16. "The Design of a Photovoltaic System with On-Site Storage for a Southwest All-Electric Residence," SAND80-7170, General Electric Company, March 1981.

7-2

APPENDIX A

POWER CONVERSION SUBSYSTEM

SPECIFICATION

TABLE OF CONTENTS

Section Title

l.

2.

3.

3.1

3.1.1

3.1.2

Scope ...................................................... 1-1 Applicable Documents ....................................... 2-1 Req u i rements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ... . . . . . . .. 3-1

Functional Requirements .................................... 3-1

Genera 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-1

Power Conversion Subsystem ................................. 3-3

3.2 Performance Requirements ............. '" ................... 3-3

3.2.1 Input Power ................................................ 3-3

3.2.2 DC to AC Inverter Operation ................................ 3-3

3.2.2.1 Input Voltage Conditions ................................... 3-3

3.2.2.2 Startup/Shutdown Voltage ................................... 3-4

3.2.2.3

3.2.3

3.2.4

3.2.5

3.2.6

3.2.7

3.2.8

3.2.9

3.3

3.3.1

Maximum Power Feature ...................................... 3-4

Short Circuit Protection ................................... 3-5

Undervoltage and Overvoltage Protection .................... 3-5

Open Circuit Protection ............. , ...................... 3-6

Efficiency ................................................. 3-6

Harmonics .................................................. 3-6

Power Factor............................................... 3-6

Controls and Indicators .................................... 3-6

Design and Construction ...... '" ........................... 3-7

Physical Characteristics ................................... 3-7

3.3.2 Service Conditions ......................................... 3-7

3.3.2.3 Shock and Vibration ........................................ 3-8

3.3.3 3.3.4 3.3.5 3.3.6 3.3.7 3.3.8 3.3.9 3.3.10

Groundi ng .................................................. 3-8 Life ....................................................... 3-8 Electrical Safety .......................................... 3-8 Electromagnetic Interference ............................... 3-9 Audible Noise .............................................. 3-9 Thermal Dissipation and Cooling ............................ 3-9 Maintenance ................................................ 3-9 Documentation .............................................. 3-10

A-I

SECTION SCOPE

This specification establishes the requirements for the performance, design,

construction and testing of a single-phase, three-wire, sixty hertz, utility­

line, voltage-controlled, photovoltaic dc to ac power inverter with associated

timing controls; hereinafter, referred to as the Power Conversion Subsystem

or PCS. The PCS is intended for use in providing the power conversion

necessary for a residential photovoltaic system application.

A-2

SECTION 2 APPLICABLE DOCUMENTS

The following documents form part of this specification to the extent

specified herein. In the event of conflict between this document and

the referenced documents, the more stringent requirement shall apply.

NFPS 70 National Electrical Code

A-3

SECTION 3 REQUIREMENTS

3.1 FUNCTIONAL REQUIREMENTS

3.1.1 GENERAL The pes shall invert the variable dc output of a solar photovoltaic array

to supply residential ac electrical service in parallel with utility

electrical service. The pes shall be operated as a current source with

an output ac voltage controlled by the utility line voltage. The PCS

shall be capable of continuous operation and its rated input power.

The PCS shall include a dc filter, inverter and transformer as shown in

Figure A-l. The inverter shall include the inversion components, control

logic for timing, automatic operation and power maximization, protective

components, control switches, adjustments and indicators.

A-4

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A-5

3.1. 2 POWER CONVERSION SUBSYSTEM

The PCS shall provide the interface between the solar array dc output

and the residential electrical service. The PCS will automatically start

operation and connect the solar array to the service panel whenever the dc

bus voltage exceeds the specified minimum value. The PCS shall automatically

eisconnect the solar array from the residential electrical service in the

event of the loss of or out of tolerance utility line voltage or the

absence of real PCS output power.

3.2 PERFORMANCE REQUIREMENTS

3.2.1 INPUT POWER

The PCS shall be capable of continuous operation at an input dc level of

168~ volts and 26 amperes maximum; not to exceed an input power of 4 KVA.

3.2.2 DC TO AC INVERTER OPERATION

The dc to ac inverter shall provide to power conditioning necessary to

convert solar power to usable ac service. The dc to ac inverter section

of the PCS shall have the following operational characteristics.

3.2.2.1 Input Voltage Conditions

The PCS shall not initiate or continue dc to ac inverter operation whenever

the real output power is zero or the ac voltage lines are outside the voltage

limits required for normal correct commutation.

3.2.2.2 Startup/Shutdown Voltage

The PCS shall automatically initiate the closure of the output contactor

and the inversion process whenever the dc input voltage rises above 156 Vdc

and the ac utility service is within the voltage limits for normal correct

A-6

commutation. For voltages above 156 Vdc and less than 180 Vdc, the PCS

shall maximum power track to within ~ 1% of the maximum power. The

PCS shall automatically terminate the inversion process whenever the real

output power is zero or the ac utility service is outside the prescribed

voltage limits. Once operation has terminated due to the ac utility

service being outside the prescribed limits, the PCS shall remain "OFF"

for that period and for 4 minutes after the ac utility service return

within the prescribed limits.

3.2.2.3 MAXIMUM POWER FEATURE

The PCS shall operate at the instantaneous maximum power point operating + voltage of the solar photovo1taic array to within - 1 percent over the

input voltage range from 156 to 180 Vdc. The PCS shall operate at 156 Vdc

whenever the maximum power point is less than 156 Vdc and it shall operate

at 180 Vdc whenever the maximum power point is greater than 180 Vdc.

3.2.3 SHORT CIRCUIT PROTECTION

The PCS shall be equipped with protective circuits or devices which will

prevent damage to the PCS due to short circuit of the input or the output.

3.2.4 UNDERVOLTAGE AND OVERVOLTAGE PROTECTION

The PCS shall not be damaged by undervo1tage or overvo1tage conditions

at the PCS input or output.

A-7

3.2.5 OPEN CIRCUIT PROTECTION

The PCS shall not be damaged by open circuit conditions appearing at the

dc input or the ac output or both simultaneously.

3.2.6 EFFICIENCY

The PCS shall have an efficiency greater than 92% at the rated input

specified in Section 3.2.1. Operating power losses shall not exceed:

o 150 Watts-Tare loss

o 3 Volts-Thyristor bridge loss

o 0.150 Ohms-Resistive loss

3.2.7 HARMONICS

The PCS RMS total harmonic content of the output current shall be less

than 30% of the fundamental at the rated input specified in Section 3.2.1.

3.2.8 POWER FACTOR

The PCS power factor shall be greater than 60% at the rated input speci­

fied in Section 3.2.1.

3.2.9 CONTROLS AND INDICATORS

The following controls and indicators shall be provided on the front panel

of the Inverter enclosure.

1. Inverter ON/OFF switch

2. Input current meter

A-8

3. Input voltage meter

4. PCS ON indicator light

3.3 DESIGN AND CONSTRUCTION

3.3.1 PHYSICAL CHARACTERISTICS

The PCS shall be housed in three wall or floor mounting enclosures meeting

the requirements of the National Electrical Code. Enclosures shall pro­

vide access for installation, service, and maintenance. The three en­

closures shall have maximum dimensions and weights as specified in

Table A-l.

TABLE A-l

PCS

Enclosure Height (in) Width

DC Filter 16 16

Inverter 30 24

Tran s former (5 KVA) 24 12

3.3.2 SERVICE CONDITIONS

Oeerating Ambient temperature

Relative humidity

Barometric pressure

A-9

(in) Deeth (i n) Weight

16 120

14 60

12 150

00 to 400 C

up to 95% noncondensing

520 to 790 mm Hg.

(1 b)

Non-Operating

Ambient temperature

Relative humidity

Barometric pressure

3.3.2.3 Shock and Vibration

_25 0 to 600C

up to 95% noncondensing

520 to 790 mm Hg.

The PCS shall be constructed to withstand normal handling and trans­

portation environments. Special packaging or restraints required for

shipment shall be provided by the supplier.

3.3.3 GROUNDING

Input and output circuits shall not be grounded within the PCS enclosures.

Enclosure safety ground connections for interconnection to the service

ground will be provided and identified by the supplier. Neutral wiring

for the transformer secondary and primary may be specified as required.

3.3.4 LIFE

The PCS shall be designed for a 20-year life with a minimum of maintenance.

Any required preventive maintenance requirements shall be identified.

3.3.5 ELECTRICAL SAFETY

The pes design and construction shall conform to the applicable

requirements and practices of the National Electrical Code (NFPA 70).

A-IO

3.3.6 ELECTROMAGNETIC INTERFERENCE

Good design practices shall be followed to minimize elctromagentic

interference and susceptibility. Conducted interference of the PCS

shall be less than 200 microvolts between 5 kHz and 3 MHz.

3.3.7 AUDIBLE NOISE

Audible noise from the PCS shall be less than 50 dB one meter from the

equipment when mounted in accordance with installation instructions.

3.3.8 THERMAL DISSIPATION AND COOLING

The PCS shall be designed to operate in the environment defined in

Paragraph 3.3.2 without external cooling devices. Integral fans or

blowers, if required, shall utilize ambient air. Interlocks shall be

provided to shut the inverter down in case of failure of internal cooling

devices.

3.3.9 MAINTENANCE

Accessibility

The PCS shall be designed to allow ready access for installation, adjustment,

and maintenance. Insofar as possible, plug-in cards and modules shall be

utilitzed to facilitate troubleshooting and repair.

Replacement

A listing of parts required to support the unit will be provided in the

Operation and Maintenance Manual. This list shall identify those items

required for operational support and maintenance.

A-ll

3.3.10 DOCUMENTATION

Drawings

Schematics, wiring diagrams, and significant assembly drawing information

shall be included in the Operations and Maintenance Manual.

Operations and Maintenance Manual

An Operations and Maintenance Manual shall be provided. It shall consist

of the following:

1. General Description (a brief overall description of function and

performance).

2. Installation Instructions (mechanical mounting and electrical connections).

3. Adjustment Procedures (set-up and calibration information).

4. Operating Instructions (description of operating controls and sequences).

5. Parts List (a list of applicable parts and replacement items).

Provision shall be made for permanent storage of the Manual in the inverter

enclosure.

A-12

APPENDIX B

ELECTRICAL SYSTEM

INSTALLATION

SPECIFICATION

PASSIVE DESIGN NORTHEAST

RESIDENTIAL PHOTOVOLTAIC SYSTEM ELECTRICAL

INSTALLATION SPECIFICATIONS

PREPARED BY:

JOHNSON & STOVER, INC.

127 TAUNTON STREET

MIDDLEBOROUGH, MASSACHUSETTS 02346

FOR:

GENERAL ELECTRIC COMPANY ADVANCED ENERGY PROGRAMS DEPARTMENT

P. O. BOX 8555 PHILADELPHIA, PA 19101

PREPARED UNDER

SANDIA CONTRACT 13-8779

B-1

ELECTRICAL SPECIFICATIONS

FOR

DETAILED RESIDENTIAL PHOTOVOLTAIC

SYSTEM PREFERRED DESIGNS

PART 1:

1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8

1.9 1.10 1.11 1.12

PART 2:

DESIGN NO.4

INDEX

GENERAL REQUIREMENTS

GENERAL REFERENCES SCOPE OF WORK WORK NOT INCLUDED QUALITY ASSURANCE SUBMISSION DATA PRODUCT DELIVERY, STORAGE, OPERATING INSTRUCTIONS AND MANUALS ELECTRICAL CHARACTERISTICS TEMPORARY LIGHT AND POWER RECORD DRAWINGS SAFETY PRECAUTIONS

PRODUCTS

2.1 RACEWAYS AND FITTINGS

HANDLING MAINTENANCE

2.2 SUPPLEMENTARY STEEL, CHANNEL, AND SUPPORTS

2.3 CONDUCTORS 2.4 SAFETY SWITCHES 2.5 GROUNDING SYSTEM 2.6 PHOTOVOLTAIC EQUIPMENT

PART 3: EXECUTION

A-I A-I A-I A-I A-I A-2 A-2

A-2 A-2 A-3 A-3 A-3

A-4

A-4 A-5 A-5 A-5 A-7

3.1 WORK COORDINATION AND JOB OPERATIONS A-8 3.2 PLANS AND SPECIFICATIONS A-8 3.3 SYSTEM IDENTIFICATION A-8 3.4 WORKMANSHIP AND INSTALLATION METHODS A-8 3.5 ARRAY ERECTION PROCEDURE A-9 3.6 FCC CABLE INSTALLATION A-I0

B-2

RESIDENTIAL PROTOTYPE PHOTOVOLTAIC ELECTRICAL

INSTALLATION SPECIFICATIONS

PART 1: GENERAL REQUIREMENTS

1.1 GENERAL

A. This Specification includes all electrical work to install a roof-mounted photovoltaic (PV) system.

B. The system consists of several types of shingles which are to be interconnected by means of AMP Industries type FCC flat conductor cable.

1.2 REFERENCES

A. Cooperate and coordinate all electrical work with other contractors on site.

B. The complete structure will be constructed under another contract. The utility service will be in place along with the house circuit breaker panel­board and the customary house wiring system. The roof will be constructed and covered with roofing felt ready for shingle installation.

1.3 SCOPE OF WORK

A. Provide all labor, materials, equipment, and super­vision necessary to complete the electrical work associated with a roof-mounted photovoltaic (PV) system, including all equipment identified.

1.4 WORK NOT INCLUDED

A. Construction of structure including roof underlay­ment and roofing felts.

1.5 QUALITY ASSURANCE

A. The work shall be executed Ln strict conformity with the latest edition of the National Electric Code and all local regulations that may apply. The installation of type FCC cable on a roof is not covered under Article 328 of the present National Electrical Code. The installation of the FCC cable shall be performed in strict accordance with manu­facturer's recommendations and in accordance with the best practiees of the trade. In case of con­flict between contract documents and a governing code or ordinance, the more stringent standard shall apply.

B-3

B. Unless otherwise specified or indicated. materials and workmanship shall conform with the following standards and specifications (latest edition):

1. National Electric Code.

2. Occupational Safety and Health Act.

3. Standards of Underwriters Labs (UL).

4. National Fire Protection Association (NFPA).

5. National Electrical Safety Code.

6. Local Codes.

C. Carry out tests. secure permits. pay fees, and arrange for all inspection of regulatory agencies for work under this section.

1.6 SUBMISSION DATA

A. Submit six (6) copies of all equipment to be incor­porated into the work for approval prior to ordering same.

1.7 PRODUCT DELIVERY. STORAGE.HANDLING

A. All equipment. upon receipt. shall be inspected for damage and shall then be stored and protected from damage until project completion.

1.8 OPERATING INSTRUCTIONS AND MAINTENANCE MANUALS

A. Provide operating instructions to designated per­sons with respect to operation functions and main­tenance procedures for all equipment and systems installed.

B. At project completion provide two (2) copies of bound brochures including all shop drawings. main­tenance manuals, and spare parts lists.

1.9 ELECTRICAL CHARACTERISTICS

A. The PV array will produce an output of approximately 152.5 volts DC, which will then be inverted to a nominal voltage of 120/240 volts, sirigle phase. Capacity of the system is approximately 4755 watts.

B-4

1.10 TEMPORARY LIGHT AND POWER

A. Provide temporary electricity from the existing house service as required to allow completion of the work. Remove any temporary wiring when no longer required.

1.11 RECORD DRAWINGS

A. Maintain two (2) copies of the documents on site and record any revisions on one set of the job pro­gresses. At project completion, transfer all changes to the other set.

1.12 SAFETY PRECAUTIONS

A. The contractor shall be completely responsible for all safety precautions to be taken by installers of the array. Refer to Appendix "PV Module and Installation Safety Notes".

B-S

PART 2: PRODUCTS

2.1 RACEWAYS AND FITTINGS

A. Conduit - General

1. No conduit shall be used smaller than 3/4" diameter. No conduit shall have more than four (4) 90 0 bends in anyone run, and where necessary pull boxes shall be provided.

2. Rigid PVC conduit shall be Schedule 40 UL listed o for 90 C. All fittings shall be solvent con-

nected. Provide threaded fittings where con­nected to metallic boxes. PVC conduit shall be Carlon. PVC conduit shall be used for exterior work and for raceways enclosing ground conductors.

3. Thin wall conduit (EMT), zinc coated steel, con­forming to industry standards shall be used for all interior raceway systems. Fittings for EMT shall be compression or set-screw type. EMT shall be equal to Pittsburgh Standard Conduit Company, Republic Steel Tube, or Youngstown Sheet and Tube Company.

4. Conduit Fittings

a. Insulated bushings shall be provided on all raceways larger than 3/4".

'b. Access fittings shall be Type LL, LR, or LB as required, and shall be equal to Appleton, Crouse-Hinds, or RACO.

B. Outlet, Pull, and Junction Boxes

1. Each outlet box shall have sufficient volume to accommodate the quantity and size conductors entering the box in accordance with the require­ments of the National Electric Code. Outlet boxes shall be pressed steel as manufactured by Steel City, RACO, or Appleton.

2. Pull Boxes or junction boxes shall be constructed of code gauge sheet metal of a size not less than required by the National Electric Code, if no size is indicated on the drawings, and shall have hinged doors.

2.2 SUPPLEMENTARY STEEL, CHANNEL, AND SUPPORTS

A. Furnish and install all supple~ntary steel, channel, and supports necessary for the proper mounting and support of all equipment. Provide minimum of 3/4" thick plywood backboards for mounting of all equip­ment at the equipment area.

B-6

B. All supplementary steel, channel, and supports shall be UL approved, be galvanized steel, and be as manufactured by Steel City, Unistrut, Power Strut, or Kindorf.

2.3 CONDUCTORS

A. All conductors shall be stranded copper of indicated on the drawings. All conductors Type THWN rated 90

0C for dry locations and

wet locations.

the size shall be o 75 C for

B. Conductors for use on the DC system shall be color coded red for positive and black for negative. AC conductors shall be color coded black for Phase A, red for Phase B, white for Neutral and green for Ground. DC conductors shall also be identified as DC by label markers.

C. All conductor terminations shall be made up by stan­dard lug connections on equipment having same. Ter­minations made up for attachment to positive or negative transition blocks at the roof and the DC input inverter or other devices not having standard lugs shall be bolted type compression lugs as manu­factured by Burndy, Thomas & Betts, or Panduit of tinplated copper. Bolts shall be 1/4-20 silicon bronze.

D. All terminations, other than located within enclosures, shall be insulated.

2.4 SAFETY SWITCHES

A. Safety switches shall be general duty 2-pole or 3-pole fused or non-fused in NEMA 1 or NEMA 3R en­closures as indicated on the drawings and shall be capable of being padlocked. Switches shall be equal to General Electric, Westinghouse, or Square D.

2.5 GROUNDING SYSTEM

A. There shall be four (4) isolated ground systems as follows:

1. Grounded Neutral: The house wiring system neutral shall be grounded only at the house panel by means of a #8 AWG connection between the panel neutral bus and the panel ground bus. The panel neutral block shall be isolated from the panel enclosure. A #8 AWG green insulated ground conductor shall then interconnect the panel ground block to the house ground bus.

B-7

2. Equipment Ground: A U8 AWG green insulated ground shall be looped between all equipment and shall be connected to each piece of equip­ment by means of a ground lug on the equipment. This conductor shall terminate at the house ground bus.

3. Varistor Ground: The U14 AWG green insulated ground conductor from the Varistor shall be con­nected through a separate conduit system with the array negative ground. This ground shall terminate at the house ground bus below the house service pane 1.

4. Array Negative Bus Ground: Provide a U8 AWG green insulated ground condu~tor from the line side of negative bus terminal at the exterior mounted overcurrent device to the house ground bus below the service panel. Run in PVC raceway along with Varistor ground.

5. House Ground Bus: Provide a 12" long 1/8" x I" copper ground bus on standoff insulators 12" above the floor below the AC panel. There shall be four (4) ground connections to the bus as follows: U8 AWG ground to house panel ground bus, U8 AWG ground to equipment ground system, U8 AWG ground at array negative bus, and U14 AWG ground for Varistor grounding. Provide a U8 AWG ground from the bus to the entering water service. In addition, provide a #8 AWG ground to a driven 3/4" x 10' long Copper Weld ground rod. This ground rod shall be located within the equipment area and shall extend 4" above the floor location.

6. Varistor Surge Protection

a. Furnish and install a Varistor for surge pro­tection, which shall be mounted in a junction box sized as required on the drawings. The junction box shall be provided with an in­sulated mounting block and terminal bar isolated from the metal structure. A '14 AWG ground wire shall be tap-connected to the positive DC conductor which is to be pro­tected by means of Burndy Servit type KS split bolt connector. This connector shall be in­sulated by taping. The load side U14 AWG ground from the Varistor shall be intercon­nected to the house ground bus located below the house panel.

b. Varistor on the positive DC side of the in­vertor shall be General Electric catalog number V275 LA40B.

B. Furnish and install a General Electric Lightning Arrester nippled to the side of the house service panelboard. Unit shall be catalog number TLP 175 and shall be connected with black leads to line buses and white to ground.

2.6 PHOTOVOLTAIC EQUIPMENT

A. The photovoltaic equipment including all shingle modules as shown on the drawings and including the roofing nails and split washers will be provided by General Electric Company.

B. The inverter package which forms an integral part of the generating and conversion system will be provided by General Electric Company and shall be installed by the Electrical Contractor.

C. FCC Cable System: The FCC cable, splice connectors, insulating patches, and crimping tool shall be as manufactured by AMP Industries and shall be fur­nished and installed by the Electrical Contractor.

D. Upon receipt of this equipment, each of the several parts shall be carefully examined to identify any possible shipping damages.

B-9

PART 3: EXECUTION

3.1 WORK COORDINATION AND JOB OPERATIONS

A. Be responsible for all equipment necessary for erection of the roof array including staging. Commencement of array erection signifies accep­tance of the surface upon which the shingles are to be installed.

B. Coordinate all work prior to commencing with all existing conditions of the structure.

3.2 PLANS AND SPECIFICATIONS

A. The drawings showing layout of equipment, espec­ially within the equipment area, show a suggested layout. Carefully check dimensions of all equipment and make any adjustments necessary to accommodate any variations.

B. Post the schematic diagram and equipment plan and elevation at a reduced scale under glass in the equipment area.

3.3 SYSTEM IDENTIFICATION

A. Provide screwed-on phenolic nameplates (black with white engraving) on all equipment. Differentiate between AC and DC equipment.

B. All raceways enclosing DC conductors shall be iden­tified by appropriate labels.

3.4 WORKMANSHIP AND INSTALLATION METHODS

A. All work shall be installed in a first-class manner consistent with best current trade practices. All materials and equipment shall be securely installed plumb and/or level.

B. The inverter cabinet shall be mounted using Korfund vibration pads. All wiring connections to this cabinet shall be in flexible metal conduit.

C. All raceways shall be properly aligned, grouped, and supported at right angles to or parallel with the principal building members.

D. Any holes drilled through structure shall be neatly made and properly sealed after equipment installa­tion.

B-IO

E. All wiring in panelboards and enclosures shall be neatly formed and grouped.

F. Be responsible for all safety precautions and rub­bish removal. Leave site in clean condition.

3.5 ARRAY ERECTION PROCEDURE

A.

B.

C.

D.

The roof will be wider than the array layout. The array. therefore. shall be centered on the roof. The excess roof area at the sides will be covered by flashing prior to the installation of the shingles.

It is recommended that the type FCC cable rows be secured to the roofing felts in their proper allign­ment prior to commencing erection of the shingles. Dimensions of FCC cable rows detailed on drawing E-2 are to cable center lines and are given exactly to the height each shingle row will advance up the roof. The connection of the shingle positive and negative leads allows some variation in the exact location of the cables. The cable row dimensions are identified so as to clear all nail holes. The positive and negative bus c~ble rows should be installed prior to connecting any Shl~gles.. . The posltlve and negatlve leads of the shlngles shall be connected to the horizontal FCC cable rows prior to nailing the shingles in place. Nailing of the shingles shall be done by means of the nails and split washers provided. The opening in the washer shall be oriented in a straight vertical position to allow future removal of the shingle with the shingle removal tool. After the shingles have been secured in place. a bead of clear silicone sealant shall be applied to the bottom edge to prevent shingles lifting during wind conditions. The leads of the shingles are of sufficient length to allow removal of the shingle and reinstallation of a new single should it become necessary. After the shingle has been electrically connected and secured in place. the excess lead length shall be folded over on itself as indicated on Drawing E-6.

The positive and negative buses each consist of three (3) runs of FCC cable. The negative leads from the first row of "SCM" shingles and the posi­tive leads of the top active row of "SCM shingles shall each be connected to a single run of FCC cable. The second and third layers of FCC cables are then interconnected to the first.

B-ll

E. The positive and negative buses shall be brought to a transition block enclosure located on the side wall via a pUllbox to be located below the clear story stool as indicated on the drawings. The bus cables shall be pulled through the pull­box and raceway to the transition block enclosure prior to connecting any shingles and before the final roof flashing is installed. Loosely secure the pUllbox to the vertical wall to allow flash­ing to be later slid behind the pullbox and over the FCC cables. After flashing in in place, re­secure the pUllbox and seal at all edges in con­tact with flashing by means of silicone sealant.

3.6 FCC CABLE INSTALLATION

A. The horizontal and vertical rows of FCC cables shall be secured to the roofing felt by means of duct tapes approximately every 6'.

B. The positive and negative buses each consist of three (3) rows of FCC cable which shall be in­stalled on top of each other. Tape the cables to­gether periodically prior to securing to the roof.

C. The horizontal runs of cables shall be terminated with end seals.

D. Terminations and splicing shall be carried out in accordance with the manufacturer's recommended pro­cedures. Special connector assemblies will be pro­vided along with an installation crimping tool. The operation of the crimping tool is such that a posi­tive connection is ensured prior to release of the tool jaws. Each splice or connection shall be in­sulated by means of a manufactured two-piece insul­ating patch.

E. Two transition blocks will be required and shall be mounted by the Electrical Contractor in an approp­riately sized NEMA 3R hinge cover enclosure on the exterior.

B-12

APPENDIX C

INSTALLATION

SAFETY NOTES

APPENDIX C

INSTALLATION

SAFETY NOTES

It is recommended that the following safety precautions be enforced during all

phases of array installation or shingle module replacement. The PV array can

be installed during daylight hours. Each shingle module can generate a maxi-

mem potential of 25 Vdc. The series connection of modules up the slant height

of the roof will provide a potential of approximately 200 Vdc from eave to

ridge. Caution must be exercised to insure that no ~onductive path is provided

across module terminals by installation personnel or equipment. The following

list itemizes key safety requirements.

o No metal ladders or scaffolding should be used

o Installation should proceed only on a completely dry roofing surface

o The negative array ground terminal should not be connected until the electrical installation is complete

o The modules should be installed one course at a time from roof edge to roof edge, and not in any staggered pattern

o No electrically conductive material should be laid over the roofing sur­face during the installation

o The installation should be accomplished working from the roof surface as much as possible

o Grounded components, such as plumbing standard pipes, should not be touched and preferrably they should be covered with an electrical in­sulating cover during the installation

o Care should be exercised not to make physical contact with module ter­minations across a multiple of installed shingles

C-l

APPENDIX D

PERFORMANCE SIMULATION

MODEL AND INPUT DATA

APPENDIX D

PERFORMANCE S:IMULATION MODEL AND INPUT DATA

The simulation model is an adaptation of an analytical model developed during previous

DOE-sponsored studies. The model permits the assessment of system performance on an

annual basis using hourly SOLMET T:MY data tapes as the input. The program calculates,

for each daylight hour, the solar array operating point voltage and power using i:Ul iterative

calculation procedure based on models for current-voltage characteristics, array temper­

ature, insolation, and battery state-of-charge, as described below. The losses in the in­

verter are then determined based on solar array output power.

Solar Array Electrical Model

The synthesis of the solar array current-voltage characteristic, as a function of the total

insolation on the surface and the solar cell temperature, is modeled based on a single cell

characteristic which is represented by the following relationship:

Where

I =

V =

ISC =

C =

=

=

=

1= C.E.ISC -.2.....-1 £exp[K(V+IRS) J-1} Rp 0

Cell output current (Amperes/ cm2)

Voltage across cell terminals (Volts)

illumination current (virtually equal to short-circuit current) (Amperes/ cm2)

Ratio of the total insolation incident on the solar cells to the reference in­

solation for the basic cell characteristics (100 mW/cm2)

Shunt resistance of the cell (Ohms-cm2)

Reverse saturation current of the ideal diode. characteristics

V oc (ISC - R )

P

exp (K V oc) - exp (K RS ISC)

D-1

K

RS

Voc

E

= = = =

Coefficient of the exponential (Volts-I)

Series resistance of the cell (Ohms-cm2)

Cell open circuit voltage (Volts)

Encapsulation loss or gain expressed as the fraction of bare cell short-cirtuit

current

ISC' RS' Rp. K and V oc are represented by polynominals of the form:

Y = aa + a1 T + a2T3 + a4T4 + a5T5 + asT6

where

T

Y

=

=

Solar cell temperature (oC)

Dependent variable (ISC. RS. ~, K, or V oc)

The values of the coefficients are selected to represent the characteristics of the solar

cells used in the module being considered. The total solar array output characteristics are

calculated based on the single cell characteristic by multiplying the voltages and currents by

the number of cells in series and parallel, respectively. In addition, the series resistance

of panel wiring is accounted for in the array characteristic.

Insolation Model

The value for total insolation (direct plus diffuse) on the sloped surface is obtained from

the values for the direct and diffuse components of the insolation on a horizontal surface as

obtained from the SOLMET TMY data tape by applying the following relationship:

= H R H [ (1 + cos (3) (1 - cos (3) ] Dill Dill + DIF 2 + p 2

where

H = Total insolation on the sloped solar array surface

HmF = Diffuse component of the solar flux incident on a horizontal surface

HDill = Direct components of the solar flux incident on a horizontal surface

D-2

f3 = angle between horizontal and solar array surface

p = the reflectance of the surrounding ground (a value of 0.4 was assumed in the

analysis)

The value of RDm is the ratio of the cosine of the solar angle of incidence (a i) on the

tilted solar array surface to the cosine of the solar angle of incidence (aW on a horizontal

surface. The value of cos a. is determined as a function of the day of year, time of day and 1

surface location and orientation in accordance with the following relationship:

cos a i = sin 6 [sin ¢ cos f3 - cos y cos ¢ sin f3 ]

+ sin y sin f3 cos 6 sin w

+ cos 6 cos w [cos y sin ¢ sin f3 + cos ¢ cos f3 ]

where

e i = Angle of incidence of beam radiation measured between the beam and the

normal to the solar array surface

¢ = Site latitude (north is positive)

6 = Solar declination angle

f3 = Angle between horizontal and solar array surface

y = Solar array surface azimuth angle (zero is due south, west of south is

positive)

w = Hour angle (zero is solar noon)

For a horizontal surface this expression reduces to:

cos eh

= sin 0 sin ¢ + cos 0 cos w cos ¢

D-3

Array Thermal Model

The temperature of a roof-moWlted solar cell module was calculated based on natural

convective cooling from the front surface of the module installation. Under this condition

the heat balance equation for the solar cell modules is given by:

where

RrOTAL = total insolation on the sloping solar array surface (W/m2)

p = ratio of solar cell area to total module area

O! = solar absorptance of solar cells s

Tamb = ambient temperature (oK)

Tsky = sky temperature (~

TR = temperature of the living space Wlder solar array (oK) = 2960K

Tcell = solar cell module temperature (oK)

h = convective film coefficient on the module front surface, (W/m2-KO) 0

h02 = convective film coefficient on the module back surface. (W/m2- oK)

E = hemispherical emittance of the front surface of the solar cell modules

(] = Stefan-Boltzmann constant

= 5.6697 x 10-8 W /m2 o!('!

The sky temperature, Tsky ' is calculated, using the relationship given in Reference 6:

= o 0552 (T )1.5 • amb

D-4

The front surface (ho) and back surface (ho2) film coefficients are calculated using te­

lationships given in Reference 14.

= 1/3

1.247 «Tcell - Tamb) cos (3) + 3.81 V

= 1/3

1. 079 «Tcell - Tamb) cos (3) + 3.81 V

where

{3 = slope angle of roof (measured from horizontal)

V = wind speed (m/s)

Compared with data reported by JPL in Reference 14 the analytical model tends to over­

predict cell temperature, with the result that predictions of cell output contain a conservative

bias.

Inverter Loss Model

The inverter loss model used in the battery storage analyses assumed a constant 87%

efficiency. A more sophisticated model of inverter losses, used in the feedback analyses and

accounting for constant loss, SCR bridge losses, and resistive losses, predicts efficiencies

ranging from 85 to 90% on an hourly basis with an annualized efficiency of 87%.

Battery Model

The charge and discharge voltage of a hybrid lead-acid battery has been modeled as a

function of battery state of charge (SOC) and instantaneous charge or discharge rate. Figure

D-1 shows a set of these characteristics as modeled based on data supplied by C&D Batteries

Division of the Eltra Company. The bottom set of curves are discharge characteristics with

discharge rates varying from O. 02C to 0.2C, where C is the cell energy capacity in Ampere­

hours. The top set of curves are charge characteristics at the same rates, assuming that

recharge starts from the fully discharged condition. Different sets of characteristics are

modeled for various battery SOC conditions. Since the battery is modeled on these actual

characteristics, the round trip efficiency for the battery varies with battery capacity and col­

lector area for the different cases analyzed. The average round trip efficiency was in the

D-5

2.80

2.. 60 CHARGE RATE

,-.. 2.40 til

~ 0 .c. w L'l

2.20 c(

~ 0 > -l -l W U 2.00 W L'l

~ W > c(

qo

1.60 DISCHARGE RATE

1.40~--------~--------~--------r-------~r-------~r-------~ . 1. 20 1.00 .80 . 60 .40 .20 .00

STATE OF CHARGE

Figure D-l. Battery Simulation Model

D-6

range of 75 to 88% which includes a constant average Ampere-hour charging efficiency of

0.952 based on the information from C&D Batteries. For a reference case of 65 m2 cell

area and a battery capacity of 20 kWh, the average round trip efficiency is 85%.

lliPUT DATA

The PV system simulation model requires input data, representing the PV system char­

acteristics and hourly histories of local weather, insolation, and residential electrical and

space conditioning loads. Each of these input items is discussed below.

PV System Data

This data provides a description of the system in terms of its electrical characteristics.

It includes such information as the number of solar cells in each series circuit and the num­

ber of parallel circuits. Cabling resistance and module interconnection resistance are

also input for determining power losses from the DC output to the inverter input. A series

resistance of 31 milliohms has been calculated for the current.

Weather Data

The National Climatic Center has recently made available rehabilitated, combined, hourly

solar radiation and meteorological data for twenty-six sites across the United States. The

solar radiation values from these SOLMET data sites have been corrected to reduce some of

the major data errors and gaps, and to provide non-measured direct radiation data on the

basis of the most recently developed correlation techniques with measured total radiation data.

The SOLMET records provide up to a twenty-three year record for the selected sites.

Sandia recently prepared a synthetic Typical Meteorological Year (TMY) for each of the

the twenty-six SOLMET sites. These TMY data tapes are based upon a selection of the most

typical January, February, etc., available in the years of record for each site. Typical

D-7

months were selected by a weighting technique for insolation, temperature and wind speed.

These TMY SOLMET records for ail 26 sites are available at GE. They provide a real

weather data base for solar system performance evaluation and comparison.

Electrical Load Data

Electrical loads for other than space conditioning are divided into three categories. The

first category is diversified or base load demand and includes lights and many miscellaneous

applications in the modern home. The second group includes cooking and clothes drying loads

while the third grouping consists of heating loads for domestic hot water. Profiles of the in­

tegrated amount of energy used during each hour of the day for the various categories of energy

usage were developed for 1977 by utilizing a wide variety of references. From the data ex­

amined, an annual usage of 5540 kWh was assumed representative of the diversified energy

usage by a typical family of four persons in 1977. Since lights and some appliances (e. g. ,

refrigeration equipment and HVAC auxiliaries) do have seasonal variations in their use, pro­

files for the four seasons were developed. No significant regional variations were found. The

cooking and clothes drying profile was found to have negligible seasonal and regional variations,

and their annual load was determined to be 2220 kWh for the 1977 time period. An annual hot

water load was similarly determined at 4940 kWh but a regional correction was applied to both

the hourly profile and the annual value to account for difference in ground temperature across

the country. Seasonal variations were also incorporated.

All the profiles and annual values developed for 1977 were modified for prOjected usage

trends in 1986 according to the rationale indicated in Table D-l.

It should be noted that the prOjected decrease in baseload usage is 1. 8% per year

reflecting a more dedicated conservation program than had been assumed for previous

preferred designs. For the earlier designs, the prOjected baseload reduction was based

on the average of two projected reductions.

analysis used the higher projected reduction.

D-8

The current

Table D-1. Seasonal Regional and Projection Adjustments of Loads

Seasonal Regional 1986 Projection Effects Variations Differences from 1977 Base Year

Base Load Profiles for No corrections Usage decreased by 1. 8%

Demand 4 seasons used per year (16.2%)

Cooking None significant No corrections Cooking reduced by 1 %/yr. Clothes Drying used Drying reduced by 1/2%/yr.

(total 6 3/4%)

Domestic Hot Profiles for 4 Regional adjustment Reduced by 1 1/4%/yr. Water seasons identified factor identified (total 11 1/4%)

(0.75 to 1.16)

The 1986 electrical load profiles were developed by applying the projected energy re­

duction factors from Table D-1 to each of the corresponding components of the total electrical

load for 1977. Profiles of the components of the average daily electrical load (exclusive of

space conditioning) for 1986 are shown in Figure D-2. The annual total of each component is

tabulated below:

Component

Baseload

Cooking and clothes drying

Domestic hot water (average) Adjustment factors

Phoenix = O. 88 Albuquerque = 1. 05 Boston .. 1. 08 Madison = 1.11

Load, kWh

4641

2070

4384

Space Conditioning Loads

Space heating and cooling loads for the residence were computed on an hourly basis

using General Electric's Building Thermal Transient Load (BTTL) program. Program in­

puts included hourly weather and insolation data, building usage schedules, and a thermal

model of the house. The thermal model was developed from the architectural plans and

D-9

analytically represented the significant heat flow paths, thermal capacitances, and heat

generating elements of the house. The model assumed two thermostatically independent

zones: one the living area; the other, the bedroom area. In winter, the living area thermostat

was set at 20°C (68<7) during the day and at 17.2oC (63°F) at night; while the bedroom thermo­

stat was maintained at 17. 2°C (63°F) day and night. During the summer, the living and bed­

room areas thermostats were set at 25. 6°C (78oF) day and night.

:I:

~ c· w en ::l > t:1 a: w Z w

3.0

2.8

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

TOTAL ELECTRICAL LOAD

DOMESTIC HOT WATER

\ (12.0 KWH/DAY)

'I I \ , I ,

I I '" \ I \ I ... -1

BASE LOAD (12.7 KWH/DAY)

-SPACE HEATING AND COOLING LOADS NOT INCLUDED

-LOADS SHOWN REFLECT 1986 PROJECTION AND TOTAL 11,400 KWH PER YEAR

-BASE AND DOMESTIC HOT WATER LOADS REPRESENT AVERAGE FOR FOUR SEASONS

-HOT WATER LOADS ADJUSTMENT FACTORS

COOKING AND CLOTHES DRYING

(5.7 KWH/DAY)

Figure D-2. Average Daily Electrical Load Profile

D-10

The house was assumed to be occupied by a four-member family. The internal sensi­

ble and latent heat generated by occupants, lighting, cooking and miscellaneous appliances

was derived from the hourly profiles of electrical loads and cooking loads established in

the previous section. The latent portion of the load was estimated from any showers, boiling

of water or other evaporative type processes occurring within the residence besides that due

to human presence.

The infiltration rate through window and door leakage was assumed to be a function of

wind speed. Since air flows are due to changes in air-stream static pressure, which, over

the surfaces of buildings, are approximately proportional to the square of wind speed, the

following equation was used in calculating infiltration gain ru the building:

Infiltration = 0.25 + 0.5 x ( m/sec wind speed )2, air change per hour 13.41

The basic house model can also be adapted to assess the effect of an attached green­

house and large south facing glass areas including doors. The south facing glass area for

the basic house design was 7. 8 m2• For this passive house design, the south facing glass 2 2 2 2

area was 53.9 m (18.1 m for the greenhouse, and 28 m for the glass doors and 7. 8 m

for glass area),

For a passive design house, the model includes a third zone for the attached greenhouse.

In winter, the greenhouse thermostat was set to 32.20

C (900

F). The model assumed that

when the greenhouse temperature exceeded 32.20

C (900

F) during the heating season, a

blower would be activated to move the hot air in the greenhouse through ductwork either

to outlets distributed throughout the living space, when a heat load existed; or to thermal

storage, when no concurrent heat load existed. Night time heat loads were supplied from

storage when stored energy was available. During the cooling season, venting of the green­

house and shading of the south facing glass doors neutralized the threat of solar heat gain.

The resulting space conditiOning loads predicted for the Boston residence by each model

are shown below.

D-ll

SPACE CONDITIONING LOADS, KWH MODEL

HEATING COOLING

BASELINE DESIGN 9759 2150

PASSIVE DESIGN 7260 2148

The effect of the greenhouse and the increased south facing glass area produced a

reduction of 25. 6% in annual heat load. The cooling load remained essentially unchanged,

since the solar gain associated with the additional south facing windows and greenhouse were

neutralized by shading and passive ventilation (open windows). The BTTL program pre­

dicted heat load reduction of 25. 6% was compared with that predicted by the Passive Solar

Handbook (Reference D-IO) "rule of thumb." This rule related heat load reduction to the

increase in south facing glazing and distinguishes between site locations and the use of night

insulation on glazing. The heat load reduction "rule of thumb" is expressed as a correlation

in Figure D-3 for Boston and Madison. The abscissa in this figure is evaluated by dividing

the increased south facing window area by the floor area. The passive design house repre­

sents a net increase in south facing window area of 38.3 m 2. The floor area of the house is 2

148.7 m. This combination of increased south facing window area and floor area translate

to a "rule of thumb" prediction of 23% reduction in heat load for Boston, which is about 10%

below the prediction based on the BTTL results. Notice that the "rule of thumb" correlation

also permits the evaluation of glazing with night insulation, which results in additional reduc­

tions in heat load. For the passive design house, the heat load reduction with night insulation

increases from 23% to 58%. For this analysis, night insulation was assumed and the "rule of

thumb" correlation was assumed; however, a conservative value of 48% for the heat load

reduction was used in the hourly adjustment of the baseline heat load to yield an annual heat

load of 5075 kWh.

For the design house in Madison, the passive solar heat load reduction amounted to 57%

based on the "rule of thumb" correlation (see Figure D-3). As with the Boston house, a con­

servative value of 48% was used in the analysis for heat load reduction.

D-12

... . z 0 .... l-t.> => Q LU

'" Q

C§ ..J

I-00: LU ::

80

70

60

so

40

30

20

10

/

/ WITH R-9 NIGHT INSULATION

/

LEGEND

--- BOSTON - -- MADISON

NOTES:

WITHOUT / NIGHT INSULATIO --

1. REFERENCE "PASSIVE SOLAR HANDBOOK"

--

o ~ ____ +-____ +-____ ~ ____ -+ ____ ~ ____ ~

o 0.1 0.2 0.3 0.4 O.S 0.6 SOLAR COLLECTOR AREA/FLOOR AREA

Figure D-3 Heat Reduction Due to South Facing Glazing

D-13

Monthly space heating and cooling load profiles for the single family residence in

Boston and Madison are listed in Table D-2. It is important to note that these space condi­

tioning loads are loads which are satisfied by the heating and cooling equipment. In the

all-electric house, the heat pump supplies these loads and creates an electrical demand

equivalent to the space conditioning load divided by the heat pump COP. The monthly pro­

files of heat pump electrical requirements are shown in Figure D-3 for Boston and Madison.

Both the space conditioning loads and the heat pump electrical requirements reflect the

geographic differences between Boston and Madison, which are at the same latitude, but are

950 miles apart. Boston has higher cooling loads than Madison; however, Madison has the

greater heating loads. The space conditioning demands are calculated hourly during the

simulation and these plots provide the monthly summaries.

D-14

Table D-2

Northern Single Family Monthly Load Profiles

SITE LOCATIONS

MONTH BOSTON MADISON (KWH) (KWH)

COOLING HEATING COOLING HEATING

I I

JANUARY 0 I 1492 0 I 1650 I I I

I I FEBRUARY 0 I 884 0 I 1286 I I

I I I I

MARCH 0 I 785 0 I 1046 I I I I I I

APRIL 0 I 181 0 I 332 I I I I I I

MAY 0 I 0 0 I 100 I I I f I f

JUNE 0 I 0 0 f 5 f f f f f I

JULY 926 I 0 808 0 I I I

AUGUST 1077 I 0 551 0 I I I

SEPTEMBER 205 I 0 11 0 I I I

OCTOBER 0 I 0 0 I 226 I I I I I I

NOVEMBER 0 I 464 0 I 793 I I I I I I

DECEMBER 0 I 1262 0 I l342 I I I I I I

I I TOTAL 2148 I 5058 l369 6779 I I I

I I

D-15

1.°1 .9

::z:: ~

.. .8+ Cl :z ~ .7+ lLJ Cl

>- .61/\ to!' a: lLJ :z .5+ \ lLJ

...J c( u .4.i \ -a: t-u lLJ .3.i ...J lLJ

t;) .2 L I

....... 0':>

.1 t o I

1.1

1.0 BOSTON 1/\ MADISON

.9

.8 '

.7

.6

I .5

.4

"- \ .3

\ \ .2

,\./. ,V, • 1

I 0

ANNUAL TOTALS ANNUAL TOTALS

SPACE LOADS • HEATING • COOLING

HEAT PUt>'IP LOAD AVERAGE HP COP

5.1 MWH 2. 1 t'1~m 2.8 r\1~m 2.6

SPACE LOADS • HEATING • COOLING

HEAT PUt~P LOAD AVERAGE HP COP

Figure D-3 Heat Pump System Electrical Requirements

For Northern Single Family Residence

6.8 MWH 1.4 MWH 4.0 MWH 2.0

APPENDIX E

ECONOMIC MODEL AND ASSUMPTIONS

ECONOMIC METHODOLOGY

APPENDIXE

ECONOMIC MODEL AND ASSUMPTIONS

Economic Methodology

Many of the simple investment evaluation techniques, such as payback time or simple

return, suffer from two major drawbacks: life of the investment is not considered, and un­

even costs and/or benefit streams cannot be handled.

The second item is of critical Importance to alternate energy systems since virtually

every economic scenario projects rising energy prices and therefore a steadily increasing

benefit stream from an alternate energy system. For this reason, considerable effort has

been made to stress ''life cycle costing" for alternate energy systems. The following sections

describe the life cycle costing model used in system sizing analysis.

Levelized Annual Cost

True life cycle cost analysis must necessarily consider the timing of costs and benefits

as well as the magnitude. A method employed in previous General Electric solar and wind

energy programs is to compare Levelized Annual Benefits (LAB), representing system energy

savings, with the Levelized Annual Cost (LAC), the levelized dollar amount required to own,

operate, and maintain a system during each year of the life of the system. Specifically, the

levelized annual cost accounts for:

1. "Paying off" system capital costs (mortgage principal)

2. Paying mortgage interest

3. Paying property taxes and insurance

For cost evaluation and comparison of systems for future implementation, it is appro­

priate to express the levelized annual cost (LAC) referenced to a particular year, e. g., 1980.

The result is the levelized annual cost in constant (base year) dollars given by:

E-l

CRF' LAC (constant ) = CRF x FCR x I + AOC

where I is the capital cost of the solar system and AOC is the annual system operating cost

which includes operation and maintenance and insurance. The parameter FCR is the fixed

charge rate and represents the yearly cost of ownership, expressed as a percent of the cap­

ital cost, I. These costs consist of mortgage interest, principal and property taxes. The

parameter CRF is the capital recovery factor, defined as the uniform periodic payment (as a

fraction of the original principal) that will fully repay a loan (including all interest) in yearly

periods over the loan lifetime at a specified yearly interest rate. The interest rate r used

to calculate CRF is called the discount rate and for the homeowner is equal to the after-tax

interest rate of the mortgage.

The relation expressing CRF as a function of r and system lifetime N is given as

N CRF = r(1+r~

(1+r) -1

The parameter CRF' is the corresponding capital recovery factor in constant (base

year) dollars. CRF' is based on the real (or inflation adjusted) discount rate, r', defined as

r'= 1 + r_ - 1

l+g

where g is the general inflation rate. The equation for CRF also applies for CRF' with

r' replacing r.

It should be noted that the LAC equation applies only to those systems without storage

batteries since no replacement costs are necessary. For systems with storage, an addition

term of the form

CRF' xl'

B (1 + r) 11

E-2

must be added to account for the replacement of the battery in the eleventh year (e. g., for

a battery life of 10 years). Here, I'B is the cost of the replacement battery in constant

1980 dollars.

Levelized Annual Benefits

The comparison of the energy cost savings of the solar system to the levelized annual

cost is accomplished by computing the levelized annual benefits (LAB) for the energy savings.

LAB is inherently a function of present and projected energy prices and may be expressed by

CRF' LAB (constant ) = CRF xMxp xE

o 0

where E represents the annual energy saved by the solar system, M is an energy saving o

multiplier which is defined as the leve lized value of an escalating cost stream which accounts

for the rate of energy price escalation over the lifetime of the system, and p is the energy o

price in year zero (for a 1986 start, year zero becomes 1985). For stand-alone systems,

minimum monthly energy charges are included as a benefit in the computation of LAB.

The multiplier M is a function of energy price escalation rate (f), system lifetime (N),

and discount rate (r), and is expressed as

M = r (1 + f) r - f [ (l+r t -(l+;t 1 *

(1 + r)N - 1

The energy price in year zero (p ) is related to the energy price in constant (base year) a

dollars per energy unit (P) through the expression

where ~ is the number of years from the base year to year zero (value of 5 was used for

a 1986 start with a base year of 1980).

*When r=f: M~RF. N

E-3

The economic viability of a sys~em can be measured through the use of the cost-to-benefit

ratio, which is defined as the ratio of the levelized annual cost to the levelized annual benefit.

The system can be economically viable when the cost-to-benefit ratio is less than unity. The

break-even system cost occurs when the ratio is exactly unity, i. e., when LAC and LAB are

equal.

Economic Assumptions

This subsection spells out the basic assumptions that will be used in the economic analysis

of PV residential systems. These assumptions concern the price of electricity in the designa­

ted regions for the 1986 time period and system capital cost. Also considered are assumptions

regarding inflation, interest, and tax rates insofar as they will affect economic comparison

results.

Model Assumptions

In order to utilize the cost-to-benefit ratio for system sizing studies, a set of economic

assumptions were developed. These fJ,ssumptions are summarized in Table E-l. Most of

these assumptions are consistent with assumptions utilized in previous residential studies as

Reference 1. All of the economic calculations were completed for a 1986 start in constant

1980$. The overall average inflation rate of 5 percent was assumed through the time frame

of the analysis. This value is low according to current rates but since the cost-to-benefit

ratio analysis becomes independent of the inflation rate and to maintain similarity to previous

work, this value was used. In addition, a resultant homeowner mortage rate of 10 per cent

for a 20-year loan was assumed with a marginal income tax rate of 35 per cent for the home­

owner. This is equivalent to a taxable income of approximately $25,000 at present tax rates.

A 20-year life will be assumed for the solar systems of interest with a battery life of 10 years.

Since several states and local communities have already exempted solar systems from prop­

erty tax, no additional property tax will be assumed. These figures imply an annual cost

or "fixed charge" of about 9. 1% of the initial photovoltaic system cost. Annual operating

costs are assumed to be $100/year for operation and maintenance and O. 5% of system cost

E-4

Table E-1. Economic Assumptions for Optimization

• 1986 Start

• General Inflation Rate: 5% • System Life: 20 Years

• Insurance: 0.5% of Capital Cost • Maintenance: $100/Year

• Electricity Price Escalation: • 1980$ 4% Over Inflation

• Battery Life: 10 Years

• Mortgage Rate: 10% • Phoenix Electricity Price: 5. 8 ¢ /kWh

• Tax Bracket: 35% • Albuquerque Electricity Price: 7.0¢/kWh

• No Property Tax

for insurance. All components of the solar system are assumed to have the same lifetime

as the system (20 years) except for batteries (10 years).

An electricity price escalation of 4% over inflation was also used in the analysis, al­

though the marginal benefit/cost analysis allows the extension to other escalation rates

and system lifetime assumptions by a constant adjustment factor as done in Reference 1.

Capital Cost Estimates

To calculate the LAC, an estimate of the system capital cost is required. These cost

estimates were made assuming 1986 price projections for equipment or 1986 National PV

Program cost goals as for the array. In addition, estimates for installation costs and all

remaining equipment costs were estimated as part of the balance of system costs. These

latter values are only estimates made prior to final system design selection since the intent

was to use these values in a relative comparison for system sizing and tradeoffs. The de­

tailed design data within this report can now be used for obtaining detailed costs for instal­

lation and all small equipment costs. All the costs are in 1980$ and include in general,

two 15% markups for distribution and contractors. These markups are probably low, but

are used in this analysis until more detailed numbers are available for distribution networks.

E-5

The system capital costs were divided into an array cost, power conditioning

cost, and balance of system costs. The balance of system costs were further separated

into a fixed cost (i.e., however small a PV installation, a minimum amount of equip­

ment, and thus, cost, is required independent of ~ystem size) and a variable cost

based on system size. The variable, or area-related costs of a photovoltaic system

include the cost of modules, array installation, and a portion of the power condition­

ing. The fixed costs obviously include the roof to load wiring, switchgear and power

conditioning installation. There are other less obvious fixed costs, however.

For example, the cost of a power conditioning unit will include basic labor,

cabinet and parts costs independent of size. In the area of operation and mainten­

ance, a large fraction of the cost will not be area related. This would include

almost all PCU and switchgear maintenance. For any given system, more or less fixed

costs may be present, but the general contributors will remain.

The array cost assumed is the National PV Program goal of 70¢/peak watt or $700/

kWp factory price. Including the markups, the cost is $925/kWp on site. The balance

of system costs were made up of array installation estimates, power conditioning sub­

system costs, and remaining equipment costs. The array installation cost estimate

was based on labor and material estimates from the 1978 Building Cost File Index for

conventional asphalt shingle installation and increased by an assumed factor of 3 to

account for the additional complexity of the PV shingle installation. The resulting

cost is $35.35/m2 per unit array installation.

Labor and material credit for weather tight replacement of the conventional shin­

gles was then given at $12.29!m2 for a net array installation cost of $23.06!m2 • These

values are consistent with residential array installation cost estimates developed by

Burt Hill Kosar Rittleman Associates, Reference 7, where non-optimized flat PV panel

installation costs were approximately $40/m2 and roof credits for integrated arrays

were approximately $11/m2

.

The power conditioning subsystem cost estimates were based on cost projections from

E-6

several inverter manufacturers assuming high production levels in 1986 obtained from

Reference 5. These projections were of the same magnitude as assumed in Reference 1

at$144/kVA in 1975 or$202/kVA in 1980 • Several current cost quotes for the inverter,

dc input filter and isolation transformer for 4,8 and 10 kVA sized systems showed a fixed

cost. independent of system size, and variable cost. dependent on system size. Based on

this data. the $202/kVA cost for 1986 was separated into fixed and variable costs and then

adjusted with two 15% markups resulting in a total PCS system cost estimate of $689 + $181/

kVA.

The remaining fixed balance of system cost estimates include costs for junction boxes,

disconnect switches, varistors, diodes, cabling and miscellaneous connectors. wire and tape

and installation labor. Applying the markups resulted in a fixed cost of $1090. All of these

system cost estimates are summarized in Table E-2. The costs listed in Table E-2 are bas­

ically direct system costs; however, imbedded in the assumed values are also the indirect

costs associated with system design and installation. Some of the indirect costs could include

architect fees. real estate fees, interest during construction, project management costs and

the cost of the contingency and spares. It is difficult to accurately estimate all of these indirect

costs and they are therefore included in general terms. The fixed costs associated with

operation and maintenance for the system are not listed separately. These costs are normally

added in the LAC calculation as a levelized annual value of$100/yr. This value relates back

to a fixed capital cost of $1590 for the economic assumptions listed in Table E-l. No

attempt was made to break out a fixed and variable portion of the operation and maintenance

costs for this analysis.

E-7

Table E-2

Array Installation and Balance of System Costs

SHINGLE ARRAY INSTALLATION ESTIMATES

Labor + Material Credit for Conventional Shingles

POWER CONDITIONING COSTS

(Based on Projected High Production Estimates for 1986) Includes Inverter, Input Filter and Transformer

Cost = $689 + $18l/kVA 2 Or Approximately $689 + $15.60/m

B-O-P EQUIPMENT COST ESTIMATES

(Includes Switches, Junction Boxes, Varistors, Busbar, Cabling)

ARRAY

VARIABLE COSTS

FIXED COSTS

Energy Price Estimates

SUMMARY

$925/kWp

2 $38.66/m

$1779

1980$

2 $35.35/m2 l2.29/m

2 $23.06/m

$689 + $15.60/m2

$1090

Strong regional differences exist in energy pricing especially in electricity. In

addition, the rates are changing very rapidly and it is difficult to continually obtain

the most recent data. Since the first design for the Southwest was completed, a number

of utilities were surveyed and provided updated average electrical energy prices for

several regions (Reference 3). The updated values for Boston and Madison are 8.32~/kWh

and 5.32~/kWh respectively. These values were used in the economic analysis.

E-8

APPENDIX F

RECTANGULAR PV SHINGLE MODULE CONSTRUCTION DETAILS

APPENDIX F

RECTANGULAR PV SHINGLE MODULE CONSTRUCTION DETAILS

The construction details of the rectangular shingle module are shown in

Figure F-I, which is a section taken through the laminated assembly. A descrip­

tion of the construction follows.

Figure F-I

Encapsulated Cell Subassembly

TEMPERED SUNADEX GLASS COVERPLATE (5.0 mm)

EVA/CRANEGLASS (0.43 mm)

CELL CIRCUIT

EVA ICRANEGLASS (0.43 mm) AL FOIL (0.03 mm)

The encapsulated cell subassembly, which is configured as a separately as­

sembled component of the module, consists of the material stack-up shown in Figure

F-I. A thermally tempered SUNADEX glass coverplate functions as the superstrate

for the subassembly. The active circuit elements, including the solar cells and

interconnectors, are sandwiched between layers of EVA/Craneglass which constitutes

the encapsulant.

A rear side aluminum foil vapor barrier is used as a necessary design feature

to increase the probability of survival under high humidity-freeze cycling environ­

ments. The EVA/Craneglass laminate provides the electrical isolation required be­

tween the active solar cell circuit components and this aluminum foil layer. The

exposed outer layer of the aluminum foil is covered with Mead Sunstorm board, so no

provisions are required to ground this foil. As depicted in Figure F-2, which is

F-l

an exploded view of this subassembly, the AMP flat conductor cable module-to-module

inter connectors are installed as part of this subassembly and emerge from the lamin­

ate as flying leads which are routed through slits in the substrate. The copper

conductor, which is equivalent to AWG12 in current carrying capacity, is covered on

both sides with a polyester insulation layer with a rated operating voltage level

of 300 V.

ALUMINUM FOIL--+--J

SHEET

EVA ADHESIVE _-+_.-J FILM

SOLAR CELL CIRCUIT----'

EVA ADHESIVE FILM -----'

Figure F-2. Exploded View of the Encapsulated Cell Subassembly

F-2

Module Assembly

The module assembly consists of the lamination of the encapsulated cell sub­

assembly to the rear cover and to the substrate foam as shown pictorially in Figure

F-3. The double-backed adhesive bonding strip is used to form the lap joint between

the glass coverplate and substrate foam and to provide the s~alant during module

installation to prevent the wind uplift forces from separating the installed shingle

layers.

ADHESIVE BONDIN':; STRIP ~

SUBSTRATE FOAM ~

ENCAPSULATED I CELL SUBASSEMBLY

REAR COVER

CONTACT CEMENT __ -0./

Figure F-3. Exploded View of Module Assembly

F-3

Mead Sunstorm board, which is a 2.0 rom thick weather-resistant solid fiberboard

material, is used as the rear cover. This material is of a laminated construction

with the core composed of highly sized reclaimed kraft fibers. All glue lines are

bonded with waterproof PVA adhesive. Both outer facings of Sunstorm board are

white -- wet strength beached vergin kraft lining paper. This liner has a mold in­

hibitor added to reduce the possibility of mildew in exterior applications. Also,

a clay coating is applied to facilitate high quality silk screen printing and various

modes of paint application. The outer facings are secured to the core with a film

of polyethylene. This film serves as a barrier, retarding water and moisture ab­

sorption, while giving added dimensional stability to the overall product. The outer

skin is B.F. Goodrich reinforced Hypalon Flexseal which covers a closed-cell poly­

ethylene foam to provide uniform thickness of the tub. Scotch-Grip Adhesive 4230

(3M Co.) is a contact cement used for the laminating adhesive for this assembly. It

bonds the aluminum foil vapor barrier of the encapsulated cell subassembly to the

rear cover and bonds the rear cover to the substrate foam. It is an economical,

water-dispersed adhesive offering excellent wet strength, and resistance to tempera­

tures as high as l630 C, and to high humidity and aging effects. This adhesive is

applied with low·pressure spray equipment, and produces no toxic or flammable noxious

fumes.

The adhesive bonding strip is used to form the lap joint between the substrate

foam and the glass coverplate and to bond and seal the overlapped joint between

courses on the roof by bonding to the rear cover of the upper layer. A 3M Scotch­

Mount double-coated tape #4008 is used for this application on the basis of its

resistance to water absorption, and outdoor weathering involving a temperature range

of -40 to 950 C with high humidity. This tape is applied to the outer surface of the

substrate foam and glass coverplate leaving the liner in place on the exposed tape

surface until such time as the overlapping shingle course is laid down.

Flat Conductor Cable Assemblies

Two flat conductor cable (FCC) assemblies, which are manufactured by AMP, Inc.,

are provided in each module. These FCC assemblies consist of a polyester insulated

copper foil strip (equivalent to AWG 12) 16 rom (0.625 inch) wide by 0.13 mm (0.005

inch) thick, which have varying lengths depending on whether the assembly is to be

F-4

used as the positive or negative lead. The outer end of each FCC is terminated

with a patented, crimp-type connector which was developed, and has been UL-approved,

for under carpet ac power distribution systems. The stripped end of each FCC is

soldered to the appropriate cell interconnectors to form the terminations for the

module. Strain relief of these solder joints is provided by bonding to FCC within

the substrate lamination between the rear core and the foam core.

Module-to-Module Interconnects

The electrical connection of the negative terminal of one module to the posi­

tive terminal of another module is accomplished through crimp connections of the

splice terminals to a common FCC carrier.

F-5

RESIDENTIAL REPORTS DISTRIBUTION

D ISTR I BUT ION:

TID-4500-R66, UC-63a (224)

L. A. Barrett (25) Department of Energy Division of Photovoltalc Energy Systems Forresta I BI dg. 1000 Independence Ave. SW Wash I ngton, CC 20585 Attn: M. B. Prince

V. Rice A. Krantz

Department of Energy D I vi s Ion of Act (ve Heat I ng and Coo II ng Office of Solar Applications for Bldgs. Wash I ngton, CC 20585 Attn: Robert D. Jordon, Director

Department of Energy Division of Passive and Hybrid Office of Solar Applications Washington, CC 20585 Attn: Michael D. Maybaum, Director

Jet PropulsIon Laboratory (15) 4800 Oak Grove DrIve Pasadena, CA 91103 Attn: R. V. Pawe II (4)

R. Ferber K. Volkmer W. Ca II aghan R. Ross R. S. Suglmura R. Weaver S. Krauthamer A. Lawson

Jet Propu 1 s I on Laboratory Solar Data Center MS 502-414 4800 Oak Grove Drive Pasadena, CA 91103

R. Tl!bors (2) MIT-Energy Laboratory E40.172 Cambridge, MA 02139

Dist-l

Solar Energy Research Institute (6) 1536 Co I e Bou I eva rd

Go I den, CO 80401 Attn: D. Feucht

S. Sill man T. Basso M. DeAnge 11 s G. Nuss R. DeBI as 10

SER I, LIbrary (2)

1536 Cole Boulevard, Bldg. #4 Go I den, CO 80401

SERI Mall Stop 15-3 1617 Cole Blvd. Go I den, CO 80401

NASA Lewis Research Center 21000 frookpark Laboratory Cleveland, OH 44135

Florida Solar Energy Center 300 State Road 401 Cape Canavera I, FL 32920 Att n: S. O1andra

Effil (3)

P.O. Box 10412 Pa I 0 AI to, CA 94303 Attn: Frank Goodman

Edgar Demeo Roger Tay I or

House Science and Technology Committee Room 374-B Rayburn Bu II ding Wash t ngton, CC 20515 Attn: Don Teague

MIT-Uncoln Laboratory (6)

p.O. Box 73 Lexl ngton, MA 02173 Att n: M. Pope

M. Russe II (2) E. Kern (3)

Off Ice of Technology Assessment

U.S. Congress

Wash I ngton, OC 20510

New Mexico Solar Energy Inst. (25)

New Mexico State University

Box 3S0L Las Cruces, NM 88003

Attn: John Schaeffer

Sandia Nat lana I Laborator I es: 2525 D. L. Caskey 2525 R. p. Clark 3141 L. J. Erl ckson ( 5) 4700 J. H. Scott 4714 R. P. Stromberg 4710 G. E. Brandvold 4720 D. G. Schueler 4721 w. P. Sch Imme I 4723 D. Chu 4723 J. L. Jackson 4723 G. J. Jones (100) 4723 T. S. Key 4723 H. N. Post 4724 L. C. Baavl s 4724 E. C. Boes 4724 A. B. Ma I sh 4723 M. Rlos 4724 C. B. St Illwell 4724 M. W. Eden burn 4726 H. H. Baxter, Jr. 4726 K. L. Blrlnger 4726 E. L. Burgess 4726 C. B. Rogers

3151 W. L. Garner ( 3)

For DOE/TIC (Un limited 8214 M. A. Pound

A. D. LIttle, Inc. Attn: C. E. May tum Acorn Park

Canbr Idge, MA 02140

A.A. Serregamo Architects

Re lease)

Attn: Anthony 5erregamo ,frch I tects

P.O. Box 332

East Sandwich, MA 02537

Aerospace Corporation (2) Att n: S. Leonard

Attn: B. Siegel

P.O. Box 902957 Los Angeles, CA 90009

AlA Research Corporation Attn: Joel H. Vicars, III 1735 New York Avenue, NW Wash I ngton, OC 20006

Alan McGree P.O. Box 2004 Austin, 1)( 78768

Dist-2

Alexander Associates Architects Attn: Fred Alexander

8200 E. Pacific Place 1204 Denver, CO 80231

American Indian Engineering Attn: Kevin J. p. Daly, AlA 1530 W. Indian School Road

Phoen I X. AZ 85015

Anderson Architects Attn: Alan Gass, AlA 1522 BI ake St.

Denver, CO 80202

Anderzhon/Diehl + Associates Attn: James D. Castner, AlA

120 W. Golf Road

Schaumburg, I L 60195

Angelo Vitiello NI Iya Ryan Inc. Attn: Ralph E. Vitiello, AlA 1915 I Street

Sacramento, CA 95814

App.lled Research & TeChnology of Utah, Inc

Attn: Don Sorenson

2555 South 900 West

Salt Lake City, UT 84119

Arch Itect, Inc. Attn: Larry W. Taylor 2570 South Harvard

Tulsa, OK 74114

Arch Itects

Attn: Douglas Juller, AlA

1951 Brookvlew Drive Kent, OH 44240

Architects Forum

Attn: Doug I as S. NI cho I s, AlA 211 E. 11th Street

Su Ite 105

Vancouver, WA 98660

Arch Itects Hawa I I Ltd.

Attn: Dennis Daniel, AlA 60 Church Street

Wa Iluku Meu I, HI 96793

Architects Weeks & Ambrose Attn: William L. Ambrose III, AlA 30 Market Square Ma II

Knoxvll Ie, TN 37902

Architecture, Architectural Plannln~

Interior Design, Graphics & Photography

Attn: John G. Lewis, AlA

P.O. Box 711 - Capitol Station R I chmon d, VA 23206

ARCO Solar, Inc. Attn: W. Hawley

20542 Plummer St.

ChatsllOrth, CA 91311

Arizona State University Attn: Jeffrey Cook, AlA College of Architecture

Tenpe, AZ 85281

Ar I zona Sunworks Attn: Bill otwell

502 H I I I Avenue

Prescott, Az 86301

Arnold J. Aho AlA Architect Attn: ~nold J. Mo, AlA P.O. Box 5291

MI ss I ss I pp I State, MS 39762

Arthur Lewis Davis Architect Attn: ~thur Lewl s Davl s, AlA 30 Journal Square

Jersey City, NJ 07306

Bahm, Raymond J. 2513 Kimberley Ct. NW

AI buquerque, i'f.1 87120

Barkmann Engineers Attn: Herman Barkrenn, PE

107 Clenega Street

Santa Fe, i'f.1 87501

Barth & Ramsbottom Attn: Bill Earth

5006 Whitaker Drive

Knoxvll Ie, TN 37919

Bartos & Rhodes Arch Itects Attn: Robert Rhodes, AlA

10 East 40th Street

New York, NY 10016

Beale's Wharf Attn: Rock Salvando Box 254

SW Harbor, ME 04609

Benham-Blair & Affiliates, Inc.

Attn: Mr. WI" I am J. Judge 1200 Northwest 63rd Street

p.O. Box 20400

Oklahoma City, OK 73156

Berkeley Solar Group

Attn: Charles S. Earnaby 3026 Shattuck Avenue

Berke I ey, CA 94625

Bever Iy Brandon 4600 Roland Avenue

Ba It I more, Me 21210

Black & Veatch Consulting Engineers Att n: Dona I d C. Gray P.O. Box 8405

Kansas City, MO 64114

Bob Schmitt P.O. Box 8196

Strongsvl lie, OH 44136

Boh II n Powe I I Brown Attn: Frank Grauman

182 N. Frankl In St reet

WI I kes-Earre, PA 18701

Brenda E I II s 109 12th Street, NE Wash I ngton, DC 20002

Brooks Waldren Associates Attn: Brooks H. Wa I dman

162 Adams Street

Denver, CO 80206

Bruce, Canpbell, Grahm Associates Attn: Ray Sui II van

16 Bridge Street

westport, CT 06880

Burns & Roe, Inc. (2) Attn: G. A. Fontana

800 Klnderkamack Road

Orade I I, NJ 07649

Burran and Smith AlA Partners Attn: James A. Burran, Jr., AlA P.O. Box 6724

Lubbock, 1X 79413

Burt Hili Kosar Rittlemann Att n: John Oster

400 Morgan Center

Butler, PA 16001

Dist-3

Ca Icara Duffendack Foss Man 101l!l, Inc.

Attn: Michael H. Foss, AlA 4610 J. C. Nichols Parkway

Kansas City, Me 64112

Ca II forn I a Energy Comml ss Ion Attn: Arthur J. Solnskl

1111 Howe Avenue

Sacramento, CA 95825

Carnegie Mellon University Attn: Vo Iker Hartkopf 519 College of Fine Arts

Pittsburgh, PA 15213

Cataldo and Waters Architects, P.C.

Attn: J. Dlar I es Cata I do, A I A 142 Droms Road

Scot I a, NY 12302

Central States Energy Research Corp. Attn: James L. Schoenfelder, AlA Box 2623

Iowa City, IA 52244

CHI Housing Inc. Att n: Doug Ooon I ey

68 South Main Street

Box 566 Hanover, NH 03755

CI rcus Stud i os Attn: W. Ted Mcntgomery Box 500

Waltsflel d, VT 05673

Clayton Yong Associates Attn: CI ayton Yong 2366 Eastlake Avenue

Seatt Ie, WA 98102

Clifford S. Nakata & Associates Attn: Clifford S. Nakata, AlA

525 North Cascade Avenue

Oolorado Springs, CO 80903

ClovIs Helmsath AssocIates Attn: Clovl s Helmsath, FAIA On the Square

Fayettevl I Ie, TX 78940

Commun I co

Attn: Wayne NI cho I as Seton VIllage R.R. 3

Box 810

Santa Fe, ~ 87501

CompetItion AdvIsory ServIce

Attn: Will Lehr

AlA 3rd Floor

1735 New York Ave., NW

Wash I ngton, OC 20006

ComprehensIve DesIgn Associates, Inc. Attn: Steven Bottlger, AlP

P.O. Box 332

State- 001 lege, PA 16801

Cooperson Breck AssocIates Attn: Todd Breck

4000 Thomps BrIdge Road

Mcntchanln, DE 19710

CrollWell, Neyland, Truemper, Levy & Gatchell, Inc. Attn: Ray K. Parker, AlA One SprIng Street

LIttle Rock, AR 72201

Crowther/Arch I tects Grou p Attn: Lawrence AtkInson, AlA 310 Steele Street

Denver, CO 80206

CRS Design AssocIates, Inc. Attn: Larry W. BIckle

2700 S. Post Oak Road, Suite 2300 Houston, TX 77056

CynthIa Howard AlA & AssocIates Attn: Cynth I a Howard

34 Ash Street

Ccrnbrldge, MA 02138

Dale Roth, ArchItect RD 2 Box 165-0

New Tr I po II, PA 18066

DanIel AIello

516 West Parkway BI vd. Tempe, AZ 85281

DanIel, Mann, Johnson & Mendenhall Attn: Walter M9lsen

3250 WIlshIre Blvd. Los Angeles, CA 90010

Davl d Ba I nbr I dge Attn: 2446 Bucklebury

DavIs, CA 95616

David FrancIs Costa Jr. & AssocIates Attn: DavId FrancIs Costa, Jr., AlA

210 Ellsworth Street

Albany, OR 97321

Dist-4

DavId Jay FeInberg ArchItect Attn: Davl d Fe I nberg, AlA Su Ite 302 10700 carIbbean Blvd. Miami, FL 33189

DavId L. SmIth ArchItect Attn: DavId L. SmIth 505 HamIlton Street Schenecta dy, NY 12305

DavId Wong cl. AssocIates Attn: David Itlng, P.E. AmerIcan SecurIty Bank Bldg. 1314 S. KIng St., SuIte 1461 Honolulu, HI 96814

Dayton Power cl. Llgh t Co. ~ttn: Bruce CurtIs P.O. Box 1247 Dayton, OH 45401

Denny Long Route 1 Box 158 Woodland, CA 95695

DesIgn DIrection Attn: DennIs John Becker, AlA 1588 Tangl ebr I ar FayettevI I Ie, AR 72701

DIck JenkIns, Vice PresIdent Product Development 10221 Wlncopln Circle ColumbIa, MD 21044

DIck Lamar ArchItect Attn: DIck Lamar, AlA 201 Woodrow Street Co I umb I a, SC 29205

Donald F. Monell ArchItect Attn: Donald F. t>bnell, AlA 11 Pleasant Street Gloucester, MA 01930

Donald M. Watts Architect Attn: Donald M. Watts 1649 HuntIngton Drive South Pasadena, CA 91030

Donald Watson ArchItect Attn: Donald Watson, AlA P.O. Box 401 Gu I I ford, CT 06437

Down I ng Leach cl. AssocI ates Attn: J 1m Leach 3985 Wonderland HI I I Avenue Boul de r, CO 80302

Dr. Stephen K. Young SAl 1710 GoodrIdge DrIve McLean, VA 22102

DubIn Bloome AssocIates

(10)

Attn: H. Fbbert Sparkes, p. E. 312 Park Road West Hartford, CT 06107

Dyer and Watson Architects Attn: James Watson 24100 ChagrIn BI vd. Cleveland, OH 44122

EA I Inc. Attn: Dr. Jerry Alcone 13300 Hugh Graham Rd. NE AI buquerque, N>4 87111

Earth Dynaml cs Attn: Peter Slack P.O. Box 1175 Boul der, CO 80002

Earthworks Attn: Steven E. GolubskI 20 West 9th Street Kansas CIty, MO 64105

Edwards cl. DanIels Associates Attn: A. Brett Bullock 525 E. 300 S Salt Lake CIty, UT 84102

Ekosea Attn: Lee Porter Butler 573 Mission Street San Francisco, CA 94105

Ellerbe AssocIates, Inc. Attn: JIm Gelfer Manager of ProfessIonal ServIces ElectrIcal DesIgn Department One Appletree Square BloomIngton, MN 55420

Ellmore/Tltus/Archltects/lnc. Attn: S. A. Titus, AlA 736 Chestnut Street Santa Cruz, CA 95060

Dist-5

Energy Arch Itects Inc. Att n: Sk I Mil burn 885 Arapahoe Boul der, CO 80302

Energy Conversion Devices Attn: Mr. LIonel Ibbbins 1675 West Map I e Road Troy, MI 48084

Energy Design & AnalySiS Co. Attn: David Schwartz, AlA 1001 Connecticut Ave., NW Su Ite 632 Wash I ngton, OC 20036

Energy Des I gn Assoc I ates Attn: Steve Naarhoof 114 E. Diamond Street But I er, PA 16001

Energy Planning & Investment Corp. Attn: RI chard Larry I>tld 11 n A I A 833 NOrth Fourth Avenue Tucson, AZ 85705

Energy Services Organization of The Georgi a Power Co. Attn: Edward Nay 7 Solar Circle Shenandoh, GA 30265

Engineers-Architects P.C. Attn: Arnold Hanson, AlA 1407 24th Avenue South Grand Forks, ND 58201

Engineers-Architects P.C. Attn: Gord Rosey 408 First Avenue Building MI not, ND 58701

Environmental Concern Attn: Bruce Mluser, A I A Box 2128 Spokane, WA 92210

Environmental Design Alternatives Attn: Doug I as G. Full er 1951 Brookvlew Drive Kent, OH 44240

Environmental Institute of Michigan Att n: Reed Mles P.O. Box 618 Ann Arbor, MI 48107

Environmental Research Laboratory Attn: Helen Kessler Tucson International Airport Tucson, AZ 85706

Envlronomlc Design Attn: Dennis N. Young, AlA W. 905 Riverside Spokan e, WA 99201

ERG, Inc. Attn: Chuck Sherman 1650 W. Alaneda Drive Suite 140

Terrp e, AZ 85282

Erwin and Akers Associates Attn: O1ar I es Dell s I 0

Benedum-Trees BI dg. Pittsburgh, PA 15222

Everett Zelgel Tumpes and Hand Attn: R. J. Mlrtl n, AlA 1215 Spruce Street Boulder, CO 80302

Ezra D. Ehrenkrantz & Associates Attn: William Meyer 19 West 44th Street ~ew York, NY 10036

Fando Martin and Mi Istead Attn: Hank Walker 608 Tennessee Avenue O1ar I eston, 'IN 25302

Fischer Stein Associates Attn: Hans J. Fischer, AlA Route 51 South Carbondale, IL 62901

Fisk Rinehart Keltch Meyer Inc. Attn: Harley B. Fisk, AlA 100 Kentucky Exec. Building 2055 Dixie Highway Ft. Mi tche II, KY 41011

Frank H. Witchey Corbett Associates Box 1009 86 East Broadway Jackson, 'rtf 83001

Fred Meyer, AlA 3611 5th Avenue San Diego, CA 92103

Dist-6

Fred W. Forbes" Assocl8tes, Inc.

Architects AlA and Engineers NSPE

P.O. Box 443

Xen I a, OH 45385

Galliher Schoenhardt "Baler Attn: fbbert P. tobrcarsky

The Courtyard No. 10

Simsbury, CT 06070

Gary Cope I and 31-81 Popiel Avenue

Memphis, TN 38111

Gary Marc I n I ak

6582 N. 90th Milwaukee, WI 53224

Geiger Berger" Associates Attn: Karl Beltlln, PE

500 Fifth Avenue

New York, NY 10036

General Electric Co. Attn: E. M. Mahall ck

Advanced Energy Programs

P.O. Box 8661 Phi ladelphla, PA 19101

Gensler Architects, Inc. Attn: James L. Gensler, AlA

819 N. Marsha II Street

Milwaukee, WI 53202

George A. Roman" Associ ates, Inc. Attn: George A. Roman, AlA

One Gateway Center Newton, MA 02158

Georgia Institute of Technology Attn: RI chard Will lams

Co liege of Engl neerl ng

Atl anta, GA 30332

Georgia Institute of Technology Engineering Exp. Station Attn: Joan Wood

225 North Avenue, NW At I anta, GA 30332

Georgi a Power Company

Attn: Gary Birdwell P.O. Box 4545

Atlanta, GA 30303

Gerken" Upham Architects, Inc. Attn: Mr. Car I Gerken

P.O. Box 155 Ormond Beach, FL 32074

GK Associ ates Attn: Drew GI I I ette

319 Holbrook Road

Bedford, NH 03102

Glass Energy Electronics

Attn: Ron Wilson

4463 Wood I and

Park Avenue North Seattle, WA 98103

Grahm Hu bentha I

Box 777 Soap Lake, WA 98851

Greenles/Reese Associates, Ltd. Attn: Frank L. Reese, A I A

6400 Flying Cloud Drive

Suite 210

Eden Pra I re, MIl 55344

Gr I mba I I /Gorrondona/Sa voye Attn: Michael D. Cortner 2352 Matarle Road

Matar I e, LA 70001

Gunnar, Blrkerts " Associates Attn: Char I es E I eckenste In

292 Harmon Street

BI rml ngham, MI 48009

H. L. Youngkln AlA Architect Attn: Harry Younkin, AlA

1202 E. Maryland Avenue

Phoen I X, AZ 85014

Hahn Jackson Lloyd Thresher Arch. " Eng. Attn: Timothy A. Henning, AlA Top Hat Road

Princeton, IN 47670

Hank I ns "Anderson, Inc. Attn: H. C. Yu

1680 Santa Rosa RI chmond, VA 23288

Harthorne Hagen Gross AlA" Assoc. Attn: Cliff Gross, AlA

220 Marina Mart 1500 Westlake N.

Seattle, WA 98109

Dist-7

Harvard University

Attn: John '-'ertln

204 PI erce Ha II Cambridge, MA 02138

Heery Energy Consultants Inc. Attn: '-'ervin Wiley, P.E.

880 W. Peachtree Street, NW

Atlanta, GA 30309

Heery & Heery, Arch Itects & Engl neers, Inc,

Attn: Mr. RI chard Ye I vi ngton 880 West Peachtree Street, NW Atlanta, GA 30309

Helen McEntire 4160 S. 1785 W.

Heritage Bank Building Su Ite 200

Salt Lake City, UT 84119

Herbert Sands 2013 S. Melborne Ct.

Me I bourne, FL 23901

Hood Mi II er Associ ates

Attn: Bobble Sue Hood, AlA 2051 Leavenworth St.

San Franc I sco, CA 94133

Interactive Resources, Inc. Attn: Carl Bouvl I Ie

11 7 Pa rk P I ace

Point Richmond, CA 94801

Iowa State University (2) Attn: David BloCk, AlA

Attn: Laurent Hodges

Physics Department

290 Co II ege of Des Ign

Ames, IA 50011

J. L. Harter Associates

Attn: James L. Harter, Sr., AlA 41 S. Tenth Street

Allentown, PA 18102

Jackson Labs Attn: Tom Hyde Otter Creek Road

Bar Harbor, ME 04609

James Sudler Associates Attn: Joa I Cronewett, A I A

200 Cable Bu Iidl ng

Denver, CO 80202

James Sudler, FAIA 120 I 18th Street

Suite 200

Denver, CO 80202

James T. Barretta Architect Attn: James T. Barretta, AlA 1832 NW 2nd Avenue

Boca Raton, FL 33432

Jammel Finn & Associates Attn: Arnold Finn

1516 E. Hillcrest Street P. O. Box 8'963

Or lando, FL 32856

Jim Denn I son Water Streat

E I I seworth, ME 04605

Joe Melendez

444 Executive Canter Blvd. Sulta 130

E I Paso, 1)( 79902

John D. Swat I sh

No. 7 WI I dwood Tra I I Bettendorf, IA 52722

John Martin Associates Architects Attn: John T. '-'ertl n, AlA 506 Heights Blvd.

Houston, TX 77007

John R. Taylor Architect Attn: John R. Taylor, AlA 815 Shady Bluff Drive

Olarlotte, I.e 28211

John Yellott Engineering Association Attn: John Yellott

901 West EI Camlnlto

Phoen I X. AZ 85021

Dist-8

JohnstCOlln ArchItects, Inc. Attn: BenjamIn J. Pollclcchl 0, AlA GKI BuIldIng 777 Goucher street JohnstCOlln, PA 15905

Jones & Mayer Attn: Olarles Mayer 13100 Manchester Road St. LouIs, MO 63131

Jones & Strange-Boston Ross BuIldIng Attn: Donald L. strange-Boston, AlA, PE Ma I n Street at 8th RIchmond, VA 23219

Joseph J. Del Clotto, Jr., ArchItect Attn: Joseph Del Clotto, AlA 201 Church Road Lansda I e, PA 19446

JSR AssocI ates Attn: Dr. John S. Reuyl 2280 Hanover Street Palo Alto, CA 94306

Kammeraad Stroop van der Leek Attn: Pau I van der Leek 355 Settlers Road He I I an d, MI 49423

KeIth Vaughan Associates Attn: Keith Vaughan 3136 E. Madison Street 59attl e, WA 98112

Kelbaugh and Lee Architects Attn: Douglas Kelbaugh, AlA 240 Nassau Princeton, NJ 08540

Kitchen & Associates Att n: Deborah K. Gawthrop Off Ice Ma nager Box 935 PhIladelphia, PA 19105

Knoell/Quldort ArchItects Attn: Hugh Knoell, Jr. AlA 1131 East HI gh I and Phoen I X, AZ 85014

Korsunsky Krank ErIckson Architects Attn: Daryl P. FortIer, AlA DIrector of DesIgn 570 Galaxy BuIldIng 330 Second Avenue South MI nnesota, MN 55401

Kruger Kruger AI ben berg Attn: Kenneth Kruger 2 Central Square CambrIdge, MA 02139

Lancaster and Lancaster ArchItects Attn: Earl M. Lancaster AlA P.O. Box 10 Auburn, AL 36830

Lane & AssocIates ArchItects Attn: John E. Lane, AlA 1318 North B Street P.O. Box 3929 Fort Smith, AR 72913

Laplckl/Smlth AssocIates Attn: Carol A. MJore 617 Park Avenue Baltimore, MD 21201

Lee R. Connell Architect, Inc. Attn: Lee R. Connell, Jr., AlA 2500 Joseph Street New Orleans, LA 70115

Leo A. Daly Attn: Arturo Bantog 1025 Connecticut Ave., NW Suite 712 Wash I ngton, DC 20036

Leon De Iler 911 22nd street Santa MonIca, CA 90403

Leonard Wrlnberg, AlA 160 H I I I a I r CI rc I e WhIte Plains, NY 10605

LI vI ng Systems Attn: Johathan Hammond Route 1 Box 170 Winters, CA 95616

Dist-9

Londe Parker Michels Consultants

Attn: Timothy I. Michels

7438 Forsyth

Su Ite 202 St. Louis, Kl 63105

Long Hoeft Architects Attn: Mr. Gary Long, AlA 1228 Fifteenth Street, Suite 401

Denver, CO 80202

Louisiana Institute of Building Sciences

Attn: RI chard C. Thevenot

830 North Street

Eeton Rouge, LA 70802

Lydia Straus-Edwards Arch. Designer Mtn: Lydl a straus-Edwards

331 Main Street South

I'bodbury, CT 06798

M. David Egan, PE P.O. Box 365 An derson, SC 29621

Manua I Perez 1056 Hunting Lodge Drive Miami Springs, FL 33166

Marce I E. Sammut Arch. & Struct. Eng. Attn: M9rcel E. Sammut, AlA

30 Anthony Circle

Newtonvll Ie, MA 02160

Mark Beck Associ ates Attn: Peter Powell, AlA 762 Fairmount Avenue

TCII'Ison, Kl 21204

Marlin H. Andersen Homes Attn: M9rlln Grant, President

6901 Lyndale Avenue South

BI ooml ngton, MN 55420

Ma rt I n Ma r I etta Corp. Mtn: M. S. Imanura P.O. Box 179

Denve r, CO 80201

Mass Design Mtn: Gordon Tully

136 Mr. Auburn St.

Cambr I dge, MA 02138

Massachusetts Institute of Technology Attn: Tim Johnson

Department of Architecture

Cambr I dge, MA 02139

Matrl x Inc.

Attn: Edward Mazrla 400 San Fe I I pe I'M Su Ite 6

P.O. Box 4683

AI buquerque, ~ 87106

Mayh II I Homes Corp. Attn: John OdegJard

P.O. Box 1778

Ga I nesvll Ie, GA 30501

McCleer Architect Mtn: MI ke McCleer

2249 FI rst Nat I ona I BI dg.

Detroit, MI 48226

K:M Mtn: Michael C. Mlrchant P.O. Box 7707

stanford, CA 94305

Merrl am, Deasy & Wh Isenant, Inc. Attn: Bruce D. Fraser, AlA 979 Osos Street Su Ite C

San Luis Obispo, CA 93401

Metcalf and Associates Attn: Susan Shaw

3222 N Street I'M

Washington, OC 20007

Miami University of Ohio Mt n: Ful I er '-bore

Department of Arch.

Oxford, OH 45056

Michael Albanes 2368 O1erry street

Denver, CO 80207

Michael Lesburg Architect Mtn: MI chae I Lesburg, AlA 1430 Massachusetts Avenue

Cambridge, MA 02136

Miller Hanser Westerbeck Be II Arch Itects, Inc. Mtn: Jay Johnson

Suite 300 Butler Square 100 N 6th street

Minneapolis, MN 55403

Dist-lO

Miller Wagner Coenen, Inc.

Attn: R:lbert M. Miller, AlA

250 N. Green Bay Road

P.O. Box 396 Neenah, WI 54956

Mogavero & Unruh Attn: David J. Mogavero

811 J Street

Sacrarrento, CA 95814

Moore, Grover & Harper Attn: R:lbert L. Harper, AlA

Ma I ne Street

Center brook, CT 06049

More, Combs, Burch Arch. & Eng. Attn: Donald H. More, AlA 3911 E. Exposition Avenue

Denver, CO 80209

Morton, Wolfberg, Alvarez, Taracldl & Associates 9400 S. Dadeland Blvd.

Miami, FL 33156

Motorola, Inc. Al10 Attn: Bob Hammond

P.O. Box 2953

Phoen I x, AZ 85062

Mr. J. Marshall Mauney, AlA Division of Plant Operation

306 Education Building

Raleigh, NC 27611

Mr. William Dorsett 930 Thurston Manhattan, KS 66502

Mue II er Assoc I ates

Attn: Bob Hedden

1900 Sulphur Spring Road

Baltimore, MD 21227

N.C. Solar Energy Assoc. Attn: Bruce Johnson, AlA

P.O. Box 12235

Research Triangle Park, NC 27709

National Homes Corp.

Att n: Steven J. WI I son

Director of Research & Technology P.O. Box 7680

Lafayette, IN 47903

Neils O. Brown Development Corrpany

Attn: Neils O. Brown, President 368 Sun .. ay Lane

RR II Creve Coeur, Me 63141

Nixon Brown Broka.. Bowen Attn: Paul G. Flehmer AlA

1800 Commerce Street

Boul der, CO 80301

Northeast Design Distribution Attn: Davl d Campbe I I

727 - 11th Ave.

New York, NY 10019

Northeast Solar Energy Center Attn: Drew A. Gillett

470 Altantlc Avenue

Boston, MA 02110

Oceanside Solar ConSUltants Attn: Ra Iph L. Sheroood 10 East Ma I n Street

Hyannis, MA 02601

Of f I ce of Franz Peter Scheuermann Attn: Franz P. Scheuermann, AlA

Park Street p.O. Box 1008

Stowe, 1fT 05672

Office of Glen H. Mortensen, Inc. Attn: Glen H. Mbrtensen, AlA

Suite 201

1036 W. R:lblnhood Dr. Stockton, CA 95207

Omer Mlthun, FAIA 2000 112th Avenue, NW

Be levu r, WA 98004

Optical Sciences Group, Inc.

Attn: 01 eter W. Grab Is 24 TI buron Street

San Rafael, CA 94901

Pacific Power & Light Corrpany Attn: BII I McTavl sh

Box 720 Casper, 'tt( 82602

Parker Croston Associates Attn: M. E. Croston, Jr., AlA P.O. Box 1927

3108 W. 6th Street Fort Worth, 1)( 76101

Dist-ll

Perez & Hurtado Architects, Inc. Attn: Jess F. Perez 850 E. Chapman Avenue &J Ite A Orange, CA 92666

Perkins & Will Attn: BII I Ebbenhausen 445 Hamilton Avenue White Plains, NY 10601

Peter D. Paul, AlA P.O. Box 271 50 Galesl Drive Wayne, NJ 07470

Peter Dobrovolny, AlA Box 133 Old Snowmass, CO 81654

Peter Van Deesser 634 Garc I a Street Santa Fe, I-M 87501

Peterson Construction Company Attn: Robert Peterson, President 6100 S. 14th Street L1ncol n, NE 68512

Pettit & Bul I Inger Architects Attn: Hell C. Pettit, AlA P.O. Box 2726 1202 East FI rst Wichita, t<S 67201

Ph I I I P West, Dona I d Bergstrom & Assoc. Attn: Edward J. tlercyn, AlA 33 East First Street Hinsdale, IL 60521

Phineas Alpers Architects, Inc. Attn: Phineas Alpers, AlA 344 Newbury Street Boston, MA 02115

Potomac Energy Group Attn: David Johnston 401 Wythe Street Alexandria, VA 22314

Price and Partners 7301 Birch Avenue Takoma Park, MD 20012

Price Roth & Muse Architects Attn: WI I I I am Prl ce p.O. Box 1014 Tr I -CI ty AI rpor t Blountvll Ie, TN 37617

Princeton Energy Group Attn: Harrison Fraker, AlA 729 A'I exander Road Princeton, NJ 08540

RA Solar Consultants, Inc. Attn: Harry E. Burns, Jr., AlA Park 20 West Blountstown Highway Tallahassee, FL 32304

Ralph E. Kiene & Associates Attn: Ralph E. Kiene, AlA 1006 Grand "Avenue Kansas City, Me 64106

Ralph Jefferson, AlA Architect 497 Springfield Avenue Summit, NJ 07901

Ramon Zambrano & Associates Attn: Dan He I I and 1015 Battery Street San Franc I sco, CA 94111

Rasmussen Hobbs Architects/Planners Attn: D. L. Hobbs, AlA 19 Sa I nt He I ens The Henry Drum House Tacoma, WA 98402

Raymond E. Phillips, Architect Attn: Raymond E. Phi /lIps, AlA 703 SW McKinley Des Mblnes, IA 50315

Raymond J. Bahm 2513 Kimberley Ct. NW Albuquerque, I-M 87120

Reyn Hendr I ckson 4480 Grand River Street Novl, MI 48050

Richard Schwarz/Nell Weber Attn: Nel I Weber, AlA 3601 Park Center Boulevard MI nneapo I Is, MIl 55416

Dist-12

Riddick Engineering COrporation,

Cons u I tants Attn: James R. Bailey, P.E.

2310 First National Building

Little Rock, AR 72201

Robb Axton, A I A 4741 Laurel Canyon Blvd.

North He I Iywood, CA 91607

Robert Dlncecco Architect Attn: fbbert 01 ncecco

326 W. Lawrence Lane

Phoen I x, AZ 85021

Robert G. Werden & Associ ates, Inc.

Attn: Willi am F. Mil burn

P.O. Box 414 Jenkl ntown, PA 20736

Robert J. Johnson, Architects 1220 Santa Barbara St.

P.O. Box 2673

Santa Barbara, CA 93101

Roche Dlnkeloo Associates Attn: Ms. Curtain

20 Davl s Street

Hamden, CT 06517

Rogers-Nage I & Langhart, Inc. Attn: Mr. fbger Crosby 1576 Sherman Street

Denver, CO 80203

Ron Plotras Northeast Carry Bu II ding

110 Water Street H8llowell, ME 04347

Ron Yeo, FAIA Architect, Inc. Attn: Ron Yeo, FAIA

500 Jasmine Avenue

Corona Del Mar, CA 92625

Ronald R. Call1lbell & Associates Attn: Jan Kafran I c 2150 North 107th Street

Seatt Ie, WA 98133

Rotz Engineers, Inc. Att n: Thomas 011 p I I s

2828 North High School Road

P.O. Box 24357

Indianapolis, IN 46224

Rowe He I mes Assoc. Arch. Inc.

Att n: Dave Fronccok

215 S. Adams Street

Ta II ahassee, FL 32301

RRI Attn: Kurt Johnson

157 Church Street

New Haven, CT 06670

Sad I ron Deck Attn: Bruce Browne II

A I ternat I ve Energy

c/o Browne II L lI11ber Route 4

Eden burgh, NJ 12134

Sam Cravotta One Design

Mounta I n Fa I I RTE

WI nchester, VA 22601

Sargent, Webster, Crenshaw, Folley Attn: Dona I d Skowron

2112 Erie Blvd. East

Syracuse, NY 13224

Schaffer Bonavo lonta Arch., Inc. Attn: t-tlrt I n Schaffer

24 West Erie Street

01 I cago, I L 60610

Schlpporelt Inc. Attn: Davl d Ursche I

One American Plaza Evanston, IL 60201

SEAGroup

Attn: Davl d Wr I ght A I A 418 Broad

Nevada City, CA 95959

Sierra Engineering Attn: Tom Carver 1129 Tudor Street

Lod I, CA 95240

Skoler & Lee Architects, p.C. Attn: Kermit J. Lee, Jr., AlA 1004 University Building

Syracus e, NY 13202

SMALC/XRE Attn: Jim Pestilio

McClellan AFB

Sacramento, CA 95652

Dist-13

Smith, Hinchman, and Gryl Is

Attn: Randal E. Swelch

455 West Fort Street

Detroit, MI 48226

Sol Tee Attn: Jim Crouch 2160 Clay Street

Den ver, CO 80211

Solar Building Corp. Att n: Joh n NewlTEln

1004 Allen

St. Louis, MO 63104

Solar Design Associates Attn: Steven J. Strong

Conant Road

L1ncol n, MA 01773

Solar Environmental Engineering Attn: Dave Gunther 2524 East VI ne Dr I va

Fort C'o I II ns, CO 80524

So I ar Processes Inc. Attn: Gordon Preiss 11 Ve I vet Lane

Myst I c, CT 06355

Solar Technology Systems Attn: Char les Orr

81A Upper St. Giles St.

Norwl ch, ENGLAND NR21AB

SolArc Attn: Anthon Iy CUtr I

2040 Addison Street

Berkeley, CA 92704

Solarex Corporation Attn: M:lrth Bozrren

1335 Plccard Drive

Rockville, /0{) 20850

South Street Design Attn: Don Prowler

2233 Grays Ferry Avenue Philadelphia, PA 19146

Southern Solar Energy Center Attn: S.C. Nelson 61 Perimeter Park

Atlanta, GA 30341

Steelcraft Corporation Attn: Gary Ford Box 12408

Menph I s, TN 38112

Sunpcwer Industries of Kent Attn: AI Abrarrson

10837 86th SE 200th Kent, WA 98031

Sunrise Bu IIders Attn: Rich Schwolsky P.O. Box 125

Grafton, VT 05146

Sverdrup and Parcel Eng & Arch Attn: Frank Kessler

1650 W. Alameda Drive Tenpe, AZ 85282

Tackett Way Lodholz Att n: George Way

3121 Buffalo Speedway Suite 400 Houston, TX 77098

Ta I bot & Associ etes

Attn: Thorres L. Alnscough, AlA P.O. Box 2224

VI rgl n I a Beach, VA 23452

Texas Tech University

Att n: Professor Car I Ch II der s Division of Architecture Box 4140

Lubbock, TX 79409

The Architects Collaborative Attn: Ms. Gall Flynn 46 Brattle Street

Cambridge, MA 02138

The Architects Taos

Attn: WI I II am MI ngenbach Box 1884

Taos, ~ 87571

The Architectural Alliance Attn: Peter Pfister, AlA 400 Clifton Avenue

MI nneapo II s, ~ 55403

The Burns/Peters Group

Attn: William L. Burns, AlA 8000 Pennsylvania Circle NE

Albuquerque, ~ 87110

Dist-14

The Burr Associates, Architecture & Planning

Attn: Donald F. Burr, FAIA P.O. Box 99885, Lakewood Center Tacoma, WA 98499

The Clark Enerson Partnership Attn: O1arles L. Thomsen 600 fIIlC Center LI nco I n, NE 68508

The Hawkeed Group Ltd. _Attn: Rodney Wright, AlA 4643 N. Clark Street 011 cago, I L 60640

The Orcutt/Wlnslcw Partnership Attn: Paul Winslow AlA 1109 North Second Street Phoen I X, AZ 85004

The Roy a I Arch. Institute of Canada (R lAC) Attn: Robbins Elliott 151 Slater ottawa Canada KIP 5H3

The Wolf Partnership Architects Attn: William G. Sch lmeneck, AlA Attn: Paul J. Schmitz, AlA 7 South 7th street Allentcwn, PA 18101

Thomas Russell 80 Slleld street West Hartford, CT 06110

ThomaS Vonler Associates Attn: Peter H. Smeal lie Suite 413 2000 P street, NW Was hi ngton, OC 20036

Thomas W. Merrill Architects Attn: Thomas W. llarrlll 321 SW Sixth AI bany, OR 97321

Total Design Four Attn: Carter Howard P.O. Drawer 3947 Corpus O1rlstl, TX 78404

Total Environmental Action Attn: Peter Tempi e Church Hili Harrlsvll Ie, NH 03450

Trellis & Watkins 6565 Pennacook Court Columbia, Ml 21045

Trynor Hermanson & Hahn Arch Itects Attn: Gilbert F. Hahn, AlA 311 Medical Arts Building Box 156 St. CI cud, ~ 56301

University of Arizona Attn: llarle Jensen Environmental Research Laboratory Tucson, AZ 85706

University of Arkansas Attn: James Lambeth, AlA 1591 Clark Fayettevl I Ie, AR 72701

UnIversity of North CarolIna Att n: Dean O1ar I es HIght Col lege of ArchItecture UNCC stat I on Charlotte, NC 28223

UnIversIty of Puerto Rico Attn: Angel Lopez Ctr for Energy and EnvIronmental Research Col lege StatIon Mayaquez, P.R. 00708

University of Southern CalIfornia Attn: Ralph Knowles School of Architecture and Fine Arts Los Angeles, CA 90007

USDA Forest ServIce EngIneerIng Attn: Robert LeCa In P.O. Box 7669 MI ssou I a, MT 59807

Van Fossen & Brase Arch. & Eng. Attn: Robert L. Brase, A I A Suite 209 5515 E. 51st street Tulsa, OK 74135

VanDerRyn Calthorpe & Partners Attn: Peter Ca I thorpe Drawer 7 Inverness, CA 94937

Walter S. WIthers Architect Attn: Walter S. ~Ithers, AlA 1250 Chambers Road Co I umbus, OH 43212

Dist-lS

Warehouse Specialist, Inc. Attn: M:lrk van Deyac I at

655 Brighton Beach Road fotlnash a, WI 54952

Warner Burns Toan Lunde Att n: Fr I tz Lunde 330 W. 42nd Street

New York, NY 10036

WED Enterpr I ses

Attn: MI ke McCullough 1401 Flowers Street

Glendale, CA 91201

Wendell H. Lovett Architect Attn: \\endell H. Lovett, FAIA

2134 Third Avenue

Seatt I e, WA 9812 1

WI I Ilam Drevo Architect Attn: WI I I lam Drevo, AlA

6125 29th Street, NW

Wash I ngton, DC 20015

WI I I lam J. Betes Architect Attn: Willi am J. Bates, AlA 57 Mar II n Drl ve West Pittsburgh, PA 15216

WIIIIIInl Morgan Architect Attn: Thomes A. McCrary, AlA

220 East Forsyth Street

Jacksonvlll e, FL 32202

Willi am Tao & Associ ates Attn: Richard Janus

2357 59th Street

St. Lou I s, MJ 63110

William Thomes Meyer, AlA Attn: William T. Meyer 353 East 72nd Street

New York, NY 10021

Wright, Pierce, Eng. & Arch. Attn: Douglas Wilkie

38 Roosevelt Avenue

Glen Head, NY 11545

Wrlght-Pletce Associates & Eng. Attn: Barbara Freeman

99 Ma I n Street

Topsham. ME 04086

ZOEworks

Attn: Garth (bIller, AlA 70 Zoe Street

San Francisco, CA 94107

Zomeworks Inc. Attn: Steve Baer P.O. Box 712

Albuquerque, I-J.1 87103

Dist-16 - -->

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