DOE Building America Case Study:Advanced Boiler Load Controllers

May 5, 2015

Overview

• GREFFEN (Green Efficient Energy) Systems – Founded March 2008

• Work with many of the Fortune 100 corporations across the United States

• Greffen Systems has installed M2Gs at 19 Ford facilities in North America

• Greffen Systems has installed M2Gs at 18 GM facilities in North America

• The M2G is now a prescriptive product for both Detroit Edison and Consumers Energy in Michigan.

– Under this program every M2G purchased qualifies for an energy rebate

Problem The M2G Addresses:What is dry cycling?

Boiler firing due to standing losses rather than

building demand• Boilers are oversized

by design

• Designed for the

coldest day of year

• Maintain set point

regardless of building

demand

Heat losses cause

unnecessary cycling,

“dry-cycling”

70+ Customer Case Studies

Independent Studies

• Department of Energy Building Technologies Program - The DOE recorded energy savings “up to 14%”in the study and re-named the “emerging class” of energy conservation technology (ALM) “Advanced Load Monitoring”.

• The Gas Technology Institute (GTI) in Des Plaines, Illinois tested the M2G over a two year period using thermal load profiles from the Department of Energy. GTI recorded results of between 10% and 17% with cycle reductions of up to 55%.

Paul Glanville

• Senior Engineer at the Gas Technology Institute (GTI) in their

Building Energy Efficiency group (7 years)

• B.S.M.E. from the University of California at Davis

• M.S.M.E. from the University of Washington in Seattle

• Registered Professional Engineer in Illinois

• Active in both ASME and ASHRAE, serving on several technical

and organizational committees

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Gas Technology Institute

> The Gas Technology Institute is an American non-profit research and

development organization which develops, demonstrates, and

licenses new energy technologies for private and public clients, with

a particular focus on the natural gas industry

> GTI’s 280,000-square-foot headquarters near Chicago, IL is home to

20+ specialized labs with equipment for design, testing and analysis

of advanced energy technologies.

> Subsidiaries working also working in

energy efficiency include: CDH Energy,

Fisher-Nickel Food Service Technology

Center, and Davis Energy Group

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Natural Gas Industry CollaborationEmerging Technology Program

> Gas Technology Institute led, utility supported, North American

collaborative targeting residential, commercial, and industrial solutions

> ETP’s principle goal is to accelerate the market acceptance of emerging

gas technologies

1010

Emerging Technology Scanning and ScreeningETP publishes technology snapshots introducing members and their

partners to the most important new technologies. Snapshots highlight

technology attributes, market and cost barriers, market readiness, and

key next steps. GTI’s ETP library contains more than 60 technology

snapshots. ETP generates roughly 20 new snapshots each year.

Learn, Coordinate, and ActETP hosts two member meetings annually and operates 9 working

groups. These forums present opportunities for members to learn from

each other and GTI Principal Investigators. These forums present

opportunities to coordinate critical program and project activities.

Demonstrate and Pilot New TechnologiesETP members, along with state and federal programs, fund the

deployment of new technologies for the purpose of validating

performance, characterizing market potential and implementation

strategies, and creating datasets to support new prescriptive efficiency

measures and marketing programs. In 2014, ETP has more than 15

active ET projects across residential, commercial, and industrial

markets. ETP publishes summary project reports for all active

projects, reports are available to all members regardless of funder. Example Technology Snapshot, more

than 60 available on ETP website

GTI’s Emerging Technology Program is the source for

identifying, reviewing, and deploying emerging technologies

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What is an ALM Controller?

> Different than OTR - Which adjusts

the setpoint as a function of outdoor air

temperature, often used with “warm

weather shutdown” and/or lead/lag

controls to lessen boiler wear.

> Usually compatible in series with

these controllers, but savings may

be reduced

> Demand Controllers limit losses from “dry cycling” - Standby losses

differentiated from building heat demand.

> These controllers monitor Supply

or Return/Supply temperatures to

differentiate. Designed only for hot

water boilers only in space heating

applications.

“Advanced Load Monitoring” Controllers:

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What is an ALM Controller?

Yields therm savings through reduced cycling

by dynamic management of the boiler

differential. Fewer, longer cycles mean:

> Longer runtime at high SSE

> Fewer pre/post purge cycles

> Fewer thermal cycles of boiler HXs

> Between 10-30% annual therm savings

claimed by vendors.

> Controller performance is highly site specific

> Limited 3rd party data published on

performance.

> 2007 study showed 12-13% savings for a

competing product

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What is an ALM Controller?

> Only suppress a boiler from firing – Don’t

turn on boilers or stop a firing boiler

> Control strategies fall into three groups -

Release a boiler to fire when:

> Demand is sensed from water temperatures

(e.g. Treturn drops 5°F after call for heat)

> Time period elapses (e.g. 10 minutes)

> Actual call for heat is detected based on

proprietary algorithms using (a) memory of

past cycling or (b) rate of change of sensed

water temperatures

> Energy savings potential greatest for: Oversized

boiler(s), boilers without OTR, large

commercial/industrial boilers, single/dual stage

> Typical boilers 50-100% oversized for

average, 15-30% for winter design conditions

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Laboratory Testing

> Compare performance of two controllers with boiler loads,

sized to low/high heating demands

> Generate heating load patterns using EnergyPlus for lab

simulation for two building types in the Chicago area, Large

Hotel and Secondary School, using automated test stand

> Simulate heating loads and determine measured/annualized

therm and cycling reductions using Chicago HDD

0

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0 60 120 180 240 300 360 420 480 540 600 660 720 780 840 900 960 1020 1080 1140 1200 1260 1320 1380 1440

Hea

t D

eman

d a

t B

oile

r (M

BH

)

Time (minutes)

175F Setpoint with 5F Differential

Test Boiler Output with Controller

Scaled Heating Load Input

Example:

School

Shoulder

Season

Pattern

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Laboratory Testing

> Performed steady state and 24-hour simulated heating

tests, with high and low heating demands.

> Compared M2G and competitor with 5°F differential to

baseline operation, with 5°F and 15°F differential settings.

As it was able to, competing ALM operated with 15°F

differential also.

> Quantified reduction in boiler cycles, gas consumed, and

primary loop temperatures.

ACAP

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Laboratory Testing

Extrapolation to Annualized Savings

> Average winter and shoulder season days assumed to represent days with greater than/less

than 20°F·day respectively, boiler is inactive for days with 5°F·day or less.

> School was assumed to be unoccupied outside of 9am-6pm on weekdays, on weekends, and

holidays. When unoccupied, boiler cycles on for 1 min. during 20 min. windows

> Fuel consumption/cycling determined by season (winter/shoulder/shut down) and occupancy.

Therm Savings Reduced Cycles

Compared to Baseline with 5°F Differential

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M2G Comp. Baseline Comp.

5°F/3°C Differential 15°F/8°C Differential

Pe

rce

nt

Re

du

ctio

n v

s 5°F

Ba

seli

ne Hotel Secondary School

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M2G Comp. Baseline Comp.

5°F/3°C Differential 15°F/8°C Differential

Pe

rce

nt

Re

du

ctio

n v

s 5°F

Ba

seli

ne

Hotel Secondary School

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Field Testing

> Four M2Gs installed at two low-rise multifamily sites, in Chicago, IL

& Cary, IL for monitoring over 2012-13 and 2013-14 seasons.

> Cary is week on/week off & Chicago has ‘control’ boiler room

> Monitoring: Boiler/Water Heater cycling, boiler and primary loop

supply/return temperatures, ambient temperatures.

> All boilers are OTR-equipped with sequencing controls and

required modifications to accommodate wider differentials

Cary site - Number of Units: 26• Most recent NG Consumption: 13,090 therms (2011)• Two boilers feeding central hydronic heating system• Central DHW off two storage WHs• Two single stage 0.4 MMBtu/hr boilers

Chicago site - Number of Units: 51• Most recent NG Consumption: 46,770 therms (3/11 – 3/12)• Split heating from two separate HW loops, fed by two boilers each• Central DHW off two storage WHs• “Control Loop” has two dual-stage 0.85/0.2MMBtu/hr boilers• “Test Loop” has two dual-stage 1.2/0.3 MMBtu/hr boilers

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Field Testing

Cary Site: 2013-14 Season

> Reduction in boiler cycling was more muted than

expected, due to:

> Portion of first monitoring year with single boiler

operation and wider differential of 22°F

> Significantly colder than average winter

> This is reflected in higher than typical utilization factors0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

10/3/13 11/22/13 1/11/14 3/2/14 4/21/14

Uti

liza

tio

n F

act

or

Boiler 1

Boiler 2

0

50

100

150

200

250

300

350

400

450

0

0.5

1

1.5

2

2.5

ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON OFF ON

10/29 11/5 11/12 11/19 11/26 12/3 12/10 12/17 12/24 12/31 1/7 1/14 1/21 1/28 2/4 2/11 2/18 2/25 3/4 3/11 3/18 3/25 4/1

He

ati

ng

De

gre

e D

ay

s (F

-Da

y)

Th

erm

s/H

DD

an

d C

ycl

es/

HD

D

Therms/HDD

Cycles/HDD

HDD

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Field Testing

Cary Site: 2013-14 Season

> Therm savings were observed, though strong winter

coupled with boiler sizing yield results below laboratory

testing. As such results may not be typical.

> At times, Boiler #1 cycled on for multiple hours

> Boiler cycling < 50/day on average

Data M2G Operation Shoulder* Winter Peak*

HDDWith 1140.3 2070.5

Without 1503.7 1727.2

Cycles/HDD

With 1.15 1.57

Without 1.38 1.40

% Reduction 16.5% -12.0%

Therms/HDD

With 1.29 1.45

Without 1.39 1.47

% Reduction 7.1% 1.4%

* “Winter Peak” are the weeks from 12/10 to 2/25, “Shoulder” are weeks before and after this period.

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Field Testing

Chicago Site: 2012-13 & 2013-14 Season

> Control boiler room monitored for two consecutive

heating seasons, test boiler room had heating season

with/without M2G – noticeable impact on differential.

> Noticeable reduction in cycling for “test” boiler room

compared to control boiler room, over 12-13 to13-14

heating seasons

> Average cycling reduced from 79 to 39 cycles/day

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0 20 40 60

Da

ily

Av

era

ge

Cy

cle

Du

rati

on

(min

.)

Daily HDD (F-Day)

2013

2014

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5

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20

25

0 20 40 60D

ail

y A

ve

rag

e C

ycl

e D

ura

tio

n

(min

.)Daily HDD (F-Day)

Enabled

Disabled

Control

Test

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15

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25

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35

40

0

10

20

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40

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60

70

Dif

fere

nti

al

(F)

Daily HDD (F-Day)

Enabled

Disabled

Test Boiler Room

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Field Testing

Chicago Site: 2012-13 & 2013-14 Season

> While “control room” shows similar behavior over two heating

seasons, M2G-equipped “test room” shows 14% therm savings

controlling for weather.

> Therms/HDD has strong linear function despite noisy data,

R^2 = 0.77/0.73 for 2013/14

> Roughly 48% of M2G cycles release to fire after drop in

supply/return T, 26% were after a 15 min. period, and rest are

“intelligence” based.

Data

Test Boiler Room Control Boiler Room

2013

(M2G

Disabled)

2014

(M2G

Enabled)

Change 2013 2014 Change

HDD* 1310.5 817.6 1470.1 785.8

Cycles/HDD 1.97 1.35 31.8% 3.86 3.92 -1.8%

Therms/HDD 0.96 0.83 14.4% 0.61 0.60 1.2%* Note that 2014 sampling period has 8 fewer days

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For More Information

For More Information

> Rowley, P. and Glanville, P. Laboratory Evaluation of an Aftermarket Boiler System, Proceedings of the 2012 ASHRAE Summer Conference, San Antonio, TX.

> Glanville, P., Rowley, P., and Schroeder D. Field & Laboratory Evaluation of Advanced Load Monitoring Boiler Controllers, Proceedings of the 2014 ASHRAE Winter Conference, New York, NY.

> Glanville, P., Rowley, P., Schroeder, D., and Brand, L. Field Test of Boiler Primary Loop Temperature Controller, prepared by GTI for the US DOE Building America Program under contract KNDJ-0-40346-03, 2014. http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/field_test_temp_controller.pdf

Research supported by Utilization Technology Development, a consortium of gas

utilities, the Emerging Technology Program of Nicor Gas, and the US Dept. of

Energy Building America Program.

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Questions?

Paul Glanville Frank SalenskySenior Engineer CEO

Gas Technology Institute Greffen Systems, Inc.

Paul.glanville@gastechnology.org frank@greffensys.com