Do’s and Don’ts in Geoexchange Design and Installation · Design and Installation Stephen Tweedie. P. Eng. Tweedie & Associates Consulting Engineers Ltd. ... Titanium CPVC/FRP

Do’s and Don’ts

in

Geoexchange®

Design and Installation

Stephen Tweedie. P. Eng. Tweedie & Associates Consulting Engineers Ltd.

Riverview, NB

May 2, 2013

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2013 GeoExchange Conference & Trade Show

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OVERVIEW

PLANNING

PIPING INSTALLATION

SYSTEM INSTALLATION

SYSTEM OPERATION

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PLANNING - 1

Open loop vs. closed loop

Water availability

Pond

River

Bay/Ocean

Well

Water Table

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PLANNING – Water Table example

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PLANNING - 1

Direct use or heat exchanger

Water quality

Oxygen

Hydrogen Ion (pH)

Chloride ion

Sulfide

Dissolved carbon dioxide, bicarbonate, carbonate

Ammonia

Sulfate

Examples of created problems

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PLANNING - 1 Fouled Pipe

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PLANNING – 1 Fouled Heat Exchanger

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PLANNING - 1

Heat exchanger materials

Carbon Steel

Copper and Copper Alloys

Stainless Steel

Aluminum

Titanium

CPVC/FRP

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PLANNING - 1

Heat exchanger types

Plate & Frame

Downhole Heat Exchanger (HDPE)

HDPE Coils

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PLANNING – 2

Horizontal vs. Vertical

Land area

Soil type

Moisture content

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PLANNING – 3

Depth vs Number of Wells

Bore diameter

Pipe size

Pumping power

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PLANNING - 4

Pipe size / spacing

Reynolds number (Re) > 2500

Pipes against wall of borehole

Friction losses / pumping power

(< 100 W/Ton)

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PLANNING - 5

Thermal Conductivity (TC) Testing

When to use

How to use

Who does it

Who interprets results

Illustration

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PLANNING – 5 TC Test in progress

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PLANNING - 6

Heat Transfer Fluid Type

Water

Brine (corrosive)

Ethanol (flammable)

Methanol (flammable, toxic)

Propylene Glycol

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PLANNING - 7

Codes and Standards

2011 ASHRAE Handbook – HVAC Applications

– Chapter 34

CSA C448 Earth Energy Systems

NFPA 30 – Flammable and Combustible

Liquids Code

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PLANNING - 8

Local Regulations

NB Department of Environment

EIA Requirements for Open Loop Earth Energy

Systems

Guidelines for Decommissioning of Water Wells

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PLANNING - 9

System Design Calculate peak and off-peak zone heating & cooling loads

Calculate annual heat rejection/absorption to account for potential loop temperature change

Select preliminary loop operating temperatures and flow rates

Correct heat pump performance from rated to actual design parameters

Select heat pumps to meet heating & cooling loads

Arrange round loop circuits to minimize cost and energy use

Conduct site survey

Determine and evaluate possible loop arrangements

Determine optimum GHX dimensions

Iterate for optimum temperatures, flows, depths, bore size, grout, etc.

Lay out interior piping

Select pumps and control methods

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PLANNING - 10

Plans and Specifications Heat pumps specified at rated conditions

Circulating pumps, expansion tanks, air separators

Fluid – volume, inhibitors, concentration, etc.

Design operating conditions

Ground loop and header layout and details

Bore depth and materials

Piping materials and testing requirements

Grout specifications and placement methods

Purge provisions and flow requirements

Build loop connections

Sequence of operations

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PIPING INSTALLATION - 1

Drilling

Size

Depth

Sequence

Casing

Drill Log

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PIPING INSTALLATION - 2

Grouting

Material - Not this

Mixture

Placement

Timing

Spacing of piping

Removal of casing

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PIPING INSTALLATION – 3

Fusion

Certification

Proper equipment

Clean conditions

Geo-vault

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Backfilling

Insulation at Building Entrance

Quality of Material

Placement

Identify Location

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Flushing and Purging

Pressure test

Remove all dirt and contaminants

Flow velocity > 2.0 ft/s

Maintain flow until water is clean and no more

air bubbles

Proper purge cart/pump

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SYSTEM INSTALLATION - 1

Liquid to Air

Smaller systems/zones

Simpler layout

No availability for “free cooling”

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Liquid to Liquid Typical of larger systems

Design flexibility

Simultaneous heating and cooling

Potential for “free cooling”

Possible to design “hybrid” systems incorporating supplemental heating supply or heat rejection components

Can incorporate other “waste heat” sources

Water-cooled refrigeration equipment

LAN rooms

Electrical rooms

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SYSTEM INSTALLATION – Free cooling

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DHW Preheat

Separate pre-heat tank

Optimize storage

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SYSTEM INSTALLATION – 4

Auxiliary heat

Prevent simultaneous operation

Minimize use

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Variable speed compressors

Reduce short-cycling

Extend life of compressors

Reduce energy use

Reduce noise

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ECM Fan and Pump Motors

Tune system to load requirements

Reduce energy use

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SYSTEM OPERATION - 1

Optimize liquid set-points with building

demand

Use space temperature feedback

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Optimize control of fans and pumps

Incorporate “auto-adapt” feature on variable-

speed wet rotor ECM pumps

Can be stand-alone or integrated with BMS

Low cost energy metering for multiple tenants

Examples

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Saving energy With an Energy Efficiency Index (EEI) of better than 0.20

an energy savings of up to 75% compared with non-

regulated pump can be achieved.

HIGHEST EFFICIENCY

0

10

20

30

40

50

60

70

80

90

100

Typicalinstalledcirculator

EuP 2013 EuP 2015 Benchmark MAGNA3

EEI

0.27

EEI

0.23

EEI

0.20

En

erg

y U

sa

ge

%

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New functionalities

The MAGNA3 comprises a variety of new features and

functionalities that make installation, setting and operation

much easier.

Easy installation

User interface with TFT display and Grundfos Eye

FLOWADAPT/FLOWLIMIT

Heat energy meter

Extended temperature range

More I/O

Bus setup

Warning and alarm log

Work history

Wireless connection

WHAT’S NEW

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Bus setup The MAGNA3 can be equipped with optional CIM modules to enable easy connection to BMS communication systems.

The CIM modules support the following field-bus standards:

LON

Profibus

MODbus

BACnet

GENIbus

GSM/GPRS

WHAT’S NEW

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Insulation shells Heating insulation shell that provides optimal thermal insulation of the

pump housing. Delivered as standard, the insulation shells are

perfectly molded to the pump shape to avoid subsequent time-

consuming adjustments.

Insulation shells for cooling applications

In order to prevent condensation and corrosion in air conditioning and

ground source heat pump systems the installer should apply a

silicone sealant to the internal surfaces of the insulation shell to

eliminate air gaps between the shell and pump housing.

ACCESSORIES

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ENJOY

THE

SAVINGS!

??????

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PIPING INSTALLATION – Grout Mixture 1

Next

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Next

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Next

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PIPING INSTALLATION – Bad Grout

Return

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PIPING INSTALLATION – Placement

Next

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PIPING INSTALLATION - Spacing

Next

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PIPING INSTALLATION - Casing

Next

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PIPING INSTALLATION - Equipment

Next

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PIPING INSTALLATION - Equipment

Next

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PIPING INSTALLATION - Conditions

Next

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PIPING INSTALLATION - Conditions

Next

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PIPING INSTALLATION – Geo-vault

Next

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PIPING INSTALLATION - Material

Next

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PIPING INSTALLATION - Location

Next

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PIPING INSTALLATION - Contaminants

Next

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Next

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Next

Documents

Do’s and Don’ts in Geoexchange Design and Installation · Design and Installation Stephen Tweedie. P. Eng. Tweedie & Associates Consulting Engineers Ltd. ... Titanium CPVC/FRP