article58 residential geothermal buyers guide 2009

8/2/2019 Article58 Residential Geothermal Buyers Guide 2009

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A Buyers Guide

for ResidentialGround SourceHeat Pump Systems


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A Buyers Guide for Residential Ground SourceHeat Pump Systems

The aim of this publication is to help readers with the decision topurchase and install a ground source heat pump (or geoexchange)system. This document is not meant to be a do-it-yourself guide.Prospective buyers should seek out qualified advice and assistance tosupplement the information provided here. The Canadian GeoExchangeCoalition, as part of its market transformation initiative, has trainedand accredited thousands of industry professionals since early 2007and a list of qualified companies is available on its website atwww.geoexchange.ca .

When considering the installation of a geoexchange system, customersshould contact utility and government agencies to ensure that their newsystem will respect relevant codes and standards, as well as building,site and other regulations.

The Canadian GeoExchange Coalition assumes no liability for injury,property damage or loss suffered by anyone using the informationcontained in this guide. It is distributed for information purposes only.

Parts of this publication are reproduced from other documents with thepermission of the Government of Canada and under fair use provisions.Important editorial work has been performed to provide prospectivecustomers with a critical decision-making tool that reflects the currentstate of the industrys market transformation and self-regulatoryapproach initiated and deployed by the Canadian GeoExchangeCoalition.

Canadian GeoExchange Coalition, 2009ISBN 978-0-9811612-4-2

Aussi disponible en franais sous le titre:Guide dachat dun systme gothermique rsidentiel

Recycled paper


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HOW TO USE THIS GUIDE 2

1 INTRODUCTION TO GEOEXCHANGE SYSTEMS 3

What is Earth Energy? 3How GeoExchange Systems Work 3GeoExchange System Variations 7Benefits of GeoExchange Systems 10Worksheet Example 12

2 GEOEXCHANGE SYSTEMS FOR A NEW HOME 15

Home Design Considerations 15System Design for a New Home 15Distribution Systems 17Controls 17The Cost of Owning a GXS 18

3 GEOEXCHANGE SYSTEMS FOR AN EXISTING HOME 21

Existing Site and Services 21System Design for an Existing Home 22Possible Upgrades 24Removal of Existing Equipment 24

4 CONTRACTOR SELECTION 25

Chosing the Right Specialists 25A Basic Contract 26

5 MAINTENANCE AND TROUBLESHOOTING 28

Servicing Requiring a Contractor 26

6 DO YOU NEED MORE INFORMATION? 29

GLOSSARY 30

CONVERSION FACTORS 33

Table of Contents


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A Buyers Guide for Residential Ground Source Heat Pump Systemsprovides homeowners with theinformation they need to plan forthe purchase of a ground sourceheat pump system in a new orexisting home.

Section 1 is an introduction toGeoExchange Systems what theyare, how they work, the different

types, the benefits they provide andhow much earth energy they needto work. Whether you are buying orbuilding a new home, or planningto retrofit your existing home,you should read Section 1.

New home buyers shouldthen read Section 2 . Here you willread about how your house designaffects a GeoExchange System .It also recommends system designsthat work best for your house typeand compares their typical operating

costs to alternative heating andcooling systems.

Section 3 is for homeownerswho want to install a GeoExchangeSystem in their existing home . Thedesign and system that are right forthe home you are living in now can bevery different from standard systems.Because of this, and to make theinstallation of your new system aseasy as possible for you and your

family, you need to plan. This sectioncovers various ways you can upgradeyour heating and cooling system,compares their operating costs andlists important steps you should takewhen servicing your system. You willalso need to read certain parts ofSection 2 that apply to your situation.

Section 4 is important for allreaders those buying or building

a new home, as well as thoseretrofitting or renovating an existinghome. It provides guidance onselecting a contractor and what needsto be covered in a basic contract. Italso covers service and maintenanceas well as basic troubleshooting.

Section 5 lists things to check beforecontacting your service contractor.

Section 6 provides sources ofadditional information.

The Guide ends with a glossary ofterms used in the GeoExchangeindustry (given in italics throughoutthe Guide , like this: ground water ).

The industry also uses other terms todescribe GeoExchange Systems : theyinclude ground- and water-sourceheat pumps , earth energy system,and geothermal heat pumps .

2 A Buyers Guide forResidential Ground SourceHeat Pump Systems

How to Use this Guide


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1What isEarth Energy?

The sun has always provided heat forthe earth. Its energy warms the earthdirectly, but also indirectly. Its heatevaporates water from the lakes andstreams, which eventually falls backto earth and filters into the ground. Afew metres of surface soil insulate theearth and ground water below. Thewarm earth and ground water belowthe surface provide a free, renewablesource of energy for as long as thesun continues to shine. The earthunder an average residential lot caneasily provide enough free energy toheat and cool the home built on it.

The free energy has only to be movedfrom the ground into your home. Thisis done either by pumping water from awell (open loop ) or by pumping a heattransfer fluid through a horizontal orvertical circuit of underground piping(closed loop ). The fluid, called theheat transfer fluid, absorbs the heat inthe ground water or soil and transfersit to the heat pump . The heat absorbedby the fluid from the solar-heatedground is extracted from it by theheat pump , and the now-chilled fluidis circulated through a heat exchanger over and over again to extract moreheat from the earth.

If your home is located near a suitablepond or lake, you can use a Geo-Exchange System (GXS) to draw onthis excellent source of free energy.

Burying a loop in the ground aroundyour home is like owning your own oilwell, but instead of pumping oil froman underground pool and burning it tocreate heat (and greenhouse gases ),you tap into clean energy that will bethere for as long as there is a sun.

A well-designed ground loop willnot hurt the earth or plants growingabove it. There is no visible part toshow that it is buried in your yard.If your system uses ground water , ithas no effect on the water other thanchanging its temperature by a fewdegrees. Finally, a welldesigned

ground water system will not wastethe water, but put it back into theground by means of a return well .

How GeoExchangeSystems Work

The heat energy taken from theground by your GXS is consideredlow-grade heat . In other words,it is not warm enough to heat yourhome without being concentrated orupgraded somehow. However, there isplenty of it the average temperatureof the ground just a few metres belowthe surface is similar to (or even higherthan) the average annual outdoor airtemperature. For example, in Toronto,the average annual air temperature isabout 8.9C, but the average groundtemperature is 10.1C. It is importantto note that this ground temperatureis 10.1C on the hottest day of summeras well as on the coldest day of winter.That is why some of the first humanslived in caves the caves wouldprotect them from the temperatureextremes of winter and summer.That is also why a GXS works so effi-ciently it uses a constant, relativelywarm source (ground or water) fromwhich to draw energy.

Basic Components of a GXS

Generally speaking, a GXS is made upof three main parts: a loop, the heat

pump and the distribution system . Thefollowing section describes some ofthe various loop designs, heat pumpsand distribution systems commonlyused in a Canadian GXS .

The loop is built from polyethylenepipe which is buried in the groundoutside your home either in a horizon-tal trench ( horizontal loop ) or throughholes drilled in the earth ( vertical loop ).The loop may also be laid on thebottom of a nearby lake or pond(lake loop or pond loop ). Your GXS circulates liquid (the heat transferfluid) through the loop and to theheat pump located inside the home.

The heat pump extracts heat fromthe ground and distributes the heatcollected from it throughout thehome. The chilled liquid is pumpedback into the loop and, because itis colder than the ground, is able todraw more heat from the surroundingsoil. These loops are often referredto collectively as a closed loop , as thesame liquid circulates through theclosed system over and over again.

Each of the ground-coupling systemsalready described utilizes an interme-

diate fluid to transfer heat betweenthe ground and the refrigerant. Useof an intermediate heat-transfer fluidnecessitates a higher compressionratio in the heat pump in orderto achieve sufficient temperaturedifferences in the heat-transfer chain(refrigerant to fluid to earth). Eachalso requires a pump to circulatewater between the heat pump andthe ground loop. Direct-expansionsystems remove the need for anintermediate heat-transfer fluid, thefluid-refrigerant heat exchanger andthe circulation pump. Copper coilsare installed underground for a directexchange of heat between refrigerantand ground. The result is improvedheat-transfer characteristics and ther-modynamic performance. However,the systems require a large amountof refrigerant and, because the groundis subject to larger temperatureextremes from the direct expansion


Introductionto GeoExchange Systems


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system, there are additional designconsiderations. In winter heatingoperation, the lower ground-coiltemperature may cause the groundmoisture to freeze. Expansion of theice buildup may cause the ground tobuckle. Also, because of the freezingpotential, the ground coil should notbe located near water lines. In the

summer cooling operation, the highercoil temperatures may drive moisturefrom the soil.

Another way is to pump ground water or well water directly through theheat pump . A GXS that uses ground water is often referred to as an open-loop system. The heat pump extracts

heat from the well water, whichis usually returned to the ground ina return well . To run an open-loopGXS , you need two reliable wells withwater that contains few dissolvedminerals that can cause scale build-upor rust over the long term, as it ispumped through the heat pumpsheat exchanger .

Residential GeoExchange System (Cooling Mode)


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Residential GeoExchange System (Heating Mode)


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In both cases, a pump circulates liquidthrough the loop and the heat pump .The heat pump chills (or collects theheat stored in) the liquid when it isbeing used as a source of heat, andcirculates it back through the loopto pick up more heat. A system fora large home will require a largerheat pump and ground loop , witha circulation pump to match.

After the GXS has taken the heatenergy from the ground loop andupgraded it to a temperature usable inyour home, it delivers the heat evenlyto all parts of the building through adistribution system . It can use eitherair or water to move the heat fromthe heat pump into the home. Forced air is the most common distribution

system in most parts of Canada,although a hot-water or hydronic

system can also be used.

Forced-Air Systems

A heat pump in a forced-air GXS usesa heat exchanger to take the heatenergy from the refrigerant to heatthe air that is blown over it. The air isdirected through ducts to the differentrooms in the home, as with any forced-air fossil fuel or electric furnace. Theadvantages of a forced-air GXS are as follows:

it can distribute fresh, outside airthroughout the home if its coupledwith a heat recovery air exchanger;

it can air-condition the home(by taking the heat from the air inyour home and transferring it to the

ground loop ) as well as heat it; and it can filter the air in your home as

it circulates through the system.

A GXS is designed to raise the heatof the air flowing through the heat

pump by between 10 and 15C;fossil fuel or electric furnaces aredesigned to raise it by 20 to 30C.That difference means a GXS mustmove more air through the home todistribute the same amount of heat asa conventional furnace . So to designan efficient, quiet forced-air GXS , thecontractor designing the ductwork

must take into account the largeramount of air to be moved.Theductwork should also have acoustic insulation installed inside the plenumand the first few metres of duct,as well as a flexible connectionbetween the heat pump and themain duct to ensure quiet operation.

Hydronic (Hot-Water)Heating Systems

As we said earlier, a heat pump canheat either air or water. The latter

type distributes the heat by meansof a hydronic (or hot-water ) heating system . If you choose it for yourhome, keep in mind that currentlyavailable heat pumps can heat waterto no more than about 50C.

This limits your choices for equipmentto distribute the heat to your home.Hot-water baseboard radiators aredesigned to operate with water heatedto at least 65 to 70C; they are lesseffective when the water is not aswarm. As a result, you will need larger

radiators or more of them todistribute the same amount of heat.Or you can reduce the heat lossfrom your home by installing moreinsulation, so you need less heat.

You can also install radiant floor ,or in-floor, heating system s. Theseare becoming more common becausethey can increase comfort and improvesystem efficiency. Again, you mustmake sure that your radiant floor heating system is designed to operatewithin the temperature capabilitiesof your GXS .

The temperature difference between

the ground loop and the hot waterdistribution system depends on theefficiency of the GXS ; the greaterthe difference, the less efficient thesystem. Typically, a GXS will extractheat from the earth at about 0C.If a radiant floor heating systemrequires a temperature of 50C toheat your home, the heat pump willproduce about 2.5 units of heat forevery unit of electricity used to operatethe system. If the system can bedesigned to operate with water at40C, it will produce 3.1units of heat

for every unit of electricity used tooperate it. In other words, it will beabout 25 percent more efficient.

Think about it this way if you havehot spring water to heat your home,you do not need a heat pump . Thehot spring is a totally free, 100 percent-efficient source of energy. But if thetemperature of the water from thewell needs to be raised 5C to be highenough to heat your home, you needsome additional energy. If it has tobe raised 20C, you need even moreenergy. The greater the temperaturedifference, the greater the additionalenergy need.



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Horizontal Loops

As the name implies, these loopsare buried horizontally, usually at adepth of about 2 to 2.5 m, althoughit can vary from 1.5 to 3 m or more.Usually trenches are excavated with abackhoe ; a chain trencher can be usedin some soil types. Fill can sometimesbe used to cover a loop in a low-lyingarea of the property. The trench canbe from 1 to 3 m wide. Four or evensix pipes can be laid at the bottomof a wide trench, while some loopdesigns allow two layers of pipe to bestacked in a trench at different levels.Loop configurations may even use aslinky or coiled configuration thatconcentrates additional pipe in atrench. Many different configurationshave been tested and approved.Make sure you ask your contractorfor references. Contractors can oftenshow you photographs of loopsthey have installed.

The area you need to install ahorizontal loop depends on theheating and cooling loads of yourhome, the depth at which the loop isto be buried, the soil and how muchmoisture it contains, the climate,the efficiency of the heat pump andthe configuration of the loop . Theaverage 150-m 2 home needs an areaof between 300 and 700 m 2. Yourcontractor will use computer softwareor loop design guidelines providedby the heat pump manufacturer to

determine the size and configurationof your earth loop .

Vertical Loops

Vertical loops are made out of HDPE pipe, which is inserted into holesdrilled in the soil. Taking in to accountdifferent canadian geological condi-tions and drilling equipment used,these boreholes are 15150 m deep,and 1015 cm around. Two lengthsof pipe are fused into a U-bend(two 90 elbows) and inserted into theborehole . The size of pipe used for theloop varies, depending on the cost ofdrilling and the depth of the borehole ;32 mm pipe is common in some areas,19 or 25 mm pipe in others. After thepipe has been placed in the borehole ,it must be grouted to prevent poten-tially polluted surface water infiltrationinto lithostratisgraphic units andaquifers. A bentonite grout is normallyused. This is to ensure good contactwith the soil and prevent surfacewater from contaminating the ground water . CSAstandards specify that

the borehole around the pipe is to befilled by means of a tremie line , ora pipe inserted to the bottom of theborehole and retracted as it is filledwith grout . This process is designed toeliminate air pockets around the pipeand ensure good contact with the soil.

The main advantage of a vertical loop is that it can be installed in amuch smaller area than a horizontal loop . Four boreholes drilled in anarea of 9 m 2 which fits easily intoan average city backyard can provide

all the renewable energy you needto heat an average 150-m 2 home.

The cost of installing a vertical loopcan vary greatly, with soil conditionsthe single most important factor.Drilling into granite requires muchheavier, more costly equipment,and is much more time-consumingthan drilling into soft clay. It is evenmore time-consuming when the soil

contains a mix of materials, such aslayers of boulders, gravel and sand.

The installation of a vertical loop inthis type of soil is three to four timesmore costly than that of a horizontal one.In areas like southern Manitobaand Saskatchewan, however, whereglacial Lake Agassiz has left 1550 mof soft clay deposits, a vertical loopcan be installed for about the same

cost as a horizontal one.

The depth of borehole needed fora vertical loop depends on the samefactors that determine the land arearequired for a horizontal one. Theland area needed for the vertical loop ,however, depends on the depth towhich the boreholes can be drilledcost-effectively. For example, if a GXSrequires 180 m of borehole in total,and is to be installed where bedrockis found at 20 m, it would usually becheaper to drill nine boreholes to a

depth of 20 m than three to a depthof 60 m. Nine boreholes wouldrequire an area of about 150 m 2,and three, an area of about 60 m 2.

Lake or Pond Loops

These types of loops can be installedvery cost-effectively for a homelocated near a lake or pond. Manyhomes in northern Ontario, forexample, are within metres of a lakethat soaks up the suns energy allsummer. The water temperatureat the bottom of an ice-covered lakeis about 4 to 5C even during thecoldest blizzard. And in the summer,the lake water can easily absorbthe heat you are trying to expelto cool your home. All you needis a year-round minimum depth of22.5 m of water in which the loopcan be protected from wave actionand ice pile-ups.



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Unless you own the lake, however,you need permission from theprovincial government, and in somecases from the Government ofCanada, to install a lake loop . Some

jurisdictions do not allow them.Destruction of fish spawning grounds,shoreline erosion, obstruction of trafficon navigable waters and potentialdamage to the environment concernseveral government departments. In

some jurisdictions, enough lake loopshave been installed that permissionis simply a matter of filling out forms.Some GXS contractors who specializein lake loop installation handle all thepermission paperwork for their clients.

In the Prairies, farm ponds areoften excavated to provide waterfor irrigation or livestock. A 7501000-m 2 pond with a constant depthof 2.5 m can do double duty as aclean source of energy. The oceanscan also supply vast amounts of

energy, but care must be taken toprotect an ocean loop from tide andwave damage. Many homes on theWest Coast already benefit fromfree,renewable ocean energy.

Open Loops

Open loops , or ground water GXS , takeheat from well water that is pumpeddirectly through the heat exchanger in a heat pump . The required flowof well water is determined by thecapacity of your heat pump . In thecoldest part of the winter, heatinga typical 150-m 2 new home takes20 00030 000 L of water per day, ora flow rate of 0.40.5 L per second(a typical backyard pool contains about60 000 70 000 L). A larger homewill need proportionally more water.You need a reliable well to supply thisvolume of water. Typically, you willalso need a second or return well to

dispose of the water by pumping itback into the ground. Most provincesregulate the use of wells, and canadvise you on the use of well waterfor GXS applications. For example,you must take care to avoid affectingyour neighbors wells when pumpingcontinuously. Regulations on the useof well water as a heat source fora GXS vary with each province.You should contact the department

with jurisdiction over ground water resources for the regulations in yourprovince.

To ensure that the well is capable ofsupplying the water on a sustainablebasis, and that the return well has thecapacity to accept the water after ithas circulated through the heat pump ,you need to carry out a pump teston your wells. In some locations, thecapacity of the aquifer is well known,and you can find out the capacityof your new well within a few hours.

In other areas, it will be necessary toperform a test by measuring the dropin water levels at specified intervalswhile the well is pumped at a knownrate for as long as 24 hours.

As well water circulates throughthe heat pump , corrosive water candamage the heat exchange r over time;additionally, water with a high mineralcontent can cause scale buildup. Mostmanufacturers can supply heat pumpsmade out of resistant materials likecupronickel or stainless steel that aremore suitable for use in open-loopsystems. Manufacturers will specifythe quality of water that is acceptablefor their equipment.Again, you mayneed to have your water tested toensure it falls within the guidelines.The department that regulates thewater resources in your provincemay be able to advise you on wherethe water can be tested.

Mechanical equipment lasts longerif it does not have to start andstop repeatedly. Well pumps are noexception. The contractor installingthe well pump and pressure systemmust be told that it will be used tosupply water for a GXS. For efficientoperation, the pump design andhorsepower must be chosen to supplythe correct amount of water. Biggeris not better. The water requirements

for the system, the height the wateris lifted from the well and the pipingfrom the well to the house and tothe return well must be taken intoaccount. To prevent the well pumpfrom short-cycling , you may needto install a larger pressure tank .These details can affect the overallefficiency of your GXS by as muchas 2530 percent.

The temperature of ground water isvery constant, ranging between 5 and12C across Canada. The temperature

of the fluid pumped through a closed loop used in a home normally dropsto slightly below freezing during thewinter. When well water is used asthe energy source during the winter,the heat pump produces more heatand will be more efficient. However,since the water must actually be liftedfrom the ground, sometimes as muchas 1530 m, you will need a morepowerful pump than the one requiredfor a closed-loop system. In addition,the same pump often supplies waterfor both the heat pump and generalhousehold use. The cost of operatingthe larger well pump often offsetsthe efficiency of running the GXS withwell well water. Ask GXS contractorsin your area about their experiencewith open-loop systems when decidingon the best option for your home.



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When you are planning any excava-tion, you must make sure the site issurveyed and that the location of anyother services, such as electrical lines,gas lines, water lines, sewer lines,septic fields or underground storagetanks, is determined. Also, when youare deciding where to install a loopon your property, keep in mind thatheavy equipment cannot operateunder overhead electrical lines.

Wherever you install the ground loopor water wells and lines for a GXS,they must be added to your site plan.This will avoid costly future repairs.The CSAstandards stipulate that thehomeowner must be provided witha copy of a drawing showing thelocation of a closed-loop system, andthat a tracing wire or tracing tap emust be laid in the ground aboveany closed-loop pipes to make findingthe system easier in the future. Inaddition, the contractor must keepa copy of your closed-loop layout for

seven years.

Benefits of Geo-Exchange Systems

Good for the Environment

More than two thirds of the energydelivered to your home by a GXS isrenewable solar energy stored in theground. This is great for your walletbecause it is free energy. It is alsogood for the environment becausethere are virtually no toxic emissions .Each kilowatthour (kWh) of electricityused to operate a GXS draws morethan 3 kWh of free, renewable energyfrom the ground.

A large part of the cost of energysupplied to your home is the expenseof getting it there. Electric transmissionlines, gas lines and oil pipelines arecostly to build and require extensiverights-of-way . Oil is shipped in tankershalfway around the world so youcan heat your home. Trucks deliveringfuel to your home need fuel andmaintenance. Shipping energy to yourhome entails real costs. They include

not only direct expenses, like buildingpipelines and maintaining transmissionlines, but also indirect costs, likedealing with emergencies. The infra-

structure needed to transport energyis large and expensive for you andthe environment. With a GXS, mostof the energy you need is moved lessthan a few hundred metres into yourhome. The cost of transporting earthenergy into your home is the costof running a circulating pump .

When a conventional airconditioning

system is installed in a home,refrigerant lines run from the outdoorcondensing uni t to the coil in thefurnace. GXS , on the other hand, areassembled and tested under controlledconditions, so that a refrigerant leakis much less likely. Also, any leak froma GXS would be much smaller, asit usually contains just one half therefrigerant charge of a conventional air-conditioning unit .

Year-Round Comfort

People living in homes with a GXSoften say, This home is the mostcomfortable weve ever lived in.There are several reasons for this.The air temperature produced by aGXS is typically about 35C. The airproduced by a fossil fuel furnace orelectric furnace is often heated to5060C much warmer than roomtemperature. This can create hot spotsin a room. Moving around the room,you can often feel temperaturedifferences of 34C.

You may have lived in a home whereyou were often about to adjust thethermostat just before the furnacecame on, and a few minutes laterhad to take off your sweater. This iscaused by oversizing the conventional heating system . Even on the coldestday, an oversized furnace may onlyrun for 15 minutes an hour, because itcan produce all the heat you need byrunning only 25 percent of the time.The thermostat is satisfied quicklywhen the furnace is on, and may evenovershoot the desired temperatureby a degree or two, and then thetemperature drops several degreesbefore coming on again. This happensbecause the cost of installing a largerfurnace is almost insignificant, sothe bigger is better attitude oftenprevails. If the heat loss of a home isreduced (by upgrading the insulationor windows), the overheating problemis made worse.

The cost of installing a larger GXS ,however, makes it prohibitive tooversize a system. As a result, it runsalmost continuously, maintaining veryeven temperatures throughout thehome. Several manufacturers buildtwo-speed units with multi-speed fans.



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These match the heating and coolingloads of your home virtually yearround. In spring and fall, when youdo not need the full capacity of thesystem, the compressor and fan willoperate at low speed, providing onlyas much heating and air conditioningas you need. As the days get colderin winter, or during very hot summerdays, the system will operate at highspeed.

Most GXS are installed with electronicthermostats that offer more precisetemperature control and that switchfrom heating to air conditioningautomatically. You will find that,on days in the spring and fall whenyou need heat in the morning andcooling in the afternoon, you aremore comfortable.

Operating Cost

As noted earlier, more than twothirds of the energy supplied by a GXSis renewable energy taken from theground. The other third comes fromthe electricity used to power the sys-tem. You only pay for the electricityyou use to operate your system.The other two thirds is free.

How does the cost of heating yourhome with a GXS compare to thecost of heating it with other fueloptions? That depends on the cost ofthe fuel and on how efficiently yourfurnace uses it. As a fossil fuel furnacesends the products of combustion(CO, CO2, SO2, NOx, etc.) up thechimney, some heat leaves the houseas well. Older furnaces with pilotlights burn some gas continuously,even when your home does not needheating.If you are using an old gasor oil furnace, you can be venting asmuch as 35 to 40 percent of the fuelyou have purchased up the chimney.

If the furnace is greatly oversized ,it may waste even more energy,because by the time it reachesoperating efficiency, it has alreadysatisfied the thermostat andshuts off.

Electric furnaces and electricbaseboard heaters do not require achimney. All the energy they generatestays in your home even if the

electric motor distributing air throughyour home is not very efficient.An electric furnace or baseboardsystem can therefore be considered100-percent efficient.

A GXS does not create any combus-tion products . As with the electricfurnace, all the electric energy usedto run the compressor , the pump andthe fan stays in the house. But sincethe system also draws additionalfree energy from the ground, it canactually produce more energy than

you put into it. Because of this, aGXS can be considered to operateat more than 100 percent efficiency.

The efficiency of a heating systemis measured as the Coefficient of Performance (COP) . Measuringthe energy your GXS produces, anddividing it by the energy you put intoit (and pay for) gives you the COP .For example, if you purchase naturalgas that could, if burned completely,produce 100 units of heat, but 7 ofthose units are lost up the chimney,the COP is as follows:(100 - 7) 100 = 0.93

GXS intended for open-loop systemshave heating COP ratings rangingfrom 3.0 to 4.0. For closed-loopheating applications the COP rating isbetween 2.5 and 4.0. See the descrip-tion under Heat Pump Selectionon page 15 for additional informationon the COP .

The worksheets on the followingpages will help you estimate the cost

of energy to heat your home and toheat water for domestic consumption.The worksheet allows you to calculateenergy costs by taking into account:

the size of your home; the number of people

in your home using hot water; the fuels available in your area; their costs; and the efficiency of the heating

equipment you are considering.

The first worksheet is for a 165-m 2home. It compares the cost of energyif you use:

electricity at a cost of $0.08/kWh; natural gas at a cost of $0.42/m 3; propane at a cost of $0.85/litre; a GXS that uses electricity

at a cost of $0.08/kWh;

a conventional electric furnace; a mid-efficiency natural gas furnace;

a high-efficiency propane furnace;and

a GXS with a COP of 3.2, whichis the minimum COP allowed inCanada for an open-loop system.



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Worksheet to Estimate Annual Cost of Heating your Home Using Different Fuels Example

Estimated Heating Energy Usage in kWhEnter the heated area of your home (in square metres) in Column A in Row 1, 2 or 3 (whichever best describes your home).Multiply the area (from Column A) by the kWh shown in Column B to calculate the kWh usage for heating your home.

A *B* COlder home insulation etc. not upgraded x 200 = 1

Average home 165 x 150 = 2 24,750R-2000 certified home x 100 = 3

Cost of Heat and Hot Water Using Electricity Ask your electrical utility for the cost of electricity per kWh. Enter it in Column C, Line 7.

CEnter the cost of electricity per kWh and enter this in Line 7 7 0.080

Multiply Line 1, 2 or 3 by Line 7 to determine the cost of heating your home using Electricity 8 $1,980Multiply Line 6 by Line 7 to determine the cost of heating water for your household using Electricity 9 $452

Cost of Heat and Hot Water Using Natural GasDetermine in what units your utility sells natural gas, and what the Basic Utility Charge is. Enter this figure in the appropriate line in Column A.

A B CCost of Natural Gas (per cubic metre) 0.42 10.35 = 10 0.041

Cost of Natural Gas (per gigajoule or GJ) 277.79 = 11Enter the COP of ONE of the gas furnaces shown in Column B in Column C B C

Old gas furnace with pilot l ight 0.65 12Newer propane or oil furnace with pilot light (before 1995) 0.76 13

Mid-efficiency propane or oil furnace 0.83 14 0.83High-efficiency propane or oil furnace 0.93 15

Divide Line 10 or Line 11 by Line 12 , 13 , 14 or 15 to calculate the cost per kWh 16 0.049Add Basic Utility Charge** 17 $120

Multiply Line 1 , 2, or 3 by Line 16 to determine the total cost of heating your home using Natural Gas 18 $1,213Multiply Line 6 by Line 16 to determine the cost of heating water for your household using Natural Gas 19 $276

Cost of Heat and Hot Water Using Propane or Oil Ask your fuel supplier for the cost of propane or oil per litre, and if there is a separate delivery or tank rental charge. Enter in Column A.

A B CPropane (cost per litre) 0.70 6.97 = 20 0.10

Oil (cost per litre) 10.69 = 21Enter the COP of ONE of the gas furnaces shown in Column B in Column C B C

Old gas furnace with pilot l ight 0.65 22Newer gas furnace with pilot light (before 1995) 0.76 23

Mid-efficiency gas furnace 0.83 24High-efficiency gas furnace 0.93 25 0.93

Divide Line 20 or Line 21 by Line 22 , 23 , 24 or 25 to calculate the cost per kWh 26 0.1075Add Fuel Delivery Charge** 27 $120

Multiply Line 1 , 2 or 3 by Line 26 to determine the total cost of heating your home using Propane or Oil 28 $2,660Multiply Line 6 by Line 26 to determine the total cost of heating water for your household using Propane or Oil 29 $607

Cost of Heat and Hot Water Using a GeoExchange SystemDetermine the COP of the GXS you are considering from the manufacturer or your contractor. Enter this in Column C.

CEnter the COP of the GeoExchange System in Line 30 30 3.20

Divide the cost of electricity in Line 7 by the COP of the GeoExchange System in Line 30 31 0.025Multiply the cost of electricity in Line 31 by 2 32 0.050

Multiply Line 1 , 2 or 3 by Line 31 to calculate the cost of heating your home with a GeoExchange System 33 $619Multiply Line 6 by Line 32 to find the cost of heating water for your household with a GeoExchange System 34 $283

* Average consumption for residences in Canada** The Basic Utility Charge or Delivery Charge is charged by most utilities for monthly service, whether the fuel is used or not. Since most homes will

have electrical service for l ighting and other uses to which a basic utility charge would be applied, it should not be added to the energy cost of homesheated with Electric Heat or a GeoExchange System.

Estimated Hot Water Energy Usage in kWhIn Column A, enter the number of people in your household in addition to yourself. Multiply the number of people by the number in Column B.

A B CFirst person in home 1st person x 1,900 = 4 1,900

Number of additional people 3 x 1,250 = 5 3,750Add Lines 4 and 5 to determine the total kWh needed to heat water for a home like yours 6 5,650


Worksheet Example

kWhkWhkWh

8 $1,99 $4

17 $118 $1,219 $2

27 $128 $2,629 $6

33 $634 $2

kWhkWhkWh


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Worksheet to Estimate Annual Cost of Heating your Home Using Different Fuels

Estimated Heating Energy Usage in kWhEnter the heated area of your home (in square metres) in Column A in Row 1, 2 or 3 (whichever best describes your home).Multiply the area (from Column A) by the kWh shown in Column B to calculate the kWh usage for heating your home.

A *B* COlder home insulation etc. not upgraded x 200 = 1

Average home x 150 = 2R-2000 certified home x 100 = 3

Cost of Heat and Hot Water Using Electricity Ask your electrical utility for the cost of electricity per kWh. Enter it in Column C, Line 7.

CEnter the cost of electricity per kWh and enter this in Line 7 7

Multiply Line 1, 2 or 3 by Line 7 to determine the cost of heating your home using Electricity 8Multiply Line 6 by Line 7 to determine the cost of heating water for your household using Electricity 9

Cost of Heat and Hot Water Using Natural GasDetermine in what units your utility sells natural gas, and what the Basic Utility Charge is. Enter this figure in the appropriate line in Column A.

A B CCost of Natural Gas (per cubic metre) 10.35 = 10

Cost of Natural Gas (per gigajoule or GJ) 277.79 = 11Enter the COP of ONE of the gas furnaces shown in Column B in Column C B C

Old gas furnace with pilot l ight 0.65 12Newer propane or oil furnace with pilot light (before 1995) 0.76 13

Mid-efficiency propane or oil furnace 0.83 14High-efficiency propane or oil furnace) 0.93 15

Divide Line 10 or Line 11 by Line 12 , 13 , 14 or 15 to calculate the cost per kWh 16Add Basic Utility Charge** 17

Multiply Line 1 , 2, or 3 by Line 16 to determine the total cost of heating your home using Natural Gas 18Multiply Line 6 by Line 16 to determine the cost of heating water for your household using Natural Gas 19

Cost of Heat and Hot Water Using Propane or Oil Ask your fuel supplier for the cost of propane or oil per litre, and if there is a separate delivery or tank rental charge. Enter in Column A.

A B CPropane (cost per litre) 6.97 = 20

Oil (cost per litre) 10.69 = 21Enter the COP of ONE of the gas furnaces shown in Column B in Column C B C

Old gas furnace with pilot l ight 0.65 22Newer gas furnace with pilot light (before 1995) 0.76 23

Mid-efficiency gas furnace 0.83 24High-efficiency gas furnace 0.93 25

Divide Line 20 or Line 21 by Line 22 , 23 , 24 or 25 to calculate the cost per kWh 26Add Fuel Delivery Charge** 27

Multiply Line 1 , 2 or 3 by Line 26 to determine the total cost of heating your home using Propane or Oil 28Multiply Line 6 by Line 26 to determine the total cost of heating water for your household using Propane or Oil 29

Cost of Heat and Hot Water Using a GeoExchange SystemDetermine the COP of the GXS you are considering from the manufacturer or your contractor. Enter this in Column C.

CEnter the COP of the GeoExchange System in Line 30 30

Divide the cost of electricity in Line 7 by the COP of the GeoExchange System in Line 30 31Multiply the cost of electricity in Line 31 by 2 32

Multiply Line 1 , 2 or 3 by Line 31 to calculate the cost of heating your home with a GeoExchange System 33Multiply Line 6 by Line 32 to find the cost of heating water for your household with a GeoExchange System 34

* Average consumption for residences in Canada** The Basic Utility Charge or Delivery Charge is charged by most utilities for monthly service, whether the fuel is used or not. Since most homes will

have electrical service for l ighting and other uses to which a basic utility charge would be applied, it should not be added to the energy cost of homesheated with Electric Heat or a GeoExchange System.

Estimated Hot Water Energy Usage in kWhIn Column A, enter the number of people in your household in addition to yourself. Multiply the number of people by the number in Column B.

A B CFirst person in home 1st person x 1900 = 4

Number of additional people x 1250 = 5Add Lines 4 and 5 to determine the total kWh needed to heat water for a home like yours 6

kWhkWhkWh

89

171819

272829

3334

kWhkWhkWh


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Low Maintenanceand Long Service Life

The heat pump in a GXS works like arefrigerator. The heat it takes from theearth is brought into your home in thesame way your fridge brings the heatfrom the food placed in it into yourkitchen by means of the coil at theback of the fridge. The only significantdifference, other than capacity, isthe addition of a reversing valve thatallows your GXS to cool your homeand send the heat out of your houseand into the earth. The compressor of a heat pump is similar to, but muchlarger than, a fridge compressor .The only other moving parts arethe blower motor and the pump tocirculate fluid through pipe buried inthe ground. Unlike an air conditioner,the equipment is located inside yourhome not exposed to dust, rain,snow and extreme temperatures. Ifthe system (i.e., the earth loop andthe distribution system ) is designed tomatch the needs of your home, it willoperate with very little maintenance,much like your refrigerator. The onlyregular maintenance you will haveto do is to make sure the air filter isclean (if you have a forced-air system ).

Inspections to clean the ductworkand fan and check that the electricalcontacts are not worn should be partof an annual service contract. If youinstall an open-loop or well-water

system , the heat exchanger in the heat pump may require regular cleaningby a qualified service contractor.

Several studies have shown thata GXS lasts much longer than aconventional fossil fuel furnace andair-conditioning system , as the GXS is not exposed to rain, snow andextreme outdoor temperaturechanges. The earth loop , if installedto CSA standards, can be expectedto perform well for 50 years or more.

Heating Domestic

Hot WaterAfter space heating and air condition-ing, heating water is the largest singleenergy user in most homes. Waterpre-heating capability can be added toyour heat pump simply by includinga heat exchanger into the refrigerant circuit inside the heat pump . Mostheat pump manufacturers offer unitswith a desuperheater . Whenever theheat pump compressor is running toheat or cool your home, water froma conventional electric water heater iscirculated through the desuperheater and heated by the hot refrigerant .When the heat pump is not running,the electric heaters in the hot watertank heat the water. Depending onhot water use, a desuperheater canprovide from 30 to 60 percent of thehot water needed in the averagehome.

Some manufacturers have takenthis concept a step further by offeringheat pumps that can produce all ofthe hot water needed on demand.These heat pumps are designed toswitch automatically from heating andcooling air (by means of a forced-air

system ) to heating water, which canbe used for domestic use or for ahydronic (hot-water) heating system .

The initial cost for this type of unitis higher, but with a large demandfor hot water, the extra cost can berecovered quickly. These units areideal for:

homes with large families and largedemands for domestic hot water;

homes with a hydronic heat distribution system in one part ofthe home and a forced-air systemin others (e.g., radiant floor heat in the garage or basement andforced-air on the main level); and

heating an outdoor swimming poolduring the summer months.

Non-Intrusive and QuietGXS use the earth or ground water to dissipate the heat from your hometo cool it. Conventional (air-cooled)air conditioners or air-source heat

pumps move the heat inside yourhome to the outside. A GXS replacesthe outdoor condensing units of aconventional system with a ground loop or well-water system that isburied underground. With a GXS,the outdoor compressor , fan noiseand space needed for a condensingunit are eliminated, leaving you witha quieter, more peaceful backyard.

Other BenefitsBecause all of the mechanicalcomponents of a GXS are inside,

they are protected from vandalismand the weather. GXS can be appliedto almost any house type and location;the type of system you choose dependson the availability of land or water,soil conditions, local regulations andother factors.



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Home DesignConsiderations

Energy-EfficientHome Design

Your decision to install a GXS in yournew home is a major step towardmaking it one of the most energy-efficient homes in the country. Butyour home is a system, and the GXS

is just one part of it. The other homedesign choices you make will affecthow much you pay for your energy,your future energy costs and howcomfortable you are in your home.These include the following:

the type and level of insulationin its walls, ceilings and floors;

the type of windows you chooseand the direction they face;

how airtight your house is;

the ventilation system;

the types of appliances andlighting; and

the landscaping around your home.

There are many energy-savingoptions you can choose from. NaturalResources Canada offers a wealth ofinformation on how to make your homemore energy efficient. Please consulttheir website at www.oee.nrcan.gc.ca.

When you make your new homemore energy efficient, you also reduce

the size and cost of the GXS you need.You can use a smaller, less costly heat pump , earth loop and distribution system .

Location of In-groundEquipment and Services

Make sure there is adequate clearancebetween the GXS and other in-grounditems like swimming pools, wells andseptic systems. Allow enough spaceto manoeuver the chain trencher ,backhoe , drill rig or other equipmentneeded to install the GXS ; the workshould be done so as to cause as littledisturbance as possible to existingpavements, walkways, easementsand other rights of access. Pipelocations should be drawn on a siteplan to reduce the risk of damagein the future.

The loop should not cross otherunderground services (gas lines, watermains, sewers, buried telephone andelectrical lines); also, you should makesure they are protected from damageand freezing both during installationand after. All installation shouldmeet the CSA standards.

System Designfor a New Home

Heat Pump Selection

How much heat does your homelose? Calculating its heat loss isthe foundation on which your GXS design is built. The care taken in theconstruction of your home determineshow much heat escapes through thecracks around its windows and doors,

and how well its insulation isinstalled.The direction your windows facedetermines how much solar energythey let into the house. The heat losscalculation, therefore, determinesthe size of GXS you need.

Your contractors heat loss calculationsshould be based on the CSAstandardsfor GXS installation. The contractorwill need a set of plans with thedimensions and construction of thewalls, ceiling and floors, and the sizeand types of windows and doorsas well as the direction they face.Winds and trees (which may shadethe windows) also affect heat loss.To measure accurately how tightly

the home is sealed, some contractorswill perform a blower door test .The contractor should give you acopy of the heat loss calculation.

The CSArequires a GXS to have theheating capacity to supply at least90 percent of the total heat requiredin your home annually. Auxiliary heat (usually electric elements installedinside the heat pump or in the duct-work) can supply the rest of the heat.Factors that influence the heatingcapacity you need for your home

include the number of occupants,the appliances and lighting, the solargain through the windows, the qualityof the construction and the climate.

Why does the CSArecommend a GXScapacity of 90 percent (not includingauxiliary heat )? Because it takes all heatsources in your home into account.The lights in your home give off heat.So do your stove, fridge, television,computer and freezer. The sun shiningthrough the windows helps heat yourhome. Finally, the people (and pets) init create a significant amount of heatas well. A heat loss calculation doesnot take this so-called internal heatgain into account. That is why aGXS that produces 90 percent of thecalculated heat loss of your home willnormally provide all of the heat yourfamily needs. And it will cost a bit less.


2GeoExchange Systemsfor a New Home


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An auxiliary heater provides additionalheat on just the coldest days (usually,electric heating elements are installedin the ductwork or built into the heat

pump ). The few hours the electricheat is needed affect your energy billsonly slightly, but can reduce the costof installing a GXS significantly. Andbecause heating is more importantthan cooling in most of Canada,the lower air-conditioning capacity

of the system is acceptable for mosthomes, and will perform betterthan a larger system.

The performance of a heat pumpis rated for both heating and coolingefficiency. This is usually expressedas the Coefficient of Performance ,or COP . The COP in the heating modeis referred to as the COP h, and inthe cooling mode as the COP c . Youcalculate it by dividing the heating orcooling capacity of the system by theenergy used to run it. For example,

if the heating capacity of a systemis 10.4 kW, and the power neededto operate the compressor , pumpand blower is 3.25 kW, the COP his 10.4 3.25= 3.2. Similarly,if the cooling capacity is 10.55 kW(36 000 Btu/h x 0.000293 = 10.55),and the power needed is 2.51 kW,the COP h is 10.55 2.51 = 4.2.(Note: Some manufacturers definethe air-conditioning efficiency of theirGXS as its Energy Efficiency Ratio(EER). The EER, expressed in Btu/hper watt, can be converted to COP c by dividing the EERby 3.413.)

Air-conditioning efficiency can beexpressed in the same terms. Youcalculate the COP c by dividing thecooling capacity of the system bythe energy input. So if the coolingcapacity of a system is 36 000 Btu/h(36 000 x 0.000293 = 10.55 kW),

and the power needed to runthe system is 2.29 kW, the COP c is 10.55 2.29 = 4.6.

The efficiency of a GXS varies as thetemperatures and flows of the liquidand air pumped through the heat

pump change. Manufacturers publishthe ratings of their GXS on the basisof a specific set of standard conditionscalled the ISO 13256-1 rating. The

rating for a closed-loop system iscalled the Ground Loop Heat Pump(GLHP)rating; the rating for anopen-loop or ground water system iscalled the Ground Water Heat Pump(GWHP)rating. When comparingquotations on equipment, make sureyou are comparing the equipmenton the basis of the same standardratings. As with any system, however,your GXS will only meet the perform-ance ratings if the whole systemis designed and installed accordingto the manufacturers specifications.

Loop Size:Is Bigger Better?

You can think of an earth loop asa rechargeable battery permanentlyconnected to a battery charger.Heat energy is drawn from the loop ,or battery, as it is needed in yourhome. If the battery is large enough, itis easily recharged by the heat energyfrom the surrounding ground, sun,rain, heat expelled during the coolingof your home, and heat emanatingfrom the earths hot core. But if yourloop battery is continuously drawndown more quickly than it can berecharged, it will be unable to provideenough energy to run your system.And there is no easy way to rechargeit quickly.

So the ground loop has to meet therequirements of your home. Someof the factors that will affect the sizeof the ground loop you need include:

the heating and coolingrequirements of your home;

the moisture content and typeof soil;

the depth at which the loop

is buried; the climate;

the amount of snow coveringthe loop in winter; and

the size of the buried pipes as wellas the distance between them.

The larger the heating and coolingloads of your home, the largerthe loop must be. Moist, dense soilconducts heat more quickly than light,dry soil. Pipe that is buried deeperhas more soil to draw heat from and

will perform better. A climate withlong cold spells will require a loop(battery) that can hold more heat.Heavy snow cover insulates the earthand helps retain the earths heat.If earth loop pipes are buried fartherapart, they are recharged by a greatermass of soil.

A competent contractor will knowthe soil conditions in your area, andwill design the earth loop on the basisof all these factors. Some heat pumpmanufacturers provide contractors

with computer software to do this.The CSArequires that a closed loopbe installed with a minimum lengthof HDPE on the basis of the variableslisted above.



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units that are switched from heatingto cooling manually to devices thatcan be programmed with a variety ofsettings, and even more sophisticatedcontrol systems that allow you toadjust the temperature of your homeover the Internet. In addition, thereare zone control systems that allowyou to heat or cool different areas ofyour home to different temperatures.

GXS are normally matched much moreclosely to the heating requirements ofyour home than conventional heating

systems . As noted above, the systemsare often slightly undersized and useelectric auxiliary heaters on the coldestdays. A programmable thermostat may actually use more energy here,because as the system is bringing thetemperature of the home up after aset period, the electric auxiliary heater may come on.

Humidifier

Humidity control is an importantfactor in maintaining comfort in yourhome. Fresh air brought into yourhome in winter holds less moisturethan the warm air inside. It can thuslower the relative humidity in yourhome to an uncomfortable level.You may want to consider addinga humidifier .

When you install a humidifier withyour GXS , you should choose onethat does not need a bypass betweenthe supply and return air ducts.

The Cost ofOwning a GXS

Operating andMaintenance Costs

More than two thirds of the energyproduced by a GXS is free energydrawn from the ground. It is easyto see why the energy costs can bemuch lower with a GXS than with

any other fuel, including natural gas.Also, earth-based system maintenancecosts are generally lower than thosefor a conventional heating and air-conditioning system . There aregood reasons for this. A conventional air-conditioning system includes anoutdoor unit used to expel heat fromyour home. This unit bears the bruntof the often severe Canadian weatherconditions that alternate betweensnow and ice in the winter, and heatand humidity in summer. It is alsosubject to the movement of the

ground around your home.This canput stress on the refrigeration lines.Air-source heat pumps are subjectto even more stresses than air-conditioning units because they areexpected to operate year-round.

The heat exchangers of fossil fuel furnaces are subjected to temperatureextremes when they operate. Theyeventually crack from the expansionand contraction of the metal.

The conditions under which an

GXS operates are much less severe.The temperatures of the heat sourceand heat sink (the loop ) are lowerand more constant than those in aconventional air conditioner or air-source heat pump . The temperaturesin the heat pump are certainly less

extreme than the flames of a fossil fuel furnace. This puts less stresson the equipment, and so results inless maintenance. The loop itself issubject only to the relatively constanttemperatures of the earth. Again,very little stress is placed on the pipe,which is virtually maintenance-free.

Again, the air filter of a GXS usinga forced-air system must be cleaned

or changed regularly, as with anyforced-air heating equipment.

Purchase Costs

The cost of installing a GXS canvary significantly in different parts ofthe country. Typically, the cost of theheat pump itself is about the same asthat of a conventional furnace and air conditioner . The cost of installing theheat pump can actually be somewhatlower, as it eliminates the costs of gasline connections, the chimney and apad for the installation of the outdoorairconditioning unit.

The cost of installing the ductworkfor a GXS should be similar to thecost of ductwork for a conventional

system . The cost of installing thedistribution system for a hydronic

system may be slightly higher thanthat of a gas boiler, however, becausethe lower water supply temperaturesfrom a GXS may require theinstallation of more floor heat pipeor a larger radiation system.

The major difference in cost betweena GXS and a conventional heatingand air conditioning system is thecost of the loop . This can vary signifi-cantly from one location to another.



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Electric furnace and air conditioning $9,000

High-efficiency propane furnace and air conditioning $11,000

GeoExchange System $23,000

The Payback

One of the questions people oftenask is, If I buy a GXS, whats thepayback? There are many factorsthat can influence the payback.We can illustrate it by looking atthe following example.

Jim and Donna are planning a160-m 2 house on a large suburbanlot. They want to heat their home asinexpensively as possible. Natural gasis not yet available, but there has beentalk of extending the gas lines pasttheir property in the next year or two.

They are considering an electricfurnace, a propane furnace that canbe converted to natural gas in a yearor two, and a GXS. Here are thequotations for all three options.

The estimated annual fuel costs are as follows:

Heating Cooling Hot Water Total

Electric furnace $1,980 $195 $452 $2,627

High-efficiency propane furnace $2,660 $195 $607 $3,462

High-efficiency gas furnace $1,213 $195 $276 $1,684

GeoExchange System $619 $94 $283 $996

A cash-flow analysis shows you your cash outlay each year for owning and operating a system. If you are financing thecost of your home over a 20-year period, the cost difference to install the heating and air conditioning system is financedas well. For example,

Energy Cost Annual Principal Totaland Interest (5%)

Electric System $2,627 $712.80 $3,339.80GeoExchange System $996 $1,821.48 $2,817.48

Annual cash-flow saving with a GXS $522.32

A simple payback is easy to calculate. Simply subtract the cost of installing one system from the cost of installing the GXS,

and divide by the fuel cost savings. For example,

The simple payback is $14,000 ($2,627 - $996) = 8.6 years.

GeoExchange System $23,000

Electric furnace and air conditioning $9,000

Difference in cost $14,000


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The difference in annual energy costsmore than makes up the differenceof the higher initial cost of installingthe GXS . When you take into accountyour monthly mortgage paymentsand the monthly energy costs of bothsystems, you end up with an extra$43.53 ($522.32 12 months) inyour pocket every month.

Of course, when you take inflation

or rising fuel prices into account,your savings are even higher.

A life-cycle cost calculation takes thecash-flow analysis a few steps further,by adding the cost of inflation on fuel,the cost of replacing your equipmentat the end of its expected life, the costof borrowing the money to install thesystem and other costs. These costsare typically estimated over a 20-yearperiod and are relatively complex tocalculate. But the following points areworth noting:

The estimated life expectancyof the heat pump in a GXS isapproximately 18 to 20 years, orabout the same as a conventional furnace . A conventional air condi-tioner or air-source heat pump canbe expected to last only 1215 years,because the outdoor unit is exposedto the weather.

The earth loop can be expected tolast 5075 years. Even if the heat

pump needs replacement after20 years, the earth loop can beexpected to last much longer.

If the cash-flow analysis shows thatyour annual savings are $522.32per year now, inflation will increasethe value of the savings with thefuel inflation rate.

If you were to invest the annualcash-flow savings in an RRSP at2.5% interest, assuming an annualinflation of 2.5% on the energy

costs, the annual cash-flow savingsof your geoexchange system wouldgrow to be worth $24,402 after20 years.



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In some soil conditions, the contractormay recommend that the dirt remainmounded over the trench for severalmonths, or even for the winter. Thedirt will settle as the rain soaks thetrench over time or the spring runoffbreaks down the larger clumps ofearth. If the extra earth is removed,there probably will be some settling,which will result in a dip in the lawnwherever the trenching was done.

The results are generally better if theearth is allowed to settle naturally.

You can speed up the soil settling bycompacting of the soil every 1020 cmas the trench is backfilled, althoughthe labour cost can be high. Soakingthe soil in the trench can acceleratethe settling process as well.

Once the soil has settled, there will benothing on your lawn to show that a

ground loop is buried on your property.

Effect on AdjoiningStructures

Make sure your GXS is designed so asnot to disturb trees, walls, overheadwires and other landscaping features.Allow space for the trenching or drillingequipment as well as the excavatedsoil. No part of your system or the coil you dig up should cross a property linewithout the written approval of yourneighbour. Also, make sure you avoidcrossing other underground services,like gas and water mains, telephonelines, power cables, sewer linesand drains, and protect them fromdamage or freezing. An earth loopmust never be placed under a septictank or cross the septic systems drain.

In general, GXS piping should beplaced well away from other servicesto avoid damage during repairoperations.

When the earth loop installationis complete, the CSA standardstates that you should make a mappinpointing its location. The simplestmethod of mapping the earth loopis to measure each significant point

of the loop (such as the boreholesand the end of a trench) from twoseparate, permanent landmarks. Forexample, you can plot the location ofa borehole from two corners of yourhome; this creates a triangle betweenthe two points and the borehole ,and makes it easy to find later. A maplike this will be valuable when you(or possibly a future owner) wantto make landscaping changes, suchas installing a decorative fountain orplanting a tree. The map should beplaced in an envelope attached to the

heat pump or some other safe place.If you are considering the purchase ofa home with a GXS already installed,ask for a map or diagram of theloop system.

The CSAstandard also states that atracing wire or tape should be laid inthe trench above the pipe, so the loopcan be located with a metal detector.A wide foil tape can also be laid inthe trench on top of the pipe, to showthat something is buried underneath.

System Design foran Existing Home

Optimum Size

The heating and cooling capacityof the GXS installed in your homeis the single most important factorthat will ensure a comfortable home,long-lasting equipment and anefficient system.

The owner of an existing home,especially an older home, generallydoes not have the house plansshowing the wall construction, ceilinginsulation and other details neededto calculate heat loss accurately.You will therefore need to measureand estimate the insulation value offeatures such as the walls, the ceilingand the windows. This information willbe helpful to the contractor preparinga quotation. Ideally, a drawingshowing the direction the house

faces, the wall dimensions, windowsizes and types, insulation values andother features for each level providesenough information to calculate theheat loss. Since the wind affects heatloss and trees may affect the coolingloads if they shade the windows,information about wind patternsand trees on the property is helpful.Some contractors will also performa blower door test . The contractorshould provide a copy of the heatloss calculation to you.

To double-check the calculated heatloss of the home, some contractorswill ask for the energy consumptionin your home for an entire year. Ifthe insulation has not been upgradedrecently, or you have built additions,the annual energy consumptionfigures can be used to estimate theheat loss of the home.



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In an existing home with a ductworksystem, there is an additional reasonto install a system that provides lessheat than the calculated heat loss.Older fossil fuel furnaces or electricfurnaces were designed to circulateless air than a GXS. It may bedifficult or impossible to upgradethe ductwork to the larger volumecapacity required by a GXS withoutcreating unnecessary air noise.

Remember when you are designinga GXS for your home, bigger is notnecessarily better.

Many of the principles that apply tothe system design of a GXS for a newhome, such as COP h , COP c , ratings forclosed- and open-loop systems andheat load calculations, also apply toexisting homes see System Designfor a New Home on page 15

Alternatives for HomesHeated with Hot Water or

Electric Baseboard HeatersA GXS can be installed in an existinghome with a hydronic (or hot-water )heating system , or a home withelectric baseboard heaters. Here aresome things you should considerif you want to install a hydronic heating system .

Hydronic Systems

There are several types of residentialhydronic systems . They include theold, heavy castiron radiators; the

more modern, compact baseboardradiators; and radiant floor heating .There are also systems that use hotwater to transfer heat to a forced-air

system by means of a fan coil unit .

Each of them can be used with aGXS, although there are presently noheat pumps that can produce waterwarmer than 50C, so the heating

capacity of the distribution systemmay be reduced. Many existinghot-water heating systems will notdistribute enough heat to yourhome unless used with water at atemperature greater than 6570C.

If you have recently upgraded theinsulation and airtightness of yourhome, however, its heat loss mayhave been reduced enough to allow

you to use a water temperature lowenough to install a GXS. Therefore,it is important that your contractorcalculates your homes heat lossagain, once the insulation work iscompleted.

Cast-Iron Radiators

These decorative heavy radiators weredesigned for use without a protectivecover. As they are often locatedwhere people could come into contactwith them, the systems were usuallydesigned to operate at about 5055C.A GXS is capable of generating50C and, with some upgrading ofthe windows and insulation in thehome, should work satisfactorilywith these systems. The piping to theradiators will almost certainly needupgrading, however. Contractors havesuccessfully used 12, 19 or 25 mmflexible PEX tubing to run new linesto the radiators.

Baseboard Radiators

Most baseboard radiator systems were

designed to be used with 6070Cwater. As a result, they are notcompatible with a GXS. The heatingcapacity of a baseboard radiator dropsby 3050 percent when supplied withwater at 50C. In most situations, itwill be difficult to make a GXS workwith baseboard radiators withoutinstalling many additional units.

In-Floor Heat

In-floor heating systems are oftendesigned for use with water tempera-tures lower than ones compatiblewith a GXS. However, if the systemin your home uses pipe installedin the void between the floor joistsrather than in concrete or withmetal reflector plates, it probablywill need water temperatures hotterthan those produced by a GXS.

Fan Coil Units

The heating capacity of a fan coil unit is directly related to the temperatureof the water circulated through it.You should have the capacity of theheating coil tested to ensure it is ableto distribute enough heat to yourhome with a GXS.

Before deciding to use the existinghot-water distribution system , thecontractor should determine that

the distribution system will heatyour home properly at the lowerGXS water temperatures.

Electric Baseboards

Electric baseboards use electricalenergy to heat the room in whichthey are located and do not use aheat distribution system . There aretwo options. The first is to build adistribution system into your home either forced-air or hydronic anduse the appropriate GXS. The secondis to use heat pumps designed to heata small space without a distribution

system . Several manufacturers buildconsole-type heat pumps in varioussizes. They are designed to be mountedagainst a wall and both heat andair-condition a single room withouta distribution system . They aretypically 120130 cm in length, 60 cmin height, and about 25 cm deep.



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Air Conditioning

Existing homes without a forced-air distribution system can be difficultto air-condition. Some types of heat

pumps , like water-water models, forexample, are able to provide chilledwater that can be used in air-condi-tioning systems. However, mosthydronic heating systems are notdesigned to provide cooling. Whena castiron or baseboard radiator, orinfloor heating system , is cooled withchilled water, condensation forms onthe cold surface of the pipes throughwhich the water is circulated. Sometypes of fan coil units can be usedfor air conditioning through the useof chilled water, but the condensationmust be collected in a condensatepan under the water coil . Also,the pipes through which the chilledwater circulates must be insulated.

It might also be appropriate to useconsole-type heat pumps (see theprevious section Electric Baseboards)to provide cooling in some areas of ahome heated with a hydronic system .

Some manufacturers produceequipment that can heat water foruse with a hydronic system and alsoheat or chill air for use in a forced-air

system . With this equipment, it maybe possible to add some ductworkto your home for air conditioning,while keeping your existing hydronic distribution system to provide heat.

Possible Upgrades

Upgrading Air Filters

See page 17 for a discussion on airfilters. Whatever your filter type,you must change or clean it regularlyto maintain the efficiency of yourheat pump .

Adding a HeatRecovery Ventilator

You can improve the indoor airquality of your home by adding aheat recovery ventilator (HRV) . Addingan HRV is also a good idea if you areimproving the sealing and insulationof your home while installing a GXS.A more airtight R-2000 home, forexample, will take in less fresh air andso justify the installation of a separatefresh-air distribution system incorpo-rating an HRV . This device adds freshair to the home,but preheats it with anair-to-air heat exchanger that transfersheat from an equivalent flow of airleaving the home. Thus the air balancein your home is maintained, while yourecover some 6080 percent of theheat energy that would otherwise beexpelled from your home.

The installation of an HRV willincrease the energy consumption ofyour home if it has no fresh air systemat all, because even though the airis preheated by the expelled air, theHRV cannot recover all of the heat.When compared to a fresh air systemwith no heat recovery, however,an HRV saves you energy costs. Thedevice can be integrated into yourexisting forced-air system or addedas a separate system to your home.

Controls

See pages 17 and 18 for a discussionon controls for a GXS in a new home.

The same controls apply to an existinghome, with some differences in theway you control the humidity.

If you are changing to a GXS froma gas or oil furnace, you will be lesslikely to need a humidifier, as the dryoutside air being drawn in to meet thecombustion demands of the furnacewill no longer be a problem.

If you plan to install an HRV , theamount of dry outside air entering thehome increases and a humidifier maybecome necessary. If you are installinga GXS and planning to use yourexisting forced-air distribution system ,it would be better to replace thestandard bypass humidifier with anon-bypass type. A bypass unit willlower the performance of the heat

pump and reduce the quantity of air

delivered to the registers. If you arekeeping your current hydronic systemas your heating distribution system , aportable humidifier may be an option,particularly if you are adding an HRV to the system.

Removal ofExisting Equipment

If your existing furnace will not beleft in as a backup system, you mustmake sure that it is removed at the

conclusion of the contract. Equallyimportant, the gas line should bedisconnected and capped properly;similarly, the oil tank must be removedand the filler hole cemented. Also,be sure to cancel any fuel supply orservice contracts oil has sometimesbeen delivered to a house wherea tank had been recently removed,but the fill line had not yet beenplugged or removed.



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Chosing theRight Specialists

The design of your GXS should not becontracted out to the first contractorwho comes around. Even though, forseveral years, certain individuals havetried to persuade clients that a simplethree-day course renders them expertsin geoexchange, the reality is nonebut the contrary. In the majority ofcases, provincial (and sometimesmunicipal) regulation requires that thework be completed by professionalsholding refrigeration or plumbingpermits and licenses as well as othertrades. Ensure that the employeesyou hire for the design and installationof your GXS hold all required authori-zations and necessary permits.

A contractor who can perform anaccurate heat loss calculation of yourresidence.

Beyond the industry professionalsexpertise, you need to do businesswith a reliable contractor who willadequately supervise the work. Yourchoice of installing a geoexchangesystem is an important investment.Therefore, it is crucial that yourapproach includes at least thefollowing steps:

Shop at serious and reputableretailers. For a list of CGC-qualified companies, visitwww.geoexchange.ca

Get a minimum of three estimates,from three different contractors.The estimate should give enoughdetail for you to assess the costsassociated with the heat pump, thedrilling, the design of the system,

the system installation, and all otherwork and related equipment like airdistribution systems, the installationof a desuperheater, etc.

Compare the price and characteris-tics of the units. In his/her quote,the contractor should clearly indi-cate the make, the model number,and the capacity of the unit.Visit manufacturers websites andbrowse distributors catalogues.Ensure that the units you arebeing offered meet the standards,

especially concerning performance.

Analyse the warranty offers.Warranties on heat pumps usuallyvary between 1-10 years andare offered by the manufacturerwhereas warranties on certainrelated equipment and labour,offered by the contractor, areindicated in a few lines on thereceipt.

Dont hesitate to ask questions.A conscientious contractor will seethat you are a serious customer andwill give exhaustive explanations.

The best way to ensure that thecontractor you chose is reliable andexperienced is to obtain referencesfrom previously satisfied clients. TheCanadian GeoExchange Coalitionwebsite has an up-to-date list of CGC-accredited installers and residentialsystem designers as well as a list ofCGC-qualified firms.

Also be weary of promised energy

savings. If a contractor makes you aquote that seems too good to be true,there is probably something fishygoing on. If a contractor insists onsuch promises, request that these bespecifically included in the contract.

Finally, be weary of promised rebatesand grants. Several public and privateorganizations offer incentive programsand financial aid of all kinds. Theseprograms each have their allocationrules, delays to respect, instructionsand limitations, obligations for the

consumer or for the contractor, etc.Even though your contractor mightbe generally well informed of theseprograms, he/she cannot be up todate on all the rules and particularitiesof each one. As the consumer,it is up to you to gain a properunderstanding of these programsby doing the necessary research.


4ContractorSelection


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A Basic Contract

Before signing a contract, ensure thata GXS installation is authorized inyour municipality and inquire aboutany required permits. Inquire aboutwhether there is a municipal by-lawto this effect, and if so, read it.

Once you have chosen your contractor,make sure that the contract providesdetails on each of the following:

The contractors permit number(s)(these can be municipal orprovincial permits);

Full coordinates of all parties;

The date of the contract andaddress of where it was signed;

Breakdown of the tasks;

The work involved at each stage;

A list of equipment;

A breakdown of costs for thematerial and labour and the priceof each good or service;

A payment schedule.

In addition, the contract shouldspecify who is responsible for reland-scaping the property and internalrefinishing, as the job is not completeuntil this work is done.

It should include the calculation ofthe heating and cooling loads forthe home, any required changesor upgrades to the ductwork, fansor filters and the electrical system,

as well as the installation and start-upof the GXS. The refurbishment ordecommissioning and removal ofexisting equipment might also beincluded. The contract must name theperson responsible for approvals andcertifications of the job and mustclearly set out warranty terms to allowa proper contract comparison. MostGXS heat pump units are coveredby a one-year warranty on parts andlabour, and a five-year warrantyon the compressor.

Never accept to conclude a verbalagreement. Without a contract andin case of mediocre work, rememberthat you have little or no recourse.Ensure that all items presented inthe initial offer are reflected in thecontract. Before signing a contract,verify the terms and conditions andread the fine print.

In several provinces, the lawprohibits a roving merchant toask for instalments. If the contractoryou are considering is not a rovingmerchant, negotiate the paymentinstalments based on the progressof the work and the delivery of equip-ment. In 2008, several consumers lostconsiderable sums of money followingbankruptcy of certain contractors.

Never pay an instalment that seemsunreasonable to you. Regulation oninstalments varies greatly from oneprovince to the next. Before commit-ting financially, consult provincialconsumer protection bodies.



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The CGC Global QualityGeoExchange Program

What Is the difference betweentraining, accreditation, and certification?

These three expressions solidaryyet distinct are the basis of theCanadian GeoEchange Coalitionsglobal quality initiative in geoexchangetechnology. The program includesfour important steps.

Training means that individualscan sign up to take one of four train-ing courses (chosen according to theirsector of specialization) and challengean exit exam. There are three distincttraining courses for installers anddesigners of residential systems andfor designers of commercial systems.

Accreditation means that individuals

have taken CGC training, havesuccessfully passed the examination,and have applied for an individualaccreditation. Different accreditationsare available for vertical loop installers,system installers, residential systemdesigners and commercial systemdesigners. Accreditation requires thefollowing:

Passing grade on the CGCexamination;

Credit check where required by law;

Proof of insurance and coverage

where required by law;

Contribution to five completedGXS installations;

Agreement to the CGC code ofconduct, etc. for two years.

Company qualification means thatcompanies who hire CGC-accreditedindividuals for the installation ofvertical loops, or the installation ordesign of systems, either as full-timeemployees or as sub-contractors, meetthe quality of work and ethics criteriaestablished by CGC. This step helpsCGC filter the serious companies fromthe less scrupulous ones. A companywho does not respect the codeof ethics established by CGC losesits accreditation and its name isremoved from the CGC website.

System certification takes place oncea system certification application isapproved by CGC. Certification meansthat the system was designed by anaccredited designer, installed by anaccredited installer, and that all thegeothermal well construction workwas performed by a qualified drillingcompany. In order for a system to becertified, it must be in line with CSAsC-448-02 standard, incorporate allmaterials and devices authorised byISO and CSA, and must be subtendedby best practices (ex: providing theas-built book to the homeowner,precise labelling of each pipe andvalve, verification and inspectionensuring the systems conformance

with all provincial regulations, etc).

Self-installs A bad idea

If you are suffering from acuteappendicitis, you probably wouldntthink to cut open your abdomenand proceed to the removal of yourappendix. The same goes for thedesign and installation of your GXS.

Certain installers ask you to playsorcerers apprentice by selling youinstallation kits at trade shows, innewspaper ads or even via internet.Flee these propositions!

Even if youve got talent or experiencein construction, self installation isnever a good idea. First of all, a self-install might not respect municipal orprovincial regulations and, if problemsarise, could nullify any heat pumpmanufacturers warranties.

A heat pump installation also involveshandling sometimes dangerousrefrigerant products as well aselectrical and plumbing work which,without being complex, must bedone by industry professionals. Again,if problems arise, your residentialinsurance might not cover thedamages caused to your property.

The several thousand dollars saved bydoing a self-install could, at the end ofthe line, represent tens of thousandsof dollars of losses and damages.Why take such a risk?


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As with any mechanical equipment,the unit will eventually not workproperly or stop altogether. Here aresome things you can check beforeyou call your service contractor.

Check the air filter.

If the energy produced by a heat pump is not removed and distributedto your home quickly enough, thepressure in the refrigerant system willshut the unit off automatically beforeit gets damaged. If the air filter isclogged enough to prevent adequateair flow through the heat pump , italso will shut down. Cleaning the filterwill restore the air flow. Never operatethe unit without an air filter, as themanufacturer may void the warranty.It also may be possible that some ofthe supply air or return air registers inthe home have been blocked off (forexample, painters may have blockedthe registers in some rooms whilepainting).

Make sure the thermostatis set properly.

If the thermostat setting is changedaccidentally, the unit may not receivea signal to heat or cool your home.Some thermostats have a separateswitch that controls whether thesystem heats or airconditions. Othersmay also have warning lights toindicate a problem with the system.

Check whether anydisconnect switchesor circuit breakers forthe heat pump are on.

Heat pumps with an electric auxiliary heater usually have separate circuitbreakers for the heat pump compressor and the auxiliary heater . If the circuit

breaker trips when you switch iton again, contact your contractor orservice company immediately.

Check the power supplyto the circulating pump.

The pump on most GXS with aclosed loop takes its power fromthe heat pump itself, although it cansometimes have a separate powersupply. The well pump for an open-loop (ground-water) system willprobably have its own pow

article58 residential geothermal buyers guide 2009

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