Saskatchewan's Green Directory Helping Saskatchewan choose a better environment

The word geothermal has come to be used for two different things.

True geothermal energy is energy extracted from hot rocks at depth; the means to do this is not within reach of the typical Saskatchewan householder.

In common terms, however, it has also (not strictly accurately) come to mean a heating system based on ground-source heat pumps (GSHPs). In such a system most of the heat is pumped from a lower to a higher temperature (from the ground to the house), but the laws of thermodynamics require that in order to do this a certain minimum electrical input is required.

• A discussion to help you decide if a ground source heat pump is the best option for your situation.

What to look for

Consider the following when selecting a GSHP:

Proper Sizing

Make sure the heating capacity of the heat pump is not too high for your home. You can get an estimate of the capacity you need in a number of ways. If you have had an EnerGuide for Houses or ecoENERGY evaluation carried out on your house, it is possible to calculate the heating capacity you require from the annual heating and hot water estimate. Or if you have reliable fuel consumption data for a full year you can run a similar calculation. Or hire an energy consultant / HVAC engineer / building physicist to estimate your heating requirement.

Standard “efficiency” rating

How much heat can a given model provide per unit of electricity used? This is measured by the heating coefficient of performance, or COP_h: this is the principal criterion on which we have created the list of approved units.

Local “efficiency”

The actual COP_h of a heat pump depends on the temperatures across which it is operated. Given that the Saskatchewan winter is somewhat colder than the standard test conditions, it is worth asking your supplier: what is the seasonal average coefficient of performance of the unit in typical Saskatchewan conditions? Our criteria in this section are based on Canadian standards. Because of climatic differences, these may be expected to give somewhat different results from the US figures quoted on some manufacturers’ websites.

Heating only, or also summer cooling?:

GSHPs can be used in both modes. If you intend to use it as an air conditioner, you should consider the EER or COP_c rating for the unit.

What working fluid is used?

(see the discussion of working fluids in the section on air conditioners) Future editions of this directory will apply a further criterion to exclude ozone-depleting working fluids.

Your supplier/installer

Designers and installers of heat pump systems should be able to demonstrate accreditation through a credible institution. At present we are aware of two such training and accreditation schemes: The Canadian GeoExchange Coalition is a Canadian industry-driven initiative: http://www.geo-exchange.ca/ The International Ground Source Heat Pump Association , based at the University of Oklahoma, is an independent US non-profit organisation with international outreach: http://www.igshpa.okstate.edu

EnergyStar

Does the unit have EnergyStar certification?

Government Grants

Grants are available in certain circumstances for GSHPs from two government programmes: EnerGuide for Houses (Saskatchewan) and ecoEnergy Retrofit (federal).

Criteria