What Is A Geothermal System And How Does It Work?

GeoExchange systems are the most cost effective HVAC systems for buildings.  They have the lowest life-cycle costs and the smallest carbon footprint.  They recover solar energy stored in the earth and transfer in into buildings.  They can be also be used to cool buildings by transferring heat from the building to the earth.  Because the earth’s temperature is very stable, they operate at extremely high efficiencies.

Every day, the earth absorbs over half of the sun’s energy. GeoExchange (also known as or Earth Energy) systems rely primarily on this stored solar energy to heat or cool a building and provide domestic hot water.  Electricity provides the power required to extract heat from the earth.  For every kW of electricity used by a geo system, anywhere from 3 to 6 kW of heat energy are pulled from the earth.

The link with the earth is done in two basic ways: open loops and closed loops. In open loop systems, water is pumped from a well.  Issues here include water quality, water management, and sustainability.  Closed loop systems are most common, and are often preferred for their reliability and low maintenance.

Closed loops use a network of High Density Polyethylene (HDPE) pipes to transfer heat to and from the earth. The pipes can be inserted into vertical boreholes, buried in horizontal trenches, or submerged in the ocean, lakes, or rivers.

The magic in the system is the ground source heat pump, which concentrates heat from the earth and transfer it into a building. The system can be reversible to provide cooling.  This isn’t new technology; the first GeoExchange system was installed over 50 years ago!  A common example of a heat pump is a refrigerator, where heat is transferred from the inside of the fridge to the room through the black grill on the back.

By transferring thermal energy rather than creating it through combustion or electrical resistance, GeoExchange systems achieve very high efficiencies. For each unit of electrical energy consumed by a heat pump, three to four units of heat energy are moved from the earth to your building.

What Is The Average Cost Of Installation?

Installation costs are specific to each site and can start as low as $20,000 for an entry level system in a 2000 square ft. home.

Factors affecting installation costs include the heating and cooling load assessment, the usage of the system, the inclusion of domestic hot water or not, the type of distribution system used inside the building, and the thermal conductivity of the local soil.

We have included a link to a Canadian GeoExchange Coalition’s publication “The Buyers Guide to Residential Ground Source Heat Pump Systems” that we feel is a useful tool for those that are serious about working out the dollars and sense for themselves.

If you would like more information on your specific system contact us for a quote.

Bottom Line: What Is The Payback Period?

Some people just want to look at the numbers. Are you wondering how cost-effective a geothermal heating and cooling system would be for your project?

Below is a Canadian Geo Exchange publication that we feel is useful to those who want to evaluate both the energy and cost savings a Geo system will produce. The download includes a work sheet that will help you to figure out just how much it will cost you per month to heat your home using a variety of different fuels. If hitting the books isn’t your thing consider asking us to conduct a feasibility study on your project.

CGC Buyers Guide for Residential Ground source Heat Pump Systems

What Kind Of Equipment Do You Use?

People ask us what a the geothermal equipment looks like and what brands we use.

Over several years of installing geothermal systems, we have used many different brands and models.

We choose equipment on a case-by-case basis, but to give you an idea, here are a few different kinds of heat pumps.

What Are Some Good Geoexchange / Geothermal Links?

Here are some useful resource sites we recommend in addition to the information we have provided here on www.exchangenergy.ca.

Enjoy!

Geoexchange Links

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• Canadian Geoexchange Coalition www.geo-exchange.ca
  
• GeoExchange BC: www.geoexchangebc.ca
  
• BC Hydro: High Performance Building Program: www.bchydro.bc.ca
  
• Terra Firma Builders: www.sirewall.com
  
• inter solar: www.intersolar.de
  
• Tekmar Controls: www.tekmarcontrols.com
  
• UPONOR Radiant Floors:  www.uponor.ca
  
• Chillventa 2010: www.chillventa.de

ADDITIONAL LINKS:

• www.digtheheat.com
  A guide to Renewable Energy including geothermal power and ground source heat pumps, solar power, wind energy, biofuels, green investment and government incentives. Clear explanations with examples, illustrations and videos.

Natural Resources Canada

Twin, 5-Ton Independent Heat Pumps On A Primary / Secondary Loop

This unique installation features two independent pond loops which allow us to test, side-by-side, different antifreeze compounds, flow rates, and loads.

The ponds are 1,100 feet away.

6,500 sq.ft. of radiant floors, full output DHW, and pool.

All circ pumps have PT ports to monitor and adjust flow rates, never seen on residential projects.

Geothermal Heating Solutions Video

How A Heat Pump Works Video

Geothermal House Design Video

Geothermal Heating and Cooling Video

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