How does a geothermal heating & cooling system work?

The temperature of the Earth’s core is over 4,000 degrees Celsius, with the inner heat radiating outward from the core and heat from the Sun radiating inward from the Earth’s surface.  In the province of Ontario, the Earth’s temperature stays constant in the top 200 meters of the crust, ranging from 6-11 degrees Celsius depending on the region’s seasonal temperature.

 

Geothermal HVAC systems utilize energy extracted from the Earth and is able to dependably distribute heating and cooling no matter what the climate as the energy extracted remains at a constant temperature throughout the year.

10

Myths about Geothermal Heating and Cooling

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There are two ways to harness the Earth’s energy

OPEN LOOP

An open loop system pumps water from a body of water (well, pond or lake) and returns it to surface water or an injection well.

CLOSED LOOP

A closed loop system utilizes a grid of pipes to pump heat transfer fluid through either a horizontal or vertical circuit of underground piping between the ground and the building.

In the winter a building is heated by collecting heat from the Earth and brought to the heat pump which concentrates the heat and supplies it to the building at 35 degrees Celsius.  This process produces 3-4.5kW of heat for every kW of electricity used.  Similarly, in the summer the heat pump removes the heat from the building, transferring it to the Earth.  As the Earth is cooler than the air in the summer, this system allows for efficient air conditioning consuming 50-70% less electricity than conventional air conditioning systems.

Watch how geothermal heat pumps heat and cool buildings by concentrating the naturally existing heat contained within the earth... a clean, reliable, and renewable source of energy.

To heat or cool a building, an electric heat pump is used to concentrate the energy in the fluid from the Earth, using technology similar to that used in refrigerators.  The system can be used with both forced-air and hydronic (hot water) heating systems.

 

 

There are both environmental and financial benefits to using a geothermal HVAC system.

 

With the prediction of the future decline in production of fossil fuels, governments worldwide need to develop energy conservation strategies that include an increased use of renewable energy.  By harnessing the heat from the ground, a geothermal system reduces the dependence on fossil fuels and subsequently the building’s overall carbon footprint.

 

The increased efficiency and lower consumption of electricity than conventional systems make geothermal systems a more cost-effective option in the long run.  The initial investment of installing a geothermal system is offset by the monthly savings in utility costs, which are only moderately affected by the fluctuating fossil fuel and electricity costs.  When properly installed, the piping in the earth has a very long shelf life and the maintenance expenses have proven to be less expensive than solar, wind and traditional power sources.

 

 

The Benefits of Geothermal

FAQ – Frequently Asked Questions

  • How much does it cost to install a geothermal system?

    The cost of installing a geothermal system depends on the type of system you choose.  You can have an open or closed loop and it can use forced air, hydronic baseboard or radiant floors for heating and cooling distribution within the building.  The initial installation cost is higher than a conventional HVAC system but the operation costs are far lower.  For a quote on what it would cost to install a geothermal system in your home or building, visit http://www.hrai.ca/contractor-locator to find a geothermal contractor near you.

  • Can a geothermal system heat my pool?

    Solar power is a better alternative for heating outdoor pools but geothermal is an efficient way to heat indoor, enclosed pools.

  • Is it possible to retrofit a home or building using oil or gas hot water heat to geothermal?

    It is possible but it basically requires that an entirely new system is built from scratch since hydronic systems use copper or aluminum hot water baseboards, cast iron radiators or radiant heat, all which operate at much higher temperatures than geothermal systems can handle.

  • Can a lake, stream or pond be used as the geothermal source?

    Generally not in extremely cold climates.  Water is not the heat source; it is a heat transfer fluid heated by the earth and is required to maintain a constant temperature.  Therefore, the water must be brought up from below the frost line in colder climates where the ground freezes in the winter.

  • Is geothermal recommended for summer homes?

    If a home is used solely during the summer months and completely closed down during the winter season (including draining all water pipes), it is not recommended to install a geothermal system.

  • What advantages are there for installing a geothermal system in a commercial building?

    The heating and cooling costs as well as the demand costs are significantly lower on a geothermal system than a conventional fossil fuel system.  It is also quiet, safe and trouble free.

  • What are the major benefits to home/building owners compared to conventional HVACR systems?

    • Lower utility bills

    • Less maintenance

    • Higher levels of even indoor comfort year-round

    • Environmentally friendly: geothermal systems burn no fossil fuels and therefore produces fewer greenhouse gas emissions

    • Safer to occupants relative to fuel burning systems as it eliminates major potential sources of CO within the home or building

    • Waste heat removed from the house or building during the cooling season can be used to provide virtually free hot water for

       additional cost savings to the end user

  • Are there uses for geothermal systems other than heating and cooling?

    Units can include a component to heat water for potable or sanitary use.  Heat pumps can also be used to control condensation to dehumidify moist indoor spaces such as indoor swimming pool areas.

  • How does a geothermal system differentiate from a conventional system?

    Geothermal systems do not use combustion to make heat unlike fossil fuel systems.

  • What is the difference between geothermal systems and air-source heat pumps?

    Air-source heat pumps extract thermal energy (heating or cooling) from the outside air whereas geothermal systems extract energy from the ground.

  • Can you integrate geothermal with a HRV unit?

    Home/building owners interested in providing fresh air and enhanced defrosting without creating negative pressure inside can integrate the geothermal system with a heat recovery ventilation (HRV) unit.

  • Can a home or building owner install a geothermal system on their own?

    It is highly recommended that all HVACR systems, including geothermal, are designed and installed by qualified and certified (licensed) contractors.  For a list of geothermal contractors near you, visit http://www.hrai.ca/contractor-locator.

  • Can a geothermal system be located in a septic bed?

    No.  The CSA Standard (CSA C448) bans placing a ground loop near septic systems.

  • How long does it take to install a geothermal system?

    This depends greatly on the soil conditions and the length and depth of the pipe required.  A qualified geothermal contractor will be able to offer more information based on your specific needs.  To find a qualified geothermal contractor near you, visit http://www.hrai.ca/contractor-locator.

  • Are there factors that can decrease the performance of a geothermal system?

    Based on the assumption that the system was properly designed and installed, the following factors could potentially affect the performance of a geothermal system:

    • Dirty air filters (fixed by cleaning the air filters)

    • Air trapped in the ground loop (fixed by purging the ground loop)

    • Declining anti-freeze levels (fixed by adding more anti-freeze to the loop)

    • Mis-setting the thermostat (human error – fixed by setting the thermostat at the correct temperature)

    • Dropping water table or increased mineral content in the ground water

  • What happens to the performance of the geothermal system when the temperature outside gets really cold?

    The temperature of the ground below the frost line maintains a constant temperature and is not generally affected by the outdoor ambient temperature.

     

    Should you have specific questions regarding the installation, cost or performance of a geothermal system, please visit

    http://www.hrai.ca/contractor-locator for a listing of geothermal contractors near you.

     

    Additional information is also available via the Canadian GeoExchange Coalition’s Frequently Asked Questions page at

    www.geo-exchange.ca/en/geoexchange_faq1.php.

     

    If your questions have still not been answered, email your inquiry to us and a representative from the Ontario Geothermal Association (OGA) will respond to you.

Additional information is also available via the Canadian GeoExchange Coalition’s Frequently Asked Questions page at

www.geo-exchange.ca/en/geoexchange_faq1.php.

 

If your questions have still not been answered, email your inquiry to us and a representative from the Ontario Geothermal Association (OGA) will respond to you.

Find a local geothermal contractor

Should you have specific questions regarding the installation, cost or performance of a geothermal system, please visit

http://www.hrai.ca/contractor-locator for a listing of geothermal contractors near you.

VISIT HRAI’s ONLINE CONTRACTOR LOCATOR TO FIND AN OGA CONTRACTOR IN YOUR AREA

FIND A CONTRACTOR

The OGA is an affiliated association of the Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI)

 

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