How to Heat and Cool a Home with Geo Thermal Power
If you've ever been in a cave, you've learned the reason why geothermal heating and cooling can be so effective. Below six feet, the earth tends to retain the environment's average annual temperature which is the key to geothermal heating and cooling.
Geothermal heat pumps are very efficient, using as little as half the energy of conventional heating and cooling systems. Unlike conventional heating, ventilation, and air conditioning, (HVAC) system, you're burning no fossil fuel on site. The major draw back is price which is usual double that of other HVAC systems, but over the system's usual life it will pay for itself several times over.
Geothermal heating systems consist of several components:
- Difficulty:
- Easy
Instructions
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The ground loop is the heart of the system. It consists of a series of pipes carrying environmentally safe refrigerant that run through the earth at a typical depth of six feet. The pipes can also be installed on the bottom of a pond or lake with a comparable constant water depth. The refrigerant flowing through the pipes either picks up heat retained by the earth or dissipates heat depending on the season.
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Piping is usually either high-density polyethylene with fused joints or copper. The length of the loop depends on the heating, air conditioning and hot water demands of the home and the local climate. A good rule of thumb is to estimate that a loop will take 400 to 600 feet of length per ton of heating and cooling capacity. The loop is installed vertically where space is at a premium.
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The refrigerant is pumped into the home where it is handled by electrically driven heat exchangers and compressors analogous to what happens in a refrigerator. In the heating cycle, the refrigerant is compressed turning it into high temperature, high-pressure liquid which will dissipate heat into the surrounding air. Before the refrigerant is sent back to the ground loop, it's allowed to expand where it becomes a low temperature, low pressure gas which absorbs heat. In the summer, the process reverses drawing heat from your home and carrying it back into the ground.
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Variable speed fans push the hot or cold air through ducts that reach all parts of the home. In some systems you'll find a single box that contains both the heat exchanger and fan, referred to as the air handler
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A desuperheater can be added to provide hot water. In the summer, heat that would be simply dissipated in the ground can be diverted to heat your home's hot water tank, dropping your cost for heating water to practically zero. In winter the desuperheater would divert heat used in the heating cycle. When the outside temperature is moderate and your HVAC system is off, you'd rely on conventional hot water heating.
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Tips & Warnings
Hire a reputable contractor recommended by your local utility, the International Ground Source Heat Pump Association or the Geothermal Heat Pump Consortium
Choose a system that is certified by the non profit Air-Conditioning and Refrigeration Institute that carries the ARI seal.
Make sure you get a warranty on the entire installed system, typically 20 or more years.
Installing a geothermal heat pump is not a do it yourself project. To see if a system like this is appropriate, undertake a thorough analysis of a home's heating and cooling needs before beginning construction.
