Geothermal Heat Pump
From Swikipedia
Introduction
A geothermal heat pump uses the constant temperature of the Earth’s interior to efficiently control the heating and cooling of a structure. In simple words, it is a central heating and/or cooling system that pumps heat to or from the ground.
Brief Description
Geothermal heat pump uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geo-solar system with even greater efficiency.
Geothermal heat pumps are also known by a variety of other names, including geo-exchange, earth-coupled, earth-energy or water-source heat pumps. Ground source heat pumps harvest a combination of geothermal power and heat from the sun when heating, but work against these heat sources when used for air conditioning.
Heat pumps provide wintertime heating by extracting heat from a source and transferring it to the building. In theory, heat can be extracted from any source, no matter how cold, but a warmer source allows higher efficiency. A ground source heat pump uses the shallow ground as a source of heat, thus taking advantage of its seasonally moderate temperatures.
In the summer, the process can be reversed so the heat pump extracts heat from the building and transfers it to the ground. Transferring heat to a cooler space takes less energy, so the cooling efficiency of the heat pump gain benefits from the lower ground temperatures.
Geothermal heat pumps use electricity, in a way that benefits the customers.
• It provides a steady base load (load form the earth's crust) for utilities, avoiding the sharp peaks of electricity
• The system uses electricity to move heat, and as the heat is already available in the ground they use a lot less electricity
• It provides more BTU's per kilowatt-hour as compared to any conventional air conditioning system
References:
http://www.homedesignersoftware.com/green/green-glossary.html
