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This comprehensive compilation of DOE documents provides unique and practical information about geothermal heat pumps, including small geothermal systems and DIY systems. Contents: Chapter 1: Small Geothermal Systems: A Guide For The Do-It-Yourselfer * Chapter 2: Using The Earth To Heat and Cool Buildings * Chapter 3: An Information Survival Kit For The Prospective Geothermal Heat Pump Owner * Chapter 4: Success Stories of the Geothermal Energy Program * Chapter 5: Ground-Source Heat Pumps: Overview of Market Status, Barriers to Adoption, and Options for Overcoming Barriers A heat pump-like an air conditioner or refrigerator-moves heat from one place to another. In the summer, a geothermal heat pump (GHP) operating in a cooling mode lowers indoor temperatures by transferring heat from inside a building to the ground outside or below it. Unlike an air conditioner, though, a heat pump's process can be reversed. In the winter, a GHP extracts heat from the ground and transfers it inside. Also, the GHP can use waste heat from summer air-conditioning to provide virtually free hot-water heating. The energy value of the heat moved is typically more than three times the electricity used in the transfer process. GHPs are efficient and require no backup heat because the earth stays at a relatively moderate temperature throughout the year. A GHP system has three major components: a ground loop (buried piping system), the heat pump itself (inside the house), and a heating and cooling distribution system. There are two main types of GHP systems. The earth-coupled (or closed-loop) GHP uses sealed horizontal or vertical pipes as heat exchangers through which water, or water and antifreeze, transfer heat to or from the ground. The second type, the water-source (or open-loop) GHP, pumps water from a well or other source to the heat exchanger, then back to the source. Because of their versatility, earth-coupled systems dominate the GHP market. Typical loop installations for the earth-