Other Types of Heat Pumps Heat pumps can extract heat from more than just the air to provide heating and cooling to a home. Air source heat pumps extract heat from the surrounding air to provide warm or cool air for a home. Heat pumps can also extract heat from the air to heat water stored in a tank. These are commonly called air-to-water heat pumps. Heat pumps can also extract heat from the ground or water to provide heat. These are commonly called ground source, or geothermal, heat pumps. Ground Source Heat Pumps. Ground source heat pumps, also known as geothermal or water source, use the relatively constant temperature of the earth or ground water as the exchange medium instead of the outside air like an air source heat pump. A ground source system is ideal for: • New homes. • Homes with large lot size for ground loops or wells. • Homes with existing ductwork where modifications can be made. • Small duplexes and triplexes where multiple units can share a single well. • Introducing central air conditioning. • Replacing a heating system for low temperature in-floor heat. • Replacing a central air conditioner and/or furnace. • Reducing reliance on propane or fuel oil. Even though we experience seasonal temperature extremes in the Midwest—from scorching heat in the summer to sub-zero cold in the winter—a few feet below the earth’s surface the ground remains at a relatively constant temperature. Since the earth absorbs heat energy from the sun, ground temperatures range from 45°F-75°F. Much like your basement the ground temperature is warmer than the air outside during winter and cooler than the air outside in summer. The ground source heat pump takes advantage of these stable temperatures to be highly efficient and exchanges heat with the earth through a ground heat exchanger. The biggest benefits of ground source heat pumps is they use up to 50% less electricity than conventional heating or cooling systems and the ground loops can last up to 50 years. According to the Environmental Protection Agency (EPA), geothermal heat pumps can reduce energy consumption—and corresponding emissions—up to 44% compared with air source heat pumps and up to 72% compared with electric resistance heating with standard air-conditioning equipment. Ground source heat pumps also improve humidity control by maintaining about 50% relative indoor humidity year-round, making them very effective in humid areas.
FIGURE 11: GROUND SOURCE – CLOSED LOOP
FIGURE 12: GROUND SOURCE – OPEN LOOP
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ELECTRIC HEAT PUMP CUSTOMER BUYING AND OPERATION GUIDE FOR SINGLE-FAMILY HOMES
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