Designing, selecting and installing a residential ground-source heat pump system
- ORNL
It's a compelling proposition: Use the near-constant-temperature heat underground to heat and cool your home and heat domestic water, slashing your energy bills. Yet despite studies demonstrating significant energy savings from ground-source heat pump (GSHP) systems, their adoption has been hindered by high upfront costs. Fewer than 1% of US homes use a GSHP system. However, compared to a minimum-code-compliant conventional space-conditioning system, when properly designed and installed, a GSHP retrofit at current market prices offers simple payback of 4.3 years on national average, considering existing federal tax credits. Most people understand how air-source heat pumps work: they move heat from indoor air to outdoor air when cooling and from outdoor air to indoor air when heating. The ground-source heat pump operates on the same principle, except that it moves heat to or from the ground source instead of outdoor air. The ground source is usually a vertical or horiontal ground heat exchanger. Because the ground usually has a more favorable temperature than ambient air for the heating and cooling operation of the vapor-compression refrigeration cycle, GSHP sysems can operate with much higher energy efficiencies than air-source heat pump systems when properly designed and installed. A GSHP system used in a residual building typically provides space conditioning and hot water and comprises three major components: a water-source heat pump unit designed to operate at a wider range of entering fluid temperatures (typically from 30 F to 110 F, or 1 C to 43 C) than a conventional water-source heat pump unit; a ground heat exchanger (GHX); and distribution systems to deliver hot water to the storage tank and heating or cooling to the conditioned rooms. In most residual GSHP systems, the circulation pumps and associated valves are integrated with the heat pump to circulate the heat-carrier fluid (water or aqueous antifreeze solution) through the heat pump and the GHX. A recent assessment indicates that if 20% of US homes replaced their existing space-conditioning and water-heating systems with properly designed, installed and operated state-of-the-art GSHP systems, it would yield significant benefits each year. These include 0.8 quad British thermal units (Btu) of primary energy savings, 54.3 million metric tons of CO{sub 2} emission reductions, $10.4 billion in energy cost savings and 43.2 gigawatts of reduction in summer peak electrical demand.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 1004674
- Journal Information:
- Solar Today, Vol. 25, Issue 1; ISSN 1042-0630
- Country of Publication:
- United States
- Language:
- English
Similar Records
Foundation Heat Exchanger Final Report: Demonstration, Measured Performance, and Validated Model and Design Tool
Case Study for the ARRA-funded GSHP Demonstration at Furman University
Related Subjects
15 GEOTHERMAL ENERGY
AIR SOURCE HEAT PUMPS
ANTIFREEZE
ENERGY ACCOUNTING
GROUND SOURCE HEAT PUMPS
HEAT EXCHANGERS
HEAT PUMPS
HEATING
HOT WATER
INDOORS
MARKET
METRICS
OUTDOORS
PRICES
REFRIGERATION
STORAGE
TANKS
TAX CREDITS
VALVES
WATER HEATING
WATER SOURCE HEAT PUMPS
Ground Source Heat Pump