heat pump
Heat pump
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For theoretical background, see Heat pump and refrigeration cycle.
Outdoor components of a residential air-source heat pump
A heat pump is a machine or device that transfers thermal energy from one location, called the "source," which is at a lower temperature, to another location called the "sink" or "heat sink", which is at a higher temperature. Thus, heat pumps moves thermal energy opposite to the direction that it normally flows. While compressor-driven air conditioners and freezers are technically heat pumps, the class includes many other types of devices, and the term "heat pump" usually implies one of the less-common devices in the class that are not dedicated to refrigeration-only.
During the operation of a heat pump, some of the thermal energy must be transformed to another type of energy before reappearing as thermal energy in the heat sink. The heat pump uses mechanical work, or some source of thermodynamic work (such as much higher-temperature heat source dissipating heat to lower temperatures) to accomplish the desired transfer of thermal energy from source to sink.[1] In the classical thermodynamic sense, a heat pump does not actually move heat, which by definition cannot flow from cold to hot temperatures. However, since the effect of the device in moving thermal energy is the same as if heat were flowing (albeit in the incorrect direction with regard to temperature difference), the "heat pump" is named by analogy.
A heat pump always moves thermal energy in the opposite direction from temperature, but a heat pump that maintains a thermally conditioned-space can be used to provide either heating or cooling, depending upon whether the environment is cooler or warmer than the conditioned-space. When pumps are used to provide heating, they are used because less input from a commercial-energy source is required than is required for newly-creating thermal energy by
From Wikipedia, the free encyclopedia
Jump to: navigation, search
For theoretical background, see Heat pump and refrigeration cycle.
Outdoor components of a residential air-source heat pump
A heat pump is a machine or device that transfers thermal energy from one location, called the "source," which is at a lower temperature, to another location called the "sink" or "heat sink", which is at a higher temperature. Thus, heat pumps moves thermal energy opposite to the direction that it normally flows. While compressor-driven air conditioners and freezers are technically heat pumps, the class includes many other types of devices, and the term "heat pump" usually implies one of the less-common devices in the class that are not dedicated to refrigeration-only.
During the operation of a heat pump, some of the thermal energy must be transformed to another type of energy before reappearing as thermal energy in the heat sink. The heat pump uses mechanical work, or some source of thermodynamic work (such as much higher-temperature heat source dissipating heat to lower temperatures) to accomplish the desired transfer of thermal energy from source to sink.[1] In the classical thermodynamic sense, a heat pump does not actually move heat, which by definition cannot flow from cold to hot temperatures. However, since the effect of the device in moving thermal energy is the same as if heat were flowing (albeit in the incorrect direction with regard to temperature difference), the "heat pump" is named by analogy.
A heat pump always moves thermal energy in the opposite direction from temperature, but a heat pump that maintains a thermally conditioned-space can be used to provide either heating or cooling, depending upon whether the environment is cooler or warmer than the conditioned-space. When pumps are used to provide heating, they are used because less input from a commercial-energy source is required than is required for newly-creating thermal energy by
References: 1. ^ The Systems and Equipment volume of the ASHRAE Handbook, ASHRAE, Inc., Atlanta, GA, 2004 2 5. ^ a b c d The Canadian Renewable Energy Network 'Commercial Earth Energy Systems ', Figure 29. . Retrieved December 8, 2009. 6. ^ Technical Institute of Physics and Chemistry, Chinese Academy of Sciences 'State of the Art of Air-source Heat Pump for Cold Region ', Figure 5. . Retrieved April 19, 2008. 7. ^ a b SINTEF Energy Research 'Integrated CO2 Heat Pump Systems for Space Heating and DHW in low-energy and passive houses ', J. Steen, Table 3.1, Table 3.3. . Retrieved April 19, 2008.