A heat pump is a device that transfers thermal energy from a heat source to a heat sink. Heat pumps can move thermal energy in a direction which is opposite to the direction of spontaneous heat flow. A heat pump uses energy to accomplish the desired transfer of thermal energy from heat source to heat sink.
Compressor-driven air conditioners and freezers are examples of heat pumps. However, the term "heat pump" is more general and applies to devices which are used for space heating, or space cooling. When a heat pump is used for heating, it uses the same basic refrigeration-type cycle employed by an air conditioner or a refrigerator, but releasing heat into the conditioned-space rather than into the surrounding environment. In this use, heat pumps generally draw heat from the cooler external air or from the ground.
Heat pumps are used to provide heating because less high-grade (i.e., low-entropy) energy is required for their operation, than appears in the released heat. Most of the energy for heating comes from the external environment, and only a fraction comes from electricity (or some other high-grade energy source). In electrically powered heat pumps, the heat transferred can be three or four times larger than the electrical power consumed, giving the system a Coefficient of Performance (COP) of 3 or 4, as opposed to a COP of 1 of a conventional electrical resistance heater, in which all heat is produced from input electrical energy.
Reversible heat pumps are designed to work in either thermal direction, in order to provide heating or cooling to the internal space. They operate by changing which coil is the condenser and which coil is the evaporator, rather than physically turn the device around. Such a function is achieved by a "reversing valve." In heating and air conditioning (HVAC) applications, the term heat pump usually refers to easily reversible vapor-compression refrigeration devices that are optimized for high efficiency in both directions of thermal energy transfer.
Other articles related to "heat pump, heat, pump":
... Absorption heat pump is essentially an air-source heat pump driven not by electricity, but by a heat source such as solar-heated water, or geothermal-heated water ... available that work on the same principle, but are not reversible and cannot serve as a heat source ...
1852 Lord Kelvin describes the theory underlying heat pump. 1855–1857 Peter von Rittinger develops and builds the first heat pump ... Webber is credited as developing and building the first ground heat pump ...
... A refrigeration cycle can be operated as a heat pump to move heat from outdoors into a warmer house ... When operated in heating mode, a heat pump is typically more efficient than a resistance heater ... can convert only the input electrical energy directly to output heat energy, while a heat pump also transfers heat from outdoors ...
... they can greatly reduce the build up of undesirable summer heat, and also help remove heat from the interior of the building ... photovoltaic-powered fan can be used to exhaust undesired heat and draw in cooler, dehumidified air that has passed by ambient Earth temperature surfaces ... A geothermal heat pump uses ambient Earth temperature to improve SEER for heat and cooling ...
... The Direct exchange geothermal heat pump is the oldest type of geothermal heat pump technology ... The refrigerant leaves the heat pump cabinet, circulates through a loop of copper tube buried underground, and exchanges heat with the ground before returning to the pump ... The name "direct exchange" refers to heat transfer between the refrigerant loop and the ground without the use of an intermediate fluid ...
Famous quotes containing the words pump and/or heat:
“The daughters of delight now pump iron.”
—Mason Cooley (b. 1927)
“For it is wretchedness that endures, shedding its cancerous light on all it approaches:
Words spoken in the heat of passion, that might have been retracted in good time,
All good intentions, all that was arguable.”
—John Ashbery (b. 1927)