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Thermodynamic heat pump cycles or refrigeration cycles are the conceptual and mathematical models for heat pump, air conditioning and refrigeration systems. [1] A heat pump is a mechanical system that transmits heat from one location (the "source") at a certain temperature to another location (the "sink" or "heat sink") at a higher temperature. [2]
Thermodynamic heat pump cycles are the models for household heat pumps and refrigerators. There is no difference between the two except the purpose of the refrigerator is to cool a very small space while the household heat pump is intended to warm or cool a house. Both work by moving heat from a cold space to a warm space.
The choice of working fluids is known to have a significant impact on the thermodynamic as well as economic performance of the cycle. A suitable fluid must exhibit favorable physical, chemical, environmental, safety and economic properties such as low specific volume (high density), viscosity, toxicity, flammability, ozone depletion potential (ODP), global warming potential (GWP) and cost, as ...
Q H = W + Q C = heat exchanged with the hot reservoir. η = W / (Q C + Q H) = thermal efficiency of the cycle If the cycle moves in a clockwise sense, then it is a heat engine that outputs work; if the cycle moves in a counterclockwise sense, it is a heat pump that takes in work and moves heat Q H from the cold reservoir to the hot reservoir.
[10] [11] For an isentropic process, if also reversible, there is no transfer of energy as heat because the process is adiabatic; δQ = 0. In contrast, if the process is irreversible, entropy is produced within the system; consequently, in order to maintain constant entropy within the system, energy must be simultaneously removed from the ...
Specifically, the heat pump transfers thermal energy using a heat pump and refrigeration cycle, cooling the cool space and warming the warm space. [1] In winter a heat pump can move heat from the cool outdoors to warm a house; the pump may also be designed to move heat from the house to the warmer outdoors in summer.
The ionocaloric heat pump is a solid-liquid based heat pumping technology with high efficiencies over very-high temperature spans. It utilizes the ionocaloric effect by changing the concentration of a salt in a mixture to modulate a material's melting point, and therefore heat content.
An air source heat pump can be used to air condition the building during hot weather, and to warm the building using heat extracted from outdoor air in cold weather. Air-source heat pumps are generally uneconomic for outdoor temperatures much below freezing. In colder climates, geothermal heat pumps can be used to extract heat from the ground ...