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Heat upgrade process

The heat collected from the source is transferred to the refrigerant in a device called the evaporator heat exchanger which in its simplest form consists of a set of parallel plates. The ducted air or the pumped collector fluid passes through one set of plates and the refrigerant, generally in the form of a low pressure, low temperature liquid, through an adjacent set of plates. As heat always moves from a hotter to a colder medium, the heat is transferred from the source to the refrigerant which is at a lower temperature. This causes the refrigerant to change state from a liquid to a low pressure, low temperature gas.

After leaving the evaporator, the refrigerant is then compressed by the compressor and transformed into a high pressure, high temperature gas. In being compressed, its temperature is raised because the temperature of a fluid rises with increasing pressure.

The refrigerant then passes through the condenser heat exchanger in which the high grade heat of the refrigerant is transferred to the heating medium of the distribution system. If this is air then it can be circulated directly throughout the dwelling using ducting. If this is water then the hot water can be distributed through radiators in the normal way to provide space heating or stored in a tank to supply hot water.

After leaving the condenser, the cooled refrigerant has changed state to a high pressure, low temperature liquid. It then passes through an expansion valve to return the refrigerant to a low pressure, low temperature liquid prior to entering the evaporator heat exchanger and restarting the cycle.

Components of a ground source heat pump system

heat pump

To provide space cooling, the heat pump can extract useful heat from a room and diffuse low grade heat into the air or ground.



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