How does a heat pump work in the summer?

Posted on: Wednesday, March 26th, 2014  In: Uncategorized

All heat pumps and air conditioning systems rely on the refrigerants pressure temperature relationship. When a refrigerant boils or evaporates, it absorbs heat at a very high rate, as is the case with all liquefied gases. Refrigerant has a lower boiling point than most liquids, which makes it easy to manipulate it so that room temperature air is the only heat source needed.  The boiling point can be controlled by altering the pressure that is placed upon the liquid.

During the summer, the heart of the heat pump, the compressor, receives cool, low pressure refrigerant vapor. This vapor is pumped into the high pressure side of the system. The hot, high pressure gas now travels through the reversing valve to the outside coil, which now functions as the condenser.

The heat is removed from the refrigerant in the condenser by the outdoor fan. This causes the refrigerant to condense into a liquid. The liquid refrigerant bypasses the first expansion valve by means of the check valve, which is a one direction valve. The now cool, but high pressure, refrigerant travels along the liquid line to the indoor unit. There it is forced through the second expansion valve, which partially restricts the flow of refrigerant. This creates a needed decrease in pressure which will allow the refrigerant to evaporate.

The refrigerant absorbs heat as it evaporates from the passing air. The cold evaporator also collects moisture which provides the home with dehumidification. The refrigerant then travels back to the compressor so that the process can be repeated over and over again.


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