Heat Pump Operating Principles

2017-02-21 10:35:57 alice 21

When inputting power, the compressor starts running, the whole system operating in circle. Actually, it is the refrigerant circulated through the heat pump using a compressor to drive the process.

1.    The refrigerant enters the compressor, in a gaseous (saturated vapor) state at lower pressure and lower temperature and exits at higher pressure and higher temperature, in a superheated gaseous state.

2.    The refrigerant then passes through the hot side heat exchanger, and in so doing changes state into a liquid. 

3.       The refrigerant then passes through an expansion valve, which forces the liquid refrigerant to flash into a gas and liquid mixture, at a pressure and temperature both lower than before entering the valve. This mixture then passes through the cold side heat exchanger, during which the refrigerant completely converts into a gas.

4.       The associated latent heat of vaporization (due to phase change of the liquid portion of the mixture into a gas) is absorbed by the heat exchanger from whatever medium the heat exchanger is in contact with. From this stage the refrigerant then enters the compressor as a saturated vapor, and the cycle repeats. 

Four Main Parts of A Heat Pump System