Air Cooled Roof-Type (Heat Pump) Air-Conditioner

Refrigeration system theory 
After being throttled the pressure of liquid refrigerant drops and the refrigerant
flows into indoor side heat exchanger to absorb the air's heat there, then it
becomes low-temperature and low-pressure steam. The steam comes into compressor
is compressed into high temperature and high-pressure gaseous refrigerant. Then
the refrigerant goes to outdoor heat exchanger and changes heat with outdoor air,
after letting out the heat it is condensed into liquid refrigerant. And the liquid
refrigerant flows into liquid vessel, then comes to expansion valve after drying
and filtrating, again flows into indoor side heat exchanger to absorb the
heat of room air. By repeating this cycle , the goal of refrigeration can be realized.