1) Compressor (Compressor) served driven refrigerant or liquid (Refrigerant) in the system by keeping the refrigerant temperature. And high pressure
2) heat exchanger (Condenser) serves as cooling of the refrigerant.
3) Evaporator (Evaporator) to absorb heat in the room to the refrigerant.
4) and reduced pressure (Throttling Device. ) serves to reduce the pressure and temperature of the refrigerant. Typically used as a Cap Capillary stick Wanderers (Capillary tube) or X-Span valve (Expansion Valve).