Air conditioning system and compressor

A variable displacement compressor for compressing refrigerant gas comprising:

• a compression mechanism for compressing the refrigerant gas;
• a crank chamber for accommodating the compression mechanism;
• a suction pressure zone into which refrigerant gas having relatively low pressure is drawn when the compression mechanism operates;
• a discharge pressure zone into which compressed refrigerant gas having relatively high pressure is delivered when the compression mechanism operates;
• a port for supplying the compressed gas to an external circuit;
• and
• a control valve for changing the cross-sectional area of the port to lower the discharge amount of the refrigerant gas discharged from the compressor, wherein the control valve is located in association with the port, wherein the control valve includes:
• a first chamber communicated with the suction pressure region;
• a second chamber communicated with the discharge pressure region;
• and
• a valve body located between the first chamber and the second chamber for regulating the port in accordance with the difference between pressure in the suction pressure zone and that of the discharge pressure zone.

An air conditioning system for cooling or heating a space, the system comprising:

• a variable displacement compressor for compressing refrigerant gas, wherein the compressor includes a compression mechanism for compressing the refrigerant gas, a crank chamber for accommodating the compression mechanism, a suction pressure zone into which refrigerant gas having relatively low pressure is drawn when the compression mechanism operates, a discharge pressure zone into which compressed refrigerant gas having relatively high pressure is delivered when the compression mechanism operates, and a port for supplying the compressed gas to an external circuit,
• wherein the external circuit comprises a heat exchanger for cooling or heating air supplying to the space, a cooling circuit including a condenser that condenses the compressed refrigerant gas, wherein the cooling circuit supplies the condensed refrigerant gas to the heat exchanger, a heating circuit for optionally supplying the compressed refrigerant gas to the heat exchanger, and a selecting valve apparatus for selectively connecting the cooling circuit or the heating circuit to the heat exchanger;
• and
• a control valve for changing the cross-sectional area of the port to lower the discharge amount of the refrigerant gas discharged from the compressor, wherein the control valve is located in association with the port, wherein the control valve includes:
• a first chamber communicated with the suction pressure region;
• a second chamber communicated with the discharge pressure region;
• and
• a valve body located between the first chamber and the second chamber for regulating the port in accordance with the difference between pressure in the suction pressure zone and that of the discharge pressure zone.