Air conditioner and heat exchanger used therein

An air conditioner comprising a system in which an inverter-drive compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger are connected together in such a manner as to allow a refrigerant to circulate through them and which is equipped with a control circuit for controlling the revolving speed of said compressor,

• wherein said indoor heat exchanger is comprised of an air-upstream-side heat exchanger and an air-downstream-side heat exchanger which are thermally separated from each other,
• wherein a temperature sensor is provided at the outlet of said air-downstream-side heat exchanger, said temperature sensor providing an output which is fed back to said control circuit, and
• wherein the revolving speed of said compressor is controlled during heating operation by said control circuit on the basis of the output of said temperature sensor in such a manner in which said output is kept in a range higher than the condensation temperature.

An air conditioner comprising a system in which a compressor, a four-way valve, an indoor heat exchanger equipped with a fan for blowing air into the room, an expansion valve, and an outdoor heat exchanger are connected together in such a manner as to allow a refrigerant to circulate through them and which is equipped with a control circuit for controlling the revolving speed of said fan,

• wherein said indoor heat exchanger is comprised of an air-upstream-side heat exchanger and in air-downstream-side heat exchanger which are thermally separated from each other,
• wherein a temperature sensor is provided at the outlet of said air-downstream-side heat exchanger, said temperature sensor providing an output which is fed back to said control circuit, and
• wherein the revolving speed of said fan is controlled during heating operation by said control circuit on the basis of the output of said temperature sensor in such a manner in which said output is kept in a range higher than the condensation temperature.

An air conditioner comprising a system in which a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger are connected together in such a manner as to allow a refrigerant to circulate through them and in which a high-pressure liquid refrigerant is injected through a regulating valve during the compressing process of said compressor,

• wherein said indoor heat exchanger is comprised of an air-upstream-side heat exchanger and an air-downstream-side heat exchanger which are thermally separated from each other,
• wherein a temperature sensor is provided at the outlet of said air-downstream-side heat exchanger, said temperature sensor is provided with an output which is fed back to said control circuit, and
• wherein the opening amount of said regulating valve is controlled during heating operation by said control circuit on the basis of the output of said temperature sensor is such a manner in which said output is kept in a range higher than the condensation temperature.

An air conditioner comprising a system in which a compressor, a four-way valve, an indoor heat exchanger, an electric expansion valve, and an outdoor heat exchanger are connected together in such a manner as to allow a refrigerant to circulate through them and which is equipped with a driving device for driving said electric expansion valve and a computing unit adapted to supply an opening amount of signal to said driving device,

• wherein said indoor heat exchanger is comprised of an air-upstream-side heat exchanger and an air-downstream-side heat exchanger which are thermally separated from each other,
• wherein a temperature sensor is provided at the outlet of said air-downstream-side heat exchanger, said temperature sensor is provided with an output which is fed back to said computing unit, and
• wherein the opening amount of said electric expansion valve is controlled during heating operation by said control circuit on the basis of the output of said temperature sensor in such a manner in which said output is kept in a range higher than the condensation temperature.

An air conditioner comprising a system in which a compressor, a four-way valve, an indoor heat exchanger, an expansion valve, and an outdoor heat exchanger are connected together in such a manner as to allow a refrigerant to circulate through them,

• wherein said indoor heat exchanger is comprised of thermally separated two heat exchangers including an air-upstream-side heat exchanger and an air-downstream-side heat exchanger which is equipped with a heater,
• wherein a temperature sensor, providing an output, is provided at the outlet of said air-downstream-side heat exchanger, and
• wherein said heat is controlled, via an input thereof, by a control circuit during heating operation on the basis of the output provided by said temperature sensor in such a manner in which said output is kept in a range higher than the condensation temperature.