Air conditioning apparatus

An air conditioning apparatus for conditioning air in a compartment, comprising:

• a casing having an air passage, in which an inside air inlet for sucking the inside air and an outside air inlet sucking the outside air are formed at one end thereof and an air outlet communicating with said compartment at the other end;
• a refrigeration cycle having a compressor for compressing refrigerant, a condenser disposed outside said air passage for condensing the refrigerant from said compressor, an electric type pressure reducing device for reducing a pressure of the refrigerant from said condenser, an evaporator disposed in said air passage for evaporating the refrigerant from said electric type pressure reducing device;
• a blower for generating an air flow in said air passage;
• outlet temperature detecting means detecting outlet refrigerant temperature of said condenser,
• high pressure detecting means for detecting high pressure of said refrigerant cycle;
• and
• a control unit for controlling said electric type pressure reducing device so that a supercooling degree of liquid refrigerant in said condenser is set to a predetermined target supercooling degree,
• said control unit including:
• supercooling degree calculating means for calculating said supercooling degree of condensed liquid refrigerant in said condenser by calculating the condensed temperature from said high pressure detected by said high pressure detecting means based on said condensed temperature and said outlet refrigerant temperature detected by said outlet temperature detecting means, and
• supercooling degree controlling means for controlling said electric type pressure reducing device in such a manner that said supercooling degree calculated by said supercooling degree calculating means is set to said target supercooling degree.

A refrigeration cycle control apparatus comprising:

• a refrigeration cycle having a compressor for compressing refrigerant, a condenser for condensing the refrigerant from said compressor, an electric type pressure reducing device for reducing a pressure of the refrigerant from said condenser, an evaporator for evaporating the refrigerant from said electric type pressure reducing device;
• high pressure detecting means for detecting high pressure of said refrigerant cycle;
• outlet temperature detecting means for detecting outlet refrigerant temperature of said condenser;
• and
• a control unit for controlling said electric type pressure reducing device so that a supercooling degree of liquid refrigerant in said condenser is set to a predetermined target supercooling degree,
• said control unit including:
• supercooling degree calculating means for calculating said supercooling degree of condensed liquid refrigerant in said condenser by calculating the condensed temperature from said high pressure detected by said high pressure detecting means based on said condensed temperature and said outlet refrigerant temperature detected by said outlet temperature detecting means, and
• supercooling degree controlling means for controlling said electric type pressure reducing device in such a manner that said supercooling degree calculated by said supercooling degree calculating means is set to said target supercooling degree.

A refrigeration cycle control apparatus comprising:

• a refrigeration cycle having a compressor for compressing refrigerant, a condenser for condensing the refrigerant from said compressor, an electric type pressure reducing device for reducing a pressure of the refrigerant from said condenser, an evaporator for evaporating the refrigerant from said electric type pressure reducing device;
• high pressure detecting means for detecting high pressure of said refrigerant cycle;
• outlet temperature detecting means for detecting outlet refrigerant temperature of said condenser;
• and
• supercooling degree calculating means for calculating a supercooling degree of condensed liquid refrigerant in said condenser based on said condensed temperature calculated from said high pressure detected by said high pressure detecting means and said outlet refrigerant temperature detected by said outlet temperature detecting means.

A supercooling degree calculating device comprising:

• a heat pump type refrigerant cycle having a compressor, a four way valve, an outdoor heat exchanger, an electric type pressure reducing device for cooling, an electric type pressure reducing device for heating, indoor heat exchanger, and an accumulator, each of which is connected with a refrigerant pipe, in which refrigerant circulates through said compressor, said four way valve, said indoor heat exchanger, said electric type pressure reducing device for heating, said outdoor heat exchanger and said accumulator in this order in a heating operation mode, and circulates through said compressor, said four way valve, said outdoor heat exchanger, said electric type pressure reducing device for cooling, said indoor heat exchanger and said accumulator in this order in a cooling operation mode;
• a high pressure detecting means for detecting high pressure of said refrigerant cycle;
• and
• outlet temperature detecting means for detecting the outlet refrigerant temperature of said condensers, wherein
• supercooling degree calculating means for calculating a supercooling degree of condensed liquid refrigerant in said condenser based on said condensed temperature calculated from said high pressure detected by said high pressure detecting means and said outlet refrigerant temperature detected by said outlet temperature detecting means.

A refrigeration cycle control apparatus comprising:

• a refrigeration cycle having a compressor for compressing refrigerant, a condenser for condensing the refrigerant from said compressor, an electric type pressure reducing device for reducing a pressure of the refrigerant from said condenser, an evaporator for evaporating the refrigerant from said electric type pressure reducing device;
• discharge pressure detecting means disposed at the portion of discharged side of said compressor and detecting the refrigerant pressure at the portion of this discharged side;
• outlet temperature detecting means for detecting outlet refrigerant temperature of said condenser;
• pressure loss physical amount detecting means detecting a physical amount related to the pressure loss of the refrigerant from a position where said discharged pressure detecting means is disposed to a position where said outlet temperature detecting means is disposed;
• and
• a control unit for controlling said electric type pressure reducing device so that a supercooling degree of liquid refrigerant in said condenser is set to a predetermined target supercooling degree,
• said control unit including:
• pressure loss calculating means for calculating a pressure loss of the refrigerant from said position where said discharge pressure detecting means is disposed to said position where said outlet temperature detecting means is disposed based on said physical amount detected by said pressure loss physical amount detecting means,
• outlet pressure calculating means for calculating an outlet refrigerant pressure at said outlet side of said condenser based on said pressure loss calculated by said pressure loss calculating means and said discharge pressure detected by said discharge pressure detecting means,
• saturated liquid refrigerant temperature calculating means for calculating temperature of saturated liquid refrigerant of dryness zero (0) in said condensers based on said outlet refrigerant pressure calculated by said outlet pressure calculating means,
• supercooling degree calculating means for calculating said supercooling degree based on said saturated liquid refrigerant temperature of dryness zero (0) calculated by said saturated liquid refrigerant temperature calculating means and said outlet refrigerant temperature detected by said outlet temperature detecting means, and
• supercooling degree control means for controlling said electric type pressure reducing device in such a manner that said supercooling degree calculated by said excessive cooling degree calculating means is set to said target excessive cooling degree.

A refrigeration cycle control apparatus comprising:

• a refrigeration cycle having a compressor for compressing refrigerant, a condenser for condensing the refrigerant from said compressor, an electric type pressure reducing device for reducing a pressure of the refrigerant from said condenser, an evaporator for evaporating the refrigerant from said electric type pressure reducing device;
• discharge pressure detecting means disposed at a discharged side of said compressor for detecting a refrigerant pressure at said discharge side;
• outlet temperature detecting means disposed at an outlet side of said condenser for detecting outlet refrigerant temperature at said outlet side;
• an ambient temperature detecting means for detecting an ambient temperature of said outlet temperature detecting means;
• and
• a control unit for controlling said electric type pressure reducing device so that a supercooling degree of liquid refrigerant in said condenser is set to a predetermined target supercooling degree,
• said control unit including:
• saturated liquid refrigerant temperature calculating means calculating the saturated liquid refrigerant temperature of dryness zero (0) in said condensers based on said discharge pressure detected by said discharge pressure detecting means,
• compensated outlet temperature calculating means for calculating compensated outlet refrigerant temperature based on said ambient temperature detected by said ambient temperature detecting means and said outlet refrigerant temperature detected by said outlet temperature detecting means, and
• supercooling degree calculating means for calculating said supercooling degree based on said saturated liquid refrigerant temperature of dryness zero (0) calculated by said saturated liquid refrigerant temperature calculating means and said compensated outlet refrigerant temperature calculated by said compensated outlet refrigerant temperature calculating means.