Abstract: In a vapor compression refrigerant cycle for an air conditioner, as a refrigerant pressure at an operation starting time of a compressor increases, a starting target rotational speed of the compressor is reduced, and the operation of the compressor is started by the reduced starting target rotational speed. Accordingly, when the operation of the compressor is started, it can prevent the pressure of high-pressure side refrigerant from exceeding an allowable pressure of the compressor, thereby preventing a safety device of the compressor from operating. Therefore, even when the operation of the compressor is started in a high load state, a pressure abnormality is not generated in the refrigerant cycle, and operation of the air conditioner can be prevented from being stopped.

Abstract: Heat exchange is performed between a discharge side refrigerant and a suction side refrigerant also at the time of a heating operation. By this, a liquid phase refrigerant containing lubricating oil in the suction side refrigerant is heated by the discharge side refrigerant, and the liquid phase refrigerant is vaporized also at the time of the heating operation, so that the amount of the liquid phase refrigerant sucked into a compressor is decreased. Accordingly, the increase of compression work of the compressor is prevented, and an opening area of an oil return hole can be expanded to such a degree that an optimum amount of lubricating oil is attained at the time of the heating operation.

Abstract: In a heat pump cycle, a first high-pressure side heat exchanger is disposed to perform a heat exchange between refrigerant discharged from a compressor and a first fluid, and a second high-pressure side heat exchanger is disposed to perform a heat exchanger between refrigerant from the first high-pressure side heat exchanger and a second fluid having a temperature lower than that of the first fluid. Accordingly, a heat quantity obtained from the heat pump cycle is the sum of a heat amount obtained from the first high-pressure side heat exchanger and a heat amount obtained from the second high-pressure side heat exchanger.

Abstract: In a refrigerant cycle system, refrigerant compressed in a first compressor is cooled and condensed in a radiator, and refrigerant from the radiator branches into main-flow refrigerant and supplementary-flow refrigerant. The main-flow refrigerant is decompressed in an expansion unit while expansion energy of the main-flow refrigerant is converted to mechanical energy. Thus, the enthalpy of the main-flow refrigerant is reduced along an isentropic curve. Therefore, even when the pressure within the evaporator increases, refrigerating effect is prevented from being greatly reduced in the refrigerant cycle system. Further, refrigerant flowing into the radiator is compressed using the converted mechanical energy. Thus, coefficient of performance of the refrigerant cycle system is improved.

Abstract: In a radiator for a supercritical cycle, a refrigerant outlet is provided at a position higher than that of a refrigerant inlet in a vertical direction such that refrigerant flows from a lower side to an upper side in the radiator. Accordingly, even when temperature of cool air to pass through the lower side of the radiator is high, the temperature of refrigerant flowing in the lower side is so high that a sufficient difference in temperature between cool air and refrigerant can be provided. As a result, a cooling efficiency of refrigerant can be improved.

Abstract: In a refrigerant cycle system, a control unit controls both a refrigerant amount discharged from a compressor and an opening degree of a pressure control valve so that theoretical efficiency of a super-critical refrigerant cycle and efficiency of the compressor are improved. Therefore, the effective coefficient of performance of the refrigerant cycle is improved, while necessary capacity of components of the refrigerant cycle is obtained.

Abstract: Heat exchange is performed between a discharge side refrigerant and a suction side refrigerant also at the time of a heating operation. By this, a liquid phase refrigerant containing lubricating oil in the suction side refrigerant is heated by the discharge side refrigerant, and the liquid phase refrigerant is vaporized also at the time of the heating operation, so that the amount of the liquid phase refrigerant sucked into a compressor is decreased. Accordingly, the increase of compression work of the compressor is prevented, and an opening area of an oil return hole can be expanded to such a degree that an optimum amount of lubricating oil is attained at the time of the heating operation.

Abstract: An automotive climate control system is disclosed. As long as an ignition switch is off, a bypass (14) is closed (in this state, a ratio between warm air and cool air is a maximum when the automotive climate control system is activated.), the blowout is set to defrost mode and the introduced air is set to external air mode regardless of the preceding modes of blowout and introduced air (when the ignition switch is on). As a result, the refrigerant leaking from an evaporator (12) flows to an external air inlet (23) smaller in air resistance. Even in the case where the ignition switch is off, therefore, the leaking refrigerant is prevented from flowing into the cabin.

Abstract: In a vehicle air conditioner with a heat pump cycle having an interior heat exchanger and an exterior heat exchanger, when a frosting on a surface of the exterior heat exchanger is determined and when a temperature of hot water supplied to a heater core is equal to or higher than a predetermined temperature, the exterior heat exchanger is defrosted in a defrosting operation. Accordingly, the defrosting operation can be performed while a sufficient heating can be obtained.

Abstract: In a heat pump cycle, a first high-pressure side heat exchanger is disposed to perform a heat exchange between refrigerant discharged from a compressor and a first fluid, and a second high-pressure side heat exchanger is disposed to perform a heat exchanger between refrigerant from the first high-pressure side heat exchanger and a second fluid having a temperature lower than that of the first fluid. Accordingly, a heat quantity obtained from the heat pump cycle is the sum of a heat amount obtained from the first high-pressure side heat exchanger and a heat amount obtained from the second high-pressure side heat exchanger.

Abstract: In an accumulator cycle, lubricating oil containing polyalkylene glycol (PAG) as a main component is used for a hermetic electric compressor. Lubricating oil mixed with refrigerant (carbon dioxide) can exhibit electric insulation resistance that causes no problems on a practical use. Since PAG has low compatibility with respect to carbon dioxide, a large amount of liquid phase refrigerant is difficult to be sucked into the compressor while being dissolved in lubricating oil. Therefore, the efficiency of the compressor is not lessened.

Abstract: In a refrigerant cycle system, refrigerant compressed in a first compressor is cooled and condensed in a radiator, and refrigerant from the radiator branches into main-flow refrigerant and supplementary-flow refrigerant. The main-flow refrigerant is decompressed in an expansion unit while expansion energy of the main-flow refrigerant is converted to mechanical energy. Thus, the enthalpy of the main-flow refrigerant is reduced along an isentropic curve. Therefore, even when the pressure within the evaporator increases, refrigerating effect is prevented from being greatly reduced in the refrigerant cycle system. Further, refrigerant flowing into the radiator is compressed using the converted mechanical energy. Thus, coefficient of performance of the refrigerant cycle system is improved.

Abstract: In a refrigerant cycle system, refrigerant compressed in a first compressor is cooled and condensed in a radiator, and refrigerant from the radiator branches into main-flow refrigerant and supplementary-flow refrigerant. The main-flow refrigerant is decompressed in an expansion unit while expansion energy of the main-flow refrigerant is converted to mechanical energy. Thus, the enthalpy of the main-flow refrigerant is reduced along an isentropic curve. Therefore, even when the pressure within the evaporator increases, refrigerating effect is prevented from being greatly reduced in the refrigerant cycle system. Further, refrigerant flowing into the radiator is compressed using the converted mechanical energy. Thus, coefficient of performance of the refrigerant cycle system is improved.

Abstract: The air heating capability of an indoor heat exchanger is limited to set the temperature of the indoor heat exchanger to a first predetermined temperature Tel or lower during heating. Thereby, fogging is prevented through re-evaporation of the condensed water in the indoor heat exchanger during heating within an air-conditioning apparatus with a hot water heater core using hot water as the heat source and the heating circuit.

Abstract: An automotive climate control system is disclosed. As long as an ignition switch is off, a bypass (14) is closed (in this state, a ratio between warm air and cool air is a maximum when the automotive climate control system is activated.), the blowout is set to defrost mode and the introduced air is set to external air mode regardless of the preceding modes of blowout and introduced air (when the ignition switch is on). As a result, the refrigerant leaking from an evaporator (12) flows to an external air inlet (23) smaller in air resistance. Even in the case where the ignition switch is off, therefore, the leaking refrigerant is prevented from flowing into the cabin.

Abstract: A heat pump cycle system which can switches cooling operation and heating operation for a compartment includes a first inside heat exchanger and a second inside heat exchanger disposed in an air conditioning case. The first inside heat exchanger is disposed in the air conditioning case at a downstream air side of the second inside heat exchanger, while being arranged in line in a flow direction of refrigerant. The first inside heat exchanger is upstream from the second inside heat exchanger in the flow direction of refrigerant during the heating operation. In the heat pump cycle system, an expansion valve is controlled so that coefficient of performance in each operation becomes approximately maximum. Thus, during the heating operation of the heat pump cycle system, a lower limit temperature of air blown from the inside heat exchangers can be increased so that temperature of air blown into the compartment is increased, while the coefficient of performance is improved.

Abstract: A CO2 cycle system having a variable capacity compressor is controlled even when the refrigerant delivery capacity of the variable capacity compressor changes. When the refrigerant delivery capacity of the variable capacity compressor decreases, the aperture of an electric expansion valve is fixed for a predetermined time To. When the refrigerant delivery capacity has not changed, the aperture of the electric expansion valve is controlled so that the refrigerant temperature and pressure on the outlet side of a system heat exchanger change along an optimal control line. As a result, because the refrigerant delivery capacity Qd of the compressor is controlled in correspondence with the intake pressure Ps, i.e., the pressure on the side of the evaporator, without being influenced by control of the expansion valve side, the CO2 cycle system can be adequately controlled.

Abstract: A scroll type compressor providing an intake groove of communicating an intake port of a fluid to be compressed such as a refrigerant and a sliding contact part of a rotation prevention mechanism in either one of the end surfaces of the front housing and the end plate of the rotor which are opposite to each other so as to enhance the reliability by reliably lubricating the sliding parts such as the rotation prevention mechanism of the scroll rotor, making the fluid to be compressed be taken into the compression portion through the intake groove, and supplying the lubricant contained in the fluid to be compressed to the sliding part such as the rotation prevention mechanism.