Abstract: A climate-control system may include a vapor-compression circuit and an air handler assembly. The vapor-compression circuit may include a compressor, an outdoor heat exchanger, and first and second working-fluid-fluid flow paths. The first and second working-fluid-flow paths are in fluid communication with the outdoor heat exchanger. The first working-fluid-flow path may include a first expansion device and a first indoor heat exchanger. The second working-fluid-flow path may include a second expansion device and a second indoor heat exchanger. The first and second indoor heat exchangers are disposed within the air handler assembly. The air handler assembly includes a return-air-inlet duct, first and second airflow paths, and a supply-air-outlet duct. The first airflow path may receive air from the return-air-inlet duct and houses the first indoor heat exchanger. The second airflow path may receive air from the return-air-inlet duct.

Abstract: A refrigeration cycle system includes a refrigeration cycle apparatus, an operation signal transmitter, a detection unit, a notification unit, and a processing unit. The refrigeration cycle apparatus includes a refrigerant circuit. The operation signal transmitter transmits an operation signal for the refrigeration cycle apparatus. The detection unit detects leakage of a refrigerant. The notification unit notifies of leakage of the refrigerant by emitting at least one of sound and light in a case in which the detection unit has detected leakage of the refrigerant. The processing unit causes the notification unit to execute test behavior of emitting at least one of sound and light in a case in which the operation signal transmitter transmits the operation signal to the refrigeration cycle apparatus.

Abstract: Disclosed is a vehicle air conditioning device including a heat pump cycle configured to compress and expand a refrigerant; a heater core; a high pressure side pressure sensor configured to detect a pressure on the high pressure side of the heat pump cycle; and a heater core inlet water temperature sensor configured to detect a temperature of cooling water at an inlet of the heater core as a heater core inlet water temperature. The heat pump cycle includes a compressor; a condenser; a water refrigerant heat exchanger and an evaporator; and a heating expansion valve and a cooling expansion valve. An estimated outside air temperature is calculated based on the high pressure side pressure detected by the high pressure side pressure sensor and the heater core inlet water temperature detected by the heater core inlet water temperature sensor.

Abstract: The present disclosure provides a variable-frequency compressor with adaptive heating power control and a method for operating the same. According to an embodiment of the present disclosure, the variable-frequency compressor includes: a compression unit, for compressing a medium entering the variable-frequency compressor; a motor, including a stator and a rotor, for driving the compression unit; and a controller, configured to adaptively control a heating power of a winding of the stator according to information of the variable-frequency compressor.

Abstract: A vehicle air-conditioning apparatus heat pump system configured so that an excessive increase in the temperature (superheat degree) of refrigerant discharged from a compressor can be prevented in air-heating operation. The heat pump system (HP) includes a compressor (C) and an indoor heat exchanger (HXC2) on a refrigerant circuit (RC). A first branched flow path (BC1) on which a first expansion mechanism (EX1) with an adjustable opening degree and a first heat absorption heat exchanger (HXA1) are arranged in series and a second branched flow path (BC2) on which a second expansion mechanism (EX2) with an adjustable opening degree and a second heat absorption heat exchanger (HXA2) are arranged in series, where the first branched flow path (BC1) and the second branched flow path (BC2) are arranged in parallel on the refrigerant circuit extending from the indoor heat exchanger to the compressor.

Abstract: A Gifford-McMahon cryogenic refrigerator comprises a reciprocating displacer within a refrigeration volume. The displacer is pneumatically driven by a drive piston within a pneumatic drive volume. Pressure in the pneumatic drive volume is controlled by valving that causes the drive piston to follow a programmed displacement profile through stroke of the drive piston. The drive valving may include a proportional valve that provides continuously variable supply and exhaust of drive fluid. In a proportionally controlled feedback system, the valve into the drive volume is controlled to minimize error between a displacement signal and a programmed displacement profile. Valving to the warm end of the refrigeration volume may also be proportional. A passive force generator such as a mechanical spring or magnets may apply force to the piston in opposition to the driving force applied by the drive fluid.

Abstract: A method of operating a refrigeration system is provided. The method includes activating an evaporator heater (306), monitoring a pressure differential within the refrigeration system (308), when the pressure differential reaches a predetermined value (310), deactivating the evaporator heater (312), and activating one or more evaporator fans (314), after deactivating the evaporator heater, to cause a thermostatic expansion valve to open.

Abstract: An air conditioning system for an open motorized vehicle can include a cab assembly defining an interior volume, the cab assembly includes an enclosed frame configured to be attached to an open vehicle, and an air conditioning unit positioned at least partially within the cab assembly, the air conditioning unit being configured to deliver conditioned air to the interior volume of the cab assembly.

Abstract: In a motor lock determination device (1), a lock determination on an electric motor (7) is performed such that: a first detection value (PI), which is a detection value (P) of a refrigerant pressure sensor (17) during a stop of an electric fan (5), is detected, and a second detection value (P2), which is a detection value (P) of the refrigerant pressure sensor (17) after the electric fan (5) is driven for a first predetermined time (?), is detected; when the second detection value (P2) is equal to the first detection value (PI) or more than the first detection value (PI), it is determined that a motor lock occurs; and when the second detection value (P2) is less than the first detection value (PI), it is determined that no motor lock occurs.

Abstract: A control system to selectively control the operation of the compressor of a mini-split air conditioning system including at least one remote evaporator operatively coupled to the compressor to receive refrigerant therethrough, a sensor to monitor the operation of the evaporator and to generate an operating control signal to turn-off the compressor when a predetermined operating condition is sensed at the evaporator and a condensate drain pan to receive or catch condensate from the evaporator, the control system comprising a condensate sensor disposed to sense condensate in the condensate drain pan at a predetermined level and to generate a condensate level signal fed to a battery powered control device including an isolated solid state relay coupled to the sensor by a control coupling device to generate a condensate level control signal fed to the sensor causing the sensor to generate the operating control signal fed to turn off the compressor when condensate within the condensate drain pan reaches the prede

Abstract: Disclosed is an air conditioner which can obtain an energy-saving effect without any change to the setting temperature set by a user and, accordingly, without causing discomfort to the user. If a capacity restriction mode is set to at least one of indoor units Y1 and Y2, the setting temperature Ts in the indoor units Y1 and Y2 is not changed and is maintained at a value set by the user and a compressor 1 is operated with the capacity less than the normal capacity.

Abstract: A heat pump apparatus includes: a refrigerant circuit which includes a compressor, a utilization-side heat exchanger for exchanging heat between water and refrigerant, an electronic expansion valve, and an outdoor heat exchanger; a controller which controls the compressor and the electronic expansion valve; a subcooling value calculating unit which calculates a subcooling value of the refrigerant circuit; a condensing pressure detector which detects condensing pressure of the compressor; a compressor rotation number detector which detects rotation number of the compressor; and an objective subcooling value extracting unit which selects and extracting an objective subcooling value stored in advance, from the condensing pressure and the rotation number of the compressor. The controller adjusts an opening degree of the electronic expansion valve so that the calculated subcooling value of the refrigerant circuit reaches the objective subcooling value.

Abstract: In one embodiment, a cryocooler drive circuit for a cryocooler motor is provided that includes: a first switching power converter configured to track a first sinusoidal input voltage signal to provide a first sinusoidal output voltage signal at a first output node; and a second switching power converter configured to track a second sinusoidal input voltage signal to provide a second sinusoidal output voltage signal at a second output node, wherein the second sinusoidal input voltage signal is an inverted version of the first sinusoidal input voltage signal such that the cryocooler motor is driven by an alternating current flowing between the first and second output nodes.

Abstract: A method for use in controlling a free piston Stirling machine having a cold end and a warm end and driven by a linear motor having an armature winding to which a drive voltage is applied. The method comprises (a) sensing internal mechanical collisions; (b) repeatedly sensing the temperature of the cold end, the temperature of the warm end and the drive voltage; (c) storing, as associated data, a value representing drive voltage, the temperature of the cold end and the temperature of the warm end at the time of sensed collisions; and (d) limiting the drive voltage to less than the drive voltage that was sensed at a collision and is stored in association with stored warm end and cold end temperatures that are proximate currently sensed warm end and cold end temperatures.

Abstract: An air conditioning apparatus includes a refrigerant circuit, an operation controlling device and a liquid refrigerant accumulation determining device. The refrigerant circuit has an accumulator. The operation controlling device performs normal operation control where each device of the heat source unit and the utilization unit are controlled in accordance with operating load of the utilization unit, and refrigerant quantity determination operation control where properness of quantity of the refrigerant in the refrigerant circuit is determined while performing the cooling operation. The liquid refrigerant accumulation determining device determines whether or not liquid refrigerant is accumulating in the accumulator. When it has been determined that liquid refrigerant is accumulating in the accumulator, liquid refrigerant accumulation control is performed to eliminate liquid refrigerant accumulation in the accumulator.

Abstract: An air-conditioning device includes a refrigerating cycle; a controller to control a refrigerant discharge capacity of a compressor of the cycle in a manner that a refrigerant evaporation temperature of an evaporator of the cycle approaches a target temperature; and a setting portion to set an upper limit for a fuel amount consumed by an engine based on at least the refrigerant evaporation temperature. The controller controls the refrigerant discharge capacity of the compressor in a manner that an actual fuel amount consumed by the engine is equal to or lower than the upper limit.

Abstract: A method and a system control an operation of a vapor compression system using a set of control inputs. A control value is determined based on an output of the operation of the vapor compression system and a setpoint for the operation of the vapor compression system. The control value is used to select at least a subset of the set of control inputs from a computer-readable medium, wherein the subset of control inputs, along or in combination with a function of the control value, forms the set of control inputs.

Abstract: A refrigeration apparatus includes a high-temperature side circulation circuit, a low-temperature side circulation circuit, a cascade capacitor, and control means. The high-temperature side circulation circuit forms a refrigerant circuit in which a high-temperature side compressor, a high-temperature side condenser, a high-temperature side expansion device, and a high-temperature side evaporator are connected by a pipe. The refrigerant circuit allows a high-temperature side refrigerant to circulate therethrough. The high-temperature side refrigerant has a carbon-carbon double bond in its molecular structure. The high-temperature side compressor has a variable discharge capacity and is configured to discharge the high-temperature side refrigerant. The low-temperature side circulation circuit forms a refrigerant circuit in which a low-temperature side compressor, a low-temperature side condenser, a low-temperature side expansion device, and a low-temperature side evaporator are connected by a pipe.

Abstract: A control system for a refrigeration unit being powered by a power source and having a compressor, an inverter and an evaporator fan is provided. The control system may include a first switch configured to selectively couple the compressor with one of the power source and the inverter, a second switch configured to selectively couple the evaporator fan with one of the power source and the inverter, and a controller operatively coupled to the first and second switches. The controller may be configured to engage the first and second switches into one of a first state and a second state based on a triggering event. In the first state, the first switch may be configured to couple the compressor with the power source and the second switch may be configured to couple the evaporator fan with the inverter. In the second state, the first switch may be configured to couple the compressor with the inverter and the second switch may be configured to couple the evaporator fan with the power source.

Abstract: The refrigeration system has an energy saving operation mode performing: a first action in which a compressor (11) and an internal fan (16) are driven while the cooling capacity of an evaporator (14) is regulated; a second action in which, when the blow-off-side air temperature in a cold storage is kept at a set value in the first action, the cooling capacity of the evaporator (14) is increased to lower the blow-off-side air temperature to a lower limit temperature of a desired temperature range containing the set value and the compressor (11) and the internal fan (16) are then stopped; and a third action in which, when the blow-off-side air temperature after the second action rises to an upper limit temperature of the desired temperature range, the first action is restarted.

Abstract: A variable flow refrigerant system having a compressor and one or a plurality of evaporators. The suction at one or the plurality of evaporators for the input to the compressor is monitored and generally corresponds to the minimum pressure of the refrigerant. The pressure is associated with a temperature and is controlled to always be above the dew point temperature of the room.

Abstract: A method for controlling a refrigeration system with a variable compressor capacity, and at least two refrigeration entities, e.g. display cases, includes controlling suction pressure by either permitting or preventing the flow of refrigerant into the evaporators of one or more refrigeration entities. The method also includes controlling compressor capacity based on a signal derived from one or more properties of the one or more refrigeration entities, said signal reflecting a possible difference between the current compressor capacity and a current refrigeration demand of the refrigeration system. The method reduces wear on compressors by avoiding switching them ON or OFF to the largest extent possible, and also prevents problems relating to conflicting control strategies due to control parameters, e.g. suction pressure, being determined based on two or more controllable parts, e.g. compressors and flow of refrigerant into refrigeration entities.

Abstract: A refrigerant cycle device includes a first refrigerant passage for guiding refrigerant from a refrigerant radiator to an inlet side of an outdoor heat exchanger, a first throttle part capable of varying an opening area of the first refrigerant passage, a second refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to a compressor-suction side, a first opening/closing part for opening/closing the second refrigerant passage, a third refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to the compressor-suction side via an evaporator, a second throttle part capable of varying an opening area of the third refrigerant passage, a bypass passage for guiding the refrigerant flowing between the refrigerant radiator and the first throttle part to a position between the outdoor heat exchanger and the second throttle part in the third refrigerant passage, and a second opening/closing part for opening/closing the bypass passage.

Abstract: An air conditioning system for a vehicle has a refrigerant cycle device which has an evaporator and a compressor and in which refrigerant is discharged from the compressor to be evaporated in the evaporator so that air passing the evaporator is cooled to be blown into a passenger compartment of the vehicle. The control unit drives the compressor at a control value which is determined based on at least one of a pressure of the refrigerant in the refrigerant cycle device and an outside-air temperature outside the passenger compartment, when the control unit actuates the compressor.

Abstract: To determine whether or not integral control is performed when a requested compressor output value is limited by an upper or lower limit, based on an evaporator temperature deviation, prevent divergence of an integral value, and make an evaporator temperature follow a target evaporator temperature during the integral control, an evaporator temperature deviation calculation means, integral control means for calculating an integral value based on an evaporator temperature deviation, and output value calculation means for calculating a requested compressor output value based on the integral value and limiting the requested compressor output value to calculate a compressor output value are provided.

Abstract: A refrigerant system is provided with a pulse width modulation valve. A compressor temperature is monitored to prevent potential reliability problems and compressor failures due to an excessive temperature inside the compressor. A control changes the pulse width modulation valve duty cycle rate to maintain temperature within specified limits, while achieving the desired capacity, and complying with design requirements of a conditioned environment, without compromising refrigerant system reliability. As the compressor temperature increases, the pulse width modulation valve duty cycle time is adjusted to ensure that adequate amount of refrigerant is circulated through the compressor to cool the compressor internal components.

Abstract: An air-conditioning system (1) for an environment, in particular for the passenger compartment of a vehicle, is provided with an evaporator (13) and a compressor (18) coupled to the evaporator (13). In a system (30) for controlling the air-conditioning system (1), a control electronics (33) switches an operating condition of the compressor (18) when the temperature of the air leaving the evaporator (13) has a pre-set relation with a threshold temperature (Tthresh). The control electronics varies the value of the threshold temperature (Tthresh) as a function, in at least certain operating conditions, of a set-point temperature (Tsp), required by a user of the air-conditioning system (1), so as to reduce the energy consumption associated to the air-conditioning system.

Abstract: In a refrigeration cycle device in which a compressor is driven by power transmitted from an engine, a torque limiter is adapted to interrupt a transmission of the power from the engine to the compressor when a torque transmitted from the engine to the compressor becomes a predetermined value. A control unit is adapted to determine whether the transmission of the power from the engine to the compressor is interrupted by the torque limiter by determining whether a deviation of a refrigerant discharge pressure of the compressor is below a predetermined pressure when the control unit commands the compressor to change the refrigerant discharge flow amount of the compressor. Thus, the control unit can determine whether the torque limiter interrupts the transmission of power from the engine to the compressor without, using a compressor revolution sensor.

Abstract: A method for adjusting a natural refrigeration cycle rate of an air conditioner includes monitoring a time between at least two sequential refrigeration “off” events or at least two sequential refrigeration “on” events, and determining whether the time is below or above a predetermined time. If the time is below the predetermined time, the method further includes increasing a refrigeration “on” temperature threshold. If, however, the time is above the predetermined time, the method further includes decreasing the refrigeration “on” temperature threshold.

Abstract: A method of controlling an air-conditioning system for a motor vehicle is disclosed. The method includes provisions for controlling a compressor to achieve a desired evaporator temperature. The method includes a step of selecting a gain parameter and a reset parameter according to the ambient temperature for use in a set of proportional-integral calculations.

Abstract: A method is provided for operating a refrigerant vapor compression system at substantially zero cooling capacity to facilitate tight temperature control within a climate-controlled environment associated with the refrigerant vapor compression system. The method includes the step of diverting substantially all refrigerant flow from the primary refrigerant flow circuit of the refrigerant vapor compression system at a first location downstream, with respect to refrigerant flow, of the heat rejection heat exchanger and upstream, with respect to refrigerant flow, of the evaporator refrigerant expansion device to reenter the primary refrigerant flow circuit at a second location downstream, with respect to refrigerant flow, of the evaporator and upstream, with respect to refrigerant flow, of the compression device.

Abstract: The present invention relates to a method for controlling a vehicle air-conditioner, which can prevent undershoot of an evaporator by performing a maximum capacity control or controlling an discharge capacity of a compressor through the outputting of an discharge capacity control value of the compressor directly before the stop of the air conditioner, and can improve the pleasant feelings of the passengers by preventing delay of response, which converges into the target temperature of the evaporator due to the delay of the decrease of the temperature of the evaporator.

Abstract: A method for operating a linear compressor including a linear drive with a stator and a rotor configured for displacement by a magnetic field of the stator against a spring force, and a compression chamber which is delimited by a displaceable piston coupled to the rotor during the operation of which an alternating current is applied to the stator in order to drive the rotor in an reciprocatingly, the method including the steps of applying, prior to operation, a direct current with a first polarity to the stator in order to displace the rotor from a rest position, measuring a first end position attained by the rotor under the action of the direct current, and controlling, during operation, the intensity of the alternating current with which the stator is excited in a manner wherein the rotor does not reach the first end position or reaches it at a reduced speed.

Abstract: A method for controlling a multi-unit air conditioning system adapted to cool or heat room spaces while passing a refrigerant in one direction or in a reverse direction is disclosed. In the method, which is applied to a multi-unit air conditioning system including at least three compressors, when a compressor re-operation is repeatedly carried out after all of the compressors have been turned off, to turn on again at least one of the compressors, repetition of the compressor re-operation is carried out for a predetermined number of different orders in such a manner that at least one of the compressors is turned on first in an associated order of the repeated compressor re-operation.

Abstract: A rotary closed type compressor is configured such that an inside of a case becomes high pressure, and the rotary closed type compressor comprises a first cylinder and a second cylinder having cylinder chambers in which eccentric rollers are housed, respectively, vanes which divide the cylinder chamber into two sections, respectively, and vane chambers in which back-face side end portions of the vanes are housed, respectively. The vane on the first cylinder side is pressed and biased by a spring member provided in the vane chamber, and the vane on the second cylinder side is pressed and biased according to pressure difference between case internal pressure introduced to the vane chamber and suction pressure or discharge pressure introduced to the cylinder chamber.

Abstract: A method to detect and respond to a coil condition in an HVAC system. The method includes calculating an initial airflow restriction value and a current airflow restriction value, which are compared. If the current airflow restriction value is greater than a first sum including the initial airflow restriction value and a first restriction factor, then a coil condition is preliminarily determined to be freezing and cooling in the HVAC system is stopped.

Abstract: The invention relates to a method for regulating a coolant circuit (2) of a vehicle air conditioning system (4). According to said method, a target value (SW(VT)) for an evaporator temperature (VT) is predetermined in a base control circuit. Said value is used to determine a control value (U) for controlling the evaporator temperature (VT) by means of an evaporator temperature regulator (16). Said control value is also fed to a ventilator fan controller (26).

Abstract: A high efficiency air conditioning system includes a pneumatically-controlled variable displacement compressor and a compressor clutch that is selectively cycled on and off to minimize series re-heating of conditioned air. Conditioned air is discharged after passing through an evaporator core, and a target value for the evaporator outlet air temperature is determined based on the desired air discharge temperature. The compressor clutch is cycled off when the evaporator outlet air temperature falls below the target value by at least a calibrated amount, and is thereafter cycled on again when the evaporator outlet air temperature rises above the target value. The target value is preferably biased to prevent compressor operation when the desired air discharge temperature exceeds outside air temperature by at least a calibrated amount and to prevent the relative humidity in the air-conditioned space from rising above a desired level.

Abstract: A system includes a compressor, processing circuitry, a first sensor detecting high-side data indicative of an operating condition of a high-pressure side of the refrigeration circuit, and a second sensor detecting low-side data indicative of an operating condition of a low-pressure side of the refrigeration circuit. The processing circuitry receives the high-side data and the low-side data from the first and second sensors and processes at least one of the high-side data and low-side data to select an operating mode for the compressor. The operating modes include a normal mode, a reduced-capacity mode, and a shutdown mode.

Abstract: A vehicle exhaust heat recovery system includes a vapor compression type refrigeration circuit, a boiler to which the refrigerant is introduced from the refrigeration circuit and heated, and an expander for generating motive power by expanding the heated refrigerant. The refrigerant circulates in the refrigeration circuit. The boiler heats the refrigerant introduced therein using exhaust heat generated by the vehicle. The refrigerant that has been subjected to expansion is recycled to the refrigeration circuit.

Abstract: A method for controlling the operation of an air conditioning system, including the steps of operating the air conditioning system until a frequency of a compressor reaches to a preset target frequency, stabilizing the operation of the system after the frequency of the compressor reaches to the preset target frequency, and operating the system at a fixed level.

Abstract: A vapor compression system includes a main vapor compression circuit having a compressor, a condenser, an expansion device and an evaporator serially connected by main refrigerant lines, the compressor having a suction port, a main discharge port and an intermediate port, and the main refrigerant lines being communicated with the main discharge port and the suction port; a bypass circuit communicated between the intermediate port and the suction portion; and a superheat sensing device positioned to sense superheat in a combined flow from the main vapor compression circuit and the bypass circuit. A method of operation of the system is also provided. The benefits of enhanced system and compressor performance, improved compressor reliability and extended system operating envelope are readily obtained.

Abstract: A method of controlling a heating cycle of a refrigeration system is provided that includes a refrigerant circuit. The refrigerant circuit includes a compressor having a suction port and an outlet having a discharge port with a hot gas compressor discharge line, a condenser for condensing the refrigerant, an evaporator for evaporating the refrigerant and an expansion valve. The method includes using refrigerant from the hot gas compressor discharge line to heat the evaporator during a heating cycle, detecting periodically a discharge superheat of the refrigerant leaving the outlet of the compressor, producing a control signal representing a difference between the detected discharge superheat and a minimum discharge superheat setpoint, adjusting the flow rate of the refrigerant to the suction port of the compressor according to the control signal so as to maintain the discharge superheat of the refrigerant at the outlet of the compressor substantially at the minimum discharge superheat setpoint.

Abstract: A method and apparatus for detecting surge in a refrigeration system that includes a centrifugal compressor having an impeller and a compressor entrance, an evaporator that receives a fluid refrigerant, a suction line that flows the refrigerant from the evaporator to the compressor entrance. The evaporator includes a heat-exchange coil supplied with a liquid through a supply line entering the evaporator. The liquid is disposed in a heat-exchange relationship with the refrigerant within the evaporator. The method and apparatus automatically and periodically performing the steps of measuring a fluid temperature of the liquid proximate the supply line entering the evaporator; measuring a refrigerant temperature of the refrigerant proximate the compressor entrance; and using the fluid temperature and the refrigerant temperature to detect surge in the refrigeration system.

Abstract: An improved cryogenic compressor with piston position sensing is disclosed. Precision optical encoders using incremental or absolute encoding are incorporated into a compressor to allow for accurate position sensing of moving elements within the compressor. Appropriate electronic circuitry is used to interpret the position data to allow the user modify the frequency and stroke of the piston within the compressor. The invention may be used in systems with multiple compressor pistons or for position data for balance weights or displacers in a cryogenic refrigeration system.

Abstract: A method for operating a vapor compression system having a compressor driven by a variable frequency drive, wherein the compressor feeds a refrigerant loop, wherein the refrigerant loop includes a cooling circuit for the variable frequency drive, and wherein a flow control member is positioned for controlling flow of refrigerant from the refrigerant loop to the cooling circuit including the steps of: sensing an operating temperature of the variable frequency drive; and controlling the flow control member based upon the operating temperature.

Abstract: A method for operating a vapor compression system having a compressor driven by a variable frequency drive, wherein the compressor feeds a refrigerant loop, wherein the refrigerant loop includes a cooling circuit for the variable frequency drive, and wherein a flow control member is positioned for controlling flow of refrigerant from the refrigerant loop to the cooling circuit including the steps of: sensing an operating temperature of the variable frequency drive; and controlling the flow control member based upon the operating temperature.

Abstract: An air conditioning apparatus includes a refrigerating cycle supplying the supercritical refrigerant pressurized by the variable displacement compressor to the outdoor heat exchanger, the expansion valve and the indoor heat exchanger, in sequence and subsequently return the supercritical refrigerant to the variable displacement compressor. The apparatus further includes a displacement control unit that establishes a limit value derived from the engine speed and further controls a discharge volume of the compressor prior to the control in the opening degree of the expansion valve, on a basis of the so-established limit value.

Abstract: A method and apparatus for detecting surge in a refrigeration system that includes a centrifugal compressor having an impeller and a compressor entrance, an evaporator that receives a fluid refrigerant, a suction line that flows the refrigerant from the evaporator to the compressor entrance. The evaporator includes a heat-exchange coil supplied with a liquid through a supply line entering the evaporator. The liquid is disposed in a heat-exchange relationship with the refrigerant within the evaporator. The method and apparatus automatically and periodically performing the steps of measuring a fluid temperature of the liquid proximate the supply line entering the evaporator; measuring a refrigerant temperature of the refrigerant proximate the compressor entrance; and using the fluid temperature and the refrigerant temperature to detect surge in the refrigeration system.

Abstract: A refrigeration cycle apparatus has a compressor, a radiator, an expansion device, an evaporator, and a variable-speed mechanism. When a rotary shaft of the compressor is rotated, the compressor increases the pressure of refrigerant. The radiator cools refrigerant the pressure of which has been increased by the compressor. The expansion device generates power using the decompression and expansion and transmits the power to the rotary shaft. The evaporator heats refrigerant that has been decompressed and expanded by the expansion device. The variable-speed mechanism is capable of changing the discharge rate of the expansion device per rotation of the rotary shaft. This permits the expansion device to increase the amount of recovered power.