Abstract: A method of shutting down a refrigeration system including: initiating a shutdown process of the refrigeration system; closing a first valve within a refrigerant circuit of the refrigeration system; operating a compressor within the refrigerant circuit; detecting a suction pressure within the refrigerant circuit; closing a second valve within the refrigerant circuit of the refrigeration system when the suction pressure is below a threshold suction pressure; and stopping operation of the compressor.

Abstract: A heat pump and a method for operating a heat pump are provided. The heat pump may include an outdoor unit including a compressor that compresses a refrigerant and an outdoor heat exchanger that exchanges heat between the refrigerant and outdoor air, a hybrid unit including at least one fluid-refrigerant heat exchanger that exchanges heat between the refrigerant supplied from the outdoor unit and a fluid, such as water, and at least one refrigerant control valve that controls an amount of refrigerant flowing through the at least one fluid-refrigerant heat exchanger, a plurality of indoor units each including an indoor heat exchanger that exchanges heat between the fluid supplied from the hybrid unit and indoor air, and a controller. The controller may calculate operation loads of the plurality of indoor units and control an opening degree of the at least one refrigerant control value based on the operation loads of the plurality of indoor units.

Abstract: A heating and cooling system includes a reversing valve configured to adjust a flow of refrigerant through the heating and cooling system, where the reversing valve includes a first configuration to flow the refrigerant through a first circuit of the heating and cooling system and a second configuration to flow the refrigerant through a second circuit of the heating and cooling system. The heating and cooling system also includes a controller configured to determine an operating parameter of a compressor of the heating and cooling system, where the controller is configured to adjust operation of the compressor based on the operating parameter to adjust a position of the reversing valve.

Abstract: A refrigeration cycle device includes a compressor, a radiator, an air-conditioning heat exchanger, a cooling heat exchanger, an air-conditioning decompression unit, a cooler-unit decompression unit, a refrigerant flow rate detector, and a controller. The radiator is configured to radiate heat of refrigerant discharged from the compressor. The air-conditioning heat exchanger absorbs heat from air to evaporate the refrigerant. The cooling heat exchanger is arranged in parallel with the air-conditioning heat exchanger in the flow of refrigerant. The air-conditioning decompression unit adjusts a decompression amount of the refrigerant flowing into the air-conditioning heat exchanger. The cooler-unit decompression unit adjusts a decompression amount of the refrigerant flowing into the cooling heat exchanger. The controller controls the operation of the cooler-unit decompression unit so that the flow rate of the refrigerant detected by the refrigerant flow rate detector exceeds a predetermined reference flow rate.

Abstract: A turbo compressor includes a housing with a refrigerant suction hole, through which a refrigerant is introduced, at a front portion thereof, and a motor case defining an accommodation space. The accommodation space includes a rotation shaft extending in a front-rear direction and a motor that is configured to rotate the rotation shaft. A first impeller is coupled to one end of the rotation shaft and a second impeller is coupled to the other end of the rotation shaft. The first impeller is configured to primarily compress the refrigerant introduced into the refrigerant suction hole. A connection passage, that surrounds the motor case extends backward from an outlet of the first impeller. The second impeller is configured to secondarily compress the refrigerant introduced through the connection passage.

Abstract: An air conditioner indoor unit, comprising a casing, and a fan casing, an electric heating assembly and a heat exchanger assembly which are disposed in the casing. The fan casing has a return air inlet and an air outlet, the electric heating assembly and the heat exchanger assembly are both disposed at the air outlet of the fan casing, and the electric heating assembly is located between the fan casing and the heat exchanger assembly. Further disclosed are an air conditioner control method, an air conditioner, and a storage medium. Since the electric heating assembly is disposed at the air outlet of the fan casing and between the fan casing and the heat exchanger assembly, the fan casing and the heat exchanger assembly can isolate a fire source that may be generated by the electric heating assembly when the electric heating assembly has a blow or other accident.

Abstract: A system includes a dynamic compressor, a variable frequency drive (VFD), and a controller. The dynamic compressor includes a motor having a driveshaft rotatably supported within the dynamic compressor, and a compression mechanism connected to the driveshaft and operable to compress a working fluid upon rotation of the driveshaft. The VFD includes a sensor configured to sense a current provided to the motor. The controller is connected to the motor and includes a processor and a memory. The memory stores instructions that program the processor to operate the motor using the VFD to compress the working fluid, receive signals representing the current from the VFD to the motor, and determine when a surge event has occurred based at least in part on the received signals representing the current from the VFD to the motor.

Abstract: Controllability of a linear motor or a compressor is improved in a linear motor system that includes: an armature having magnetic poles and winding wires; a mover having a permanent magnet; and a power conversion unit that outputs AC power to the winding wires, in which the mover and the armature are relatively movable, and the mover or the armature is connected to an elastic body. The linear motor system further includes: a position detection unit that detects and outputs the position of the mover with respect to the armature, a position estimation, or a current detection unit that outputs the value of current flowing through the winding wires; and a control unit that controls the output of the power conversion unit on the basis of the output of the position detection unit, the output of the position estimation unit, or the output of the current detection unit.

Abstract: A cooling system implements various processes to improve efficiency in high ambient temperatures. First, the system can flood one or more low side heat exchangers in the system. Second, the system can direct a portion of vapor refrigerant from a low side heat exchanger to a flash tank rather than to a compressor. Third, the system can transfer heat from refrigerant at a compressor suction to refrigerant at the discharge of a high side heat exchanger.

Abstract: A refrigeration system includes a valve and a controller. The valve is configured to control the flow of refrigerant into an evaporator, the refrigerant having an associated liquid setting comprising a temperature and a pressure at which the refrigerant flows through the valve. The controller is operable to adjust the liquid setting, the adjusted liquid setting comprising a temperature and a pressure selected to improve energy efficiency under conditions currently being experienced by the refrigeration system, wherein the controller is operable to adjust the temperature and the pressure simultaneously such that the adjustment does not interfere with operation of the valve.

Abstract: A steady-state data processing method includes resetting a cumulative change of target determination data and a data detection period as 0; obtaining the detected target data; calculating the cumulative change of the target data. When the calculated cumulative change of the target data is less than a preset threshold, adjusting the data detection period, or when the calculated cumulative change of the target data is not less than the preset threshold, recording a data detection period. When the recorded data detection period is less than a preset time threshold, determining a target data result obtained in the period as unsteady-state data of the device; or when the recorded data detection period is not less than the preset time threshold, determining the target data obtained in the data detection period as steady-state data.

Abstract: A method for operating a temperature control system is disclosed. The method includes monitoring an interior and exterior temperature of a structure, defining a first time range and a second time range, associating one or more operating parameters of the temperature control system with the first time range, associating one or more operating parameters of the temperature control system with the second time range, monitoring operational time and operational load of the cooling system for the first time range, predicting a space temperature and an outdoor air temperature for a subsequent time period, and controlling a ventilation subsystem during the second time range based upon the monitored operational time and operational load of the cooling subsystem for the first time range, the predicted space temperature, the predicted outdoor air temperature, and the one or more operating parameters of the cooling subsystem associated with the second time range.

Abstract: A connected oven, including a set of in-cavity sensors and a processor configured to automatically identify foodstuff within the cooking cavity, based on the sensor measurements; and automatically operate the heating element based on the foodstuff identity.

Abstract: A system includes a sensor and a controller for a refrigeration or HVAC system having a compressor. The sensor senses a temperature of the compressor during operation of the compressor. The controller is configured to determine a rate of change of the temperature relative to time and to perform one or more procedures to protect the compressor based on the rate of change of the temperature. The one or more procedures to protect the compressor include shutting down the compressor, throttling a pressure regulator valve of an evaporator associated with the compressor, adjusting an expansion valve associated with the evaporator, reducing speed of the compressor, and partially or wholly unloading the compressor.

Abstract: Apparatus for controlling a cryogenic cooling system is described. A supply gas line (3A) and a return gas line (3B) are provided which are coupled to a compressor (1) and to a mechanical refrigerator (2) via a coupling element (4). The coupling element is in gaseous communication with the supply (2A) and return gas lines and supplies gas to the mechanical refrigerator (2). The pressure of the supplied gas is modulated by the coupling element in a cyclical manner. A pressure sensing apparatus (6) monitors the pressure in at least one of the supply and return gas lines. A control system (5) is used to modulate the frequency of the cyclical gas pressure supplied by the coupling element in accordance with the pressure monitored by the pressure sensing apparatus. An associated method of controlling such a system is also described.

Abstract: Provided are an air conditioner and a method of controlling the same. The air conditioner includes an indoor unit including an indoor heat exchanger, a first outdoor unit connected to the indoor unit, the first outdoor unit including a first compressor compressing a refrigerant and a first outdoor heat exchanger, a second outdoor unit including an engine generating a power by using combustion gas, a generator supplying electricity into the first compressor by using the power generated in the engine, a second compressor compressing the refrigerant by using the power of the engine, and a second outdoor heat exchanger, and a controller determining an additional operation of the second compressor on the basis of required cooling or heating load while the first compressor operates.

Abstract: A pilot on-off valve in a refrigeration cycle device includes a main on-off valve that opens or closes a bypass passage through which a high-pressure side portion and a low-pressure side portion of a cycle communicate with each other, and a pilot valve that opens or closes a communication passage through which an inflow port and an outflow port of the pilot on-off valve communicate with each other. When the main on-off valve opens the bypass passage, the pilot valve opens the communication passage in a state where a refrigerant passage, in which a refrigerant flowing out of the pilot on-off valve flows, is closed.

Abstract: An air-conditioning apparatus includes a intermediate heat exchangers operating as a condenser or an evaporator and allows each intermediate heat exchanger to exchange heat between a refrigerant heated or cooled in a refrigeration cycle on a heat source side and a heat transfer medium flowing through a heat transfer medium circuit on a use side such that heat energy produced on the heat source side is transmitted to use side heat exchangers. A controller calculates the heat transfer medium temperature difference between a heat transfer medium inlet and outlet temperatures. When a detected value of a heat transfer medium temperature detecting device deviates from a predetermined range, the controller changes the target heat transfer medium temperature difference and controls a heat transfer medium flow control device, such that the heat transfer medium temperature difference reaches the changed target heat transfer medium temperature difference.

Abstract: A refrigeration system including a condenser; a (single) linear compressor that is activated and deactivated by a pulse width modulation switching device; a pulse width modulation refrigerant flow switch; at least two evaporators operably connected in parallel with one another with at least one evaporator associated with the refrigerator compartment that operates at a first refrigerant fluid pressure and with at least one other evaporator associated with the freezer compartment that operates at a second refrigerant fluid pressure; and a plurality of refrigerant fluid conduits operably connecting the condenser, the linear compressor and the evaporators into a refrigerant fluid flow circuit and such that the evaporators are capable of running simultaneously at different pressure levels and refrigerant flows from the evaporators, to the pulse width modulation refrigerant flow switch and through the pulse width modulation refrigerant flow switch.

Abstract: The present application provides a refrigeration system using a flow of a carbon dioxide refrigerant. The refrigeration system may include a flash tank, a number of temperature suction compressors for a temperature suction cycle, and a flash gas bypass system positioned between the flash tank and the cycle compressors. The flash gas bypass system may include one or more oversized flash gas compressors so as to alternate between the temperature suction cycle and a flash tank suction cycle.

Abstract: A method for controlling operation of a vapor compression system (1), and a vapor compression system (1) are disclosed. The vapor compression system (1) comprises a compressor (2), a heat rejecting heat exchanger (3), a controllable valve (4), a receiver (5), at least one expansion device and at least one evaporator arranged along a refrigerant path having refrigerant flowing therein. The vapor compression system (1) is capable of being operated in a subcritical control regime as well as in a supercritical control regime.

Abstract: A heat pump includes a valve system that connects a receiver tank in fluid communication with an indoor heat exchanger, wherein the valve system, operating under a novel control scheme, works in conjunction with the receiver to control the heat pump's effective refrigerant charge. To avoid suction or discharge pressure faults and to help prevent slugs of liquid refrigerant from entering the heat pump's compressor as the heat pump switches between heating and cooling modes or switches between heating and defrost modes, the control scheme provides momentary periods of transition between those modes of operation. In some embodiments, the valve system comprises a check valve connected in parallel flow relationship with a two-position receiver valve, wherein the check valve has an appreciably higher flow coefficient than that of the receiver valve.

Abstract: A variable displacement compressor adjusts the pressure in a control pressure chamber and controls the displacement in accordance with the adjusted pressure. Refrigerant is supplied via a supply passage, and released via a bleed passage. The compressor includes a first control valve for adjusting the cross-sectional area of the supply passage for refrigerant. The compressor further includes a second control valve that adjusts the cross-sectional area of the bleed passage in accordance with the opening/closing state of the first control valve. The second control valve adjusts the cross-sectional area of the bleed passage such that the cross-sectional area when the first control valve is in the closed state is larger than that when the first control valve is in the opened state. The back pressure chamber is located in a section of the bleed passage that is located between the second control valve and the control pressure chamber.

Abstract: A refrigeration apparatus includes a compressor receiving refrigerant through an injection pipe and of discharging the refrigerant, a condenser, an electronic expansion valve connected by piping to another end of the injection pipe, a subcooling coil, a solenoid valve configured to control inflowing of the refrigerant through the injection pipe into the compressor, an injection bypass pipe connecting the injection pipe and a pipe on a suction side of the compressor, a solenoid valve configured to control passage of the refrigerant flowing through the injection bypass pipe, a high-low pressure bypass pipe connecting a pipe on a discharge side of the compressor and the pipe on the suction side of the compressor, a solenoid valve configured to control passage of the refrigerant through the high-low pressure bypass pipe, and a controller configured to control a frequency of the compressor and opening and closing of each of the solenoid valves.

Abstract: An air conditioning system having a cooling mode and a free-cooling mode is provided. The system includes a refrigeration circuit, two pressure sensors, a controller, and a pump-protection sequence resident on the controller. The refrigeration circuit includes a compressor and a pump. The first pressure sensor is at an inlet of the pump, while the second pressure sensor is at an outlet of the pump. The controller selectively operates in the cooling mode by circulating and compressing a refrigerant through the refrigeration circuit via the compressor or operates in the free-cooling mode by circulating the refrigerant through the refrigeration circuit via the pump: The pump-protection sequence turns the pump to an off state based at least upon a differential pressure determined by the controller from pressures detected by the first and second pressure sensors.

Abstract: In a swash plate type compressor, provided is an introduction flow passage through which refrigerant is introduced from a suction chamber. Further, a differential pressure control valve is provided on the introduction flow passage. The differential pressure control valve acts due to a differential pressure (Pc?Ps) between a crank pressure Pc and a suction pressure Ps. An opening of the introduction flow passage is adjusted by the differential pressure control valve so as to prevent the crank pressure Pc from exceeding a predetermined value. According to the swash plate type compressor, an excessive elevation of the crank pressure Pc can be prevented without a usage of a check valve.

Abstract: Detection of reverse rotation or operation of a refrigerant compressor is provided. In one aspect, a detection technique includes starting the compressor and determining the compressor is rotating in a reverse direction if a dome temperature of the compressor fails to exceed a first predetermined threshold at or before expiration of a first predetermined period of time following starting, the refrigerant pressure at a refrigerant inlet of the compressor remains constant for a second predetermined period of time following starting, and/or the frequency of pressure oscillations of the refrigerant at the refrigerant inlet exceeds a second predetermined threshold. Another technique for determining the compressor is rotating in the reverse direction involves analyzing a waveform associated with motor current, motor torque, or refrigerant pressure. Further embodiments, forms, features, and aspects shall become apparent from the description and drawings.

Abstract: A method is disclosed for controlling a discharge pressure of a compressor relative to a suction pressure of the compressor. The discharge pressure and suction pressure of the compressor are monitored and compared with a predetermined maximum pressure ratio of discharge pressure to suction pressure. If the pressure ratio of discharge pressure to suction pressure exceeds a predetermined pressure ratio limit less than the maximum pressure ratio, a controller unloads the compressor. The predetermined pressure ratio limit is determined relative to the measured suction pressure. The discharge pressure and suction pressure are further monitored and the compressor is inhibited from being reloaded for a predetermined time delay. After the predetermined time delay has elapsed, the compressor is reloaded only if i) the discharge pressure falls below a predetermined reload pressure and ii) the chiller system requires additional cooling capacity.

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 machine for producing liquid and semi-liquid consumer food products comprises one or more containers (2) for a basic product of the consumer product to be made; a refrigeration system (3) acting on the containers (2) to reduce the temperature of the basic product; the refrigeration system (3) comprising a predetermined refrigerant; the refrigerant being carbon dioxide and the refrigeration system (3) being set up to carry out a transcritical refrigeration cycle on the refrigerant.

Abstract: A variable displacement compressor with a compensated suction shutoff valve (SSV). The SSV prevents noise generated by a suction reed valve at low refrigerant flow rates in an internal suction region from propagating to an air conditioner evaporator by moving a piston to obstruct an opening and restrict fluid communication. The degree of restriction is decreased by an opening force generated by refrigerant at an external suction pressure acting over a first area, and increased by refrigerant at a crankcase pressure acting over a second area. The second area is smaller than the first area so that at high refrigerant flow rates, the effect of crankcase pressure is reduced so that the restriction is reduced and the compressor operates at greater efficiency. The piston position is also influenced by refrigerant at a pressure intermediate the external suction pressure and the internal suction pressure acting over a third area.

Abstract: Techniques herein describe a pumping system, adapted to reduce or eliminate fluid cavitation. Optionally, the pumping system is adapted for application to a passive fluid recovery system. In one example, the pumping system includes a pump and a thermal sub-cooling device. The thermal sub-cooling device may sub-cool fluid input to a pump and heat fluid output from the pump, particularly under start-up conditions. In a further example, a controller manages power supplied to both the pump and the thermal sub-cooling device, to transition from an ambient temperature start-up condition to an elevated temperature operating condition.

Abstract: An air-conditioning system control apparatus for controlling an air-conditioning system of a vehicle equipped with a motive power engine, having: a device for determining whether there is a history of a load that has been applied to a compressor, operated by the output of the motive power engine, equal to or greater than a threshold, during operation of the air-conditioning system; a device for carrying out initial operation process of the air-conditioning system if the load history determination device determines that there is a history of a load equal to or greater than the threshold has been applied to the compressor; and a device for carrying out liquid accumulation resolution process when liquefaction of a refrigerant occurs in the compressor only if the load history determination device determines that there is no history of a load equal to or greater than the threshold has been applied to the compressor.

Abstract: A vehicle air conditioning system includes a controller that initially controls operation of a compressor to switch between inactive and active states in response to detecting that an operating condition is equal to or surpasses a first operation threshold. The controller determines a first time delay occurring between initiating the switch from one of the inactive and active states to the other of the compressor, and an actual change in the operating condition. The controller subsequently defines a first limit that is offset from the first operation threshold such that the controller controls the operation of the compressor to subsequently switch from the one of inactive and active states to the other in response to detecting that the operating condition is equal to or surpasses the first limit.

Abstract: A system and a method for operating a variable-displacement compressor are provided wherein a volume of a compression chamber of at least one cylinder is varied during a compression cycle, wherein during the cycle the at least one cylinder is alternately coupled to a low pressure side and a high pressure side of the compressor. A first thermodynamic state of the low pressure side and a second thermodynamic state of the high pressure side can be estimated and a current compression ratio ( v in v out ) of the compressor can be estimated. Accordingly, a compressor displacement (D) as a function of the compression ratio ( v in v out ) can be calculated. From this, a compressor torque (M) depending on the calculated displacement (D) can be computed, and the compressor torque (M) can be provided to a control unit for operating the compressor or an engine coupled to the compressor.

Abstract: A cooling system is provided that comprises: a refrigerant loop having a pump; an evaporator heat exchanger thermally coupled to a heat source, the evaporator plumbed in the loop; a condensing heat exchanger and a receiver plumbed in the loop; and an equalizing conduit plumbed between an inlet to the condenser and the receiver and comprising a flow regulating valve.

Abstract: In a hybrid-electric vehicle that includes a cabin, methods and systems are provided for modifying a first curve for engine coolant temperature (ECT) warm-up trajectory. The system includes a processor configured to execute software instructions, and a memory configured to store software instructions accessible by the processor. In one embodiment, the software instructions comprise an offset lookup table that is configured to generate, based on a calculated thermal power loss across a heater core and an ambient air temperature, an offset value for modifying the first curve for ECT warm-up trajectory to produce a desired curve for ECT warm-up trajectory that is offset from the first curve. The desired curve for ECT warm up trajectory is used to adjust temperature in the cabin so that fuel consumption can be reduced.

Abstract: A compressor drive torque estimating device to be adapted for a system provided with a refrigeration cycle in which a refrigerant is circulated by a compressor driven by a drive source mounted in a vehicle, comprising heat load detecting means for detecting a heat load of the refrigeration cycle, a storage unit storing a plurality of estimated drive torque characteristics establishing correlation between a drive torque change characteristic of the compressor and an elapsed time from a time of start of operation of the compressor, an estimated drive torque characteristic selecting means for selecting the one of the plurality of estimated drive torque characteristics stored in the storage unit based on detected values detected by the heat load detecting means, and an estimated drive torque calculating means for calculating an estimated drive torque of the compressor based on the estimated drive torque characteristic selected by the estimated drive torque characteristic selecting means.

Abstract: A compressor inlet pressure estimation apparatus for a refrigeration cycle system is disclosed. An electronic control unit 14 answers YES by judging that the command to start a compressor 2 is issued when an air-conditioning switch is turned on in step S100. After that, the electronic control unit 14 answers NO in the case where a timer count time Tc is shorter than a predetermined time T1 in step S120. At the same time, Tefin_C is set to 15° C. in step S130. The lower one of Tefin_C and Tefin determined in this way is determined as Tefin_d (step S150). After that, Tefin_d is input to the first-order lag function to acquire Tefin_AD(N). Then, the control proceeds to step S170, where the estimated value Ps_es(N) of the refrigerant inlet pressure of the compressor 2 is determined using Tefin_AD(N) and Gr.

Abstract: The present invention includes a novel fuel management and auxiliary power system and apparatus having a control module in control of auxiliary equipment and accessories and climate control functions of a vehicle, while the vehicle's engine is not running. The system of this invention is capable of detecting warning states and providing status indicators to an operator on a graphical user interface. At the graphical user interface, the operator is capable of initiating start up of the system and accessing status and historical technical data of the system.

Abstract: A refrigerant system is provided with a suction pulse width modulation valve, and a pulse width modulation control for controlling this valve. System pressures, such as the pressure on the evaporator and the condenser are monitored. The measured system pressures are maintained within a band of acceptable lower and upper limits. As the pulse width modulation control cycles the valve, the refrigerant pressures in the evaporator and the condenser tend to fluctuate. The control ensures those fluctuations are within the limits by controlling the duty cycle of the valve.

Abstract: A refrigeration device includes a switching valve control section for outputting a switching signal for controlling a four-way switching valve to a predetermined switching state when starting a compression mechanism; and a switching determination section which, when starting only a first compressor as a start-up of the compression mechanism, outputs a low differential pressure signal if a differential pressure between a high-pressure port and a low-pressure port in the four-way switching valve falls below a determination value in a determination operation after the switching signal being outputted by the switching valve control section. After the switching determination section outputs the low differential pressure signal, a capacity control section starts a second compressor.

Abstract: A dynamic system controls indoor relative humidity and temperature to achieve specified conditions by applying multiple stages of dehumidification. In addition to a stage that increases dehumidification by reducing the speed of the indoor blower, the system uses a reheat coil and multiple valves that allow the reheat coil to function as either a subcooling coil or a partial condenser. Thus the system can maintain specified indoor temperature and humidity conditions even at times when no heating or cooling is needed. The system may have an outdoor condensing unit including a compressor and a condenser operably connected via refrigerant lines to an indoor unit to form a “split system” refrigerant loop.

Abstract: A capacity control system for a variable capacity compressor includes target suction pressure setting means for setting, based on external information input from external information detection means, a target suction pressure for controlling the pressure in a suction pressure region as a control target, suction pressure estimation means for estimating, based on the external information, a pressure that is estimated to prevail in the suction pressure region if the variable capacity compressor is operated with a maximum discharge capacity, and discharge capacity determination means for determining, based on the suction pressure estimated by the suction pressure estimation means and the target suction pressure set by the target suction pressure setting means, whether the variable capacity compressor is operating with the maximum discharge capacity or with a controlled discharge capacity.

Abstract: A refrigeration cycle apparatus 100 is provided with a refrigerant circuit 106, an injection flow passage 111, and a high-pressure supply passage 130. The refrigerant circuit 106 includes a low-pressure stage compressor 105, a high-pressure stage compressor 101, a heat radiator 102, an expander 103, a gas-liquid separator 108, and an evaporator 104. The expander 103 and the low-pressure stage compressor 105 are coupled by a power-recovery shaft 107. The refrigeration cycle apparatus 100 is further provided with a flow passage-switching mechanism that selectively connects one of the evaporator 104 and the high-pressure supply passage 130 to the low-pressure stage compressor 105. The flow passage-switching mechanism, for example, is constituted by an on-off valve 131 and a check valve 132.

Abstract: A helium management control system for controlling the helium refrigerant supply from a common manifold supplies cryogenic refrigerators with an appropriate helium supply. The system employs sensors to monitor and regulate the overall refrigerant supply to deliver an appropriate refrigerant supply to each of the cryogenic refrigerators depending on the computed aggregate cooling demand of all of the cryogenic refrigerators. An appropriate supply of helium is distributed to each cryopump by sensing excess and sparse helium and redistributing refrigerant accordingly. If the total refrigeration supply exceeds the demand, or consumption, excess refrigerant is directed to cryogenic refrigerators which can utilize the excess helium to complete a current cooling function more quickly.

Abstract: A turbo chiller equipped with a high-efficiency two-stage turbo compressor is provided. In a turbo chiller including a control unit for controlling the degrees of opening of first inlet guide vanes of a first impeller and second inlet guide vanes of a second impeller, the control unit has a slave mode in which the second inlet guide vanes are operated so as to be dependent on the first inlet guide vanes in a slave-mode priority region, and an independent mode in which the degree of opening of the second inlet guide vanes is increased independently of the first inlet guide vanes in an independent-mode priority region.

Abstract: An inverter-integrated electric compressor has a control device. The control device estimates a compressor suction pressure based on the temperature of the power element of the inverter, or directly measures the compressor suction pressure by a sensor, or estimates the compressor suction pressure based on a compressor suction temperature or on a compressor housing temperature. Further, the control device calculates a motor torque based on a motor rotational speed, a motor phase current, and a motor phase voltage, estimates a compressor discharge pressure based on the compressor suction pressure and the motor torque, and estimates a compressor discharge temperature based on the compressor suction pressure and the compressor discharge pressure. The electric compressor has a discharge temperature detection device in place of a conventional thermal protector.

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 variable displacement compressor adjusts the pressure in a control pressure chamber and controls the displacement in accordance with the adjusted pressure. Refrigerant is supplied via a supply passage, and released via a bleed passage. The compressor includes a first control valve for adjusting the cross-sectional area of the supply passage for refrigerant. The compressor further includes a second control valve that adjusts the cross-sectional area of the bleed passage in accordance with the opening/closing state of the first control valve. The second control valve adjusts the cross-sectional area of the bleed passage such that the cross-sectional area when the first control valve is in the closed state is larger than that when the first control valve is in the opened state. The back pressure chamber is located in a section of the bleed passage that is located between the second control valve and the control pressure chamber.