Abstract: A method for operating a closed circuit vapour compression refrigeration system is disclosed. The system may operate with supercritical pressure on a high pressure side, and includes at least one compressor, at least one heat rejector, at least two in parallel connected heat absorbers, at least one variable expansion means up flow of each heat absorber and at least one control unit for controlling the variable expansion means, connected to a set of sensors. The flow rate of the refrigerant through each of the variable expansion means, is controlled by the control unit, coordinating the flow of refrigerant through each of the variable expansion means to maintain a control parameter within a set range. Any surplus charge resulting from the control is buffered on a low pressure side of the system. Furthermore a refrigeration system based on a closed vapour compression circuit is described.

Abstract: The present invention provides a refrigeration cycle apparatus using a first compressor and a second compressor driven by an expander and including a high and low pressure heat exchanger, in which a low-pressure-side outlet of the high and low pressure heat exchanger is bypassed to a low pressure portion or an intermediate pressure portion to adjust an inlet density at the expander and thereby provide high efficiency. The high and low pressure heat exchanger of the refrigeration cycle apparatus of the present invention changes an amount of heat exchange between a high-pressure refrigerant and a reduced-pressure refrigerant branched from the high-pressure refrigerant at an inlet portion of the high and low pressure heat exchanger and reduced in pressure to adjust the density of the refrigerant flowing in the expander so that power recovered by the expander and power required by the second compressor match.

Abstract: A refrigerating apparatus, where refrigerant reaches a supercritical state in at least part of a refrigeration cycle, includes at least one expansion mechanism, an evaporator connected to the expansion mechanism, first and second sequential compression elements, a radiator connected to the discharge side of the second compression element, a first refrigerant pipe interconnecting the radiator and the expansion mechanism, a heat exchanger arranged to cause heat exchange between the first refrigerant pipe and another refrigerant pipe. Preferably, a heat exchanger switching mechanism is switchable so that refrigerant flows in the first refrigerant pipe through the first heat exchanger or in a heat exchange bypass pipe connected to the first refrigerant pipe.

Abstract: A refrigeration apparatus uses supercritical range refrigerant, and includes a multi-stage compression mechanism, a heat source-side heat exchanger, a usage-side heat exchanger, a switching mechanism switchable between cooling and heating operation states, an intermediate heat exchanger integrated with the heat source-side heat exchanger, and an intermediate heat exchanger bypass tube connected to the intermediate refrigerant tube so as to bypass the intermediate heat exchanger. The intermediate heat exchanger is connected to an intermediate refrigerant tube to draw refrigerant discharged from the first-stage compression element into the second-stage compression element, and functions as a cooler of the refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element. The intermediate heat exchanger bypass tube ensures that refrigerant does not flow to the intermediate heat exchanger when a reverse cycle defrosting operation is performed.

Abstract: An inlet air flow guide for a condensing unit of an air cooled direct expansion (ACDX) air conditioning unit. The flow guide has a panel having at least a portion spaced from a surface of the condensing unit to define a plenum for cooling air to enter the condensing unit from one side. A condensing unit of an ACDX air conditioning unit has a refrigerant cooling coil disposed in an opening, and the inlet air flow guide defines a plenum to provide an air flow passage to the opening from one side thereof. According to a method, the inlet air flow guide is installed onto the condensing unit of an ACDX air conditioning unit, wherein a panel of the flow guide has at least a portion spaced from a surface of the condensing unit to define a plenum for cooling air to enter the condensing unit from one side.

Abstract: A refrigerant vapor compression system includes a flash tank disposed in series refrigerant flow relationship in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit upstream of the flash tank. A refrigerant vapor line is provided to direct refrigerant vapor from the flash tank to an intermediate pressure stage of the compression process. A refrigerant-to-refrigerant heat exchanger operates to transfer heat from refrigerant flowing through the primary refrigerant circuit to refrigerant flowing through the refrigerant vapor line.

Abstract: In a refrigeration apparatus (1) for which refrigerant containing a compound represented by a molecular formula of C3HmFn(note that m=1-5, n=1-5, and m+n=6) is used, a compressor including a first compression mechanism (20A) and a second compression mechanism (20B) inside a casing (11) is used in order to reduce or prevent decomposition of refrigerant due to an increase in discharge temperature of a compressor (10) performing a compression phase of refrigerant in a refrigeration cycle.

Abstract: A refrigeration system comprises a plurality of compressors and a plurality of condensing units comprising a first condensing unit having a first control module and at least one additional condensing unit having an additional control module. Each condensing unit has at least one compressor of the plurality of compressors. A communication link is connected to the first control module and at least one additional control module. The first control module controls the plurality of compressors based on communication with the at least one additional control module via the communication link.

Abstract: A cascade refrigeration system using a first refrigerant or a high stage and a second, R-744, refrigerant for low stage refrigeration has a defrost system including a defrost compressor, a defrost inlet heat exchanger and defrost outlet heat exchanger. The defrost inlet heat exchanger receives a defrost portion of second refrigerant and adds an additional defrost heat load thereto from first refrigerant, thus evaporating defrost portion. Defrost portion is then compressed into high pressure defrost vapor potion in the defrost compressor. The defrost vapor portion is then circulated through a selected evaporator, where a defrost heat, augmented by additional defrost heat load, defrosts selected evaporator, defrost vapor being at least partially condensed into defrost condensed portion which is liquefied in defrost outlet heat exchanger.

Abstract: A cooling system includes a compressor for compressing a refrigerant from a subcritical state to a supercritical state, a cooler for transferring heat from the refrigerant, an expander for expanding the refrigerant in the supercritical state, an expansion valve for expanding the refrigerant from the supercritical state to the subcritical state and an evaporator for transferring heat from a cooling fluid to the refrigerant in the subcritical state. Work extracted by the expander provides power to the compressor. A method for cooling a vehicle includes compressing a refrigerant from a subcritical state to a supercritical state, cooling the refrigerant, expanding the refrigerant in the supercritical state where work produced by expanding the refrigerant is used to compress the refrigerant, expanding the refrigerant from the supercritical state to the subcritical state, cooling a cooling fluid with the refrigerant in the subcritical state and cooling vehicle components with the cooling fluid.

Abstract: A refrigeration apparatus includes a compression mechanism, a heat source-side heat exchanger, a usage-side heat exchanger and an intercooler. The compression mechanism has compression elements arranged so that refrigerant discharged from a first-stage compression element is sequentially compressed by a second-stage compression element. The intercooler is connected to an intermediate refrigerant tube arranged and configured to draw refrigerant discharged from the first-stage compression element into the second-stage compression element. The intercooler is arranged and configured to cool the refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element.

Abstract: A refrigeration apparatus includes a compression mechanism, a heat source-side heat exchanger, a usage-side heat exchanger, a switching mechanism and an intermediate heat exchanger. Refrigerant discharged from a first-stage compression element is sequentially compressed by a second-stage compression element. Each of the heat source-side heat exchanger and the usage-side heat exchanger functions an evaporator or radiator. The switching mechanism is configured to switch between a cooling operation state and a heating operation state. The intermediate heat exchanger is configured to cool refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element when the switching mechanism has been set to the cooling operation state, and to evaporate refrigerant whose heat is radiated in the usage-side heat exchanger when the switching mechanism has been set to the heating operation state.

Abstract: A refrigeration cycle apparatus (100) includes an expander-compressor unit (1) including a first compression mechanism (11) and an expansion mechanism (13), and a sub compressor (2) including a second compression mechanism (21). The first compression mechanism (11) is connected in parallel with the second compression mechanism (21) in a refrigerant circuit (30). The refrigeration cycle apparatus (100) further includes a bypass passage (6) bypassing the expansion mechanism (13). A first flow control valve (61), a gas-liquid separator (62) and a second flow control valve (63) are provided sequentially to the bypass passage (6) from an upstream side. An injection passage (7) guides a gas refrigerant separated from a liquid refrigerant in the gas-liquid separator (62) to the second compression mechanism (21).

Abstract: An economizer (24) is provided in a multistage compression refrigeration system including a refrigerant circuit in which a multistage compressor, a condenser, a multistage expansion mechanism, and an evaporator are sequentially connected. The economizer (24) includes: a tank (24a) having an introducing portion (24d) for introducing a refrigerant of the refrigerant circuit, a liquid outlet (24a) for guiding a liquid refrigerant into the evaporator, and a gas outlet (24c) for guiding a gas refrigerant into a medium pressure portion of the multistage compressor; and a float expansion valve (25), which forms part of the multistage expansion mechanism and is attached to the liquid outlet (24b), and whose throttle amount is adjusted according to a level of the liquid refrigerant in the tank (24a). Multiple ones of the liquid outlet (24b) and multiple ones of the float expansion valve (25) are provided.

Abstract: A refrigerating apparatus for keeping an inside of a storage at a predetermined low-temperature state includes first and second refrigerant circuits including compressors, condensers, decompressors, and evaporators, connected circularly with pipings to form refrigerating cycles, the circuit having a first or second refrigerant sealed therein as a working refrigerant, a first sensor which detects a temperature of a cascade condenser constituted by integrating the evaporator of the first refrigerant circuit and the condenser of the second refrigerant circuit in a heat exchangeable manner, first and second controllers which control operation performances of the first and second compressors in a variable manner based on first and second sensor detected temperatures in order that the first and second sensor detected temperatures are first and second temperatures, respectively, and a second sensor which detects a temperature inside the storage.

Abstract: A refrigerant vapor compression system includes a first compression device, a refrigerant heat rejection heat exchanger, an expansion device, a refrigerant heat absorption heat exchanger, a second compression device, and a refrigerant-to-refrigerant heat exchanger having first refrigerant flow pass, a second refrigerant flow pass and a third refrigerant flow pass, with the second refrigerant flow pass disposed in heat exchange relationship with each of the first refrigerant flow pass and the third refrigerant flow pass. The second refrigerant flow pass is interdisposed in an economizer circuit.

Abstract: As discussed herein, a first aspect of the present invention provides a high-efficiency heat pump that includes a frame, as well as a first circuit, a first compressor, a condenser heat exchanger, a first electronic expansion valve, an evaporator heat exchanger, and a controller. The first circuit, the first compressor, the condenser heat exchanger, the first electronic expansion valve, and the evaporator heat exchanger can be supported by the frame. The first compressor, the condenser heat exchanger, the first electronic expansion valve, and the evaporator heat exchanger can be connected to the first circuit. The controller can be in electronic communication with the first electronic expansion valve, and the controller can be configured to control operation of the first electronic expansion valve and/or the second electronic expansion valve.

Abstract: In a refrigeration system in which a compressor mechanism including a plurality of compressors, oil separators (37a, 37b) are provided at a discharge pipe (56a) of a first compressor (14a) and a discharge pipe (56b) of a second compressor (14b), respectively. An oil return passageway (32) for returning refrigerating machine oil from the oil separators (37a, 37b) to a compressor mechanism (40) is configured to combine streams of refrigerating machine oil separated in the oil separators (37a, 37b) and distribute the combined refrigerating machine oil to the first compressor (14a) and the second compressor (14b).

Abstract: A compressor includes a compression mechanism having lower and upper stage compression chambers. Refrigerant compressed in the lower-stage compression chamber is further compressed in the higher-stage compression chamber. An intermediate injection pipe is arranged to inject refrigerant between the lower-stage and the higher-stage compression chambers. The compression mechanism includes at least one fixed member having a fixed end plate, and at least one movable member having a movable end plate section facing the fixed end plate with at least one of the compression chambers interposed between the end plate sections. At least one intermediate back pressure chamber is formed to face a back surface of the movable end plate section. The intermediate back pressure chamber communicates with a discharge side of the lower-stage compression chamber, and is arranged such that internal pressure of the intermediate back pressure chamber acts on the movable end plate section.

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: An air conditioner having two compressors enables, when one compressor is started, the phase advance capacitor for the other compressor to be temporarily separated and used in parallel with the phase advance capacitor for the one compressor. These compressors can have an increased starting torque without using a starting capacitor.

Abstract: A refrigeration cycle apparatus (100) includes: a first compressor (101); a second compressor (102) connected in parallel with the first compressor (101) in a refrigerant circuit (200); a radiator (103) for cooling a refrigerant compressed by the first and second compressors; an expander (104) coupled to a rotation shaft of the first compressor (101); an evaporator (105) for evaporating the refrigerant expanded by the expander (104); and a controller (115).

Abstract: A high efficiency R744 air conditioning and refrigeration system and cycle comprises a vapor compressor and two independent ejectors operatively connected to high and low-pressure sides of the compressor, respectively. The two ejectors reduce the overall pressure ratio of the mechanical vapor compressor resulting in dramatically increased thermodynamic cycle efficiency. As one example of its potential applications for residential, commercial or industrial uses, a 150 ton capacity of a water-cooled chiller designed in accordance with the present invention is predicted to provide the power consumption as low as 0.47 kW/ton, when operated in accordance with the cooling methods of the present invention, which corresponds to 7.47 of Coefficient of Performance (COP).

Abstract: A single speed compressor is provided with a switching device and control for turning the compressor drive motor ON and OFF in repeated succession at a selected ON time/OFF time ratio within a selected cycle time interval. The ON/OFF ratio and cycle time interval are selected to maintain desired temperature and/or humidity control within a conditioned space.

Abstract: An HVAC controller, a method of operating an HVAC controller and an HVAC system employing the controller or the method. In one embodiment, the HVAC controller includes: (1) a processor couplable to at least two refrigerant pressure sensors via separate data paths to receive input signals therefrom and further couplable to a compressor stage and a condenser fan to provide output signals thereto and (2) memory coupled to the processor and configured to store a software program capable of causing the processor to command the compressor stage and the condenser fan to turn on irrespective of a state of an input signal generated by either of the at least two refrigerant pressure sensors and generate alternative error messages at least partially depending upon whether or not a high pressure shutdown occurs after the processor commands the compressor stage and the fan to turn on.

Abstract: An HVAC unit includes an HVAC motor and a system controller. The HVAC motor is coupled to a motor controller. The motor controller is configured to receive a command signal bearing a digitally encoded operating level of the HVAC motor. The system controller is coupled to the motor controller, and is configured to transmit the command signal to the motor controller. The system controller modulates the command signal with the digitally encoded operating level in response to a service demand.

Abstract: In a heat-source unit (15) which heats heating-medium water inside of a heat storage tank (16), a refrigerant circuit (30) is provided with a low-stage compressor (52), a high-stage compressor (62) and an expander (65) for power recovery. The low-stage compressor (52) is rotated by an electric motor (54) connected to a drive shaft (53) thereof. The high-stage compressor (62) is rotated by an electric motor (64) and the expander (65) connected to a drive shaft (63) thereof. A high-stage control section of a controller (90) adjusts the rotational speed of the high-stage compressor (62) in such a way that a value measured by an outlet water-temperature sensor (77) becomes a target temperature. A low-stage control section adjusts the rotational speed of the low-stage compressor (52) in such a way that a value measured by a discharge pressure sensor (74) becomes a target high pressure.

Abstract: An air conditioning system includes a refrigeration cooling coil in fluid communication with process air, a refrigeration circuit containing refrigerant, a heat exchanger in fluid communication with the refrigerant and water, the heat exchanger adapted to transfer heat from the refrigerant to the water, a hot water coil in fluid communication with the water, a desiccant rotor having a process portion in fluid communication with the process air and a reactivation portion, and a reactivation blower adapted to move reactivation air over the hot water coil and through the reactivation portion of the desiccant rotor. A method of conditioning air is also described.

Abstract: A sub-compressor (23) is provided between a compressor (22) and a power-recovery device (24). A refrigerant after preliminarily being compressed by the sub-compressor (23) is allowed to flow into the compressor (22). Since the sub-compressor (23) and the power-recovery device (24) have approximately the same temperature, heat transfer hardly occur therebetween. Heat transfer occurs between the compressor (22) at high temperature and the sub-compressor (23) at low temperature. However, even if the heat from the compressor (22) heats the refrigerant in the sub-compressor (23), the refrigerant discharged from the sub-compressor (23) is delivered to the compressor (22), and thus the temperature of the sub-compressor (23) scarcely increases.

Abstract: A system and method for reduction of diluent gaseous nitrogen (DGAN) compressor power in combined cycle power plant. A vapor absorption chiller (VAC) may be utilized to generate and transmit cooled fluid, such as water, to one or more heat exchangers located upstream and/or downstream of at least one compressor of the DGAN compressor system. Utilization of these heat exchangers may cool the temperature of the nitrogen, which may allow for less energy to be expended by the DGAN in compression of the nitrogen.

Abstract: A system includes an evaporator unit, a first condensing unit and a second condensing unit. The first condensing unit includes a first heat exchanger coil, a first compressor, and a first oil separator, which removes oil from a refrigerant prior to the refrigerant reaching the first heat exchanger coil. The second condensing unit includes a second heat exchanger coil, a second compressor, and a second oil separator, which removes oil from a refrigerant prior to the refrigerant reaching the second heat exchanger coil. The first oil separator is isolated from the second oil separator to prevent communication of oil therebetween.

Abstract: A method and system for controlling operation of a vapor compression system (13) includes monitoring at least one component condition of the system (13), comparing a predetermined setpoint to the at least one component condition, and loading or unloading at least one of a first compressor (18) or a second compressor (20) of the system (13) in response to the comparison of the predetermined setpoint to the at least one component condition.

Abstract: A CO2 cooling and heating apparatus and method permit simultaneous production of high-temperature heat source and low-temperature heat source having a temperature difference therebetween. The apparatus/method uses CO2 (carbon dioxide) as a refrigerant, and has a first refrigerating cycle circuit where the refrigerant is compressed to a supercritical zone and then decompressed via an expansion device to a pressure/temperature level of the CO2 triple point or below to thereby attain evaporation. The apparatus can include multistage compressors, intermediate cooler disposed in a first refrigerant flow path between a condenser and the expansion device.

Abstract: A refrigeration system for a transport refrigeration unit and a method of operating the refrigeration system for cooling a temperature controlled cargo space are disclosed. The refrigeration system includes a primary refrigerant circuit including a refrigerant compression device, a motor for driving the compression device; a variable speed drive for varying the speed of operation of the compression device; and a controller operatively associated with the variable speed drive and the compression device. The controller controls the cooling capacity of the refrigeration system by selectively controlling the speed of said compression device in a first continuous run mode of operation and by selectively powering on and powering off said compression device in a first cycling mode of operation.

Abstract: The invention relates to a cryogenic refrigeration device intended to transfer heat from a cold source to a hot source via a working fluid flowing through a closed working circuit including the following portions in series, namely: a portion for the substantially isothermal compression of the fluid, a portion for the substantially isobaric cooling of the fluid, a portion for the substantially isothermal expansion of the fluid, and a portion for the substantially isobaric heating of the fluid. The compression portion of the working circuit includes at least two compressors disposed in series and the expansion portion of the working circuit includes at least one expansion turbine, said compressors and expansion turbine(s) being driven by at least one high-speed motor including an output shaft.

Abstract: A refrigeration apparatus uses a refrigerant that operates in a region including critical processes, and includes a compression mechanism having first and second compressors, a heat-source-side heat exchanger, an expansion mechanism, a utilization-side heat exchanger, an intercooler, and an intermediate refrigerant pipe. The first compressor has a first low-pressure compression element and a first high-pressure compression element to increase pressure of refrigerant more than the first low-pressure compression element. The second compressor has a second low-pressure compression element and a second high-pressure compression element to increase pressure of refrigerant more than the second low-pressure compression element. The intermediate refrigerant pipe causes refrigerant discharged by the first and second low-pressure compression elements to pass through the intercooler and be sucked into first and second high-pressure the compression elements.

Abstract: A multi-compressor heat pump system configured to provide heating and cooling over a range of ambient temperatures. The compressors can be operated independently and alone or together in series for maximum output. Heat exchangers are selectively fluidically connected to the compressors to enable refrigerant flow between the compressors and at least two heat exchangers in a manner that enables the heat pump system to be selectively operable in various modes. Preferred aspects include selectively operating the compressors based on the ratio of the evaporating and condensing pressures of the refrigerant within the heat pump system, a mixing chamber between the compressors, and a lubricant management system to prevent the accumulation of a lubricant in one of the compressors.

Abstract: A refrigerant vapor compression system has a primary refrigerant circuit including a compression device, a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger, and an economizer circuit including an economizer refrigerant line. A bypass flow control device controls refrigerant vapor flow through a bypass line extending between the economizer refrigerant line and a suction pressure portion of the primary refrigerant circuit. A flow control apparatus operatively associated with the economizer refrigerant line provides different flow resistance to refrigerant flow through the economizer refrigerant line in a first direction from an intermediate stage of the compression device to the suction portion of the primary refrigerant circuit and in a second direction from the economizer into an intermediate pressure stage of the compression device.

Abstract: Refrigerant circuit (2) comprising a low pressure compressor unit (38) having a low pressure refrigerant outlet (42) in a low pressure sub-circuit (4) and a higher pressure compressor unit (8) having a higher pressure refrigerant inlet (12) in a higher pressure sub-circuit (6), wherein the low pressure refrigerant outlet (42) and the higher pressure refrigerant inlet (12) are fluidly connected with each other, further comprising an oil reservoir (56) connected by a low pressure oil inlet conduit (54) to the low pressure sub-circuit (4) for receiving oil therefrom and connected via an oil discharge (62) to the higher pressure sub-circuit (6).

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 compression system for an air conditioning system includes first and second compressors. The first compressor includes a first compression chamber in which a fluid introduced from an outside of the first compressor is compressed, and a first case defining a first space into which the fluid compressed in the first compression chamber is introduced. The second compressor includes a second case defining a second space into which the fluid compressed in the first compressor is introduced, and a second compression chamber in which the fluid introduced from the second space is compressed. The second compressor operates independently of the first compressor, and a connecting line connects the first and second compressors.

Abstract: A heat pump system is disclosed that utilizes an accumulator fluidly connected between a boost compressor output and a primary compressor input. The accumulator is multifunctional in that it allows the refrigerant from the boost compressor to be cooled with refrigerant from other parts of the system if necessary. The accumulator also serves to receive and cool the oil separated from the refrigerant near the output of the primary compressor. A method for distributing oil among the compressors is also disclosed.

Abstract: An air conditioner for a vehicle comprises a refrigeration cycle including a variable displacement compressor for refrigerant which uses an engine as a drive source, a condenser, and an evaporator, a displacement adjustment means for outputting a displacement control signal to the compressor, and a compressor torque calculation means for calculating the torque of the compressor. The compressor torque calculation means includes at least two torque estimation means of a saturation region torque estimation means corresponding to a case where the compressor is driven at a maximum discharge displacement and a displacement control region torque estimation means corresponding to a case where it is driven at a discharge displacement other than the maximum discharge displacement, and also includes a correction means for correcting the calculation of the torque of the compressor when a change in engine rotational speed greater than a set value is detected.

Abstract: Methods, systems, and apparatus for linearizing control of a commercial refrigeration system. In an embodiment of the invention, a controller is configured to receive a non-linear sensed suction pressure and convert the suction pressure to a linear temperature equivalent. The linear temperature equivalent is used by the controller to achieve efficient system operation over an entire range of operating temperatures.

Abstract: A refrigerant circuit (20) is provided with an intermediate pressure heat exchanger (40) and a gas/liquid separator (51). In a cooling mode, a part of refrigerant condensed in an outdoor heat exchanger (36) flows into injection piping (43). The refrigerant admitted into the injection piping (43) is pressure reduced down to an intermediate pressure during its passage through an injection expansion valve (44), evaporates in the intermediate pressure heat exchanger (40), and is supplied to an intermediate pressure port (32) of a compressor (31). In a heating mode, refrigerant condensed in an indoor heat exchanger (71) is pressure reduced down to an intermediate pressure during its passage through an indoor expansion valve (72) and then flows into the gas/liquid separator (51). And, the intermediate pressure gas refrigerant within the gas/liquid separator (51) is supplied to the intermediate pressure port (32) of the compressor (31).

Abstract: A refrigeration system (20A) comprises an evaporator (27) for evaporating a refrigerant, a two-stage compressor (32) for compressing the refrigerant, a single-stage compressor (34) for compressing the refrigerant, a heat rejecting heat exchanger (24) for cooling the refrigerant, a first economizer circuit (25A), and a second economizer circuit (25B). The first economizer circuit (25A) is configured to inject refrigerant into an interstage port (48) of the two-stage compressor (32). The second economizer circuit (25B) is configured to inject refrigerant into a suction port (52) of the single-stage compressor (34). The single-stage compressor (34) is configured to discharge into the interstage port (48) of the two-stage compressor (32).

Abstract: A refrigeration system (20A) comprises an evaporator (27), a two-stage compressor (32) for compressing a refrigerant, a second compressor (34) for compressing the refrigerant, a heat rejecting heat exchanger (24) for cooling the refrigerant, a first economizer circuit (25A), and a second economizer circuit (25B). The first economizer circuit (25A) is configured to inject refrigerant into an interstage port (48) of the two-stage compressor (32). The second economizer circuit (25B) is connected to the second compressor (34).

Abstract: A refrigeration cycle apparatus 100 includes a first compressor 101, a second compressor 102 provided in parallel with the first compressor 101, a radiator 103 for cooling a refrigerant compressed by the compressors 101 and 102, an expander 104 for recovering power while expanding the refrigerant cooled by the radiator 103, an evaporator 105 for evaporating the refrigerant expanded by the expander 104, a rotation shaft 123 connecting the first compressor 101 to the expander 104 so that the first compressor 101 uses the power recovered by the expander 104, a controller 112 for executing a control including a step of increasing a flow rate of the refrigerant gradually during a defrosting operation in which frost formed on the evaporator 105 is melted by allowing the refrigerant having a high temperature to flow through the evaporator 105.

Abstract: A medium- and low-temperature integrated refrigerating/freezing system (40) comprises an integrated unit (41), a medium-temperature refrigerating cabinet (43), a low-temperature freezing cabinet (42) and corresponding connecting pipes (44). The integrated unit (41) further comprises a common condenser (54) for condensing the high-temperature and high-pressure gaseous refrigerant in the medium-temperature refrigerating system and the low-temperature freezing system, a common reservoir (55) for the storage of the high-temperature and high-pressure liquid refrigerant in the medium-temperature refrigerating system and the low-temperature freezing system, a subcooling adjusting mechanism (56, 57) for adjusting the subcooling degree in the low-temperature freezing system and a suction temperature adjusting mechanism (431, 432, 58) for adjusting the suction temperature of the low-temperature freezing system.

Abstract: An air conditioner comprises: a first compression unit (C1) and a second compression unit (C2) for respectively compressing a refrigerant; an outdoor heat exchanger (200) provided at an outdoor unit and connected via the secondcontrol valve (400) to the first compression unit (C1) and the second compression unit (C2); and indoor heat exchanger (100) provided at an indoor unit is connected via the secondcontrol valve (400) to the first compression unit (C1) and the second compression unit (C2) and via the expansion valve (700) to the outdoor heat exchanger; and a first control valve (500) for controlling a refrigerant flow by selectively connecting the first compression unit (C1) and the second compression unit (C2) in series or in parallel. As the first compression unit (C1) and the second compression unit (C2) are selectively connected to each other in series or in parallel, a capacity of the air conditioner is varied according to a change of an indoor temperature and fabrication cost is minimized.