Abstract: An optional unit (30) including a high pressure side compressor (31) and a gas-liquid separator (33) is provided between an outdoor unit (20) including a low pressure side compressor (21) and an indoor unit (40). During a defrosting operation, refrigerant discharged from the low pressure side compressor (21) defrosts an outdoor heat exchanger (21) while refrigerant in the gas-liquid separator (33) is sucked into the high pressure side compressor (31) and is then discharged to the suction side of the low pressure side compressor (21). The optional unit (30) includes an injection pipe (36) for returning part of the refrigerant discharged from the high pressure side compressor (31) to the suction side of the high pressure side compressor (31) in the defrosting operation. Hence, the refrigerant flowing into the high pressure side compressor (31) from the gas-liquid separator (33) is gasified by the high-temperature discharged refrigerant.

Abstract: A refrigeration cycle apparatus (100) includes a first compressor (101), a second compressor (102), a radiator (4), an evaporator (6), and a pipe branching portion (30). The first compressor (101) has a first compression mechanism (1) and an expansion mechanism (5). The second compressor (102) has a second compression mechanism (2). The pipe branching portion (30) serves as a flow passage for introducing a refrigerant from the evaporator (6) to the first compression mechanism (1) and the second compression mechanism (2), respectively. The pipe branching portion (30) includes an inlet pipe (31) for receiving the refrigerant from the evaporator (6), a first branch outlet pipe (32) for introducing the refrigerant flowing into the inlet pipe (31) to the first compression mechanism (1), and a second branch outlet pipe (33) for introducing the refrigerant flowing into the inlet pipe (31) to the second compression mechanism (2).

Abstract: A multi-zone transport refrigeration system. The system includes a compressor, a condenser, a refrigerant circuit, a first temperature control zone and a second temperature control zone. A controller is configured to identify a priority zone and a non-priority zone based upon a first magnitude of a difference between a first temperature set point and a first zone temperature derived from the first air temperature sensor, and a second magnitude of a difference between the second temperature set point and a second zone temperature derived from the second air temperature sensor. A non-priority zone is isolated from the refrigerant circuit for a pre-defined period in order to maximize a refrigerant flow to the priority zone.

Abstract: A compression machine includes a refrigerant condenser, an expansion device, a refrigerant evaporator, a first compressor and a second compressor. Each compressor is arranged to receive lower pressure refrigerant vapor from the evaporator and to deliver higher pressure vapor to the condenser independently of the other compressor. The first compressor operates when the compression machine is operating in a first duty mode, for example a water-cooling mode. The second compressor operates when the compression machine is operating in a second duty mode, for example one of a water-heating mode or a brine cooling. The first compressor is selected for optimal performance in the first duty only and the second compressor is selected for optimal performance in the second duty mode only.

Abstract: A coaxial economizer for use in a chiller system comprising an inner housing and an outer housing having a common longitudinal axis. The outer housing has an inlet for receiving a fluid from a upstream compressor stage of a multistage compressor and an outlet for conveying a fluid to a downstream compressor stage of a multistage compressor. A flow chamber forms a fluid flow path about the inner housing. A flash chamber is coterminous with the flow chamber and flashes fluid in a liquid state to a gas state. A flow passage between said flash chamber and the flow chamber for conveying a flashed gas from the flash chamber to the flow chamber; wherein the flashed gas conveyed from the flash chamber and the fluid received from the inlet of the outer housing mix along the fluid flow path toward the outlet of the outer housing.

Abstract: Provided is an air conditioning system comprised of a plurality of indoor units connected to each other in parallel, each having an expansion valve, and an outdoor unit including a plurality of compressors, in which at least one of the compressors provided to the outdoor unit is a capacity modulation compressor including an electromotive driving unit for driving a plurality of compression units capable of selectively compressing a working fluid, and the electromotive driving unit for the capacity modulation compressor has a stator with a coil wound around thereon and a rotor rotating inside the stator, the rotor being an LSPRM including a rotor core, flux barriers, permanent magnets and conductive bars.

Abstract: A refrigerant system has at least one unloader valve selectively communicating refrigerant between the compressor compression chambers and a point upstream of the evaporator. When the compressor is run in unloaded mode, partially compressed refrigerant is returned to a point upstream of the evaporator. In an unloaded mode, a higher refrigerant mass flow rate passes through the evaporator, as compared to prior art where the by-passed refrigerant was returned downstream of the evaporator. This increases system efficiency by more effectively returning oil which otherwise might be left in the evaporator back to the compressor. Also, the amount of refrigerant superheat entering the compressor in unloaded operation is reduced as compared to the prior art compressor systems, wherein the by-passed refrigerant is returned directly to the compressor suction line. Reduced refrigerant superheat increases system efficiency, improves motor performance and reduces compressor discharge temperature.

Abstract: A transport refrigeration system with a direct drive compressor arrangement is provided with a variable speed electrically driven booster compressor that operates in series with the direct drive compressor. The speed of the booster compressor is controlled to either boost or decrease the system capacity. The booster compressor also acts to regulate the flow of refrigerant from the evaporator during periods of operation in which the direct drive compressor might otherwise become overloaded.

Abstract: Disclosed is a compressor (12) for a refrigeration system (10) including a housing (30) and at least one compressor impeller (24, 26) located in the housing (30) capable of compressing a refrigerant flow (14) through the compressor (12). At least one refrigerant pathway (44, 62) is located inboard of an outer surface (48) of the housing (30) and extends from a first compressor impeller (24). Further disclosed is a refrigeration system (10) including a compressor (12) having at least one refrigerant pathway (44, 62) located inboard of an outer surface (48) of the housing (36) and extending from a first compressor impeller (24) of at least one compressor impeller (24, 26). Further disclosed is a method of flowing refrigerant through a compressor (12).

Abstract: An energy efficient and highly versatile electrically-powered air conditioning and heating system for mobile vehicles. Multiple variable-speed compressors operate in series and parallel modes giving an exceptionally wide range of operating capacity making the system suitable for combined on-highway and no-idle use in trucks. In series mode, the single-stage compressors function like a two-stage compressors for increased energy efficiency. A unique power control and storage system has multi-voltage input and output capability without the use of DC-DC or DC-AC converters. A battery management system is incorporated which is compatible with all advanced battery technologies and offers cell-level charge and discharge control.

Abstract: A system and method of controlling a compressor rack having a plurality of variable capacity components is provided. A variable capacity component is selected from the plurality of variable capacity components as a designated variable capacity component. The designated variable capacity component is operated by varying a capacity of the designated variable capacity component. Each variable capacity component of the plurality of variable capacity components, except for the designated variable capacity component, is operated at a fixed capacity corresponding to one of a maximum and a minimum capacity of the variable capacity component.

Abstract: A refrigerant compressor circuit for use in a liquefaction plant includes a first compression string driven by a first driver; a second compression string driven by a second driver, a pre-cooling refrigerant compression stage arranged in the first compression string to receive a stream of pre-cooling refrigerant at an inlet pressure and discharge the pre-cooling refrigerant at an outlet pressure, a first compression stage arranged in the first compression string to compress a mixed refrigerant gas from a first pressure to a second pressure, and, a second compression stage arranged in the second compression string to compress the mixed refrigerant gas from the second pressure to a third pressure. The pre-cooling refrigerant compression stage and the first compression stage of the circuit are co-axially mounted on a first shaft drivingly coupled to a first driver in the first compression string.

Abstract: A hermetic compressor is provided, including a casing, having a suction pipe and discharge pipe connected thereto, a driving motor installed within the casing, a compressing device installed within the casing and operated by the driving motor to form compression chambers, an oil separator that separates oil from a refrigerant discharged from by compressing device, and an oil collecting pipe through which the oil separator communicates with the compression chambers. With this structure, oil can be appropriately supplied to one or more compressors based on capacity, thus improving reliability of oil distribution and enhancing compressor performance.

Abstract: A centrifugal compressor assembly for compressing refrigerant in a 250-ton capacity or larger chiller system comprising a motor, preferably a compact, high energy density motor or permanent magnet motor, for driving a shaft at a range of sustained operating speeds under the control of a variable speed drive. Another embodiment of the centrifugal compressor assembly comprises a mixed flow impeller and a vaneless diffuser sized such that a final stage compressor operates with an optimal specific speed range for targeted combinations of head and capacity, while a non-final stage compressor operates above the optimum specific speed of the final stage compressor.

Abstract: To provide a multistage compressor including an injection circuit, which can continue high-efficiency and high-capacity operations even if the injection circuit is turned on/off in accordance with operating conditions. A multistage compressor includes a high stage side compressing mechanism suctioning the intermediate pressure refrigerant gas compressed with a low stage side compressing mechanism to perform two-stage compression, and an injection circuit for injecting an intermediate pressure refrigerant into the intermediate pressure refrigerant gas suctioned to the high stage side compressing mechanism, the high stage side compressing mechanism including a capacity control mechanism for bypassing a refrigerant gas that is being compressed to a suction side, the injection circuit including an on/off mechanism for performing on/off control of refrigerant injection, and the capacity control mechanism and the on/off mechanism being operated in conjunction with each other.

Abstract: A refrigeration cycle apparatus 100 is provided with a working fluid circuit 106 and a first bypass passage 112. The working fluid circuit 106 is formed of a first compressor 101, a heat radiator 102, an expander 103, an evaporator 104, a second compressor 105, and flow passages 106a to 106e connecting these components in this order. The expander 103 and the second compressor 105 are coupled to each other by a power-recovery shaft 107 so that the second compressor 105 is driven by the power recovered by the expander 103. The first bypass passage 112 communicates between a portion from the discharge port of the first compressor 101 to the suction port of the expander 103 in the working fluid circuit 106 and a portion from the outlet of the evaporator 104 to the suction port of the second compressor 105 in the working fluid circuit 106, at the time of activation of the refrigeration cycle apparatus 100.

Abstract: Disclosed is an air conditioner which includes a plurality of compressors, a common inlet pipe through which fluid flows to the compressors, a plurality of inlet pipes branching off from the common inlet pipe which are connected to the compressors, a plurality of outlet pipes connected to the compressors through which refrigerant discharged from the compressors passes, and a plurality of bypass pipes connected to the compressors through which fluid discharged from the compressors passes. The fluid which passes through the plurality of bypass pipes is distributed to the plurality of compressors through the common inlet pipe.

Abstract: In a refrigerant circuit (5) of an air conditioner (1), a single-stage compression refrigeration cycle is performed. In the refrigerant circuit (5), a second heat exchanger (40) is provided downstream a first heat exchanger (30). In the first heat exchanger (30), high-pressure refrigerant of a high-pressure flow path (31) is cooled by exchanging heat with first intermediate-pressure refrigerant of an intermediate-pressure flow path (32). First intermediate-pressure gas refrigerant generated in the first heat exchanger (30) is supplied to a first compression mechanism (71). Second intermediate-pressure refrigerant having a pressure lower than that of the first intermediate-pressure refrigerant is supplied to an intermediate-pressure flow path (42) of the second heat exchanger (40). In the second heat exchanger (40), high-pressure refrigerant of a high-pressure flow path (41) is further cooled by exchanging heat with the second intermediate-pressure refrigerant of the intermediate-pressure flow path (42).

Abstract: A heat pump system has a single heat source unit connected to at least one load unit to heat water to a high temperature. A hot water supply system 100 (heat pump system) includes a heat source unit 10 provided with a first compressor 11, a four-way selector valve 12 and a heat source heat exchanger 13, and a load unit 50 provided with a first flow controller 51, a first load heat exchanger 52, a second compressor 53, a second load heat exchanger 54, and a second flow controller 55. A main circuit A is formed by connecting the first compressor 11, the four-way selector valve 12, the heat source heat exchanger 13, the first flow controller 51 and the first load heat exchanger 52 with a liquid pipe 1 and a gas pipe 2 sequentially. A load refrigerant circuit B is formed by connecting the second compressor 53, the second load heat exchanger 54, the second flow controller 55, and the first load heat exchanger 52 with a load refrigerant pipe line 56 sequentially.

Abstract: A refrigerant system having tandem compressors includes at least two compressors of different types. By utilizing the two distinct compressor types, a greater difference in the provided capacity of the two compressors can be achieved at part-load conditions, as well as a particular compressor type can be engaged at specific environmental conditions to provide the most efficient operation of the refrigerant system.

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device that is in fluid communication with the first fluid circuit. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor, a second expansion device, and an evaporator that is in fluid communication with the second fluid circuit. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. At least one of the first or second compressors is a variable speed compressor.

Abstract: An optimizer for modulating the speed of an indoor fan and first and second stage compressors of a two staged refrigeration system with a plurality of relays and an already existing power source. The optimizer is comprised of a speed modulation device, a supply air temperature sensor, and a controller. The speed modulation device is located in proximity to the existing power source and configured to collect current and power related information from the refrigeration system and power source to send to the controller. The supply air temperature sensor is linked to the indoor fan of the two staged refrigeration system and operable to obtain supply air temperature values. The controller is linked in communication with the speed modulation device and supply air temperature sensor and is operable to generate a system mode based on the power, current, and supply air temperature information. Speed commands are then sent to the speed modulation device to modulate the speed.

Abstract: A distillation column is disclosed with a folded design. The column includes a plurality of rectification zones and corresponding stripping zones Each rectification zone is linked to a heat pump or a stage of a heat pump. Overhead vapor from the top rectification zone is compressed and used to heat bottoms liquid from the bottom stripping zone. Similarly, overhead vapor from the middle rectification zone is compressed and used to heat liquid from a middle stripping zone and overhead from a lower rectification zone is compressed and used to heat liquid taken from the uppermost or top stripping zone. A single multiple stage heat pump compressor may be utilized as opposed to a plurality of heat pumps Because the heat exchanger from each rectification-stripping zone pair has a lower duty, economical stab-in heat exchangers may be utilized.

Abstract: Provided is an air conditioning system using ground heat. The system includes one or more indoor units, at least one outdoor unit, a ground heat exchanger, and a plurality of auxiliary heat sources. The one or more indoor units condition indoor air. The at least one outdoor unit communicates with the indoor units via a plurality of pipes, and includes an outdoor heat exchanger where heat exchange occurs. The ground heat exchanger is connected with the outdoor heat exchanger of the outdoor unit, and laid under the ground to allow heat to be exchanged between ground heat and a circulating medium circulating through the ground heat exchanger. The plurality of auxiliary heat sources are installed on one side of the outdoor unit to assist heat exchange of the outdoor heat exchanger. Two or more auxiliary heat sources are simultaneously used, or one of them is selectively used.

Abstract: A refrigerating apparatus in which a two-stage compression refrigeration cycle is performed includes a refrigerant circuit and a volume ratio changing unit. The refrigerant circuit is connected to a compressor having a plurality of compression mechanisms mechanically connected together with a single drive shaft. The compression mechanisms include four cylinder chambers. The volume ratio changing unit is configured to change a ratio of a suction volume of a low-pressure compression mechanism to a suction volume of a high-pressure compression mechanism.

Abstract: A refrigerant vapor compression system includes a flash tank disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. The flash tank has a shell defining an interior volume having an upper chamber, a lower chamber and a middle chamber. A first fluid passage establishes fluid communication between the middle chamber and the upper chamber and a second fluid passage establishing fluid communication between the middle chamber and the lower chamber. An inlet port opens to the middle chamber. A first outlet port opens to the upper chamber and a second outlet port opens to the lower chamber.

Abstract: A refrigerating apparatus having a plurality of compressors includes an injection circuit (40) which includes a first injection pipe (37) branched from a first refrigerant pipe (32) of a refrigerant circuit (10) and branch injection pipes (37a, 37b, 37c) branched from the first injection pipe (37), a subcooling pressure-reducing valve (29) provided to the first injection pipe (37), and flow rate adjusting valves (30a, 30b, 30c) provided to the branch injection pipes (37a, 37b, 37c), respectively, thereby providing an appropriate refrigerant injection to each of the compressors.

Abstract: A coaxial economizer for use in a chiller system comprising an inner housing and an outer housing having a common longitudinal axis. The outer housing has an inlet for receiving a fluid from a upstream compressor stage of a multistage compressor and an outlet for conveying a fluid to a downstream compressor stage of a multistage compressor. A flow chamber forms a fluid flow path about the inner housing. A flash chamber is coterminous with the flow chamber and flashes fluid in a liquid state to a gas state. A flow passage between said flash chamber and the flow chamber for conveying a flashed gas from the flash chamber to the flow chamber; wherein the flashed gas conveyed from the flash chamber and the fluid received from the inlet of the outer housing mix along the fluid flow path toward the outlet of the outer housing.

Abstract: The present invention proposes a water circulation system associated with a refrigerant cycle that can selectively heat-exchange water for cooling and heating and hot water supplying with at least one of a first refrigerant and a second refrigerant. Therefore, the present invention can improve the operation efficiency of the water circulation system associated with the refrigerant cycle.

Abstract: A refrigeration circuit has a mono- or multi-component refrigerant, especially CO2, circulating therein, said refrigeration circuit enabling an transcritical operation, said refrigeration circuit comprising, in the direction of refrigerant flow, a compressor unit, a condenser/gascooler, a high pressure control valve, a collecting container, and at least one evaporator having an expansion device connected upstream thereof, wherein a flashgas line having a medium pressure control valve arranged therein is provided between an upper portion of the collecting container and the suction line leading to the compressor unit, wherein a temperature, pressure or liquid level sensor is provided in or at the collecting container, wherein a bypass line having a medium pressure holding valve arranged therein is provided connecting the line between the condenser/gascooler and the high pressure control valve to the line between the collecting container and the expansion device(s), and wherein a control unit is provided said co

Abstract: A system for desuperheating hot gaseous refrigerant using both a heat exchanger and a dispersed Venturi-driven injection of liquid refrigerant is disclosed. Further, a system, relating to cooling at least one compressed superheated refrigerant fluid prior to condensing, relating to extending the life of at least one condenser is disclosed.

Abstract: Disclosed herein is a fluid circuit in which a compressible fluid and an incompressible fluid flow in a mixed state including an upstream side space and a downstream side space in which internal pressures repeatedly alternate between high pressure and low pressure, and a pump unit having an inlet connected to the upstream side space and an outlet connected to the downstream side space. The pump unit has two check valves arranged in series in a direction in which fluid movement is allowed from the upstream side space to the downstream side space, and a middle part, having a predetermined capacity, formed between the check valves.

Abstract: A heat pump controls heating and/or cooling using a refrigeration cycle unit and a booster module, The refrigeration cycle unit includes a compressor to compress a coolant, a first heat exchanger to condense the coolant compressed in the compressor, an expansion mechanism to expand the coolant condensed in the first heat exchanger, and a second heat exchanger to evaporate the coolant expanded in the expansion mechanism. The booster module separates a gaseous coolant from the coolant flowing from the first heat exchanger to the expansion mechanism and then allows for compression of the separated gaseous coolant or coolant evaporated in the second heat exchanger.

Abstract: A refrigerating system including an air conditioning system and a cooler system is provided. An air conditioner-side refrigerant passage may be connected to a cooler-side refrigerant passage to allow refrigerant to flow between the air conditioning system and the cooler system. Thus, if a cooler-side compressor experiences abnormal operation, cooler-side refrigerant may be compressed by an air conditioner-side compressor so as to maintain cooling performance of the refrigerating system.

Abstract: A heat pump type cooling/heating apparatus comprises a coolant injection path and a gaseous coolant adjustment valve. The coolant injection path may be split between a cascade heat exchanger and an evaporator of a low-temperature refrigeration cycle to inject coolant into a low pressure side compressor, or between a water coolant heat exchanger and cascade heat exchanger to inject coolant into a high pressure side compressor of a high temperature refrigeration cycle.

Abstract: The invention relates to a refrigerating circuit (10) adapted to circulate, in operation, a refrigerant in a predetermined flow direction, said refrigerating circuit (10) comprising a compressor stage (12), said compressor stage (12) having a suction side and a pressure side, and at least one heat dissipating heat exchanging unit (14) connected to said pressure side of said compressor stage (12) via a pressure line (24), said heat dissipating heat exchanging unit (14) having an inlet side (14a) and an outlet side (14b) and including a condenser/gas cooler unit (16), and a liquid refrigerant return line (26) connecting said outlet side of said heat dissipating heat exchanging unit (14) to said pressure line (24).

Abstract: A refrigerant vapor compression system includes a flash tank receiver disposed in the refrigerant circuit intermediate the refrigerant cooling heat exchanger and the refrigerant heating heat exchanger. The flash tank receiver, which receives a liquid/vapor refrigerant mix, also functions as a receiver. A refrigerant charge control apparatus includes at least one sensor for sensing an operating characteristic of the refrigerant circulating through the refrigerant compression device, and a controller operative to selectively adjust a secondary expansion device to increase or decrease the flow of refrigerant passing into the flash tank receiver to provide a circulating refrigerant charge consistent with maintaining a desired system operating characteristic.

Abstract: A dual turbo centrifugal chiller includes: first and second evaporators connected in series or in parallel; first and second condensers connected in series or in parallel; and first and second compressors including impellers, wherein cold water passes through the second evaporator after passing through the first evaporator, and cooling water passes through the second condenser after passing through the first condenser, the first compressor containing a refrigerant connects the first condenser to the second evaporator, and the second compressor containing a refrigerant connects the second condenser to the first evaporator, and the impellers of the first compressor and second compressor are rotated simultaneously using a single driving unit.

Abstract: Multi-stage refrigerant systems operate with a lower stage compressor of a first type and a higher stage compressor of a second type. In one embodiment, the lower stage compressor type is selected to have the most beneficial characteristics at lower pressure operation, while the higher pressure stage compressor type is selected to have the most beneficial characteristics at higher pressure operation.

Abstract: The air exchanger comprises at least one tubular circuit for evaporating a refrigerant and thermally conducting fins (40) fastened to the tubular evaporation circuit and at least one tubular circuit (35) for condensing a refrigerant, which is connected via thermally conducting fins (40) to the evaporation circuit.

Abstract: An air conditioning system is able to decrease the amount of refrigerant between a first expansion device and an injection valve and thus adjust the pressure of an injected refrigerant by decreasing the opening degree of the first expansion device and maintaining the opening degree of a second expansion device upon opening of the injection valve, thereby making the system stable upon opening of the injection valve. Furthermore, upon starting up a compressor, the opening degrees of the first and second expansion devices are partly decreased based on the start-up of the compressor and then gradually opened again, and upon completion of the start-up of the compressor, the opening amounts of the first and second expansion devices and the injection valve are controlled, thereby making the cycle more stable.

Abstract: A refrigerant circuit (15) is provided with a low-pressure stage oil separator (26) for separating refrigerating machine oil out of refrigerant discharged from a low-pressure stage compressor (21) and returning it to the suction side of the low-pressure stage compressor (21), and a high-pressure stage oil separator (36) for separating refrigerating machine oil out of refrigerant discharged from a high-pressure stage compressor (31) and returning it to the suction side of the high-pressure stage compressor (31). The efficiency of oil separation of the low-pressure stage oil separator (26) is set lower than that of the high-pressure stage oil separator (36).

Abstract: A two-stage cascade refrigeration system is provided having a first refrigeration stage and a second refrigeration stage. The first refrigeration stage defines a first fluid circuit for circulating a first refrigerant, and has a first compressor, a condenser, and a first expansion device that is in fluid communication with the first fluid circuit. The second refrigeration stage defines a second fluid circuit for circulating a second refrigerant, with the second refrigeration stage having a second compressor, a second expansion device, and an evaporator that is in fluid communication with the second fluid circuit. A heat exchanger is in fluid communication with the first and second fluid circuits to exchange heat between the first and second refrigerants. At least one of the first or second compressors is a variable speed compressor.

Abstract: A refrigeration system is provided for use with an ultra-low temperature freezer having a deck and a refrigerated cabinet supported above the deck. The system has a first refrigeration stage and a second refrigeration stage. The first stage defines a first fluid circuit for circulating a first refrigerant. The first stage has a first compressor, a condenser and a first expansion device that is in fluid communication with the first fluid circuit. The second stage defines a second fluid circuit for circulating a second refrigerant. The second stage has a second compressor, a second expansion device and an evaporator that is in fluid communication with the second fluid circuit. The system includes an insulated enclosure supported within the deck and a split-flow heat exchanger that is in fluid communication with the first and second fluid circuits and which is located within the insulated enclosure.

Abstract: A triple-pipeline type first outdoor unit 2 provided with a first compressor 20 and a first outdoor heat exchanger 21, a plurality of indoor units 4A to 4D are provided, a second outdoor unit 3 provided with a second compressor 30, a second outdoor heat exchanger 32, and a second expansion valve 33, the first outdoor unit 2 is provided with a first four-way valve 60 that makes a refrigerant discharge pipe 25 of the first compressor 20 and a high-pressure gas pipe 7 capable of communicating with each other and if all the indoor units 4A to 4D perform a cooling operation at the same time, the first four-way valve 60 shuts off the communication between the refrigerant discharge pipe 25 and the high-pressure gas pipe 7, while a third four-way valve 51 is switched so as to connect a gas pipe 35d to the high-pressure gas pipe 7.

Abstract: A refrigeration apparatus includes a multi-stage compression mechanism, heat source-side and usage side heat exchangers each operable as a radiator/evaporator, a switching mechanism switchable between cooling and heating operation states, a second-stage injection tube, an intermediate heat exchanger and an intermediate heat exchanger bypass tube. The intermediate heat exchanger bypass tube ensures that refrigerant discharged from the first-stage compression element and drawn into the second-stage compression element is not cooled by the intermediate heat exchanger during a heating operation. Injection rate optimization controls a flow rate of refrigerant returned to the second-stage compression element through the second-stage injection tube so that an injection ratio is greater during the heating operation than during a cooling operation.

Abstract: A CO2 vapor compression system is provided with at least one pressure relief device which is designed to open when the pressure in the low pressure side exceeds the predetermined level because of exposure to high temperatures during non-operational periods. A pressure relief device is provided near the compressor suction inlet to relieve one section of the circuit and another is provided upstream of an unloading valve to relieve pressure in another section thereof.

Abstract: A triple-pipeline type first outdoor unit 2 connected to three inter-unit pipelines 5 made up of a high-pressure gas pipe 7, a low-pressure gas pipe 6, and a fluid pipe 8 and a second outdoor unit 3 connected by two pipelines of a gas pipe 35 and a fluid pipe 36 are provided, in which a fluid pipe 36 of this second outdoor unit 3 is connected to the fluid pipe 8, while a gas pipe 35 of the second outdoor unit is selectively connected to the high-pressure gas pipe 7 or the low-pressure gas pipe 6 using a valve-element kit 50 having a four-way valve 51.

Abstract: Provided is a refrigeration circuit including a compressor such as a compressor having a built-in motor, a condenser, a pressure reduction and expansion means, and an evaporator. The refrigeration circuit uses R1234yf as a refrigerant and provides therein a radical-capturing agent or a polymerization inhibitor. When the R1234yf as a new refrigerant is used and there is a possibility that radicals are formed, it is possible to prevent or suppress generation of radicals and prevent polymerization of R1234yf so that a target performance can be realized even when the new refrigerant is used.

Abstract: A refrigerant cycle is disclosed having a number of compressors operating in tandem and supplying a compressed refrigerant to a refrigerant system. Discharge lines communicate a compressed refrigerant to a central discharge line for receiving flow from all tandem compressors. A control is operational to determine a number of compressors need to be operated or whether some compressors should be shutdown to satisfy load requirements. Shutoff valves are placed on discharge lines outwardly of the shell of the compressors. That can be shutdown during part load operation. These shutoff valves are closed when their associated compressors are stopped to prevent backflow of refrigerant from operating compressors through the shutoff compressor, and into the system suction side. Additionally, high pressure differential across the compressor internal discharge check valve is eliminated and the possibility of compressor flooding through a discharge line is reduced.