Abstract: A system and method for water purification by capture of contaminants in an aqueous mixture is described herein. A system and method for regenerating the capture system is also described. An integrated capture and regeneration system and method is also described including a separation vessel that houses a capture bed and an electrode in electrical contact with the bed and a power source for applying a voltage to the electrode. The applied voltage enhances capture of the contaminant from aqueous liquid on the capture bed and modulation of the applied voltage enhances release of contaminant on the capture bed into aqueous wash liquid to regenerate the bed. The aqueous wash liquid may contain a counter ion that binds to the contaminant forming an aggregate contaminant phase that separates from the aqueous wash liquid.

Abstract: A system includes a dynamic compressor and a controller having a processor and a memory. The compressor includes a first compressor stage having a first variable inlet guide vane (VIGV) and a second compressor stage having a second VIGV. The memory stores instructions that program the processor to operate the compressor at a current speed, a first position of the first VIGV, and a second position of the second VIGV to compress the working fluid, and to determine if a condition is satisfied. If the condition is not satisfied, the processor is programmed to continue to operate the compressor at the current speed, the first position of the first VIGV, and the second position of the second VIGV. If the condition is satisfied, the processor is programmed to change the second position of the second VIGV to a third position and maintain the first position of the first VIGV.

Abstract: A refrigeration system includes an evaporator configured to receive a flow of refrigerant and transfer heat into the refrigerant within the evaporator to provide cooling for a temperature-controlled space, an expansion valve operable to modulate the flow of refrigerant into the evaporator, a liquid level sensor configured to measure a level of liquid accumulated within a component of the refrigeration system, and a controller configured to operate the expansion valve to increase the flow of refrigerant into the evaporator or decrease the flow of refrigerant into the evaporator based on the level of liquid measured by the liquid level sensor.

Abstract: The disclosed technology includes devices, systems, and methods for heat pump systems configured to operate in low ambient temperatures. The disclosed technology can include a heat pump water heater system having an evaporator, a first compressor configured to compress refrigerant to a first pressure, and a second compressor configured to compress the refrigerant to a second pressure. The second pressure can be greater than the first pressure. The heat pump water heater system can include a preheater configured to receive the refrigerant at the first pressure and heat water and a condenser configured to receive the refrigerant at the second pressure and heat water. The water can be passed through the preheater before being passed through the condenser.

Abstract: A heating, ventilation, and air conditioning (HVAC) system includes a reheat valve configured to receive a refrigerant flow and regulate division of the refrigerant flow provided to a reheat coil and a condenser. The HVAC system also includes a condenser fan configured to draw a flow of outdoor air across the condenser and a controller communicatively coupled to the reheat valve and the condenser fan. The controller is configured to monitor a position of the reheat valve and to control operation of the condenser fan based on a correspondence between the position of the reheat valve and a threshold degree of opening.

Abstract: An EXV (electronic expansion valve) control system includes an EXV controller for controlling an EXV within the refrigerant loop of an HVAC system. The EXV controller implements a master control algorithm that includes a plurality of sub-control algorithms and an initial series of branching decision points to determine the current mode of operation and to execute select sub-control algorithms corresponding to the current mode of operation, while not executing the sub-control algorithms corresponding to the other modes of operation. The sub-control algorithms implement various combinations of PID (Proportional Integral Derivative) control and feed-forward control, the results of which can be mapped to specific control instructions for the EXV.

Abstract: An example transport refrigeration system includes first and second refrigeration circuits configured to cool first and second transport compartments, respectively. An electric machine powers the first and second refrigeration circuits. A controller is configured to monitor a temperature of the electric machine, and reduce a cooling capacity of a selected one of the first and second refrigeration circuits based on the temperature exceeding a first threshold.

Abstract: A chilled water distribution system includes a chilled water loop in fluid communication with a plurality of buildings and also in fluid communication with a plurality of chiller stations. A monitoring and control system communicates with one of the chiller stations, hereinafter referred to as a “controlled” chiller station because it is configured with one or more variable frequency drives that are controlled by the monitoring and control system to modulate the speed of at least one chiller station component such as, but not limited to, a pump or a fan. By way of this modulation process, a differential pressure of the chilled water loop may be maintained in a “sweet spot” so as to optimize chiller station output while minimizing chiller station energy consumption.

Abstract: A refrigeration system includes an evaporator configured to receive a flow of refrigerant and transfer heat into the refrigerant within the evaporator to provide cooling for a temperature-controlled space, an expansion valve operable to modulate the flow of refrigerant into the evaporator, a liquid level sensor configured to measure a level of liquid accumulated within a component of the refrigeration system, and a controller configured to operate the expansion valve to increase the flow of refrigerant into the evaporator or decrease the flow of refrigerant into the evaporator based on the level of liquid measured by the liquid level sensor.

Abstract: A subcooling controller includes a sensor and a processor. The sensor measures one or more of a temperature external to a first heat exchanger that removes heat from carbon dioxide refrigerant, a temperature of the carbon dioxide refrigerant, and a pressure of the carbon dioxide refrigerant. The processor determines that one or more of the measured temperature external to the first heat exchanger, the temperature of the carbon dioxide refrigerant, and the pressure of the carbon dioxide refrigerant is above a threshold and in response to that determination, activates a subcooling system. The subcooling system includes a condenser, a second heat exchanger, and a compressor. The condenser removes heat from a second refrigerant. The second heat removes heat from the carbon dioxide refrigerant stored in a flash tank. The compressor compresses the second refrigerant from the second heat exchanger and sends the second refrigerant to the condenser.

Abstract: An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. A valve connecting the warm end of the cylinder to a buffer tank allows a partial expansion and recompression of gas in the cold displaced volume that increases the refrigeration produced in each cycle with the same compressor flow rate.

Abstract: A system includes a high side heat exchanger, a first load, a second load, a third load, a first compressor, a second compressor, a third compressor, and a fourth compressor. The high side heat exchanger removes heat from a refrigerant. The first load uses the refrigerant to remove heat from a first space proximate the first load. The second load uses the refrigerant to remove heat from a second space proximate the second load. The third load uses the refrigerant to remove heat from a third space proximate the third load. The first compressor compresses the refrigerant from the first load. The second compressor compresses the refrigerant from the second load. The third compressor compresses the refrigerant from the third load and the refrigerant from the second compressor. The fourth compressor compresses the refrigerant from the first compressor.

Abstract: A refrigeration apparatus including a compressor (301), a condenser (302), an expansion device (304), and an evaporator (305), fluidly connected to form a refrigeration cycle for a refrigerant, wherein the compressor (301) has a variable working capacity, and wherein the expansion device (304) has a configurable flow resistance with respect to the refrigerant passing through the expansion device. The apparatus further includes a controller (300) which is configured to determine a current working capacity of the compressor (301) and to control the resistance of the expansion device (304) in dependence on the current working capacity of the compressor (301). The controller (300) is further configured to control the resistance of the expansion device (304) in order to achieve a mass flow of the refrigerant through the expansion device (304), which mass flow corresponds to a mass flow of the refrigerant through the compressor (301).

Abstract: A heating, ventilation, and air-conditioning (HVAC) system comprises a plurality of sensors, a tandem compressor comprising a first compressor and a second compressor, and a controller communicatively coupled to the plurality of sensors and the tandem compressor. The controller is operable to operate threshold logic that turns off the tandem compressor if the tandem compressor is operating outside of a threshold range. The controller is further operable to determine a temperature demand of a structure associated with the HVAC system based on data received from at least one of the plurality of sensors and determine that the HVAC system requires a change of state to meet the temperature demand. The controller may disable the threshold logic for a pre-determined period of time in response to determining that the HVAC system requires the change of state and perform the change of state independently of the threshold logic.

Abstract: In a refrigeration system having a compressor, a heat rejection heat exchanger, a heat absorption heat exchanger, and a controller for controlling the same, embodiments of a system, apparatus and methods for the same can control at least one refrigeration system component such as an expansion valve responsive to dynamic system conditions.

Abstract: An economized refrigeration system includes a main refrigerant circuit having a condenser, an evaporator, an economizer, an expansion device intermediate the condenser and the economizer, and a main compressor fluidly connected by a main refrigerant line. The system also includes an economized refrigerant circuit including an auxiliary compressor system and an auxiliary refrigerant line fluidly connecting the economizer to the auxiliary compressor system and fluidly connecting the main refrigerant line to the auxiliary compressor at a location intermediate the main compressor system and the condenser. The auxiliary compressor system is independently controllable with respect to the main compressor system.

Abstract: A refrigeration trailer (reefer) truck power unit controller employs a plurality of power sources including a propulsion vehicle source driven mechanically by a diesel engine of the vehicle, and having an enhanced alternator having a pulley ratio for increasing idle speed power generation, and a passive vehicle source including a bank of solar panels disposed on the vehicle. The controller is configured for refrigerating a payload area of the vehicle utilizing power from the power sources, and employs a voltage converter for augmenting the power from the propulsion vehicle source for use with a native vehicle charging//starting system, and a transport load transformer for converting power from the power sources for powering the refrigeration system. A bank of batteries stores power from the sources for subsequent dispersal to the refrigeration unit.

Abstract: A method includes determining a pressure difference across a scroll compressor of a cooling system. The pressure difference is compared to a minimum differential pressure value. Pressure differences across the scroll compressor that are less than the minimum differential pressure value are associated with unloading the scroll compressor. Parameters including a pressure set point value and an absolute minimum pressure value are increased when the pressure difference is less than the minimum differential pressure value. Subsequent to the increasing of the parameters, the parameters are decreased when the pressure difference is greater than a sum of the minimum differential pressure value and a hysteresis value.

Abstract: A disclosed device cryogenic refrigerator includes a first stage displacer; a first stage cylinder configured to form a first expansion space between the first stage cylinder and the first stage displacer; a second stage displacer connected to the first stage displacer; and a second stage cylinder configured to form a second expansion space between the second stage cylinder and the second stage displacer, wherein a helical groove is formed on an outer peripheral surface of the second stage displacer so as to helically extend from a side of the second expansion space toward the first stage displacer, wherein the second stage cylinder includes a first flow resistor communicating with a side of the first stage displacer in the helical groove, and a buffer portion communicating with a side of the first stage displacer in the first flow resistor.

Abstract: In a temperature control system using a controlled mix of high temperature pressurized gas and a cooled vapor/liquid flow of the same medium to cool a thermal load to a target temperature in a high energy environment, particular advantages are obtained in precision and efficiency by passing at least a substantial percentage of the cooled vapor/liquid flow through the thermal load directly, and thereafter mixing the output with a portion of the pressurized gas flow. This “post load mixing” approach increases the thermal transfer coefficient, improves control and facilities target temperature change. Ad added mixing between the cooled expanded flow and a lesser flow of pressurized gas also is used prior to the input to the thermal load. A further feature, termed a remote “Line Box”, enables transport of the separate flows of the two phase medium through a substantial spacing from pressurizing and condensing units without undesired liquefaction in the transport lines.

Abstract: A method for freeze protection for a temperature control system, and a temperature control system for controlling the temperature of a temperature-controlled space at a set point temperature. The method includes monitoring a discharge air temperature, monitoring a return air temperature, setting a target temperature to equal the set point temperature, controlling the return air temperature at the target temperature, and adjusting the target temperature based on the return air temperature when the discharge air temperature drops to one of at or below freezing.

Abstract: A refrigeration apparatus includes a multistage compression mechanism, switching mechanisms, intercoolers, oil separators, and a control unit. The multistage compression mechanism has one high-stage-side compression mechanism and a plurality of low-stage-side compression mechanisms connected in series. The switching mechanisms are connected to blow-out pipes of the low-stage-side compression mechanisms. The switching mechanisms switch between cooling and heating operation cycles. The intercoolers cool refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The oil separators are disposed between the switching mechanisms and the intercoolers. The oil separators separate lubricating oil from refrigerant blown out from the low-stage-side compression mechanisms during the cooling cycle. The control unit controls the multi-stage compression mechanism and the switching mechanisms.

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: An air conditioning system includes a phase separator separating a gaseous refrigerant and a liquid refrigerant from a flowing refrigerant, an evaporator evaporating the liquid refrigerant separated by the phase separator, and at least one compressor including a first compressing part receiving the refrigerant via the evaporator and a second compressing part receiving both of the gaseous refrigerant separated by the phase separator and the refrigerant via the first compressing part.

Abstract: According to the present invention, an air condition comprises: a first compressor and a second compressor which compress a refrigerant through multiple stages; a condenser which condenses the refrigerant compressed by the second compressor; a first flow channel through which a portion of the refrigerant condensed by the condenser passes, in order to be cooled; a supercooling heat exchanger having a second flow channel for exchanging heat with the first flow channel; an expansion instrument which expands the refrigerant cooled by the supercooling heat exchanger; a shell-tube-type evaporator which evaporates the refrigerant expanded by the expansion instrument, and which is connected to a location requiring cold water via a water pipe to supply cold water to said location requiring cold water; a first bypass channel which guides the refrigerant condensed in the condenser to the second flow channel; a supercooling expander installed in the first bypass channel; and a second bypass channel which interconnects th

Abstract: A refrigerant vapor compression system includes a compression device, a heat rejecting heat exchanger, an economizer heat exchanger, an expander and an evaporator disposed in a refrigerant circuit. An evaporator bypass line is provided for passing a portion of the refrigerant flow from the main refrigerant circuit after having traversed a first pass of the economizer heat exchanger through the expander to partially expand it to an intermediate pressure and thence through a second pass of the economizer heat exchanger and into an intermediate pressure stage of the compression device. An economizer bypass line is also provided for passing a portion of the refrigerant from the main refrigerant circuit after having traversed the heat rejecting heat exchanger through a restrictor type expansion device and thence into the evaporator bypass line as liquid refrigerant or a mix of liquid and vapor refrigerant for injection into an intermediate pressure stage of the compression device.

Abstract: An air-conditioning system for vehicle temperature control incorporates a thermostat having contacts, and a circulation contour, including a condenser, an expansion valve essentially connected with the condenser, an evaporator connected sequentially with the expansion valve, a first tee splitter connected to a common line, a second tee splitter connected to the condenser, a main compressor connected with the first tee splitter and with the second tee splitter, a supplemental compressor connected with the first tee splitter and the second tee splitter. The supplemental compressor is operatively controlled by the thermostat and powered by a supplemental battery. In embodiments, the supplemental compressor is electrically connected with the supplemental battery and operatively controlled by a control circuitry including a power relay, an air-condition relay, and the contacts of thermostat. The proposed system reduces pollutions and saves energy.

Abstract: Method and apparatus for cooling a stream in a heat exchanger against a refrigerant fluid being cycled in a refrigerant circuit. The cycling of the refrigerant fluid includes feeding a first refrigerant fluid into an axial compressor and compressing it to obtain a compressed first refrigerant fluid. The compressed first refrigerant fluid is then fed into a centrifugal compressor, with a second refrigerant fluid. The compressed first refrigerant fluid and the second refrigerant fluid are compressed in the centrifugal compressor, thereby obtaining a compressed refrigerant fluid mixture. The compressed refrigerant fluid mixture is cooled in a heat exchanger and subsequently separated into at least two streams. The at least two streams are evaporated at different pressure levels of a heat exchanger in heat exchanging contact with the stream to be cooled, and from the at least two evaporated streams the first and second refrigerant fluids are retrieved.

Abstract: A refrigerant cycle is provided with a multi-port compressor or compressor stages connected in series, and multiple condensers. A single evaporator communicates with the plurality of condensers. At least one of the plurality of condensers receives fully compressed refrigerant while the other condensers receive refrigerant at intermediate pressure. A control can optionally direct refrigerant to the condensers to achieve desired system heat rejection characteristics and operating conditions. One or multiple reheat coils may be associated with the evaporator and are arranged either in series or in parallel to provide a desired dehumidification function and reheat stages. One or several of the intermediate pressure condensers may be utilized for the reheat function as well.

Abstract: Disclosed herein is an apparatus for controlling the capacity of an air conditioner and a control method using the same. The capacity control apparatus is configured in such a fashion that a 3-way or 4-way direction-switching member and a low-pressure equalizing solenoid valve are provided at a refrigerant path of the air conditioner having a pair of first and second compressors, so that the compression capacity of the air conditioner is adjusted into three stages of 100%, 60%, and 40% using the first and second compressors, enabling easy variable-capacity operation. This has the effect of considerably reducing energy consumption and of preventing wear of the first and second compressors via a rapid compensation of a pressure unbalance between both the compressors.

Abstract: A scroll compressor is provided with a multiple-speed motor. A control selects a speed for operating the motor, along with selecting between several available options for the system capacity adjustment to meet external load demands in a most efficient and reliable manner. The disclosed embodiment includes an economizer circuit, an unloader function, and an optional suction modulation valve. By utilizing each of these features in combination with the multi-speed motor for the compressor, the present invention is better able to tailor provided capacity to desired capacity.

Abstract: A compressor controlling apparatus including a bypass unit connected between an outlet and an inlet of the compressor and a control unit. The control unit reduces pressure difference between the outlet and the inlet of the compressor by the bypass unit to start the compressor when the compressor is to be started. The compressor is started while pressure equilibrium is achieved by the bypass unit, thereby preventing poor start-up of the compressor caused due to excessive pressure difference, and thus improving reliability of the compressor.

Abstract: A multi-stage refrigeration system is provided. The refrigeration system includes a first compression element which produces a first compressed refrigerant stream. A mixer combines the first compressed refrigerant stream with an auxiliary refrigerant stream. A second compression element is coupled to the mixer and produces a second compressed refrigerant stream. A first heat exchanger receives the second compressed refrigerant stream and generates a cooled stream. A stream splitter receives the cooled stream and provides first and second output streams. A first expansion valve receives the first output stream and controls the flow of the first output stream and a second expansion valve receives the second output stream and controls the flow of the second output stream. A second heat exchanger generates the auxiliary refrigerant stream provided to the mixer.

Abstract: A two-stage compression rotary compressor is provided that includes a low-stage compressing section and a high-stage compressing section housed within a cylindrical sealed housing oriented vertically, a low-stage suction pipe that is connected to a suction side of the low-stage compressing section and sucks in a low-pressure refrigerant, a low-stage discharge pipe the is connected to a discharge side of the low-stage compressing section and discharges the refrigerant from the low-stage to outside of the sealed housing, a high-stage suction pipe that is connected to a suction side of the high-stage compressing section and sucks in the refrigerant discharged from the low-stage, a low-pressure connecting pipe that connects the low-stage suction pipe and an accumulator, and guides the refrigerant inside the accumulator to a suction side of a low-stage compressing section, and an intermediate connecting pipe that connects the low-stage discharge pipe and the high-stage suction pipe, wherein an inner diameter of th

Abstract: A coil of an electric motor is cooled by refrigerant. A controller for the electric motor controls a current supplied to the coil within a range less than or equal to a predetermined maximum value. A temperature detection section detects either a temperature of the coil or a temperature about the coil. When a detection temperature that is detected by the temperature detection section prior to activation of the electric motor reaches a predetermined reference temperature, a limiting section executes a limiting control to limit an upper limit value of the current supplied to the coil to a limiting value that is less than the maximum value. Accordingly, the coil of the electric motor is protected without stopping the operation of the electric compressor immediately after activation.

Abstract: An apparatus and method for compressing gas refrigerant using two different compressors operated alternatively in a series or parallel mode for obtaining two different compression ratios and thereby provide efficient operation for both a relatively lower suction pressure and a relatively higher suction pressure. This system avoids an unbalanced mass flow rate when the compressors are operated in series by unloading a downstream one of the compressors. When operated in the series mode, refrigerant is bypassed back to a suction inlet of the downstream compressor during a portion of a compression stroke of the downstream compressor for equalizing the mass flow rate through the two compressors.

Abstract: Disclosed related to a co-generation according to the present invention has some advantages in that the heat of the refrigerant recovered at the supply heat exchanger is used for the water boiling as well as the heat recovered at the drive source is used for water boiling when the air conditioner is under the air-cooling mode and has a water boiling request by comprised as an electric generator; a drive source operating the electric generator; a waste heat recovery heat exchanger recovering the exhaust gas heat of the drive source; a water boil heat exchanger installed for boiling water; an air conditioner air-conditioning indoor air; a radiant heat exchanger radiating heat to outside; a supply heat exchanger installed on the refrigerant path of the air conditioner; and a heat transfer path connecting the waste heat recovery heat exchanger, water boil heat exchanger, and the radiant heat exchanger, and the supply heat exchanger.

Abstract: A system includes a plurality of distributed refrigeration units respectively coupled to discrete refrigeration circuits. Each refrigeration unit may include a variable compressor, a fixed compressor, a condensing unit, and a controller. The controller compares an operating condition of the refrigeration unit to a refrigeration circuit set point to select a compressor staging capable of achieving the refrigeration circuit set point.

Abstract: An improved cold climate air-source heat pump comprising at least a primary compressor, a booster compressor, a first heat exchanger associated with an indoor environment and a second heat exchanger associated with an outdoor environment and with one heat exchanger acting as an evaporator and the other heat exchanger acting as a condenser, an expansion device, flow conduit means for circulating a refrigerant fluid in a closed loop, a first sensor means for sensing the temperature of the internal ambient air, a second sensor means for sensing the temperature of the external ambient air, a third sensor means for sensing the temperature of the refrigerant fluid flowing between the booster compressor and the primary compressor, a fourth sensor means for sensing the operative state of the primary compressor, a primary compressor operation control means responsive to inputs from the first sensor means, and a booster compressor operation control means responsive to inputs from the second, third, and fourth sensor me

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

Abstract: A compressor has at least three-rotors. A first compression path between first inlet and outlet ports is associated with interaction of the first and second rotors. A second compression path between second inlet and outlet ports is associated with interaction of the first and third rotors. At least partial independence of the ports permits the first and second inlet ports to be at a different pressure or the first and second outlet ports to be at a different pressure. Fully or partially separate circuits in a refrigeration or air conditioning system may be associated with the first and second compression paths.

Abstract: A tandem compressor system is utilized that receives refrigerant from a common suction manifold, and from a common evaporator. From the compressors, the refrigerant passes to a plurality of condensers, with each of the condensers being associated with a separate zone for heat rejection, preferably at different temperature levels. Each of the condensers is associated with at least one of the plurality of compressors. By utilizing the common evaporator, yet a plurality of condensers, the ability to independently control temperature and amount of heat rejection to a number of zones is achieved without the requirement of having a dedicated circuit with multiple additional components. Thus, the overall system cost and complexity can be greatly reduced. In embodiments, one or more of the plurality of compressors can be provided by a compressor bank, having its own plurality of compressors.

Abstract: A refrigerant system is provided where the functions of an economizer heat exchanger and liquid-suction heat exchanger are combined. The two configurations are disclosed with a single common heat exchanger construction. In a first configuration, a series of valves selectively routes only one of two possible refrigerant flows through a common heat exchanger such that a control can selectively activate either an economizer heat exchanger circuit or a liquid-suction heat exchanger function. In a second configuration, both refrigerant flows are passed to the common heat exchanger through separate fluid lines and are selectively activated by the control. Variations of the second configuration are also disclosed.

Abstract: An air conditioning system includes a primary or engine-driven compressor that is driven by a primary driving source or engine, and a secondary or motor-driven compressor that is driven by a secondary driving source or motor. The air conditioning system increases in advance an output of the secondary or motor-driven compressor before the primary or engine-driven compressor is stopped. Further, when a load of the secondary or motor-driven compressor becomes a predetermined value while the secondary or motor-driven compressor is in operation, the primary or engine-driven compressor is activated.

Abstract: An object of the present invention is to provide a refrigerant cycle apparatus which can reduce a production cost while hastening equalization of pressure in a refrigerant circuit after a compressor is stopped, the apparatus comprises a bypass circuit which causes an intermediate-pressure area to communicate with a low-pressure side of a refrigerant circuit, a valve device provided to this bypass circuit and a control device which controls opening/closing of this valve device, and the control device constantly closes the valve device but opens it in order to release a flow path of the bypass circuit concurrently with the stop of the compressor.

Abstract: In a refrigerating apparatus comprising a plurality of application-side heat exchangers (41), (45, 51) for air-conditioning and for cold-storage/freezing, it is configured so as to be capable of corresponding to various types of operation patterns when a compression mechanism (2) is configured by two compressors (2A, 2B). In order to continue operation even if one compressor is broken, a switching mechanism such as a four-way selector valve (3C) is provided on the suction side of the two compressors (2A, 2B), so that a plurality of operation patterns can be performed in a predetermined operation mode.

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.

Abstract: Multiple refrigerant circuits are operated in parallel, and each has an economizer cycle. One of the two circuits may have a greater capacity than the other. By controlling the two circuits to run in economized, conventional, bypassed, or economizer bypassed operation, the control is able to match demanded capacity. Moreover, by exercising similar technique, the control can provide better humidity control, can limit or maintain head pressure, and can avoid power consumption peaks.

Abstract: Step control in capacity modulation of a refrigeration or air conditioning circuit is achieved by rapidly cycling a solenoid valve in the suction line, economizer circuit or in a bypass with the percent of “open” time for the valve regulating the rate of flow therethrough. A common port in the compressor is used for economizer flow and for bypass.

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.