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: A cooling system comprising a compressor (20) and controlled by means of an electronic circuit (TE), the electronic circuit (TE) comprising a measuring circuit (ME) for measuring an electric power (Pn) supplied to the compressor (20) a microcontroller (10), a time variable (td), the measuring circuit (ME) effecting a measurement of the electric power (Pn) supplied the compressor (20), the microcontroller (10) comparing the measure. An electric power with reference-power values (Prl) and (Prd) previously stored in the microcontroller (10), the microcontroller altering the state of operation of the compressor (20) in function of the electric power (Pn) and of the time variable (td). A method of controlling a compressor (20), which comprises steps of storing a variable (Pn(te)) at a power value (Pn) measured at the moment when a period of time (te) counted from the moment of turning on the compressor (20) has been, and altering the value of the time variable (tD).

Abstract: An air conditioner has a variable capacity rotary compressor, which allows the compressor to be smoothly re-started, thus increasing start reliability of the compressor. The air conditioner includes a compressor rotated in opposite directions. A drive unit rotates the compressor in a forward or reverse direction. A start determining unit determines whether the compressor has started to rotate in a forward direction or not. A control unit operates the drive unit so as to rotate the compressor in a direction opposite to the forward direction, and then re-start the compressor in the forward direction, when the compressor has failed to start. The air conditioner and a method of controlling the air conditioner allow the compressor to be smoothly and rapidly re-started even when the compressor has failed to re-start, thus increasing start reliability, and shortening a time required to re-start the compressor.

Abstract: In order to reduce refrigerant leakage from an automotive air conditioning system, the leakage paths are kept sealed by automatically reducing the output of a variable displacement compressor (12) after initial operation of the engine for a predetermined number of five minutes, and then only for a predetermined number of ten seconds, that is, so long as there has been an air conditioning on signal by the operator. After the reduction in output for ten seconds, the output of the compressor (12) is returned to full output for a predetermined number of two air-conditioning minutes, which is then followed by another ten seconds of reduced output.

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 compressor for a vehicle air conditioner includes a pressure sensor and a torque computing unit for computing the compressor torque. The compressor also has a communication unit that allows data communication with other devices based on vehicle data communication protocols. The torque computing unit and the communication unit are integral with the compressor. Therefore, it is possible to calculate the driving torque quickly, and an engine electronic control unit can control an engine such that the torque required for the compressor can be quickly generated.

Abstract: The invention proposes an air conditioning installation furnished with an injection computer (42), with an air conditioning apparatus and with an electronic control device (401). The installation furthermore comprises measurement facilities making it possible to establish values relating to the temperature of the external air stream at the inlet of the condenser, to the pressure at the outlet of the compressor (123), and to the pressure at the inlet of the compressor (122). The electronic control device (401) implements the solving of a linear equation, relating the mass flow rate of the refrigerant to the values measured by the measurement facilities so as to calculate an estimate of a quantity relating to the refrigerant. On the basis of this quantity, the electronic device can estimate the power absorbed by the compressor (14).

Abstract: The object of the present invention is to provide a method of operating a refrigeration cycle which is capable of preventing oil from staying in an evaporator and ensures high coefficient of performance as well as sufficient circulation of oil. An electronic expansion valve is controlled such that during normal operation, refrigerant is always in a superheated state at the outlet of an evaporator, and the refrigerant is periodically forced to have negative superheat for a predetermined time by a superheat control device. Thus, during normal operation, the refrigerant sucked into a variable displacement compressor always has superheat, whereby the refrigeration cycle can operate with high coefficient of performance and an engine driving the variable displacement compressor can be operated at high fuel efficiency. Also, the refrigerant is temporarily controlled so as to have negative superheat.

Abstract: A method for controlling load capacity in an air conditioning unit comprising the steps of initializing a saturated condensing temperature upper bound (SCT_UP), comparing a saturated condensing temperature (SCT) to a maximum condensing temperature threshold (MCT_TH), unloading a single load capacity step, allowing the air conditioning unit to stabilize, and setting the SCT_UP equal to the SCT after the unloading, and increasing the load capacity by one capacity step if increased load capacity is required, the SCT is less than or equal to the MCT_TH, and the SCT<the SCT_UP.

Abstract: Disclosed herein is an air conditioning unit and method of operating the same. The air conditioning unit has a power level control unit (6) for controlling the level of power supplied to a motor (2a) of a compressor. The power level control unit (6) is comprised of a first supplying unit (6a) for supplying first level power to the compressor motor (2a), and a second supplying unit (6b) for supplying second level power to the compressor motor (2a). If an operation cycle of the compressor corresponds to a loading operation, the power level control unit (6) supplies first level power for compressing a cooling agent through the first supplying unit (6a). Further, if an operation cycle of the compressor corresponds to an unloading operation, the power level control unit (6) supplies second level power less than the first level power through the second supplying unit (6b).

Abstract: An air conditioning system for a vehicle includes a hybrid compressor having a first compression mechanism driven by a drive source for driving the vehicle and a second compression mechanism driven by an electric motor, means for selecting a drive source, a means for detecting a refrigeration cycle condition, and means for estimating a power consumption of the compressor due to a selected drive source and a power consumption of the compressor due to a non-selected drive source in response to a value detected by the means for detecting a refrigeration cycle condition, when one drive source has been selected. Through this estimation, an preferred drive source may be selected in response to the condition of the refrigeration cycle or a thermal load.

Abstract: An air conditioning system 1 includes a primary compressor (an engine-driven compressor 6) driven by a primary driving source (an engine 2) and a secondary compressor (a motor-driven compressor 7) driven by a secondary driving source (a motor 3). When a required cooling capability is equal to or greater than a predetermined value, the air conditioning system 1 causes the primary compressor (the engine-driven compressor 6) to be driven by the primary driving source (the engine 2) and adjusts the rotational speed of the secondary compressor (the motor-driven compressor 7), whereas when the required cooling capability is equal to or smaller than the predetermined value, the air conditioning system 1 causes the secondary compressor (the motor-driven compressor 7) to be driven by the secondary driving source (the motor 3) so as to control the rotational speed of the primary compressor (the engine-driven compressor 6).

Abstract: To provide an air conditioning system which simultaneously eliminates shortage of lubricating oil of a variable displacement compressor and degradation of cooling efficiency of the system. An air conditioning system is configured to have a variable displacement compressor under flow rate control by a proportional flow rate control solenoid valve forming a variable orifice in a discharge-side refrigerant flow passage, and a constant differential pressure valve for controlling a differential pressure (PdH?PdL) across the variable orifice, developed depending on a flow rate Qd of refrigerant, to a constant level, and an expansion valve of a normal charge type. By providing the expansion valve of the normal charge type, it is possible to always hold refrigerant at an outlet of an evaporator in a superheated state, whereby even during low load operation, high cooling efficiency can be maintained.

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: The object of this invention is to provide an air conditioner with a variable capacity compressor (2) parallely connected to a fixed capacity compressor (4), and a method of controlling the operation of such an air conditioner. When it is required to start the fixed capacity compressor (4) in addition to an operation of the variable capacity compressor (2) due to an increase in the sum of the required cooling capacities of indoor units (9), an outdoor control unit (13) starts the fixed capacity compressor (4) during an unloading mode operation of the variable capacity compressor (2) where the pressure difference between the outlet side and inlet side of the variable capacity compressor is minimized. The fixed capacity compressor (4) is thus smoothly started without causing an induction of excessive starting current, and improves the operational reliability of the air conditioner.

Abstract: Disclosed are an air conditioner in which one or more compressors are operated so that the refrigerant compression capacity of the operating compressor(s) is variably changed in accordance with a cooling or heating load for cooling or heating air in a room, and a method for controlling an electronic expansion valve of the air conditioner.

Abstract: A heat pump water heater system includes a compressor that has a variable clearance volume that can be selectively controlled to control the mass flow rate of refrigerant from the compressor. Under higher ambient air temperature conditions, the variable volume is increased to keep refrigerant in a variable clearance volume chamber and to decrease the mass flow rate of the refrigerant from the compressor. Under lower ambient air temperature conditions the variable volume is decreased to increase the mass flow rate. The variable clearance volume allows for maintaining optimum system performance under a variety of ambient air temperature conditions.

Abstract: In a vapor-compression refrigerant cycle system, a switching device is provided to switch one of a first mode where high-pressure refrigerant discharged from a compressor is directly introduced to an exterior heat exchanger and a second mode where the high-pressure refrigerant is directly introduced to an interior heat exchanger. When the second mode is set, the pressure of the high-pressure refrigerant is set higher than a predetermined pressure by a constant-pressure control valve. Accordingly, it can prevent heating capacity of the interior heat exchanger from being greatly changed even when thermal load of the vapor-compression refrigerant cycle system is changed, and heating capacity of the interior heat exchanger can be improved in the second mode.

Abstract: A variable displacement compressor includes a suction chamber, a discharge chamber, and a crank chamber. The compressor also includes a first path for allowing communication between the crank chamber and the discharge chamber, and a second path for allowing communication between the crank chamber and the suction chamber. Moreover, the compressor includes a valve assembly. The valve assembly includes a valve positioned within the first path, and the valve assembly controls a pressure in the crank chamber by varying a position of the valve. The compressor also includes an orifice mechanism. The orifice mechanism includes a plate having a hole formed therethrough, and an elongated member positioned within the hole. Specifically, the elongated member is movable within the hole, and an annulus of the orifice mechanism is defined between the elongated member and an interior surface of the hole.

Abstract: A refrigerating apparatus including three compressors (2A, 2B, 2C) and application side heat exchangers (41) (45, 51) for two channels is formed so that a first compressor (2A) is used only for the application side heat exchangers (45, 51) in a first channel of a circuit, a third compressor (2C) is used only for the application side heat exchanger (41) in a second channel of the circuit, and a second compressor (2B) is used in a switchable manner between the application side heat exchangers (45, 51) in the first channel of the circuit and the application side heat exchanger (41) in the second channel of the circuit. Thus, not only the pipe arrangement at suction side is simplified, but also operation control is streamlined.

Abstract: A cooling system including a pulse-width modulated variable capacity compressor operable between on-cycles and off-cycles, and in electrical communication with the compressor and operable to respectively synchronize opening and closing thereof with on- and off-cycles of the compressor.

Abstract: A refrigerant cycle is provided with a control that monitors system conditions such as current, voltage or temperature at a compressor motor or refrigerant state conditions at compressor ports. A protection switch on the motor is operable to stop operation of the compressor should a system condition exceed a predetermined maximum. The control monitors a system condition, and determines that the system condition indicates the protection switch may be actuated as the condition is moving toward the predetermined limit. Under such conditions, the control moves the compressor to a less loaded mode of operation such that it is less likely that the protection switch will actuate.

Abstract: Several control algorithms reduce the likelihood of insufficient oil return to the compressor. One algorithm is useful in a multi-circuit refrigerant system. A control reduces the cooling capacity of one of the circuits if the number of compressor start/stop cycles becomes excessive. By reducing the capacity, the control will reduce the number of compressor start/stop cycles for a circuit. In this manner, the oil continues to circulate through the circuit, and is more efficiently returned to the compressor. Another problem area associated with a poor oil return back to the compressor is when there is low mass flow rate of refrigerant circulating through the system. Various ways of increasing the refrigerant mass flow rate are disclosed to ensure proper oil return to the compressor. Also, if oil return problems are likely due to an undesirably high oil viscosity at the vapor portion of the evaporator or suction line, then steps are taken to reduce oil viscosity.

Abstract: A compressor torque estimate device is used for a variable displacement compressor whose displacement is variable based on a compressor control signal for estimating a compressor torque of the compressor. The compressor torque estimate device includes a torque calculator and a corrector. The torque calculator calculates a torque required for driving the compressor based on the compressor control signal, thereby obtaining a calculated torque. The corrector corrects the calculated torque by a procedure of first-order lag, thereby obtaining a corrected torque. The corrector also estimates the corrected torque to be the compressor torque.

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

Abstract: In a vehicle air conditioner, a compressor is driven by a vehicle engine, and a displacement of the compressor is controlled based on a cooling load. When a post-evaporator air temperature (TE) is higher than a predetermined value (TEO+?), it is determined that the cooling load is large, and the compressor is forcibly controlled at maximum displacement that is larger than a control value controlled based on the cooling load. Accordingly, the post-evaporator air temperature (TE) can be rapidly reduced to be lower than the predetermined value (TEO+?), so that a driving time of the vehicle engine can be made shorter. As a result, fuel consumption efficiency of the vehicle engine can be effectively improved.

Abstract: Disclosed herein are a variable capacity rotary compressor and a refrigerant cycle system having the variable capacity rotary compressor. The compressor includes a cooling unit and a pressure reducing unit to reduce temperature and pressure of a bypassed refrigerant, thus allowing the bypassed refrigerant to have the same temperature and pressure as when entering a cylinder at first. The compressor includes the cylinder in which a refrigerant is compressed. An inlet pipe delivers the refrigerant into the cylinder. An outlet pipe delivers the refrigerant out of the cylinder. A bypass hole is provided at a predetermined position of the cylinder to bypass the refrigerant from the cylinder, thus varying a compression capacity. A bypass pipe connects the bypass hole to the inlet pipe to allow the refrigerant bypassed through the bypass hole to enter the cylinder. The cooling unit cools the refrigerant flowing through the bypass pipe.

Abstract: The present invention concerns an on-vehicle air-conditioner, resolving problems of the prior art, and allowing to perform cooling, heating, dehumidification or others efficiently even for vehicles of low waste heat, such as hybrid cars taking electricity and gasoline as energy source, idle stop coping cars or battery cars taking only electricity as energy source, or other vehicles, by cooling by loading a refrigeration circuit, using for example CO2 refrigerant, and provided with an electrically driven two-stage compression system compressor, and at the same time, installing a refrigerant heat exchanger for cooling the refrigerant, compressed in the first stage in a way to exchange heat with the car interior air, and using conveniently also for heating together with the heat of the cooling water for cooling the engine.

Abstract: A cooling system for a motor is prevented from exhibiting a thermal fatigue failure due to a temperature cycle. The operation or stopping of the cooling motor fan 6 of the forced cooling system is controlled using the difference between the temperature thereof and the operation start temperature Tis of the power converter 3. Thus expansion of the temperature range is suppressed.

Abstract: An air-conditioning system with a refrigerant medium circulating in a refrigerant loop has a variable-stroke compressor with a high-pressure outlet chamber, a drive chamber and an intake suction chamber. A first valve regulates a first flow of refrigerant medium from the high-pressure outlet chamber to the drive chamber, and a second valve regulates a second flow of refrigerant medium from the drive chamber to the intake suction chamber. The first and second valves operate independently of each other under the control of a control unit, and the variable stroke of the compressor is controlled by the first and/or second flow of refrigerant medium.

Abstract: A vehicle air conditioning control apparatus having an externally controlled type compressor 3 and an externally controlled type cooling electric fan 9 is disclosed in which a control map, for determining a duty ratio for a fan motor 10 in terms of a compressor discharge pressure Pd, is determined based on the maximum efficiency point, for providing the maximum fuel consumption, that allows a total engine load torque, represented by a total sum of an engine load torque caused by the externally controlled type compressor 3 and an engine load torque caused by a fan motor 10, to be a minimum torque, and a duty voltage to be applied to the fan motor 10 is controlled using the compressor outlet pressure Pd and the control map which is determined.

Abstract: Disclosed are an air conditioning system with two compressors and a method for operating the same, so as to variably change a compression capacity of a refrigerant according to the variation of cooling load. Herein, when a full operation order is inputted to the two compressors in order to satisfy increased cooling load, the first compressor is first operated, and then the second compressor having a compression capacity of a refrigerant smaller than that of the first compressor is additionally operated, so that a current peak value for operating the compressors does not exceed an allowable current range of a circuit breaker installed in a home or building, thereby safely controlling the air conditioning system and simultaneously allowing the current to be provided to other electric appliances, thus improving users' convenience.

Abstract: A refrigeration cycle apparatus having a linear compressor is provided with a volume circulation rate instruction unit for obtaining a volume circulation rate Vco of a refrigerant in accordance with refrigerating capacity required of the refrigeration cycle apparatus, on the basis of an ambient temperature of an indoor heat exchanger (evaporator), a target temperature set on the evaporator by the user, and an ambient temperature of an outdoor heat exchanger (condenser). A volume circulation rate detector is provided for detecting a volume circulation rate Vcd of the refrigerant that actually circulates in a refrigerant circulation path of the refrigeration cycle apparatus; and an inverter is provided for generating an AC current for driving the linear compressor. The inverter is controlled so as to decrease a difference between the volume circulation rate Vco and the volume circulation rate Vcd.

Abstract: Disclosed herein is an air conditioner and method of controlling the same. The air conditioner includes a compressor having a capacity variable according to a duty control signal. The duty control signal controls the compressor to undergo a loading time for maintaining a loading state in a cycle and an unloading time for maintaining an unloading state in a cycle. The air conditioner further includes a control unit for determining the loading time and the unloading time according to the variation of a total required cooling capacity to generate the duty control signal even before a corresponding cycle is over, if the total required cooling capacity has been varied in a corresponding cycle while the compressor is operated, and controlling the compressor according to the duty control signal.

Abstract: To provide a transportable cooling unit for maintaining a transport volume at a defined temperature, comprising a closed cooling circuit and a controller sensing a temperature present within said transport volume and controlling said cooling circuit so as to provide the cooling power demanded at said evaporator for maintaining said defined temperature and minimizing energy consumption, said controller operates said closed cooling circuit between a maximum possible heating power and a maximum possible cooling power in a sequence of different operational stages, said controller further operates said closed cooling circuit in each one of at least two upper operational cooling stages at a compressor speed related cooling capacity different from said compressor speed related cooling capacity in said other upper operational stages and within said respective upper operational stages said controller operates a compressor in an uninterrupted mode and adjusts said cooling power stepless speed control of said compressor

Abstract: A cooling system including an evaporator, a suction line, a two stage compressor, a gas cooler and a capillary tube. The suction line receives gaseous or two phase refrigerant from the evaporator, the compressor receives the gaseous or two phase refrigerant from the suction line, and the gas cooler cools compressed refrigerant discharged from the compressor. The capillary tube carries refrigerant from the gas cooler to the evaporator, and the suction line may include two straight portions with two portions of the capillary tube helically wound therearound, with a bypass valve around the capillary tube, and an accumulator between the suction line portions. An inter-cooler is between stages of the compressor, and a pan collects water condensate from the air side of the evaporator, and the refrigerant tube carries cooled refrigerant from the gas cooler through the pan. A controller selectively turns the compressor on and off based on temperature or pressure sensed by a sensor.

Abstract: Disclosed are an air conditioning system, in which the total operating capacity of compressors is variably controlled in accordance with a cooling or heating load in a room, and a method for controlling the air conditioning method, thus improving comfortableness in the room, reducing an electric power consumption rate, and increasing cooling or heating efficiency. The air conditioning system includes an indoor heat exchanger for cooling a room by heat-exchanging a refrigerant with air in the room; an outdoor heat exchanger for condensing the refrigerant; a plurality of compressors for compressing the refrigerant; and a control unit for controlling operation of the plural compressors in accordance with the cooling or heating load in the room.

Abstract: An air conditioning system for cooling a vehicle passenger compartment is disclosed. The system includes an air duct, a refrigerant circuit, a variable displacement compressor, and a controller. The air duct directs air conditioned air into the vehicle passenger compartment. The refrigerant circuit circulates a refrigerant, wherein a first portion of the circuit is exposed to the air duct and a second portion of the circuit is exposed to air external of the vehicle passenger compartment. The variable displacement compressor is in fluid communication with the refrigerant circuit, wherein the compressor has a control valve for regulating refrigerant flow between a compressor crankcase and a compressor discharge chamber and between the compressor crankcase and a compressor suction chamber. The controller in electrical communication with the variable displacement compressor for controlling refrigerant flow and a displacement of the compressor by actuating the control valves.

Abstract: Components for HVAC systems used in hybrid and fuel cell vehicles are mounted in modular configuration on a frame with air conditioning components connected to one another by metal pipes welded to the components. An alternating current motor, integral with a compressor, is driven by 310 volt alternating current from an inverter, which inverter converts 310 volt direct current that is used to power the vehicle. PTC heaters in fluid communication with an evaporator employed by the air condition system are directly energized by the 310 volt direct current. The modular system is mounted directly on the chassis of the vehicle, facilitative assembly of the vehicle, and is readily removable as a unit from the chassis for repair or replacement.

Abstract: A refrigerating machine includes a plurality of compressors driven by motors each having an armature core incorporating a squirrel cage conductor and a permanent magnet which is magnetized so as to allow the motor to serve as a synchronous motor, and a compressor drive circuit for selectively driving the motor at a power source frequency by a commercial power source or at a variable frequency by an inverter. Thus, the overall efficiency of the refrigerating machine can be enhanced.

Abstract: A controlled compressor apparatus enables a hybrid compressor in an idle-stopping vehicle to operate more efficiently when driven by a motor alone. The controlled compressor apparatus includes a compressor 110, included in a refrigeration circuit 200, of a variable volume type for compressing a refrigerant; a motor 120 powered by a battery 12 to operate; and a controller 130 for selecting the driving force provided either by the engine 10 or the motor 120 to drive the compressor 110 and control its discharge volume. The controller 130 causes the motor 120 to operate the compressor 110 such that the compressor 110 is turned on or off at a discharge volume of the compressor 110 that larger within a variable range than that required for operating the refrigeration circuit 200.

Abstract: There is provided a cooling apparatus which can improve cooling efficiency of an evaporator while preventing freezing of articles housed in a cooled space thereof. The cooling apparatus comprises: a control device which controls a compressor; and a temperature sensor in the chamber which can detect a cooled state in a refrigerator main body to be cooled by the evaporator. The control device stops running of the compressor if the compressor is continuously run for a predetermined time, and changes the continuous running time of the compressor for stopping the same based on a temperature in the chamber of the refrigerator main body detected by the temperature sensor in the chamber.

Abstract: In a vehicle air conditioner, a variable displacement compressor has a control valve for continuously changing a discharge capacity of the compressor, and a control unit calculates an electrical value DT to be applied to the control valve based on the following formula of DT=DT(n−1)+Kp[(En−En−1)+C/(Ti×En)]. In this formula, En=Te−Teo, Kp=Kp′/(Ph×Ph′), Ti=Ti′/(Ph×Ph″), C is a sampling cycle, n is a positive number, Kp′, Ti′, Ph′ and Ph″ are constants, Ph is a refrigerant pressure at a high pressure side, Te is a detected air temperature at an air outlet of the evaporator, and Teo is a target evaporator air temperature that is calculated based on an outside air temperature Tam. Accordingly, the compressor can be stably controlled in a wide thermal load range.

Abstract: A pressure equalization method and system is provided for starting a compressor while maintaining the condenser at a high pressure and includes a valve and a bleed port. The compressor has a compressor inlet for receiving a fluid at a first pressure and a compressor outlet for discharging the fluid at a second pressure, and is operable to compress the fluid from the first pressure to the second pressure. The valve is proximate to and in fluid communication with the compressor outlet and is movable to an open position when the compressor is operating to permit the fluid at the second pressure to flow through the valve and is movable to a closed position when the compressor stops operating to prevent backflow of the fluid at the second pressure through the valve toward the compressor inlet. The bleed port is upstream of the valve and in fluid communication with the compressor inlet to equalize the pressure of the fluid contained in the compressor when the compressor stops operating.

Abstract: An air conditioning system 1 includes a primary compressor (an engine-driven compressor 6) that is driven by a primary driving source (an engine 2), and a secondary compressor (a motor-driven compressor 7) that is driven by a secondary driving source (a motor 3). The air conditioning system 1 increases in advance an output of the secondary compressor (a motor-driven compressor 7) before the primary compressor (the engine-driven compressor 6) is stopped.

Abstract: A vapor compression system includes a compressor, a gas cooler, an expansion device, and an evaporator. Refrigerant is circulated through the closed circuit cycle. Preferably, carbon dioxide is used as the refrigerant. Adaptive control is employed to optimize the coefficient of performance of the vapor compression system. As the system changes over time, a model that operates the system is modified. The model is determined by an adaptive control algorithm including variable coefficients. As the model changes, the variables of the adaptive control algorithm change. A control of the gas cooler is then adjusted to regulate the high pressure of the system, and therefore the coefficient of performance. In a first example, Least Mean Squares (LMS) is used to modify the variables of the adaptive control algorithm to optimize the coefficient of performance. In a second example, the coefficient of performance is optimized by a slowly varying periodic excitation method.

Abstract: When a compressor apparatus is operated at a maximum displacement for 60 minutes or longer, an ECU controls a pressure control valve to gradually change the refrigerant pressure in a swash plate chamber in a manner that gradually reduces the displacement of the compressor apparatus. In this way, it is possible to create a state, in which a relatively large pressure difference is created between a refrigerant inlet side and the swash plate chamber. Thus, refrigerant oil accumulated in the swash plate chamber can be returned to the refrigerant inlet side of the compressor apparatus at the time of gradually reducing the displacement of the compressor apparatus.

Abstract: Disclosed is a method for operating a plurality of compressors of an air conditioner in accordance with a cooling or heating load in a room, in which a power supply unit for supplying power to the compressors is protected when a cooling or heating load in a room is the highest grade. The method comprises the steps of: (a) determining the cooling or heating load in the room; and (b) sequentially operating the plural compressors when it is determined as a result of the step (a) that the cooling or heating load in the room is in the highest grade.

Abstract: Disclosed are an apparatus and a method for controlling a plurality of compressors of an air conditioner. The apparatus comprises a counter, a timer, and a controller. The counter serves to count the number of times of operations/stoppages of the plural compressors according to loads. The timer serves to sense a time taken for the plural compressors to be operated/stopped a designated number of times counted by the counter. The controller serves to control the operations of the plural compressors based on the time sensed by the timer. The apparatus senses the time taken for the plural compressors to be operated/stopped the designated number of times, and determines whether or not a load is eliminated based on the sensed time, thereby properly controlling the operations of the compressors. Accordingly, the apparatus of the present invention reduces the consumption of power and increases air conditioning efficiency of the compressors.

Abstract: The object of the present invention is to provide a method of controlling a refrigeration cycle such that maximum refrigerating capacity can be educed when the refrigeration cycle is started, the driving torque of a variable displacement compressor can be reduced when an automotive vehicle performs standing start or acceleration, and the refrigeration cycle can be operated with the maximum efficiency in a steady operating condition.