Abstract: An air conditioning system including an outdoor heat-exchanging unit, at least one indoor heat-exchanging unit, a gaseous refrigerant line connected between the outdoor heat-exchanging unit and the indoor heat-exchanging unit, to allow a refrigerant in a gaseous state to flow between the outdoor heat-exchanging unit and the indoor heat-exchanging unit, and a pressure compensation device for increasing a pressure of the gaseous refrigerant flowing through the gaseous refrigerant line. The pressure compensation device is located along the gaseous refrigerant line at a position closer to the indoor heat-exchanging unit than to the outdoor heat-exchanging unit. A pressure compensation device for use in an air conditioning system is also provided.

Abstract: A refrigerant system can be operated in either vapor injection mode or unloaded mode. A restriction to the vapor injection flow is incorporated into the refrigerant system. The restriction is placed on the vapor injection line upstream of a point where the injection line meets the unloader line. In this case, the flow is restricted for the vapor injection mode of operation to a desired level. However, when the refrigerant system operates in the unloaded mode, there is no restriction to the by-pass flow, which is beneficial to the system performance in this mode of operation. In one of the embodiments, the restriction area can be adjusted to achieve the best performance during the vapor injection mode of operation in relation to the operating conditions.

Abstract: An expensive expansion device may be eliminated in favor of a less expensive pressure regulator in a CO2 vapor compression system such as is used in a bottle cooler or small-capacity air conditioner, refrigerator, or other system.

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: A defrost refrigeration system comprises first compressors and second compressors serially positioned with respect to one another such that refrigerant going through a compression stage in the refrigeration cycle passes sequentially through the first compressors and the second compressors. A first line extends from an exit of one of the first compressor and the second compressor of the compression stage, and is in fluid communication with the evaporator stage in a defrost cycle and is adapted to receive a defrost portion of refrigerant compressed in the compression stage. Valves switch evaporators between the refrigeration cycle and the defrost cycle, by stopping/allowing a flow of refrigerant from the condensation stage to the evaporators of the evaporation stage in the refrigeration cycle, and for allowing/stopping a flow of said defrost portion of refrigerant to defrost the evaporators in the defrost cycle.

Abstract: A heat pump system and method is presented having a primary compressor, a booster compressor, an economizer, a microprocessor, an air temperature sensor, and a temperature sensor for sensing a temperature commensurate with the boiling temperature of refrigerant in the outside coil. The microprocessor effects controlled operation of the primary compressor, the booster compressor and the economizer when a thermostat calls for heat and in accordance with predetermined ranges of air temperature. The microprocessor calculates a defrost trigger temperature, and defrost operation is initiated when the sensed refrigerant boiling temperature is lower than the trigger temperature for a period of time.

Abstract: An air conditioning system including a first compressor and a second compressor provided in parallel with the first compressor to vary compression capacity. The second compressor includes a housing having a compressing chamber, a vane that moves forward and backward in a radial direction of the compressing chamber, a vane guide groove formed in the housing to guide the forward and backward movements of the vane, and a vane controller that controls the operation of the vane in order to vary capacity. The vane controller includes a control valve that switches a fluid path so as to selectively apply suctioning pressure of the second compressor and discharge pressure of the first compressor to the vane guide groove and a controller that controls a fluid path switching operation of the control valve by a pulse width modulation (PWM) method in accordance with air conditioning load.

Abstract: The vapour compression device according to the invention comprises an internal heat exchanger, a low-pressure compressor and an associated gas cooler, a fluid distributor separating the fluid into a main circuit of the cycle and into an auxiliary cooling circuit of the cycle, an auxiliary expansion system placed on the auxiliary cooling circuit, and a main expansion system placed on the main circuit of the cycle. The device also comprises a high-pressure compressor and an associated gas cooler placed on the main circuit of the cycle. The method for performing a transcritical fluid cycle according to the invention preferably comprises an isentropic compression step of the fluid, on the main circuit of the cycle, to reach a maximum high pressure greater than a critical pressure of the fluid, and an isobaric cooling step of the fluid to substantially reach a cold source temperature.

Abstract: A heat pump system is disclosed that utilizes one or two compressors and multiple heat exchangers to provide forced air heating, radiant heating and/or water heating for an interior space. A controller directs energy to these multiple system outputs to provide maximum comfort, effectively utilize any excess energy, address fluctuations in energy output, prevent unsafe operating conditions and avoid intermittent compressor operation. The system may provide energy for a water heater in both heating and cooling mode, and control operation of the water heater to utilize system energy whenever possible and avoid use of a conventional water heater heating element. Load Management Control is also provided so that the system may be shut down remotely by a utility company.

Abstract: A compressor has an inlet, an outlet, and at least an intermediate first port therebetween. A condenser is coupled to the compressor to receive refrigerant. First and second evaporators are coupled to the condenser to receive refrigerant. Conduits define a return flowpath from the first evaporator to the compressor inlet and a second return flowpath from the second evaporator to the intermediate port. A bypass conduit extends between a first location between the first evaporator and the compressor inlet and a second location between the second evaporator and the first port.

Abstract: CO2 refrigeration circuit (2) for circulating a refrigerant in a predetermined flow direction, comprising in flow direction a hear-rejecting heat exchange, (4), a receiver (10) having a liquid portion (12) and a flash gas portion (14), and subsequent to the receiver (10) a medium temperature loop (20) and a low temperature loop (24), wherein the medium and low temperature loops (24) each comprise in flow direction an expansion device (26, 28), an evaporator (30, 32) and a compressor (46, 38), the refrigeration circuit (2) further comprising a liquid line (16) connecting the liquid portion (12) of the receiver (10) with at least one of the medium and low temperature loops (20, 24) and having an internal heat exchanger (54), and a flash gas line (50) connecting the flash gas portion (14) of the receiver (10) via the internal heat exchanger (54) with the inlet of the low temperature compressor (46), wherein the internal heat exchanger (54) transfers in use heat from the liquid flowing through the liquid line (16

Abstract: In the case that heat absorbing means that function in selectively different temperature ranges, are provided in a refrigerating cycle, an object is to provide a refrigerating apparatus capable of suppressing the deterioration of efficiency in either temperature range to make a highly efficient operation possible. The refrigerating apparatus includes a compressor, a radiator, first heat absorbing means, and second heat absorbing means provided in parallel with the first heat absorbing means. The first heat absorbing means includes first decompressing means, a first heat absorber, and a first heat exchanger capable of heat exchange between a refrigerant which has come from the first heat absorber and a refrigerant flowing in the first decompressing means.

Abstract: A tandem compressor refrigerant system where an economizer circuit and reheat coil are incorporated to provide additional flexibility and control over overall system capacity and sensible heat ratio as well as to increase system efficiency. In this system, tandem compressors deliver compressed refrigerant to a common discharge manifold, and then to a common condenser. From the common condenser, the refrigerant passes to a plurality of evaporators, with each of the evaporators being associated with a separate environment to be conditioned. Each of the evaporators is associated with one or several of the plurality of compressors. By utilizing the common condenser, yet a plurality of evaporators, the ability to independently condition a number of sub-environments is achieved without the requirement of the same plurality of complete separate refrigerant circuits for each compressor.

Abstract: In a refrigerant cycle apparatus which is operated at a supercritical pressure on a high-pressure side, for a purpose of maintaining or enhancing performances or reducing generation of clogging or a dimension of a capillary tube, a compressor has a first compression element, and a second compression element which compresses a refrigerant compressed by the first compression element, a gas phase refrigerant in an intermediate pressure receiver is sucked into the second compression element of the compressor, a liquid phase refrigerant in the intermediate pressure receiver is pressure reduced in a second pressure reducing device, and introduced into an evaporator, and the first pressure reducing device comprises a capillary tube on an upstream side of the refrigerant, and throttling means on a downstream side of the capillary tube.

Abstract: A subcooling heat exchanger and subcooling expansion valve in a refrigeration system provide subcooling of a pre-subcooled portion, for refrigerating a thermal load, of condensed refrigerant liquid by a pre-subcooling portion of the condensed refrigerant liquid. The amount of subcooling of the pre-subcooled portion is determined by measuring, with a pressure sensor, refrigerating suction pressure exerted by refrigerating compressors of the system. A controller then controls, based on the refrigerating suction pressure, modulation of mass of pre-subcooling portion, relative pre-subcooled portion, and expansion thereof in the subcooling expansion valve, which controls the amount of refrigerant heat exchanged, and therefore subcooling of pre-subcooled portion, between the pre-subcooling portion and the pre-subcooled portion in the subcooling heat exchanger. The pre-subcooling portion is then subsequently compressed by a subcooling compressor.

Abstract: A multi-air conditioner comprising: a plurality of indoor units for exchanging the heat with indoor air; a plurality of outdoor units, each outdoor unit having an outdoor heat exchanger for exchanging the heat and a compressor for compressing a fluid; a connecting pipe for connecting the indoor units with the outdoor units; and a pressure equalizing pipe for communicating the outdoor heat exchanger of one outdoor unit with the compressor of at least one other outdoor unit, so that the multi-air conditioner is capable of improving stability, reliability and efficiency of a system by equalizing the low pressure between the indoor units in heating and equalizing the high pressure between the outdoor units in cooling.

Abstract: There is provided a rotary compressor capable of preventing deterioration of performance following plug fixing carried out to prevent falling-off of a spring member. The rotary compressor comprises a cylinder constituting a rotary compression element, a roller engaged with an eccentric portion formed in a rotary shaft of an electric element, and eccentrically rotated in the cylinder, a vane abutted on the roller to divide an inside of the cylinder into a low pressure chamber side and a high pressure chamber side, a spring member for always pressing the vane to the roller side, a housing portion of the spring member, formed in the cylinder, and opened to the vane side and a hermetically sealed container side, a plug positioned in the hermetically sealed container side of the spring member, and inserted into the housing portion to fit into a gap, and an O ring attached around the plug to seal a part between the plug and the housing portion.

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 air conditioning unit for vehicles with work-doing expansion of the carbon dioxide is provided, the air conditioning unit including a combined refrigeration and heat pump circuit, wherein the air conditioning unit is switchably configured to change a flow direction of a refrigerant for switchable operation from the refrigeration circuit to the heat pump circuit. A method for operating the air conditioning unit is also provided.

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 heat pump is provided with a discharge valve on a discharge line. The discharge valve can be positioned to modulate or pulse refrigerant flow from the discharge line heading toward an indoor heat exchanger, when in a heating mode. By providing this restriction, the pressure and the temperature of the refrigerant increases. This increased temperature provides additional heating capacity as well as increases the temperature of the delivered indoor air, minimizing “cold blow” and making the end user more comfortable. The use of discharge valve can also minimize or entirely eliminate the ON/OFF unit cycling, as the amount of heat delivered can be precisely controlled by pulsing or modulating the valve, thus reducing unit cycling losses, improving user comfort and enhancing reliability.

Abstract: A refrigeration system has first and second evaporators which may be operated at first and second temperatures. Refrigerant from a lower temperature evaporator may be returned to a compressor suction port. Refrigerant from the higher temperature evaporator may be returned to an intermediate port.

Abstract: An air conditioner incorporates valve devices mounted in a plurality of indoor units, respectively, for allowing refrigerant discharged from an outdoor heat exchanger to be introduced into one or more indoor units that are in operation. The refrigerant is prevented from being introduced into the other indoor units that are not in use, and therefore, oil is prevented from being accumulated in the other indoor units that are not in use. Also, an appropriate amount of refrigerant is supplied to the indoor units that are in operation, and therefore, reliability and efficiency of the air conditioner are improved.

Abstract: A method for controlling operations of an air-conditioner includes: a step in which when an operation load of an air-conditioner increases, if an outputted compressing capacity of the air-conditioner is smaller than a compressing capacity corresponding to the operation load and an operation frequency of the first compressor is a maximum frequency of the first compressor, a second compressor is operated; and a step in which when the operation load is reduced, if the outputted compressing capacity of the air-conditioner is greater than the compressing capacity corresponding to the operation load and the operation frequency of the first compressor is a minimum frequency of the first compressor, the second compressor is stopped.

Abstract: A compact and efficient compressor is provided, based on using magnetic bearing technology, which can operate at high speed and comprises a reliable control system. The compressor of the present invention makes use of two separate compressors mounted on a single common motor, thus sharing a single drive. The balancing of the thrust at high RPM is improved by using a pair of electromagnetic bearings.

Abstract: In the case where a 100 percent heat recovery operation mode is performed without using an outdoor heat exchanger in a refrigeration apparatus which is provided with utilization-side heat exchangers of a plurality of piping systems and in which liquid-side communication lines are arranged into a single line, a backflow prevention mechanism (37) for preventing liquid refrigerant exiting an indoor heat exchanger (41) from flowing in a direction other than in the direction of cold storage and freeze storage heat exchangers (45, 51) is disposed for providing stable flow of refrigeration through the circuit even when the temperature of outside air is low, whereby the capability to provide refrigeration is prevented from degrading.

Abstract: A refrigeration system includes a compressor having a compressor housing and operable to compress a flow of refrigerant. A pump is operable to provide a flow of oil to the compressor. A portion of the oil mixes with the flow of refrigerant and the remainder of the oil flows into the compressor housing. A valve is movable between an open position and a closed position. When in the closed position, the valve is operable to inhibit the addition of oil above a predetermined level within the housing.

Abstract: A tandem compressor refrigerant cycle with an economizer circuit is introduced to provide additional capacity and improve system efficiency. In this system, tandem compressors deliver compressed refrigerant to a common discharge manifold, and then to a common condenser. From the common condenser, the refrigerant passes to a plurality of evaporators, with each of the evaporators being associated with a separate environment to be conditioned. Each of the evaporators is associated with one of the plurality of compressors. By utilizing the common condenser, and yet a plurality of evaporators, the ability to independently condition a number of environments is achieved without the requirement of the same plurality of separate complete refrigerant circuits for each of the environments. In some embodiments, several of the plurality of compressors can be provided by compressor banks having its own plurality of compressors.

Abstract: A unitary air conditioning system comprises an outdoor unit including a compressor for compressing a refrigerant, an outdoor heat exchanger for heat exchange of the refrigerant and an expander connected to the outdoor heat exchanger, for expanding the refrigerant; a duct installed inside a zone of a building; a central blower unit having a heat exchanger connected to the outdoor unit through a first refrigerant pipe and a blower for supplying the air heat-exchanged by the heat exchanger to the duct; and an individual blower unit including a heat exchanger connected to the outdoor unit through a second refrigerant pipe and a fan for sending the air heat-exchanged by the heat exchanger and disposed in a zone in the building, for individually cooling or heating the zone.

Abstract: A tandem compressor system is disclosed that delivers compressed refrigerant to a common discharge manifold, and then to a common condenser. From the common condenser, the refrigerant passes to a plurality of evaporators, with each of the evaporators being associated with a separate environment to be conditioned. A reheat function is provided by a reheat coil(s) for one or several environments such that desired temperature and humidity levels are achieved. Various reheat concepts and system configurations are disclosed, where the reheat coils are interconnected or independent from each other, as well as each evaporator is associated with a single or a plurality of the reheat coils.

Abstract: A vapor compression system including an evaporator, a compressor, and a condenser interconnected in a closed-loop system and a method of operating such a system. The method includes the conversion of expanded liquid heat transfer fluid from a liquid form to a high quality liquid vapor mixture before delivery to the evaporator.

Abstract: A method and apparatus for a recirculating system with single feed that incorporates a liquid transfer vessel that helps prevent the vessels in the system from flooding, provides easy displacement of liquid refrigerant from the flooded vessels while economizing refrigerant liquid lines with insulation, pumps, and valves in the refrigeration system.

Abstract: A capacity control algorithm for a multiple compressor liquid chiller system is provided wherein the speed and number of compressors in operation are controlled in order to obtain a leaving liquid temperature setpoint. In response to an increase in the load in the chiller system, the algorithm determines if a compressor should be started and adjusts the operating speed of all operating compressors when an additional compressor is started. In response to a decrease in the load in the chiller system with multiple compressors operating, the algorithm determines if a compressor should be de-energized and adjusts the operating speed of all remaining operating compressors when a compressor is de-energized.

Abstract: A heat reclaim refrigeration system uses a first compressor to elevate the amount of latent heat reclaimable by the system and to reclaim this heat using heat reclaim means, such as heat reclaim coils, for practical applications, such as heating a building. In addition, the system reduces pressure required from a second compressor used for refrigeration, and energy consumed thereby, especially during cold periods of the year when a refrigerant condensing means has lower condensing requirements.

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: An apparatus for converting a refrigerant pipe of an air conditioner comprises: a valve housing installed at a position where respective refrigerant discharge pipes of plural compressors are put together, having a valve space portion therein, and having a first refrigerant inlet, a second refrigerant inlet, a detour refrigerant inlet, a refrigerant outlet and a bypass outlet at upper and lower portions thereof; a bypass pipe for connecting the refrigerant outlet of the valve housing to refrigerant suction pipes of the compressors so that a refrigerant discharged from each refrigerant discharge pipe of the plural compressors can be introduced to the refrigerant suction pipes of the plural compressors; an open/close valve slidably installed at the valve space portion of the valve housing so that a refrigerant discharged from the refrigerant discharge pipes can be selectively introduced into a refrigerant circulation pipe of a condenser or the bypass pipe; and an open/close valve driving means installed at the v

Abstract: An apparatus for converting a refrigerant pipe of an air conditioner comprises: a valve housing installed at a position where respective refrigerant discharge pipes of plural compressors are put together, having a valve space portion therein, and composed of a first refrigerant inlet, a second refrigerant inlet, a refrigerant outlet, a bypass outlet, and a detour refrigerant outlet at upper and lower sides thereof; a bypass pipe for connecting the refrigerant outlet of the valve housing to refrigerant suction pipes of the compressors so that a refrigerant discharged from each refrigerant discharge pipe of the compressors can be introduced into the refrigerant suction pipes of the compressors; an open/close valve slidably installed in the valve space portion of the valve housing so that a refrigerant discharged from the refrigerant discharge pipe can be selectively introduced into the refrigerant circulation pipe of the condenser or the bypass pipe; and an open/close valve driving means installed at the valve

Abstract: It is an object of the present invention to provide a refrigerant cycle apparatus which can optimize the capability of releasing heat from a refrigerant in a gas cooler and an auxiliary heat exchanger under use conditions at a low cost. There are provided an intermediate cooling circuit which once releases heat from a refrigerant discharged from a compressor and then returns the refrigerant to the compressor, and a fan which ventilates an inter cooler of the intermediate cooling circuit and a gas cooler. The inter cooler has substantially the same ventilation area as that of the gas cooler.

Abstract: In a refrigerating apparatus in which a plurality of application-side heat exchangers (41, 45, 51) are connected to a heat-source side heat exchanger (4), liquid lines for a plurality of channels in a refrigerant circuit (1E) share a liquid side communication pipe (11) in order to reduce the number of pipes. Further, the liquid side communication pipe (11) is provided adjacent to a low-pressure gas side communication pipe (15) for at least one channel so as to contact it in order to supercool a liquid refrigerant by a low-pressure gas refrigerant. Thus, workability for connecting the pipes is improved and a refrigerating ability may not be decreased even if communication pipes (11, 15, 17) become long.

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: The present invention is capable of eliminating the line unit in an air conditioner that includes a plurality of heat source units, and hold increases in onsite line construction to a minimum while making it possible to adjust the amount of refrigerant in the air conditioner. The air conditioner includes a plurality of heat source units, a refrigerant liquid junction line and a refrigerant gas junction line, user units, and a refrigerant supply circuit. The refrigerant supply circuit is used in situations in which some of the plurality of heat source units stop operating in response to the operational burden of the user units, and is formed from refrigerant removal lines that remove refrigerant that accumulates inside stopped heat source units to the exterior thereof, and an oil equalization line and oil removal lines that connect the refrigerant removal lines of each stopped heat source unit and the intake sides of the compression mechanisms of the operating heat source units.

Abstract: An apparatus and a method for controlling oil of a multi-compressor installed in an air conditioner includes a microcomputer for sequentially stopping compressors installed in the air conditioner for a preset time and then sequentially operating the compressors when the preset time elapses; and oil pipes connected to the compressors and balancing oil in the compressors, so that damage of the compressors due to imbalance of refrigerating machine oil is prevented by uniformly dividing oil of a multi-compressor installed in the air conditioner.

Abstract: A refrigerant cycle is provided with a compressor system, capable of simultaneously delivering refrigerant to multiple condensers operating at different temperature levels. A single evaporator communicates with these condensers. One of the condensers receives fully compressed refrigerant while the others receives refrigerant at an intermediate pressure. A control can optionally direct refrigerant to only one of these condensers to achieve desired heat rejection and other operational characteristics. Various system configurations with multiple compressors and condensers are also disclosed.

Abstract: The present invention aims to prevent the occurrence of liquid compression at the second rotary compression element before it happens while improving the compression efficiency with an intermediate cooling circuit in a refrigerant cycle apparatus which comprises an internal high-pressure type multi-stage compression compressor, and the invention is summarized in that the apparatus comprises an intermediate cooling circuit which allows refrigerant discharged from the first rotary compression element of a compressor to dissipate heat, where a microcomputer performs control on the number of revolutions of the compressor to maintain the temperature/pressure of refrigerant so that the refrigerant does not condense at the output of the intermediate cooling circuit, where such a control is done in response to outputs from an outside-air temperature sensor, a refrigerant temperature sensor, and a signal from a controlling apparatus of a refrigerating apparatus body.

Abstract: A system and method are provided for variable speed operation of a screw compressor to obtain increased capacity and efficiency. The screw compressor is connected to an induction motor driven by a variable speed drive, wherein the screw compressor has a variable output capacity that is dependent on the output speed of the motor. To obtain increased capacity and efficiency, the screw compressor is operated at a speed greater than the screw compressor's rated speed and does not include a slide valve. The maximum operating speed of the screw compressor, which speed is greater than the rated speed, is related to the maximum operating speed of the motor when operated at a voltage and frequency provided by the variable speed drive that is greater than the motor's rated voltage and frequency in a constant flux or constant volts/Hz mode.

Abstract: A system and method are provided to increase the horsepower of an induction motor. One technique for increasing the horsepower of a motor is to connect the motor to a variable speed drive that is providing an output voltage and frequency greater than the standard line voltage and frequency. The connection of the variable speed drive to the induction motor enables the motor to be operated in constant flux or constant volts/Hz mode and provide a greater output horsepower. Another technique for increasing the horsepower of a motor is to use a dual voltage motor configured for lower voltage operation and then provide the motor with the corresponding voltage and frequency for higher voltage operation. The higher voltage and higher frequency can be provided by a variable speed drive with or without voltage boost. A variable speed drive without voltage boost, but with frequency boost, can be used in situations where the standard main voltage is greater than the lower voltage rating.

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: An evaporator system comprised of two individual refrigerant circuits, integrated in such a way that if one circuit is not in operation, no portion of the airflow through the evaporator fails to come into contact with the refrigerant in the active circuit. This eliminates the possibility of so-called bypass air (air passing through inactive region of evaporator). An extreme example of bypass air is illustrated in the use of a split face evaporator where on half of the evaporator is active and the other half is inactive. The purpose of such an integrated dual circuit evaporator being to improve part load performance of a refrigerating or air conditioning system when one circuit of the system is inactive.

Abstract: A compressor assembly having a first compression mechanism operatively coupled to a first motor and a second compression mechanism operatively coupled to a second motor. The first compression mechanism compresses the vapor from a low pressure to an intermediate pressure and the second compression mechanism compresses the vapor from the intermediate pressure to a discharge pressure. An electrical circuit supplies electrical current to the first and second motors during operation of the compressor assembly. The electrical circuit includes means for, during start-up of the compressor assembly, initiating the supply of electrical current to the first motor at a first time and initiating the supply of electrical current to the second motor at a second time wherein the first time precedes the second time by a time lapse.

Abstract: For a purpose of realizing a refrigerant cycle apparatus capable of exactly detecting a pressure reverse phenomenon caused in a compression element of a compressor of a multistage compression type, in the refrigerant cycle apparatus in which the multistage compression type compressor constitutes a refrigerant circuit, including an electromotive element, and first and second compression elements driven by the electromotive element in an airtight container to suck an intermediate-pressure refrigerant gas compressed by the first compression element into the second compression element and to compress and discharge the refrigerant gas, the apparatus comprising: a sensor for detecting a discharge refrigerant pressure of the first compression element; and a control device into which an output of the sensor is input, the control device detects reverse of the discharge refrigerant pressures of the first and second compression elements based on the discharge refrigerant pressure of the first compression element.