Abstract: Thermal management in a vehicle involves a compressor to output a refrigerant in vapor form for circulation in a refrigerant loop. A thermal management system includes a heating, ventilation, and air conditioning system in the refrigerant loop including an evaporator and an HVAC condenser, and an exterior condenser in the refrigerant loop configured to vent heat to an exterior of the vehicle. A first variable refrigerant flow valve controls a flow rate of the refrigerant output by the compressor into the HVAC condenser, and a second refrigerant flow valve controls a flow rate of the refrigerant output by the compressor into the exterior condenser. A controller controls the first refrigerant flow valve and the second refrigerant flow valve based on a target output temperature for the HVAC condenser.

Abstract: An electronic expansion valve, a heat exchange system, and a control for controlling an electronic expansion valve. The electronic expansion valve includes: a valve body; a first temperature sensor configured to detect an evaporator temperature Teva; a second temperature sensor configured to detect a compressor inlet temperature Tsuc; a third temperature sensor configured to detect a compressor outlet temperature Tdis; a fourth temperature sensor configured to detect a condenser temperature Tcon; and a controller, which is associated with the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor, and which adjusts an opening degree of the valve body based on temperature signals from the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor.

Abstract: A temperature control device for controlling a temperature of a temperature adjustment target part is provided.

Abstract: A dynamic refrigeration system may automatically, at pre-determined time periods on-the-fly, adjust a refrigerant system's refrigerant pressures to predetermined optimal efficiency pressures as the internal and external heat loads change over a range. This may result in the refrigerant system pressures closely operating within a range of predetermined optimal efficiency pressures. This system may automatically instantaneously fine tune and balance on all air conditioning, heat pump, and refrigeration systems as the internal and external heat loads are continuously changing dynamically. The system may include a small liquid refrigerant pump and refrigerant storage tank, one or more wired or wireless pressure transducers and temperature sensors, and a “brain” to make decisions to keep the system instantaneously set at factory specs all the time. The system may include a wireless communication means so it can instantaneously report its operating condition, loads, and cost of operating.

Abstract: An apparatus for connecting a wireless sensor may include a charging battery which is self-powered, a measurement sensor configured for performing wireless communication and receive power from the charging battery, and a vehicle controller configured to be connected to the measurement sensor through wireless communication and receive measured data.

Abstract: A system may include a compressor, a first passageway, a valve and a control module. The compressor includes a compression mechanism operable to compress a working fluid. The first passageway is in fluid communication with an oil sump of the compressor and the compression mechanism. The valve is disposed along the first passageway and movable between an open position allowing lubricant from the oil sump to flow to the compression mechanism and a closed position restricting lubricant from the oil sump from flowing to the compression mechanism. The control module is in communication with the valve and configured to move the valve between the closed position and the open position based on an operating parameter indicative of a temperature of the compression mechanism.

Abstract: Methods, systems, and apparatus for an active fuel cooling system (“fuel cooling system”). The fuel cooling system includes a fuel tank configured to store fuel. The fuel cooling system includes one or more pipes positioned adjacent to, in contact with, or within the fuel tank that are configured to deliver refrigerant that cools the fuel tank. The fuel cooling system includes a compressor for pumping the refrigerant through the one or more pipes to cool the fuel stored within the fuel tank. The fuel cooling system includes an electronic control unit connected to the compressor and configured to operate the compressor to pump the refrigerant through the one or more pipes to cool the fuel stored in the fuel tank.

Abstract: A vehicle air conditioner which is capable of inhibiting liquid return to a compressor and generation of noise due to bumping in an accumulator. There are executed a heating mode to close a solenoid valve 17, open a solenoid valve 21, let a refrigerant radiate heat in a radiator 4, decompress the refrigerant through an outdoor expansion valve 6, let the refrigerant absorb heat in an outdoor heat exchanger 7, and send the refrigerant to an accumulator 12, and a dehumidifying and heating mode to open the solenoid valve 17, close the solenoid valve 21, decompress the refrigerant through an indoor expansion valve 8, let the refrigerant absorb heat in a heat absorber, and generate heat in an auxiliary heater 23. A valve position of the outdoor expansion valve 6 is reduced for a predetermined period of time before shifting from the heating mode to the dehumidifying and heating mode.

Abstract: An apparatus for connecting a wireless sensor may include a charging battery which is self-powered, a measurement sensor configured for performing wireless communication and receive power from the charging battery, and a vehicle controller configured to be connected to the measurement sensor through wireless communication and receive measured data.

Abstract: When a refrigerant amount balance control is executed, in indoor units where the refrigerant supercooling degree is lower than an average refrigerant supercooling degree, the refrigerant pressure on a downstream side of indoor expansion valves decreases since the degrees of opening of the valves are decreased. On the other hand, in an indoor unit where the refrigerant supercooling degree is higher than the average refrigerant supercooling degree, although the degrees of opening of the valves are made high, the refrigerant pressure on the downstream side of the valves decreases and this decreases the refrigerant pressure on the downstream side of the indoor expansion valve, so that the difference in pressure between on the upstream side and on the downstream side of the indoor expansion valve increases and the liquid refrigerant staying at an indoor heat exchanger of the indoor unit consequently flows out into a liquid pipe.

Abstract: A CO2 refrigeration system (1) includes: a compressor (3), a gas cooler (5), a temperature sensor (17) and an electronic control system (13), the electronic control system including a processor device (15) arranged to control operation of the compressor (3) according to input signals received from the temperature sensor (17), wherein the temperature sensor (17) is positioned to read an output temperature of the gas cooler. A method for controlling a compressor (3) in a CO2 refrigeration system (1) is also disclosed.

Abstract: When a dehumidifying heating operation is performed by a heat-radiating operation of the interior condenser and a heat-absorbing operation of the exterior heat-exchanger and the evaporator, a control device of an air conditioner for vehicle decreases the valve opening degree of the electronic expansion valve to be equal to or less than a predetermined opening degree before opening the solenoid valve for dehumidification in a closed state, opens the solenoid valve for dehumidification after decreasing the valve opening degree of the electronic expansion valve to be equal to or less than the predetermined opening degree, and then increasing the valve opening degree of the electronic expansion valve to be greater than the predetermined opening degree after opening the solenoid valve for dehumidification.

Abstract: A control system for a compressor is provided. The control system includes a controller and first and second control portions. The first control portion is configured to assess an actual temperature of an evaporator and a target temperature of the evaporator and to generate a first compressor speed command signal. The second control portion includes a pressure calibration value and is configured to receive a pressure reading of the climate system, to compare the pressure reading to the pressure calibration value and to generate a second compressor speed command signal. The controller device includes data and is configured to receive the first compressor speed command signal and the second compressor speed command signal and to transmit a control signal to the compressor for causing the compressor to operate at a commanded compressor speed based on the first compressor speed command signal, the second compressor speed command signal, and the data.

Abstract: An air-conditioning apparatus directly detects leakage of a plurality of types of refrigerant by computing refrigerant concentrations, and ensure safety. On the basis of calibration curve information, a computing device computes the concentration of heat source side refrigerant in a heat medium relay unit from detected information received from a concentration detecting device.

Abstract: The invention relates to a structure of a multi-storey computer center building, which is suitable for accommodating a multiplicity of racks, each of which has storage space for computer hardware. The building has a first cooling circuit in order to dissipate heat generated by the computer hardware and the first cooling circuit is designed to supply at least some of the racks with a coolant. The first cooling circuit is also designed to remove the heated coolant from at least some of the racks. And, the racks have heat exchanger devices, which are suitable for transferring the generated heat to the coolant.

Abstract: An air conditioning device is used in a motor vehicle. The air conditioning device includes air conditioning circuit, which includes a compressor (14), a condenser (11), and/or an internal exchanger, an electric expansion valve (12) which opening ratio is changed according to a control signal, and an evaporator (13), which are traversed in this order by a refrigerant fluid and a control unit (40) capable of controlling a control signal of the expansion valve so as to regulate a control variable relating to the superheating of the evaporator or to the sub-cooling of the condenser (11) according to a chosen regulation rule.

Abstract: An air-conditioning apparatus includes refrigerating cycle systems each connecting a compressor for compressing a refrigerant, a refrigerant flow path switching device, a heat source side heat exchanger for exchanging heat for the refrigerant, an expansion device for adjusting the pressure of the refrigerant, and heat exchangers related to heat medium which exchanges heat between the refrigerant and heat medium different from the refrigerant, by piping so as to constitute refrigerant circuits; and heat medium side systems each connecting pumps for circulating the heat medium for the heat exchangers related to heat medium, use side heat exchangers for exchange heat between the heat medium and air of an air-conditioning target space and heat medium flow switching systems for switching the heat medium which passes through each heat exchangers related to heat medium to each use side heat exchanger, by piping so as to constitute a heat medium circulation circuit.

Abstract: A power supply device includes a refrigeration cycle having a compressor, a motor, an inverter-integrated charger, a heat exchanger unit, and a controller having a determining unit. The inverter-integrated charger selectively controls operation of the motor using electrical power of a battery and charge of the battery with external power. The heat exchanger unit cools a cooling-necessary part of the inverter-integrated charger using refrigerant in the refrigeration cycle. When the vehicle is stopped and the battery is charged with the external power, the controller makes the inverter-integrated charger serve as: a charger to perform the charge of the battery; or an inverter to control the operation of the motor, thereby driving the compressor, upon determination that the cooling-necessary part needs to be cooled by the determining unit.

Abstract: A two temperature electronic expansion valve control for variable speed compressors that utilizes a correlation between airflow percentage and heat exchanger pressure drop to control the operation of an expansion valve. An indoor airflow percentage request may be communicated from an outdoor controller to an air handler controller. Using a correlation between airflow percentage and pressure drop across the heat exchanger, the airflow percentage may be used in predicting an outlet pressure of refrigerant exhausted from the heat exchanger. The predicted pressure drop may be used in determining a saturated temperature for the exhausted refrigerant. The determined saturated temperature may be compared to a sensed temperature of the refrigerant at the outlet of the heat exchanger to determine a superheat value, which is compared to a reference superheat value in determining the degree to open or close the expansion valve.

Abstract: A refrigeration vapor compression system including a compressor, an electronic expansion valve with closed loop feedback into a controller, sensors to measure and monitor the system superheat and sub-cooling, and condenser fans controlling the flow of air through the condensing coils, the refrigeration system is operated in at least one of two functional modes to either give priority control to the level of superheat in the system or maintain a minimum level of sub-cooling in the system.

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

Abstract: A compressor is connected with an evaporator, a condenser, and an electrically controlled valve for circulating a working fluid in a system for recovering waste heat to provide heated water. A controller can be configured to adjust an operating capacity of the compressor to maintain output of a condenser temperature sensor at a condenser temperature set point, except when output of a compressor discharge pressure sensor indicates that a maximum operating pressure of the compressor has been exceeded. In such case the controller reduces the operating capacity of the compressor. The controller may further be configured to shut down the compressor when the discharge pressure sensor indicates that a shutdown pressure has been exceeded.

Abstract: A system and method for monitoring an overheat condition of a compressor is provided. A compressor connected to an evaporator. A suction sensor outputs a suction signal corresponding to a temperature of refrigerant entering the compressor. A control module is connected to the evaporator sensor and the suction sensor and determines an evaporator temperature, calculates a suction superheat temperature based on the evaporator temperature and the suction signal, and monitors an overheat condition of the compressor by comparing the suction superheat with a predetermined suction superheat threshold.

Abstract: For cooling operation, a refrigeration apparatus includes a heat-source-side valve opening controller for controlling a degree of opening of a heat-source-side expansion valve so that pressure of a refrigerant flowing into the utilization-side expansion valve in the cooling operation becomes equal to or lower than a predetermined reference pressure value. For heating operation, the refrigeration apparatus includes a utilization-side valve opening controller for performing, when a low-quantity utilization unit in which a quantity of the refrigerant falls below a quantity of the refrigerant required for delivering capacity of the utilization unit is found among a plurality of the utilization units in the heating operation, valve opening reducing operation of reducing a degree of opening of the utilization-side expansion valve of the utilization unit except for the low-quantity utilization unit.

Abstract: A refrigeration system includes a refrigerant circuit performing a vapor compression supercritical refrigeration cycle. The system includes a compression mechanism, a heat source heat exchanger, an expander, and a utilization heat exchanger. The expander includes, for two-stage compression, a high pressure side and a low pressure side throttle mechanism, both variable in the amount of throttling. A controller is configured to derive a target value, providing a maximum COP, for the pressure of high pressure refrigerant in the refrigerant circuit based on the temperature of refrigerant at the outlet of either the heat source side heat exchanger or the utilization side heat exchanger, whichever becomes a heat dissipation side heat exchanger functioning as a heat dissipation unit and on the temperature of a medium exchanging heat with refrigerant in the heat dissipation side heat exchanger, at the inlet of the heat dissipation side heat exchanger.

Abstract: To provide an air-conditioning apparatus capable of achieving energy saving, a pump control of controlling the operating capacity of a pump is performed such that an opening degree of a heat medium flow control device, controlled by a heat-medium-flow-control-device control, approaches a target opening degree, and a refrigeration cycle of a refrigerant circuit is controlled such that the temperature of a heat medium, whose flow rate is controlled by the heat-medium-flow-control-device control and the pump control, approaches a target temperature.

Abstract: In a refrigeration system (10) that includes a refrigerant circuit (20) configured by connecting a plurality of circuit component parts including a compressor (30), a pressure reduction device (36, 39) and a plurality of heat exchangers (34, 37) and operates in a refrigeration cycle by circulating refrigerant through the refrigerant circuit (20), a refrigerant state detection section (51) is provided for detecting the refrigerant temperatures and entropies at the entrance and exit of each of the compressor (30), the pressure reduction device (36, 39) and the heat exchangers (34, 37), and a variation calculation section (52) is provided that uses the refrigerant temperatures and entropies detected by the refrigerant state detection section (51) to separately calculate the magnitude of energy variation of refrigerant produced in each of the circuit component parts.

Abstract: A heat pump system, the operation of which is controlled using a temperature difference between a water inlet and a water outlet of a heat exchanger, exchanging heat between a refrigerant and water, and a control method thereof. The heat pump system includes temperature sensors installed on a water circulation pipe unit at water inlet and outlet sides of a heat exchanger, and heats a load to a set temperature by controlling a compressor or an expander according to a difference between temperatures sensed by the temperature sensors. Here, a temperature of water transmitted to the load is set to be greater than a target load temperature by a reference value, and if the temperature difference is smaller than a designated value, the operation of the heat pump system is stopped.

Abstract: A control apparatus and associated method for a refrigeration system are provided. The control apparatus includes sensors capable of detecting controlled refrigerator zone temperatures and superheat levels of refrigerant vapour exiting an evaporator. The control module receives input from the sensors, compares the input to a determined controlled refrigerator zone set point and a learned superheat level, and generates an output with respect thereto. In particular the output modulates an electronic evaporator pressure regulating (EEPR) valve between an open and a closed position in response to detecting abnormal operation of the thermostatic expansion valve or electronic expansion valve.

Abstract: Provided is a multi-evaporation system which carries out a multi-evaporation process in an air-conditioning cycle of a vehicle air conditioning system, thereby enhancing system efficiency. The multi-evaporation system includes a compressor 10 which sucks and compresses refrigerant; a condenser 20 which condenses the refrigerant compressed in the compressor 10; an expanding means 30 which receives the refrigerant condensed in the condenser 20 through an inlet port 31, branches the refrigerant into at lest two or more, discharges the refrigerant through at least two or more discharging part 32a to 32n, and throttles the refrigerant before or after the refrigerant is branched; and an evaporator 40 which comprises at least two or more evaporating parts 41 to 4N so as to receive and evaporate the refrigerant discharged from the expanding means 30 and then introduce the evaporated refrigerant into the compressor 10.

Abstract: Refrigerant sent from a heat source side circuit (14) to utilization side circuits (11, 12, 13) is made to be single-phase liquid by using cooling means (36, 45) or a vapor-liquid separator (35). Variable-opening utilization side expansion valves (51, 52, 53) are provided in the utilization side circuits (11, 12, 13) so that an expansion process in a refrigeration cycle is performed also in the circuits.

Abstract: A refrigeration apparatus includes a condensing unit, a flow distributor, and an evaporator connected to the condensing unit via the flow distributor. A pressure detector is configured to detect condensation pressure of the refrigerant. A calculation unit is configured to calculate a target condensation pressure of refrigerant necessary for the refrigerant to be an evaporation temperature in the evaporator. A controller is configured to control the condensing unit so that the condensation pressure of the refrigerant becomes equal to or more than the target condensation pressure.

Abstract: In a refrigeration cycle apparatus having an expansion mechanism, a method to swiftly generate a pressure difference upstream and downstream of the expansion mechanism of, thereby enhancing the starting performance of the refrigeration cycle apparatus The apparatus has a compression mechanism, a utilizing-side heat exchange, an expansion mechanism for recovering power, and a heat source-side heat exchanger. The revolution number of the heat source fluid transfer means is made smaller than a target revolution number or the heat source fluid transfer means is stopped during a predetermined time after the compression mechanism is started. When the compression mechanism is started, the pressure difference can be generated upstream and downstream of the expansion mechanism for a short time, the operation of the expansion mechanism does not become unstable, vibration and noise can be prevented, and the refrigeration cycle apparatus can swiftly be started.

Abstract: A control device for an air-conditioning system of a vehicle comprises an evaporator, a compressor with externally controlled variable displacement, and an expansion valve. The control device comprises a control block that receives a reference temperature indicating a desired temperature of the air downstream of the evaporator, and an effective temperature of the air present downstream of the evaporator. The control device-supplies a control signal for the compressor to bring the effective temperature substantially equal to the reference temperature. An observer module receives the control signal and supplies a temperature disturbance indicating an estimate of the oscillatory effect generated by an expansion valve on the temperature of air downstream of the evaporator when a compressor is driven by the control signal. An adder block removes from the effective temperature the temperature disturbance so as to eliminate the oscillatory effect on the effective temperature downstream of the evaporator.

Abstract: The invention relates to an air-conditioning unit (1) comprising an air circuit with an air inlet (5), a main fan (10) and an air outlet (6) designed to be connected to a chamber such as, for example, an aircraft parked on the ground, preferably via one or more flexible ducts, and a refrigerant circuit comprising a heat exchanger/evaporator (12) positioned in said air circuit to cool the air by evaporating the refrigerant, a compressor (17) and a condenser (18) for condensing the refrigerant before it is returned to the heat exchanger/evaporator (12). Said heat exchanger/evaporator (12) comprises several parallel circuits (19) each having at least one regulator valve (20).

Abstract: A refrigerant circuit (20) includes, in order to perform a vapor compression supercritical refrigeration cycle, a compression mechanism (30), an outdoor heat exchanger (21), an expansion mechanism (40), and an indoor heat exchanger (23). The expansion mechanism (40) includes, for the two-stage expansion of refrigerant in the refrigerant circuit (20), a first throttle mechanism (41) variable in the amount of throttling and a second throttle mechanism (42) variable in the amount of throttling. In the cooling operation mode, there is derived a target value for the pressure of high pressure refrigerant in the refrigerant circuit (20), from the temperature of refrigerant at the outlet of the outdoor heat exchanger (21) and the temperature of air at the inlet of the outdoor heat exchanger (21).

Abstract: A system and method for monitoring an overheat condition of a compressor is provided. A compressor connected to an evaporator. A suction sensor outputs a suction signal corresponding to a temperature of refrigerant entering the compressor. A control module is connected to the evaporator sensor and the suction sensor and determines an evaporator temperature, calculates a suction superheat temperature based on the evaporator temperature and the suction signal, and monitors an overheat condition of the compressor by comparing the suction superheat with a predetermined suction superheat threshold.

Abstract: The present invention discloses a refrigerator having multi-cycle refrigeration system, comprises a main control circuit, a temperature sensor and a refrigeration cycle loop, wherein the main refrigeration cycle loop is composed of a compressor, a condenser, a main capillary, a freezing evaporator, a refrigerating evaporator and a gas returning pipe connected in series, and wherein, an auxiliary refrigerating cycle branch, which can be controlled independently, is added to refrigerating chamber, i.e. the magnet valve is connected to the downstream of the condenser, and the magnet valve has two output ports, one of which is connected to the main capillary, and the other is connected to an auxiliary refrigerating cycle branch, and the downstream of the branch is connected to the gas returning pipe.

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: An inexpensive heat exchanger is disclosed, wherein the heat exchanger is made up of a plurality of plates and each plate has at least one channel defined in the plate. The plates are stacked and bonded together to form a block having conduits for carrying fluids, and where each fluid is in thermal communication with the other fluids.

Abstract: There is disclosed a refrigerant cycle apparatus capable of avoiding occurrence of an abnormal rise in a pressure on a high-pressure side in advance, comprising: a throttling mechanism including a first capillary tube, and a second capillary tube which is connected in parallel to the first capillary tube and whose flow path resistance is smaller than that of the first capillary tube; and a valve device for controlling refrigerant circulation into the first and second capillary tubes, so that a refrigerant is passed into the second capillary tube at the time of starting of a compressor.

Abstract: A selectively controllable valve is arranged in a refrigeration circuit which interconnects the evaporator and the condenser and is controlled so that a pressure differential is built up across the valve. The valve is selectively opened to allow “batches” of working fluid to pass therethrough. In some embodiments, the working fluid which is allowed to pass through the valve, is heated in a chamber to increase the amount of pressure on the downstream side of the valve. This produces expanded pressurized working fluid which increases the pressure in the condenser and forces previously condensed and liquefied working fluid through a flow restricting transfer device into an evaporator. Condensation of the just heated gas in the condenser subsequently reduces the pressure on the downstream side of the valve and establishes conditions suitable for the passage of a further amount of gaseous working fluid while itself becoming liquid to be forced through the flow restricting transfer device.

Abstract: Disclosed are an apparatus and a method for controlling the operation of an air conditioner, in which one or more compressors are operated so that the total refrigerant compression capacity of the operating compressors is variably changed according to a cooling or heating load to be eliminated, and an opening degree of an electronic expansion valve is controlled between minimum and maximum values set according to the total refrigerant compression capacity of the operating compressors, thus stably operating the air conditioner and preventing the refrigerant in a liquid state from being introduced into the compressors and the compressors from overheating.

Abstract: Disclosed herein is a system and method for controlling the degree of superheat of an air conditioner. The air conditioner includes a compressor controlled in a pulse width modulation manner according to duty control signals, a condenser, an electronic expansion valve and an evaporator so as to form a refrigeration cycle. An entrance temperature sensor situated at the entrance of the evaporator and an exit temperature sensor situated at the exit of the evaporator are connected to a control unit. The control unit calculates the degree of superheat of the evaporator using the difference between mean entrance and exit temperatures of the evaporator sensed by the entrance temperature sensor and the exit temperature sensor for a period of time corresponding to a duty cycle period of the compressor, and regulates the opening of the electronic expansion valve according to the calculated degree of superheat.

Abstract: A two-compartment cooling apparatus which achieves a plurality of refrigeration cycles by controlling refrigerant paths, thus increasing cooling efficiency and cooling speed of the cooling apparatus. A compressed refrigerant provided by a compressor is selectively provided to first and/or second evaporators via first, second and third expansion units and a path control unit. The path control unit controls the flow of the refrigerant through the expansion units and the evaporators to vary the cooling in the respective compartments in response to temperature measurements made in the respective compartments.

Abstract: Disclosed is a method for controlling the aperture ratio of a linear expansion valve (LEV) so as to control the flow rate of refrigerant circulating in an air conditioning system. The LEV aperture ratio is controlled to range from the minimum value to the maximum value, which are determined according to the compressor's capacity and the cooling and heating modes. The LEV aperture ratio is controlled also based on the compressor's operating status, the change of the indoor fan's air volume, and whether or not the indoor fan operates. Such LEV control enables refrigerant to always be circulated at a suitable flow rate, improving the cooling and heating efficiencies, and also prevents liquid refrigerant from flowing into the compressor, securing high reliability of the compressor.

Abstract: A vehicle air conditioner includes a main blower and a sub-blower for blowing air into a passenger compartment. A heat exchange unit for performing a heat exchange with air blown by the main blower is disposed in a case, and the case is provided with a front air passage and a rear air passage. A rear air duct through which air in the rear air passage is introduced to a rear area in the passenger compartment is connected to the case, so that an air flow resistance in the rear air passage becomes larger as compared with the air flow resistance in the front air passage. Further, the sub-blower is disposed integrally with the case for blowing air in the rear air passage to the rear area in the passenger compartment. Accordingly, it can effectively prevent a shortage of an air conditioning capacity in the rear area of the passenger compartment.

Abstract: Disclosed is a method for controlling the aperture ratio of a linear expansion valve (LEV) so as to control the flow rate of refrigerant circulating in an air conditioning system. The LEV aperture ratio is controlled to range from the minimum value to the maximum value, which are determined according to the compressor's capacity and the cooling and heating modes. The LEV aperture ratio is controlled also based on the compressor's operating status, the change of the indoor pan's air volume, and whether or not the indoor pan operates. Such LEV control enables refrigerant to always be circulated at a suitable flow rate, improving the cooling and heating efficiencies, and also prevents liquid refrigerant from flowing into the compressor, securing high reliability of the compressor.

Abstract: Methods and systems consistent with this invention control a hot gas bypass valve in a refrigeration system including a centrifugal compressor, a condenser, an evaporator, and a hot gas bypass line between the compressor and the evaporator. Such methods and systems continuously sense for a surge condition during operation of the refrigeration system, indicate a surge condition when the refrigeration system is operating under surge conditions, and open at least partially the hot gas bypass valve in response to the sensed surge condition to return the refrigeration system to operating under non-surge conditions. Methods and systems consistent with this invention also sense a present head parameter representative of the present head of the compressor, sense a present load parameter representative of the present load, and control the hot gas bypass valve so as to avoid surging in the compressor in response to the present head parameter, the present load parameter, and stored head and load parameters.

Abstract: The high side pressure of a vapor compression system is selected to optimize the coefficient of performance by measuring the heat sink inlet temperature with a temperature sensor. For any heat sink inlet temperature, a single optimal high side pressure is selected which optimizes the coefficient of performance. The optimal high side pressure for each heat sink inlet temperature is preset into a control and is based on data obtained by previous testing. A pressure sensor continually measures the high side pressure. If the high side pressure is not at the optimal value, the expansion device setting is adjusted to alter the high side pressure to the optimal value.