Abstract: A ripening room is disclosed for ripening perishable products, such as fruits and vegetables, and more particularly bananas, in which the air flow and temperature are closely controlled by the room construction and by a cooling control system that achieves uniform ripening of the fruit regardless of the physical location of the fruit within the room. These desired results are accomplished using a minimum quantity of energy and cooling capacity by use of an improved cooling controller that gradually changes the temperature setpoint over time to allow the cooling (refrigeration) system to operate near its full capacity without any periods of intense cooling (due to sudden changes of the temperature setpoint, as in the prior art). The uniform ripening is also achieved by an improved air distribution system that provides a greater back pressure in portions of a ripening room that, in conventional designs, receives far too much air flow.

Abstract: A thermoelectric water chiller system for cooling fluids, and including a cold sink which defines quiescent areas where convection currents are minimized to facilitate ice formation around the cold sink is provided. The cold sink cooperates with water held in a sealed tank. A cover member which covers the cold sink can be employed which would cooperate with the tank to form a fluid-tight seal therewith. Components needing periodic cleaning are preferably removable from the system, but the tank could be permanently installed. A fan-cooled thermoelectric module assembly is used to form the ice block adjacent the bottom of the tank which chills the water. A variable-speed fan and current to the thermoelectric module are controlled by a control circuit with inputs from various temperature sensors positioned on and within various portions of the chiller system, including sensors to monitor ambient air temperature about the chiller system.

Abstract: A method and apparatus for changing operational modes of a transport refrigeration unit, where the unit is capable of operating in a continuous heating/cooling mode or an automatic start/stop heating/cooling mode. A supply air temperature sensor measures the temperature of the air exiting the unit, a return air temperature sensor measures the temperature of the air returning to the unit, and an ambient air temperature sensor measures the temperature of the ambient air outside the unit. A controller electrically connected to the sensors determines if the ambient air temperature is above or below a pre-determined setpoint temperature, determines if the temperature differential across the return and supply air sensors is above or below a pre-determined upper threshold or a pre-determined lower threshold, and then changes the operational mode of the unit based upon such determinations and the prior operational mode of the unit.

Abstract: A centrifugal type refrigerant compressor comprises at least one impeller (17, 18), electric motor (27) and drive shaft (22) mounted on non-lubricated radial bearings, such as magnetic or foil gas bearings (23, 24), with axial locating means (26) associated with the shaft (22) to restrict axial movement thereof with respect to the compressor housing (12). The housing (12) encases the motor (27) and the compressor and defines the gas inlet (31) and the gas outlet (16) passageways. Gas throttling means (34) is provided in the inlet (31), and a control means (30) varies the speed of the motor (27) and the throttling means (34) to control the compression ratio and mass flow through the compressor in accordance with the refrigeration load.

Abstract: A method for controlling the temperature of a compartment of a refrigerator, the compartment utilizing at least two spaced apart temperature sensors, such that, even when one of the sensors malfunctions, the compartment is cooled without any degradation of efficiency. The sensors detect respective temperatures in the compartment. While the sensors are operating normally, the detected temperatures are stored. In the event one of the sensors malfunctions, an abnormal average temperature is calculated using: (i) previously stored temperatures of the abnormally operating sensor, and (ii) a temperature recently detected by the normally operating sensor. Thereafter, the calculated abnormal average temperature is compared with a reference temperature to control the operation of a fan.

Abstract: In an automobile air-conditioner comprising a compressor with variable discharge capacity for compressing a refrigerant, an outlet temperature sensor for sensing an outlet temperature at an outlet of at least one of a heat sink and a radiator, a room temperature sensor for sensing a room temperature inside the automobile, an outside air temperature sensor for sensing an outside air temperature outside the automobile, and a room temperature setting unit for setting the room temperature to a desired temperature, a first arithmetic operating unit carries out an arithmetic operation according to at least the room temperature, the outside air temperature, and the desired temperature, to obtain a target temperature. A second arithmetic operating unit predicts the rotation speed of the compressor with a predetermined feed-forward arithmetic expression to obtain a predicted rotation speed.

Abstract: The invention entails the use of a positive displacement pump (4) magnetically coupled to an drive motor (42) located in a conduit arrangement (60) this is parallel to the liquid line of the refrigeration system as in FIG. 5. This parallel conduit arrangement also includes a pressure regulating valve that will regulate the amount of pressure added to the liquid line by the parallel pump and piping arrangement. In addition, a check valve (47) is located in the liquid line to maintain the pressure differential added to the liquid line. This parallel piping arrangement (60) is desirable in order to allow a constant, pre-determined pressure to be added to the liquid line regardless of variations in flow rate of the liquid refrigerant. In addition, the parallel piping arrangement allows the system to operate without liquid line obstruction in the event of pump failure.

Abstract: A temperature controlling method for a refrigerator and an apparatus therefor are provided, in which a sensing error between temperature sensors is corrected, thereby maintaining the interior temperature of the refrigeration compartment in equilibrium.

Abstract: An energy-efficient refrigeration system includes an electrically controlled refrigerant storage device that is coupled to the refrigeration system to selectively receive refrigerant from and dispense refrigerant to the operating loop of the refrigeration system. The refrigerant storage device includes a storage vessel, means for selectively displacing refrigerant from the storage device into the operating loop, and a refrigerant storage device controller coupled to the means for displacing refrigerant so as to control the mass of refrigerant in the storage vessel in correspondence with the cooling demand on the refrigeration system so that the compressor drive motor is loaded for optimal efficiency for a given cooling demand on the system. The means for displacing refrigerant from the vessel of the storage device typically comprises a temperature control element, such as a heating element or solid state heat pump, that is electrically coupled to the controller and thermally coupled to the vessel.

Abstract: A humidity control device includes a microcontroller, a variable impedance humidity sensing circuit and a zero crossing detector circuit. The humidity sensing circuit and zero crossing circuit are provided with an AC line voltage and both have outputs which are provided to the microcontroller. The humidity control device also includes a semiconductor switch circuit which switches the AC line voltage to an external electrical device, such as a dehumidifier or heater, at the zero crossing.

Abstract: A method of controlling refrigerant pressure during elevated ambient temperature conditions in a refrigeration unit having a refrigerant compressor driven by a prime mover, and controllable suction line modulation. The method includes the steps of detecting the actual load PML on the prime mover, sensing the ambient temperature AA, and providing a dynamic load limit DLL as a function of the ambient temperature AA. The actual load PML is compared with the dynamic load limit DLL, and the suction line modulation is changed as a function of the comparison step to cause the actual load PML to follow the changing dynamic load limit DLL. The invention also includes a method of preventing excessive on-off cycling of a refrigeration unit during low ambient temperature conditions, with the refrigeration unit operating in a cycling start-stop mode to control the temperature of a conditioned space to a selected set point temperature SP.

Abstract: When a user manually sets a desired (target) temperature for a refrigerator chamber, a control mechanism automatically determines a range of target temperatures having upper and lower limits. Actuation and deactuation of the refrigeration cycle is controlled in response to a comparison of the chamber temperature with the upper and lower limits, respectively. When an outside temperature surrounding the refrigerator rises above a reference temperature, those upper and lower limits are automatically lowered. Also, the control mechanism compares the manually set temperature with a range of temperatures which the refrigerator is capable of achieving and automatically selects an achievable temperature if the manually selected temperature lies outside the achievable range. Moreover, a quick-freeze operation of the control mechanism enables a freezing chamber to be brought rapidly to a cold temperature.

Abstract: A fan control system for the evaporator of refrigerating appliances, of the type in which the internal air is forced to circulate, by action of a fan (20), through the evaporator (30) of a refrigerating circuit, fed by a compressor (40), the system comprising: a first temperature sensing means (S1), detecting the temperature of the circulating air at the air inlet of the evaporator (30); a second temperature sensing means (S2), detecting the temperature of the evaporator (30); and a control circuit (50), producing: a fan stop control signal, when the difference between the values of the temperatures detected by the first and second sensors (S1, S2) reaches a stop value, below which the heat transfer from the forced circulating air to the evaporator is lower than the heat transfer from the fan (20) to the air; and a fan start control signal, when the difference of temperatures reaches a certain start value corresponding to a temperature of the evaporator (30) substantially lower than the temperature of the air

Abstract: Energy efficient independent temperature control is achieved in refrigerators by minimizing system run time. A freezer thermostat activates the refrigeration system when the freezer compartment requires cooling and a fresh food thermostat which controls a damper between the two compartments. The two thermostats are operatively connected so that the freezer thermostat is prevented from switching off whenever the fresh food thermostat calls for cooling in the fresh food compartment. Thus, only the freezer thermostat is able to activate the refrigeration system, while either of the thermostats can inactivate the system.

Abstract: Energy efficient independent temperature control is achieved in refrigerators by minimizing evaporator fan on time. A circuit including a first switch responsive to a freezer thermostat and a second switch responsive to a fresh food thermostat controls operation of the refrigeration system and the evaporator fan. The first and second switches are connected so that the refrigeration system and the evaporator fan can be activated only when the freezer thermostat demands cooling. A fan interlock having one or more relays prevents the first switch from inactivating the evaporator fan if the fresh food thermostat demands cooling. Thus, the evaporator fan only runs while the refrigeration system is operating or has immediately shut off.

Abstract: An apparatus for detecting is disclosed for detecting a low level of refrigerant circulating through a motor vehicle refrigerant circuit. The apparatus comprises an electronic logic module, and a pressure transducer and a thermistor preferably located in the refrigerant circuit between the compressor and the evaporator. The pressure transducer generates a signal indicative of the refrigerant pressure, from which the module derives a saturation temperature of the refrigerant. The saturation temperature is compared with the measured temperature to determine if a superheat condition exists indicative of low refrigerant charge exists. When the refrigerant remains at a predetermined level of superheating, the compressor clutch is disengaged to interrupt circulation through the refrigerant circuit.

Abstract: A heat pump type air conditioner for an automotive vehicle is provided with a compressor to which an outer condenser and a inner condenser are connected through a three-way valve. The inner condenser is connected to an inner evaporator through an expansion valve. The air conditioner further includes a control unit which defines a relationship among a heating property, a physical amount according to which workload of the compressor is varied, and thermal operating condition of at least one of the inner evaporator and the inner condenser. The control unit determines the physical amount at a value from the relationship for the heating property and the detected thermal operation condition by sensors, and controls the compressor according to the determined physical amount.

Abstract: A method and software/firmware fixed capacity compressor control system for varying the set point temperature of a evaporator in response to changes in ambient temperature in order to produce optimum cooling in the passenger compartment of a vehicle while preventing frost from accumulating on the fins of the evaporator. The system includes an evaporator probe and an outside ambient sensor and firmware for computing set-point steady state temperatures values over a wide range of ambient temperature. Also circuits are provided for cycling ON and OFF a fixed capacity compressor in a manner to achieve optimum cooling in the passenger compartment of the vehicle in response to the computed evaporator set point temperatures.

Abstract: A radiation detector comprises a thermopile and a thermocouple connected in series. The cold junction of the thermocouple is connected to a remote temperature reference. A calibrator in the thermopile/thermocouple circuit weights the output signals of the two devices to provide a combined output signal which changes with both sensed radiation and ambient temperature. The device may be calibrated for an environmental control system to control heating or cooling based on both air temperature and radiant temperature of surrounding surfaces. In another application, the thermocouple and calibrator provide a simple signal adjustment to provide an internal temperature reading from a sensed surface temperature. For example, the circuit can provide a core temperature reading from detected ear temperature.

Abstract: In order to cool food in a display compartment, a cold air stream is generated by refrigeration means, preferably a fan, an evaporator and a condenser, and is passed through the display compartment from its inlet to its outlet. The air temperatures at the inlet and outlet may be sensed by sensors in which case control means are responsive to a signal from the output of both the sensors and control the operation of the refrigeration means to maintain the air temperature in the display compartment within a narrow predetermined range.

Abstract: An air conditioning system suitable for use in an electric vehicle. In the air conditioning system, a refrigerant gas circulatory system of the heat pump type for selectively effecting cooling and heating is disposed inside the electric vehicle and comprises lines which interconnect three heat exchangers, a directional control valve, a compressor and an expansion valve to one another. A control device is provided so as to activate and inactivate the heat exchanger, the directional control valve and the compressor. Before the expected running of the vehicle, at least a portion of the refrigerant gas circulatory system can be operated by the control device using a drive source different from the drive source used for running the vehicle. Accordingly, a comfortable room environment can be established for the expected time on riding by activating the air conditioning system in an unmanned state.

Abstract: Apparatus for and method of rapidly bringing a controlled space to a desired temperature. The technique is particularly applicable to the maintenance of controlled temperature spaces for the transportation of perishable cargo, such as in refrigeration trucks. Immediately following completion of the loading process, it is desirable to bring the internal temperature of the controlled space to the proper operating point as quickly as possible to retard spoilage. However, it is necessary to avoid unacceptable overshoot to prevent damage to the cargo by freezing. The disclosed system employs multiple sensors and a control algorithm to permit pull down to occur as rapidly as possible without unacceptable overshoot.

Abstract: Loss of oil due to oil feedback is prevented in a screw compressor in a refrigeration application due to low capacity operation. The apparent suction temperature is compared to the temperature of the water exiting the evaporator to determine the apparent superheat and the loading is increased upon the apparent superheat reaching a predetermined level. Upon sensing a predetermined difference, an electronic slide valve block is initiated to prevent further unloading and loading may be initiated in a fixed amount, incrementally or on a pulsed basis.

Abstract: A microprocessor-based air conditioning/refrigeration control system adapted for use with a variable speed compressor measures acceleration of the compressor and the temperature or pressure of the refrigerant exiting therefrom, determines the rate of change of the temperature or pressure of the refrigerant, and decreases acceleration of the compressor if the rate of change of the temperature or pressure of the working fluid indicates surging of the compressor. Superheat of the refrigerant is maintained at a first predefined level while the compressor is operating at constant speed and is increased to a second, higher predefined level while the compressor is accelerating.

Abstract: An operation controller for an air conditioner designed to decrease a difference between an ambient temperature and a set temperature by varying the number of revolutions of a compressor, includes: a means for calculating an operation ratio of the compressor; and a means for determining the range of varying an operation frequency of the compressor in accordance with the operation ratio.

Abstract: An environmental control system disclosed includes a refrigeration loop including a variable speed compressor having an inlet and an outlet, a condenser, an evaporator and variable speed evaporator fan for moving air across the evaporator, a compressor speed control, a superheat monitor for monitoring the condition at the inlet of the compressor and a primary superheat control responsive to the superheat monitor for establishing the speed of the evaporator fan to maintain a predetermined superheat condition.

Abstract: A detected temperature T.sub.m of the atmosphere of a remote controller is read in at a predetermined detection time interval. When a difference between a present or new detected temperature T.sub.m and a last or old detected temperature T.sub.m(old) is above a predetermined value, a first correction value corresponding to the temperature difference (T.sub.s -T.sub.m) is added to a set temperature T.sub.s set in advance to thereby determine a set temperature T.sub.sc. On the other hand, when a difference between a present or new detected temperature T.sub.m and a last or old detected temperature T.sub.m(old) is less than the predetermined value, a second correction value corresponding to the temperature difference (T.sub.s -T.sub.m) is added to the last or old set temperature T.sub.sc(old) to thereby determine a corrected set temperature T.sub.sc, thus to operate a compressor motor in dependency upon a difference between the corrected set temperature T.sub.

Abstract: A microprocessor based device which monitors the operation of a compressor in a refrigeration system and automatically shuts the compressor down if a monitored condition is abnormal. Sensors in the refrigeration system sense conditions such as refrigerant pressure and temperature, superheat, oil pressure and motor current draw. If a sensed condition is outside of a safety range and remains there for a time out period, an alarm condition is indicated and the device generates a alarm signal and shuts down the compressor. A detachable display module includes a keypad for carrying out field programming and a LCD screen for displaying the refrigerant conditions and programming prompts and commands. A rest button permits resetting twice before a service call is required.

Abstract: Compressor discharge capacity is controlled by using the smaller value as a desired cooling temperature for control, comprising a first desired evaporator cooling temperature computed from the pattern of the desired cooling temperature characterized by its being high when a cooling load is low, with a second desired evaporator cooling temperature computed from the pattern of the desired cooling temperature characterized by its being high when the outdoor temperature is moderate, and by its being low when the outdoor temeprature is low or high. Therefore, if the desired temperature is set high in a passenger compartment when the outdoor temperature is high, or if a cooling load is low when the outdoor temperature is low, the desired cooling temperature can be kept low for controlling while maintaining high dehumidifying capacity.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: In an air conditioning system, thermistors measure evaporator inlet and outlet temperatures and compressor body temperature. When the differential between inlet and outlet temperatures is below a first threshold and the compressor temperature is above a second threshold, very low refrigerant charge is indicated and the compressor is turned off. Also, if compressor temperature reaches a critical value, the compressor is turned off regardless of the temperature differential across the evaporator.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: A system for controlling the operation of an HVAC system which includes a direct expansion coil, a condenser, a pre-cool coil, and a control system. The control system includes a controller and sensors. The controller receives signals indicative of air flow through the direct expansion coil from the sensors, compares the received signal to a stored air flow rate, and disables the compressor if the stored air flow rate is equal to or greater than the stored value. The controller is also adapted to vary air flow into an occupied space for small changes in the cooling load. In addition, the controller can artificially load the compressor during periods of small cooling load by restricting flow of a cooling agent between the cooling tower and the condenser, or by directing warm water from the condenser through the pre-coil coil.

Abstract: On each refrigerant piping to an indoor heat exchanger of each indoor unit, there is provided a flow control valve of which target opening (.theta.t) is selected separately according to an air-conditioning load of each indoor unit. Provided, the flow control valve which will have a maximum target opening (.theta.t.sub.max) selected, is fully opened, with the remaining flow control valves having such an opening greater than each of respective target openings (.theta.t) by a given value (.DELTA..theta.). Meanwhile, a target frequency (Ft) of output power from an inverter is selected, following the total of air-conditioning loads of respective indoor units; provided, an actual frequency (F) of output power of the inverter is selected in such a value lower than the target frequency (Ft) by a given value (.DELTA.F).

Abstract: A control system for an automotive air conditioning system includes temperature sensors at the evaporator and at the compressor of the air conditioning system and a controller responsive to signals from the sensors to control cycling of the compressor clutch. The controller is operative to monitor the cycle rate of the compressor clutch (i.e., the duration for which the clutch is engaged in any given cycle) and to provide command signals to control air conditioning system when the clutch cycle rate exceeds or falls below predetermined values. The controller is programmed so that at a predetermined level of sensed humidity in the vehicle to change the predetermined evaporator temperature values at which the clutch is engaged or disengaged so as to change the moisture content in the air flowing across the evaporator before it is supplied to the interior of the vehicle.

Abstract: A temperature controller is provided for controlling a coolant temperature in a liquid coolant system including a liquid circulation circuit, in which coolant for cooling a machine circulates, and a refrigeration circuit for cooling the coolant. The operating capacity of a compressor of the refrigeration circuit is variably adjusted by an inverter, and when the operating condition of the machine is changed, the frequency value for driving the compressor is varied in accordance with the change. Accordingly, it is possible to immediately correspond to the change of a liquid temperature to be generated in the future. In addition, an appropriate control mode can be selected as a control for varying the frequency in combination with a normal feedback control, such that the liquid temperature may converge on a set value or may be co-changed to a room temperature.

Abstract: An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprises a sensor for detecting an intake air temperature, defined by a temperature of air flowing through an evaporator, placed just behind the evaporator, an intake pressure sensor for detecting an intake manifold pressure, and a CPU for determining whether the cooling requirements of the evaporator are satisfied on the basis of the intake air temperature compared to a predetermined value. The CPU controls the compressor in such a manner that the discharge volume of refrigerant discharged from the compressor is decreased only when the cooling requirements are met. Thus, the automatic air conditioning system prevents uncomfortably warm conditioned air from being discharged through a vent door under acceleration conditions.

Abstract: A refrigerant loss prevention system is disclosed that monitors a number of variables within a refrigerant circuit including both environmental and refrigerant conditions and arrives at expected refrigerant conditions utilizing the sensed environmental conditions. The sensed refrigerant conditions are compared to the expected refrigerant conditions, and alarms are actuated should the two differ by more than a preset amount. The refrigerant loss prevention system continues to operate when the refrigerant circuit is off to identify leaks even during long periods of down time, such as winter.

Abstract: An automatic device for producing ice cubes has separate probes for measuring the temperature of the environment, and, for measuring the temperature of water supplied to an input of the device, the probes being connected to a monitoring device operative to calculate the optimum operation of the device under any particular climatic conditions.

Abstract: An ice maker including freeze and harvest controls is disclosed. The evaporator includes a unitary evaporator and ice mold. A compressor and condenser cool the evaporator to freeze ice on the mold in a normal refrigeration cycle and the mold is defrosted by hot gas to harvest ice from the ice mold. The temperature of the ice mold and the liquid line temperature of the condenser are sensed to control the length of time of the ice forming cycle.

Abstract: In an ice making machine having an evaporator unit formed therein with a multiplicity of individual freezing cells and provided thereon with an evaporator in thermal exchange relationship with the freezing cells to freeze water circulated into the freezing cells during a freezing cycle, an electric control apparatus for the ice making machine is arranged to ascertain a frequency of an electric power supplied to the machine, to detect an actual freezing temperature of the evaporator unit, to determine an optimum freezing temperature necessary for complete freezing of all the water in the freezing cells in operation under the power supply of the ascertained frequency, to maintain the freezing cycle until the actual freezing temperature becomes lower than or equal to the optimum freezing temperature and to terminate the freezing cycle and initiate a harvest cycle for discharge of formed ice cubes from the freezing cells when the actual freezing temperature has become lower than or equal to the optimum freezing t

Abstract: A method of controlling a refrigeration system by determining an average air temperature by sensing and averaging evaporator return and discharge air temperatures, and developing an average error by using the average air temperature and a selected set point temperature. The average air temperature is then used to calculate a proportional error and an integral error, and the discharge air temperature is used to calculate a floor error. The proportional error, integral error and floor error are weighted by predetermined gain factors and then summed to provide an error signal which is used to modulate the capacity of the refrigeration system, with the control mode depending upon the location of the error signal relative to set point.

Abstract: An automobile air-conditioner of the type having a variable displacement compressor, wherein a desired degree to which an evaporator is cooled is calculated by a desired cooling degree calculation means, and a desired rotational speed of a blower is calculated by a desired rotational speed calculation means. The results of calculation by both of the calculation means are used for controlling the displacement of the variable displacement compressor. Thus, the displacement of the compressor is corrected in immediate response to a change of thermal loads.

Abstract: A control device for an air conditioner including a compressor driven by an inverter is disclosed. The control device comprises a floor temperature sensor as well as a room temperature sensor for detecting representative room temperature. A standard operation frequency of the compressor is determined on the basis of the difference between the target temperature and the representative room temperature detected by the room temperature sensor. Adjustment is made to the standard operation frequency according to the difference between the temperatures detected by the two temperature sensors, thereby obtaining an operation frequency of the compressor.

Abstract: A refrigerating system including a refrigerant circuit having a condenser, evaporator and wobble plate type compressor with a variable displacement mechanism. Two passages communicate between the crank chamber and the suction chamber in the cylinder block. A bellows is disposed in a first passage and controls the communication between the crank chamber and the suction chamber response to crank chamber pressure. A control valve is disposed in the second passage and controls communication between the crank chamber and the suction chamber in the second passage in response to a signal generated outside of the compressor. A control circuit controls the generation of the signal in response to thermodynamic characteristics related to the evaporator. The signal activates or deactivates the second control valve when the characteristic indicates a value beyond a predetermined range of values.

Abstract: An air-conditioning apparatus for automobiles comprises a device for detecting the internal air temperature providing the temperature in the automobile cabin, a device for detecting the atmospheric air temperature, a device for setting a target value of the internal air temperature, a device for calculating a target value of the air blowdown temperature from the output signals of the aforementioned three devices, a device for calculating a compensation amount for the compressor capacity from the difference between the target value and the output signal of a device for detecting the actual air blowdown temperature, and a device for controlling the compressor capacity in accordance with the result of the calculation.

Abstract: A method and apparatus for electronically pressure sealing and leak testing an idle centrifugal chiller system wherein a small positive differential is maintained between the internal refrigerant vessel pressure of the chiller system and the ambient atmosphere. This differential pressure is maintained by selectively applying heat to the refrigerant.

Abstract: An automobile air conditioner system includes a variable displacement compressor having a wobble plate and a pressure control valve disposed in the compressor for controlling the pressure in a crank chamber. The pressure control valve is operative under the control of predetermined conditions, such as the temperature of an evaporator.

Abstract: In the air conditioning control apparatus of the present invention, the frequency determining means determines not only an operation frequency for the compressor depending on the load determined based on the detected room temperature and the set room temperature, but also an upper limit for the compressor operation frequency based on the air flow rate of the outlet air from the upper and lower outlet ports of the indoor unit and the successive operation time of the compressor. As a result, even if the compressor carriers out cooling operation under too great of a load, the temperature of the air blown off from the upper outlet port of the indoor unit is prevented from dropping down to less than a certain value, thereby eliminating economically the problem wherein dew is produced on the outer surface of the ceiling plate and so on.

Abstract: A control device for a compressor in an automotive air conditioning system is disclosed which includes a pressure sensor disposed on a conduit concerning an evaporator and the compressor for detecting a refrigerant pressure at an outlet side of the evaporator. A control unit compares a pressure change ratio based on the detected refrigerant pressures with a predetermined pressure change ratio and selects either one of two ranges of predetermined values in accordance with the compared results, and further compares the refrigerant pressure with the predetermined values, thereby controlling the operation of an electromagnetic clutch which is mounted on the compressor and the capacity of the compressor in accordance with the last mentioned compared results.