Abstract: When a malfunctioning condition of an internal temperature detecting unit of a refrigerator is detected, the compressor and fan of the refrigerator are periodically driven to prevent stored food from going bad, and the malfunctioning condition is indicated by visual and audio indicators.

Abstract: In general, clean cold water can be made available in a household by means of either an expensive refrigerator with a cold water dispenser or a separate cooler and bulky, replaceable water bottles. A simple solution to the problem involves a carbon filter and cooling reservoir combination for mounting in a refrigerator, a pipe system containing a faucet for dispensing cold water and returning water to the filter, and a pump/timer combination for periodically recycling the water in the pipe system through the filter, whereby cold water is always virtually instantaneously available at the faucet.

Abstract: A system for preventing fogging in air conditioning systems is disclosed. The system employs a strategy whereby if fogging conditions are present, the temperature of the evaporator is stepped downwardly in increments which allow the surface of the evaporator to stabilize thereby eliminating localized cold spots.

Abstract: A refrigeration unit, and method of operating same, having a compressor driven by a prime mover. The prime mover is selectively operable in either a continuous mode which includes heating and cooling cycles, or in start-stop cycling mode which includes cooling and null cycles, to control the temperature of a conditioned space relative to a predetermined set point temperature. In one embodiment, the cycle mode is operable only when the set point temperature is in a predetermined temperature range, the limits of which are selectable. The prime mover is operated in the continuous mode, notwithstanding the selection of the cycle mode, when the set point temperature is not within the temperature range authorized for cycle operation.

Abstract: A temperature controller for facilitating the storage of wine and like perishables in a household refrigeration unit includes a temperature sensing device, adapted to be positioned in a chilled compartment of the refrigeration unit, and a temperature controller circuit, operatively connected to the temperature sensing device, for overriding an internal thermostat of the refrigeration unit. The temperature controller circuit maintains the refrigeration unit's chilled compartment at a desired user selected wine storage temperature by periodically enabling and disabling the supply of electrical power from an external power supply to the refrigeration unit's chiller (e.g., compressor). The temperature controller circuit is maintained in a housing adapted to be positioned on or adjacent the refrigeration unit. The housing may also include a display for visually indicating the temperature of the chilled compartment.

Abstract: Load sharing is achieved in a multiple compressor system by a program in a computer which sends signals to, and receives data from, a microcontroller located at each compressor. One compressor, designated as the lead compressor, furnishes its operating parameters, via the computer, to all the other, lag, compressors. The operating parameters include inlet valve position and bypass valve position of each compressor and the microcontroller controls the actuatation of both valves. When system demand decreases, compressors are gradually unloaded, and then stopped to go off-line. When system demands increase, compressors are first started, and then gradually loaded before going on-line. Compressors go both on-line and off-line subject to certain time delays so that compressors are gradually added to, or shed from, the load. To equalize running time, all compressors in the system may undergo a periodic rotation and compressors go off-line in reverse order that they came on-line.

Abstract: A method of operating a refrigeration unit to improve the uniformity of temperature distribution in a conditioned space, with the refrigeration unit including a refrigerant compressor and an evaporator fan driven at a selectable one of high and low operating speeds by a prime mover arrangement. The method includes the step of periodically operating the compressor and evaporator fan at the higher of the two operating speeds, notwithstanding a set point temperature control algorithm calling for operation of the compressor at the lower of the two speeds. When the refrigeration unit is operating in a continuous mode, the value of a constant entered into an operating program by the user determines the minimum number of minutes of each hour the prime mover should be forced to operate in the higher speed mode.

Abstract: A method of operating a refrigeration system having a compressor driven by an engine, with the refrigeration system being operable in a first control mode to hold the temperature of a conditioned space at a selected set point temperature, and in a second control mode to maintain the engine in a ready-to-start condition. The second control mode includes monitoring the ambient temperature, and determining a dynamic set point temperature as a function of ambient temperature. The engine is started and stopped to maintain engine startability, and also as a function of the dynamic set point temperature, to maintain the temperature of the conditioned space at the dynamic set point temperature while maintaining the engine in a ready-to-start condition. Control is changed from the second to the first control mode, when a programmed start feature is activated, with the time of such mode change being a function of the difference between the ambient temperature and the selected set point temperature.

Abstract: A microwave sourced heat exchanger in an inverted, truncated frusta-pyramidal or frusta-conical shaped configuration. A heat conductive medium is carried within microwave transparent pipes toward a microwave source having one or more magnetrons along a split path of increasing parameter. The magnetrons sequentially operate in a cyclic pattern such that the respective magnetrons do not operate when their respective operating temperatures exceed their respective maximum safe operating temperatures. The sequential use of multiple magnetrons increases the efficiency and operating life of the magnetrons. The geometrical design of the microwave heat exchanger allows the heat conductive medium anywhere in the conduit to be directly exposed to microwaves. Further, the geometry of the microwave heat exchanger induces a thermal siphon when the heat conductive medium within is exposed to a microwave source placed at the exchanger's broader base.

Abstract: A temperature control method for use in a refrigerator comprises a normal operation step for controlling a compressor and a fan to maintain a temperature inside a refrigerating compartment between a positive limit temperature and a negative limit temperature, both derived from a set temperature input by a user; a door-open control step for stopping the fan when a door-open is detected; a reset temperature setting step for setting a reset temperature based on said door-opening time; and a reset temperature operation step for executing a cooling operating by driving a compressor and a fan until the temperature inside the refrigerating compartment decreases to the reset temperature, lower than the set temperature, if it is detected during the normal operating that the reset temperature has been reset.

Abstract: An electronic controller receives an evaporator inlet (or outlet) temperature sensor signal and measures the time required for the evaporator to be heated from compressor clutch cut-out to compressor clutch "ON". Depending upon the elapsed time, the controller selects from a predetermined schedule, a new value CLHOFF of the evaporator inlet temperature at which the compressor is next cut-out, raising CLHOFF for lighter thermal loading to prevent evaporator icing and freeze-up and lowering CLHOFF for heavy thermal loading to prevent unwanted compressor cycling.

Abstract: An automotive air conditioning system utilizing an electrically operated refrigerant expansion valve controlled by a micro-computer. The compressor clutch cut-off is controlled by a suction pressure sensor at high thermal load. At partial flow conditions of the expansion valve, representative of moderate evaporator thermal loading, the micro-computer controls compressor clutch "ON" time from an accumulated count incremented by a predetermined amount according to suction pressure change. When the accumulated count over successive signal sampling intervals reaches a predetermined maximum the clutch is cut-out based on the count which is representative of a predetermined time interval.

Abstract: A microprocessor based control for an automotive air conditioner receives inputs from transducers which measure suction gas pressure and temperature and ambient air temperature and provides outputs for compressor clutch control and instrument panel lights. The control includes a table of warning temperatures and critical temperatures of suction gas for various ranges of ambient temperature. The control is programmed to carry out the process of comparing compressor on times to a threshold and shutting down the compressor when the on times are repeatedly less than the threshold, looking up table values for warning temperature and critical temperature for the current ambient temperature, comparing suction gas temperatures to the table values and shutting down the compressor when the temperature is repeatedly above the critical temperature and giving a warning when the temperature is repeatedly above the warning temperature.

Abstract: An air conditioning system (10) for an aircraft, the air conditioning system (10) having a separator (14) located between the high pressure side of a compressor (12) and a condenser (18). A timer (34) activated normally open solenoid (32) is located on a separator drain line 28 to periodically dump the lubricant accumulated in the separator (14) back into the compressor (12).

Abstract: A room air-conditioning device controls the temperature of a room without making people in the room uncomfortable even during a transient period in which an influence of a disturbance is conspicuous. The air-conditioning device comprises a blower drive unit, a temperature detector for detecting the temperature of air supplied by a blower, a temperature setting unit for setting a target temperature of air, a temperature information operation unit for providing temperature information to be provided to a temperature adjusting unit and the blower drive unit, according to the signals from the temperature detector and temperature setting unit, an elapsed time operation unit for calculating an elapsed time of the operation of the air-conditioning device; and a blower drive voltage setting unit for providing a blower drive voltage signal according to the temperature information and elapsed time.

Abstract: An electronic controller receives a suction pressure sensor signal and measures the time required for the evaporator to be heated from compressor clutch cut-out to compressor clutch "ON". Depending upon the elapsed time, the controller selects from a predetermined schedule, a new value CLHOFF of the suction pressure P.sub.s at which the compressor is next cut-out, raising CLHOFF for lighter thermal loading to prevent evaporator icing and freeze-up and lowering CLHOFF for heavy thermal loading to prevent unwanted compressor cycling.

Abstract: An air conditioning apparatus in which one outdoor unit is connected to several indoor units through respective refrigerant tubes and signal conductors. The outdoor unit has compressors for discharging refrigerant and an outdoor heat exchanger. Each outdoor unit has an indoor heat exchanger and an indoor heat exchanger temperature sensor. When an operating device signals a check node, the compressors are stopped for a predetermined time period. Then the compressors are operated to sequentially discharge refrigerant to each indoor unit. A checking device then monitors the signal conductors of each indoor unit for a signal indicating a certain temperature condition. Based on the signals received, the checking device determines whether the indoor units are properly connected to the outdoor unit.

Abstract: A method of controlling the operation of an HVAC system comprising the steps of: accepting an input; selecting a first mode of operation if the input has a value in excess of a first predetermined limit; selecting a second mode of operation if the input has a value less than a second predetermined limit; selecting a third mode of operation if the input has a value which is between the second and the first predetermined limits.

Abstract: A refrigerator comprising a refrigeration cycle which comprises a compressor, condenser, first capillary tube and first cooler connected into a loop, and a quick freezing refrigerant circuit connected in parallel with the first cooler and comprising a second capillary tube and a second cooler connected in series therewith. The refrigerant is passed through the first cooler for usual operation, or alternatively through the quick freezing circuit for quick freezing. During quick freezing, the first cooler is held out of operation, and the refrigerant has its pressure reduced in two steps by the first and second capillary tubes and is evaporated in the second cooler only, giving a low temperature effective for quick freezing. During usual operation, no refrigerant flows into the second cooler, which therefore remains free of frosting. The frost deposited on the second cooler during quick freezing disappears during the usual operation. Thus, the second cooler is substantially free from frost.

Abstract: A drive control apparatus for controlling the operation of an air conditioner comprises a 24-hour air-conditioning mode, a selector for selecting one of drive and release positions of the 24-hour air-conditioning mode, a load-responsive air-conditioning mode under which the air conditioner is operated in dependence on a load in a space to be air-conditioned, a drive control for effecting one of drive and stop controls of the load-responsive air-conditioning mode, and a preferential output unit for outputting a signal from the drive control in preference to an output signal from the selector. An output from the preferential output unit may be used to drive the operating frequency of the compressor at a predetermined number of revolution, to drive an indoor fan either continuously or intermittently at a predetermined number of revolution, and/or to deflect a vertical deflector blade to a predetermined position.

Abstract: In a freezer machine having a refrigeration system in the form of a circulation circuit including a compressor, a condenser, an evaporator coil arranged for thermal exchange with a freezing receptacle, and a solenoid valve of the normally closed type disposed within a bypass circuit of the circulation circuit to supply therethrough the hot gas outflowing from the compressor directly into the evaporator coil when it has been energized, an electric control circuit for the freezer machine is designed to repeatedly measure a first predetermined period of time, for instance four hours, in a condition where said compressor is being deactivated, to measure a second predetermined period of time, for instance three minutes, upon each lapse of the first predetermined period of time and to activate the compressor for the second predetermined period of time upon each lapse of the first predetermined period of time and energize the solenoid valve in response to activation of the compressor.

Abstract: An air-conditioning control system for use in an automotive vehicle comprises a variable capacity compressor having capacity thereof being variable by an external control signal, at least one first cooling unit for cooling a vehicle compartment, and a second cooling unit for cooling a refrigerator. A first valve is arranged between the compressor and the first cooling unit for connecting them to cause same to form a cooling circuit when the first valve is open. A second valve is arranged between the compressor and the second cooling unit for connecting them to cause same to form a refrigerating circuit when the second valve is open. A valve control unit controls opening and closing of the first and second valves.

Abstract: A refrigerating circuit apparatus comprises a variable capacity compressor for compressing refrigerant, an inverter circuit for supplying a variable output frequency to the compressor, a memory for storing data representing at least two different control modes including a first mode wherein the output frequency of the inverter circuit is changed at one frequency changing rate until the difference between the actual pressure value of refrigerant flowing into the compressor and a set value is minimum and a second mode wherein the output frequency of the inverter circuit is changed at a different frequency changing rate until the difference between the actual pressure value of refrigerant flowing into the compressor and the set value is minimum, a select switch for selecting either first or second mode stored in the memory and a control circuit for varying the output frequency of the inverter circuit based on the selected mode to control the rotation speed of the compressor.

Abstract: A residential HVAC system includes a heat pump having a compressor arranged to heat a domestic hot water vessel and to heat or cool a storage vessel which is connected to a heat exchanger within the residence. Temperature sensors are provided at critical locations throughout the system and current and voltage sensors are coupled to the power lines feeding the residence. A microprocessor controls the operation of the compressor and other components of the heat pump system in response to measured tempertures, in response to the level of energy supplied to the residence and in response to the existence of on- or off-peak time intervals to operate the compressor and/or resistive heating elements to condition the hot water and storage vessels for subsequent use and to control an interior fan to condition the space. Operation of the compressor is controlled during on-peak intervals as a function of the resident's life style as reflected in power usage and requested comfort level.

Abstract: Methods and apparatus for controlling the load temperature of a transport refrigeration system to a selected set point temperature by operating modes which include a high capacity cooling mode and a lower capacity cooling mode. The rate of change of the load temperature is monitored by time and temperature integration when the lower capacity cooling mode is entered, to insure that the lower capacity cooling mode has adequate capacity to reduce the load temperature to set point within an acceptable period of time. If the set point temperature is not reached within a period of time which is a function of time, load temperature relative to set point, and the rate of change of load temperature relative to set point, a signal is provided which forces the system to the higher capacity cooling mode until the set point temperature is reached.

Abstract: A deodorizing apparatus includes a case having an air inlet and an air outlet, an ozone generator of the discharge type disposed in an air flow channel between the air inlet and the air outlet, an acceleration device disposed in the air flow channel at the air outlet side thereof for accelerating the decomposition of odors and ozone, a fan provided within the case, an electric motor provided within the case for driving the fan, and device disposed in the air flow channel at the air inlet side thereof for preventing an excess of ozone from flowing out. As a result, odors can be efficiently removed by a decomposition with ozone, while the leakage of residual ozone is minimized.

Abstract: A refrigerator comprising a refrigeration cycle which comprises a compressor, condenser, first capillary tube and first cooler connected into a loop, and a quick freezing refrigerant circuit connected in parallel with the first cooler and comprising a second capillary tube and a second cooler connected in series therewith. The refrigerant is passed through the first cooler for usual operation, or alternatively through the quick freezing circuit for quick freezing. During quick freezing, the first cooler is held out of operation, and the refrigerant has its pressure reduced in two steps by the first and second capillary tubes and is evaporated in the second cooler only, giving a low temperature effective for quick freezing. During usual operation, no refrigerant flows into the second cooler, which therefore remains free of frosting. The frost deposited on the second cooler during quick freezing disappears during the usual operation. Thus, the second cooler is substantially free from frost.

Abstract: A demisting control system of an air conditioner for automotive vehicles, which comprises an evaporator, and a variable capacity compressor capable of being controlled in capacity from the outside. An actual cooling degree of the evaporator is detected. At least two desired cooling degrees of the evaporator are set. The detected actual cooling degree and each of the set at least two desired cooling degrees are compared with each other. On the basis of the comparison results, a value of the capacity to which the compressor is to be controlled is determined. The at least two desired cooling degrees are selected one by one in predetermined sequence and each selected desired cooling degree is compared with the actual cooling degree as above for a predetermined time period exclusively provided therefor. The compressor is driven so that its capacity is brought to the value of capacity determined as above.

Abstract: A refrigerator having a quick cooling system which can cool food stored therein quickly by operating a refrigerating cycle regardless of refrigerator compartment temperature. The refrigerator includes a time setting device and a control device. By using the time setting device, the desired completion time of the quick cooling operation is set. The control device determines a time at which the quick cooling operation is to be started by subtracting a predetermined time period for which the quick cooling operation is carried out from the desired completion time. The control device compares a present time with the quick cooling operation starting time, and when the present time has reached the quick cooling operation starting time, starts the quick cooling operation automatically. Quick cooling operation is automatically started and completed at the desired time, preventing cooled food from heating again, for example by defrosting operation before being taken out.

Abstract: A method of controlling a refrigeration compressor involves momentarily energizing the compressor after extended off periods. When the temperature of a comfort zone remains below its set point temperature for an extended period, such as at night, periodically energizing the compressor for brief periods improves the confort level of the zone.

Abstract: A cold-accumulation type refrigerator having variable length cycle for cooling by means of the cold-accumulation material. The cycle length is a function of refrigerator load. The refrigerator includes a refrigerating cycle to cool a refrigerator compartment and the cold-accumulation material, a load detecting device, such as a room temperature detecting device, to measure an amount of a load to be cooled, clock counting device to generate a time data, and a control device, such as microcomputer. The control device controls the operation of the refrigerator which operates in a first mode (ordinary cooling operation), a second mode wherein the refrigerator compartments are cooled by means of the cold accumulation material and a third mode wherein the cold accumulation material is cooled. The control device controls the time period for second and third mode operation as a function of load to be cooled.

Abstract: An electric refrigerator is disclosed which includes first and second coolers independently disposed in a freezer and a refrigeration chamber, respectively, a compressor for delivering a refrigerant therefrom, an electromagnetic valve for switching a refrigerant channel including the first and second coolers between a first referigerant flow path for supplying the refrigerant to only the first cooler and a second refrigerant flow path for supplying the refrigerant to both the first and second coolers, and a control circuit for causing the electromagnetic valve to form the first refrigerant flow path for a predetermined time interval and for causing the electromagnetic valve to form the second refrigerant flow path by preventing interruption of the compressor when the predetermined time interval has elapsed and an air temperature in the refrigeration chamber is higehr than a predetermined temperature.

Abstract: The invention relates to a refrigeration unit of the type having a vessel for cooling water and a heat exchanger for the liquid to be cooled mounted in the vessel. Evaporator tubing is mounted on the inner wall of the vessel and a sensor mounted a predetermined distance from the tubing monitors the formation of an ice layer on the tubing. Control regulation which prevents both freezing and undesired heating of the cooling water is based on controlling the compressor providing first and second temperature ranges associated respectively with first and second sequentially generated time periods.

Abstract: A microprocessor controlled system for use in a refrigeration system which includes a plurality of pulse controlled solenoid flow control valves suitable for use as expansion valves is disclosed. A pulse width modulated control signal is generated for cyclically opening and closing the flow through the solenoid expansion valve. The duty cycle of the pulsed control signal determines the average flow rate through the valve. The microprocessor controls, periodically, the opening of each expansion valve to permit full flow therethrough to flush any accumulated compressor lubrication oil logged in any associated evaporator coils.

Abstract: A control circuit for a refrigerator in which the compressor is operated in a pre-cool cycle prior to automatic defrost and in a rapid cooling mode. The control circuit defrosts immediately following rapid cooling when a defrost signal is produced during rapid cooling.

Abstract: An electronic de-icing thermostat adapted to be connected to an air-cooling apparatus, such as an air conditioner, to control its state of operation. The thermostat includes means for generating a digital electrical signal representative of a desired temperature setpoint, means for measuring the ambient temperature of the thermostat and means for generating control signals for deenergizing the compressor in the air-cooling apparatus for a first preselected period of time whenever the compressor is determined to have run continuously for a second preselected period of time in order to inhibit the accumulation of ice on the cooling element of the air-cooling apparatus. The device preferably includes means for adaptively adjusting the length of the second and/or first preselected periods of time as a function of the change in the rate of change of the ambient temperature measured during the operation of the air-cooling apparatus.

Abstract: A heat pump type air conditioning apparatus having a variable capacity compressor, wherein the compressor capacity is changed in accordance with the load of the air conditioning apparatus. The revolutions of the compressor, i.e., the compressor capacity, is controlled to be low when heating cycle restarts after finishing a defrosting cycle.

Abstract: An apparatus for applying a cooling water spray to the heat exchanger of an air conditioning condenser unit is disclosed. The apparatus includes a solenoid valve for controlling the flow of water, a spray nozzle positioned so as to direct the cooling water spray onto the air intake side of the heat exchanger, and a control unit for controlling the solenoid valve. The control unit is essentially a very low frequency oscillator or timer, the "OFF" and "ON" durations of which are independently selectable.

Abstract: The invention provides a variable cycle moisturizing control circuit for a gas-liquid contact pad (8, 18) in humidifiers (1), precoolers (17) and the like, supplied with fluid from a solenoid valve (34). Temperature sensitive electric circuit means (FIG. 4) cyclically actuates the valve between ON and OFF states for intermittently moisturizing the pad with an intermittent flow of liquid, and includes means (26, 30) for variably changing the intermittent flow in response to temperature by changing the relative timing of the ON and OFF timed intervals such that the duration of one increases relative to the other. User accessible preadjustment means (38, 40) manually changes the length of one of the timing intervals, to preset the initial relative timing of the intervals according to pad size to afford a relatively longer ON time for larger pads, whereafter the other interval is automatically varied in response to increasing temperature.

Abstract: A programmable maintenance timer system suitable for use with industrial equipment such as a centrifugal water chilling system and a telemetry system including a microprocessor-based computer with a programming device for presetting selectively a maintenance time interval representing a number of hours before a maintenance service is to be performed, for counting down the time interval to zero, and for generating an output signal after the time interval has reached zero to the telemetry system so as to alert service personnel that the industrial equipment is due for a scheduled maintenance. The timer system also includes a non-volatile memory device to record permanently the total elapsed operating hours in the preset maintenance time interval so as to avoid loss of such information upon a power failure and/or back-up battery failure.

Abstract: A refrigerating system comprises screw compressor means which is adapted to control the capacity thereof by means of a slide valve provided in the compressor means and operatively associated with hydraulic actuator means. The hydraulic actuator means has hydraulic fluid supplying means and hydraulic fluid discharging means, both of which are connected thereto and provided with stop valve means, respectively, for controlling the supply and the discharge of a hydraulic fluid to and from the hydraulic actuator means to permit the latter to hydraulically actuate the slide valve. The refrigerating system further comprises means for selectively switching the operation mode of the system, means for detecting the outlet water temperature of an indoor heat exchanger of the system, and temperature control means for setting a water temperature for service.

Abstract: A refrigeration system is disclosed having a purge system with means for monitoring operation of the purge system and for taking corrective action in response to excessive purge system operation. Preferably, the monitoring means is a microcomputer control system for monitoring purge pump operation to determine if the purge pump has operated continuously for a period of time greater than a predetermined amount of time. If the purge pump has operated continuously for a period of time greater than the predetermined amount of time, then the microcomputer control system overrides normal purge pump operation and maintains the purge pump inoperative for a selected time period before attempting to resume normal operation. The microcomputer control system counts the number of consecutive times that normal purge pump operation is overridden and totally disables the purge system if the number of consecutive overrides exceeds a preselected number.

Abstract: A cooling device for use in ale coolers, automatic beverage machines, air-conditioning apparatus or the like, said cooling device mainly comprising a series-connected evaporator 3, a compressor 4, a lamella condensor 5 and an air displacing member 6 for generating a cooling air stream P along the condensor lamellae, wherein means, such as a polarity commutating electric motor or flaps, for inverting the direction of flow of the cooling air along the condensor lamellae at periodical intervals in order to blow back the dust deposited on the lamellae and to conduct it to the outside.

Abstract: A refrigerator having a control device is provided with a refrigerating cycle system constructed by connecting in series a compressor, a condensor, capillary tubes, a storage compartment evaporator and a freezing compartment evaporator. This control device comprises a first control circuit to forcefully cool the freezing compartment evaporator upon receipt of a first instruction signal, a second control circuit for removing the frost deposited on the freezing compartment evaporator upon receipt of a second instruction signal, and a preferential control circuit, which, in case an operation based on a preferentially issued instruction signal is taking place, and, during this interim, a delayed instruction is given, causes an operation based on the delayed instruction signal to be commenced only after the operation based on the preferential instruction signal is brought to an end.

Abstract: This invention provides a freezer/refrigerator system which has a compressor driven by an engine of a vehicle to equally supply a refrigerant under pressure to a cooler unit and a freezer/refrigerator unit. An electromagnetic valve is disposed in a refrigerant inlet pipe of the cooler unit, while a constant-pressure expansion valve which is opened at a given pressure corresponding to a proper vaporizing temperature of the refrigerant is disposed at the refrigerant inlet pipe of the freezer/refrigerator unit. A control circuit supplies a control signal to the electromagnetic valve which is opened for 1 minute and closed for 15 seconds. The refrigerant is alternately supplied to the cooler unit and the freezer/refrigerator unit upon opening/closing of the constant-pressure expansion valve in accordance with changes in the pressure of the refrigerant.

Abstract: The refrigerant compressor of a motor vehicle air conditioning system in which the compressor is normally cycled on and off according to cooling demand is maintained continuously on or continuously off during idle operation according to a measure of the compressor duty cycle. During non-idle operation, a measure of the compressor duty cycle is compared to a reference duty cycle corresponding to a cooling demand above which it is desired to maintain the compressor on during idle operation and below which it is desired to maintain the compressor off during idle operation. At the onset of idle operation, the compressor is maintained on or off, and at the expiration of a time period corresponding to the duration of idle operation typically encountered in stop and go driving, normal compressor cycling is resumed.

Abstract: A refrigeration apparatus having an ice making mechanism disposed in a refrigerated space and including an ice harvesting mechanism. The mechanism includes a thermostat responsive to the temperature of the refrigerated space for controlling operation of the refrigeration apparatus. A control is provided for selectively causing operation of the ice harvesting mechanism alternatively as a function of total clock time from a preceding ice harvesting cycle, or as a function of an accumulated time of operation of the refrigeration apparatus as controlled by the thermostat. In one form, a manually controlled selector switch is provided. In another form, the selector switch is automatically controlled by the setting of the refrigeration apparatus thermostat. In another form, the selector switch is made to be automatically responsive to a temperature condition within the refrigeration apparatus.

Abstract: A refrigerating apparatus comprises two refrigerant circuits connected in a parallel fashion which include a common condenser. An evaporating temperature in an evaporator of one refrigerant circuit is set to a relatively high temperature compared with that of an evaporator of the other refrigerant circuit, so that a two-temperature evaporation type refrigerating apparatus is formed and a compressor of one refrigerant circuit can be intermittently driven for each predetermined time period in a forced manner. In a defrosting mode, the condenser is made to operate as an evaporator, whereby the evaporator included in the other refrigerant circuit is defrosted.

Abstract: A compressor protector system is an air conditioning system that includes a compressor driven by an engine through an electromagnetic clutch. If the refrigerant charge is below the level necessary for proper compressor cooling and lubrication a pressure or temperature responsive switch cycles at an excessive rate. A digital counter adds the number of cycles occuring over a given time, compares the rate of switch pulses to a predetermined maximum and operates to disengage the clutch and signal the vehicle operator that corrective action to restore the refrigerant charge is required.

Abstract: A solid state circuit for cycling the refrigerant compressor of an automotive air conditioning system on and off in accordance with a refrigerant vapor condition and for detecting the duration of compressor energization periods as an indication of low refrigerant charge. If a condition of low refrigerant charge is detected, the compressor is disabled and an instrument panel lamp is lit to notify the operator of the vehicle of the low refrigerant charge condition.