Abstract: An evaporator fan control system is provided for a multi-compartment refrigerator that coordinates operation of the evaporator fan among a cooling cycle for a freezer compartment, a cooling cycle for a fresh food compartment, and an adaptive defrost cycle. An adaptive defrost timer control module is utilized to coordinate operation of the evaporator fan. This control module includes an embedded electronic controller having control logic programmed to operate the evaporator fan whenever either of the thermostats requires cooling, and to lock out operation of the evaporator fan whenever the system is performing a defrost cycle.

Abstract: An evaporator fan control system is provided for a multi-compartment refrigerator that coordinates operation of the evaporator fan among a cooling cycle for a freezer compartment, a cooling cycle for a fresh food compartment, and an adaptive defrost cycle. An adaptive defrost timer control module is utilized to coordinate operation of the evaporator fan. This control module includes an embedded electronic controller having control logic programmed to operate the evaporator fan whenever either of the thermostats requires cooling, and to lock out operation of the evaporator fan whenever the system is performing a defrost cycle.

Abstract: The invention provides a method of defrosting an evaporator coil of a transport temperature control unit. The transport temperature control unit may be operable to circulate refrigerant through the evaporator coil for cooling a conditioned space within a transportable vehicle and may be operable to maintain an air temperature of the conditioned space within a range of a desired temperature. The method may include sensing the air temperature of the conditioned space, enabling a warm load defrost when the air temperature of the conditioned space is greater than the desired temperature, initiating a first defrost cycle for removing condensate from the evaporator coil and terminating the first defrost cycle. The first defrost cycle has a defrost duration time. The method may also include establishing a defrost interval time dependent on the defrost duration time and initiating a second defrost cycle after the defrost interval time expires.

Abstract: A method and system for executing a hot gas heating cycle in a mobile refrigeration unit includes diverting a flow of hot gas by bypassing a condenser into a receiver and restricting the flow, thereby raising a discharge pressure and temperature of the unit. The discharge pressure of the unit is monitored, and the restriction is regulated when the discharge pressure reaches a predetermined pressure. A combination of small and large orifice hot gas valves is used, or optionally a hot gas stepper valve. A solenoid valve or an evaporator expansion valve is optionally used to meter refrigerant into the heat loop.

Abstract: Method and apparatus for providing an automatic defroster function for a surface in a vehicle including a sensor for detecting the presence of mist or ice on such a surface, means for generating control signals, on the basis of the sensor data, for a number of functions in the car for an optimum defroster function on said surface, means for receiving these control signals, and means for receiving control signals from a temperature regulator in the car for a number of functions in the car. A number of the control signals from the temperature regulator are intended to control the same functions as the control signals for the optimum defroster function, and the same means are used for receiving control signals for optimum defroster function and for receiving some of the control signals from the temperature regulator. The means for receiving control signals are intended, in the event of conflict, to select those control signals that are designed to give the best defroster function.

Abstract: A system for recovering potable water from the water vapor in ambient air at a wide range of temperature and humidity conditions. The system is especially adapt at operating efficiently at low temperatures and/or low humidities. The system is able to operate efficiently at low temperatures and/or low humidities by employing a mechanism for enhancing the buildup of frozen water on the surfaces used to condense the water vapor from ambient air.

Abstract: A device for indicating the formation of ice in refrigeration appliances, such as the refrigerators of domestic use, comprising a display (50), which is mounted inside the refrigeration cabinet (10) and formed by a demarcated region (51), defined by a heat sensitive element, whose color is enhanced and distinguished when submitted to a determined temperature condition that is reached when said demarcated region (51) is contacted by the layer of ice (G) accumulated on the evaporator (30).

Abstract: An automatic defrost system for a refrigerating device, comprising, in a cabinet, an evaporator and a condenser, and a defrost air circuit having: a first circuit portion; a second circuit portion receiving a certain defrost airflow from the first circuit portion and positioned adjacent to the condenser, in order to be heated by the latter; a third circuit portion, which is positioned adjacent to the evaporator, so as to selectively heat it when the heated defrost airflow passes through the second circuit portion and to conduct the defrost airflow to the first circuit portion; and a valve means, which selectively permits the passage of the defrost airflow from the second circuit portion to the third circuit portion.

Abstract: A transportation refrigeration system operable in a cooling mode, a defrost mode, and a heating mode to condition air in an air-conditioned space. The system comprises a refrigeration circuit fluidly connecting a compressor, a condenser, a tank, and an evaporator. The evaporator is in thermal communication with the air-conditioned space. A heating circuit fluidly connects the compressor, the tank, the evaporator, and a heater. A defrost circuit fluidly connects the compressor, the tank, the evaporator, and the heater. The tank has a base and the first opening is spaced a first distance above the base and the third opening is spaced a second greater distance above the base.

Abstract: The present invention relates to a method for defrosting a refrigerator with two evaporators, and more particularly, to a method for defrosting a refrigerator with two evaporators, in which the two evaporators are operated on the same time when defrosting time points of the two evaporators are close.

Abstract: An apparatus and method for measuring the total thermal resistance to heat flow from the air to the evaporative cooler fins of a refrigeration system. The apparatus is a frost sensor that measures the reduction in heat flow due to the added thermal resistance of ice (reduced conduction) as well as the reduction in heat flow due to the blockage of airflow (reduced convection) from excessive ice formation. The sensor triggers a defrost cycle when needed, instead of on a timed interval. The invention is also a method for control of frost in a system that transfers heat from air to a refrigerant along a thermal path. The method involves measuring the thermal conductivity of the thermal path from the air to the refrigerant, recognizing a reduction in thermal conductivity due to the thermal insulation effect of the frost and due to the loss of airflow from excessive ice formation; and controlling the defrosting of the system.

Abstract: In an automatic vending machine in which a number of items are stored in a commodity storage and cooled by a cooling unit included in a refrigerating circuit, a temperature sensor detects a storage temperature within the commodity storage to produce a temperature signal. Responsive to the temperature signal, a calculating unit calculates a temperature variation rate prior to a defrosting operation of a defrosting unit, which is intermittently carried out for the cooling unit. With reference to the temperature variation rate, a defrost control part controls the defrosting operation.

Abstract: A hot gas defrost system for a refrigeration cycle, including at least a compressor, reversing valve, condenser and evaporator. During defrost, the reversing valve directs the superheated refrigerant from the compressor to the evaporator. The hot gas traverses the evaporator coil which, in turn, causes the ice or frost to melt. The hot gas defrost refrigeration system may also include a receiver to store the refrigerant during the refrigeration and defrost cycles.

Abstract: A multi-chamber refrigeration system is described. The refrigeration system comprises a first refrigeration compartment within a housing, and a second refrigeration compartment within the housing and mechanically coupled to the first refrigeration compartment. A control unit is electrically coupled to the first refrigeration unit and the second refrigeration compartment. A compressor is coupled to the control unit through a first solenoid valve and through a second solenoid valve. The first solenoid valve is operable to alter an operating temperature of the first refrigeration compartment, and the second solenoid valve operable to alter an operating temperature of the second refrigeration compartment.

Abstract: A de-icing system operable to facilitate the removal of ice from the door (18) and closure surface (22) of a low temperature refrigeration or ultra-low freezer device (10) and to thereby ensure proper operation of the device (10) and protect its contents. The de-icing system employs manually activated heaters (32) and a timing circuit (38) to thaw the ice. Because the de-icing system focuses heat only on specific, ice-sensitive areas, the temperature of the freezer's interior compartment (14) remains constant so that the contents need not be removed during the de-icing process. In use, an operator activates the de-icing system a few minutes prior to opening the freezer door (18). When the door (18) is opened, the melted or loosened ice can be removed with a soft cloth. If the operator forgets that the heaters have been activated, the timing circuit (38) automatically terminates the de-icing process and stops the heaters (32) before the freezer's interior storage temperature has been affected.

Abstract: A device for defrosting the finned cooling assembly of a refrigeration system having an ellipsoid transparent polymer material housing a light source. The light source is positioned substantially in correspondence with one of the focal points of the ellipsoid. A sensor for the light beam radiated by the light source and reflected by an inner surface of the ellipsoid recognize variations in the luminous intensity of the beam caused by the formation of frost along the path of the light beam. A plurality of finned cooling assemblies are activated by the signal emitted by the sensor.

Abstract: The present invention is directed toward a control system for an ice making system. The ice making system includes an ice maker, and an ice storage bin for receiving ice pieces formed by the ice maker. The control system controls the ice maker and includes optic elements for emitting and receiving a beam of light directed across the upper portion of the bin. The control system senses when the ice maker is ready to harvest ice pieces and then directs a beam of light or light signal from a first side of the ice storage bin, across the bin toward a second side of the ice storage bin. The control system senses for the light signal at the second side of the ice storage bin and if ice pieces block the path of the light signal, the control system prevents ice harvesting from the ice maker. The optic elements of the control system include a light emitting element and a light receiving element.

Abstract: A method and apparatus of an externally mounted radiant reflector defrost heater, is a curved reflector combined by means of electrical insulators to a discrete heating means to form an apparatus to reduce ice buildup on a heat pump system's exterior unit heat exchangers through a non-reverse cycle defrost, via an apparatus which can be installed into a newly manufactured heat pump or by the retrofit of said apparatus onto an existing heat pump system, on site at location, said apparatus operating a non-reverse cycle defrost; independent of and uninterrupted by the said heat pump system's reversing valve defrost cycle.

Abstract: Heat exchange equipment comprising a compressor which is connected to an indoor heat exchanger and also to two outdoor heat exchangers, and flow-direction changing means to change the direction of flow in the heat exchangers whereby each of the outdoor heat exchangers can be defrosted whilst the other continues to remove heat from its surroundings. Pressure lowering means are provided between the two outdoor heat exchangers.

Abstract: An air conditioner comprising a refrigerant forward path branching on a discharge side of a compressor in an outdoor unit, one of the branched portions being defined by connecting a first four-way valve, a first outdoor heat exchanger and a first outdoor expansion valve to one another in this order, and the other of the branched portions being defined by connecting a second four-way valve, a second outdoor heat exchanger and a second outdoor expansion valve in this order, the path extending to an indoor unit from the respective outdoor expansion valves through a liquid-side piping, and returning to the outdoor unit from the indoor unit through a gas-side piping to branch, one of the branched portions being connected to the first four-way valve via a check valve placed in communication in a forward direction and the other of the branched portions being connected to the second four-way valve, the air conditioner being controlled such that, when heating operation is switched to defrosting operation, the second f

Abstract: In an automatic vending machine in which a number of items are stored in a commodity storage and cooled by a cooling unit included in a refrigerating circuit, a temperature sensor detects a storage temperature within the commodity storage to produce a temperature signal. Responsive to the temperature signal, a calculating unit calculates a temperature variation rate prior to a defrosting operation of a defrosting unit, which is intermittently carried out for the cooling unit. With reference to the temperature variation rate, a defrost control part controls the defrosting operation.

Abstract: A supplemental heat source in a pool heating system consisting of a heat reserve element, a contactor, a switch/relay, a light and an accessory switch. The contactor engages the supplemental heat reserve element when the ambient temperature drops to the middle forty degree range. The supplemental heat source replaces the compressor as the heat source and allows the compressor to defrost.

Abstract: A refrigerator including a freezer compartment is provided with a Stirling cycle refrigeration system including a displacer located within the freezer compartment and an external compressor which is fluidly coupled to the displacer. An electronic controller is provided to adjust a time phase relationship between the compressor and the displacer to establish a first phase condition for cooling of the freezer compartment and a second phase condition for establishing a defrost cycle for the refrigerator. The electronic controller is responsive to operator control inputs and sensor inputs. The phase relationship between the compressor and displacer is changed by substantially 180° from the first phase condition to the second phase condition.

Abstract: A control system for mobile air conditioning systems for controlling the rate at which the system compressor or clutch is cycled between operational and decreased refrigerant flow, by selectively controlling the response time of certain system control signals to flow demand changes including de-icing control, from interactions between de-icing control and flow control valves, as well as system overall control. Upon the detection of an icing condition, the response of the control system is delayed to a degree to control the rate at which the capacity of the compressor can be cycled with in design limits. The delay feature allows the differential used in differentiating between icing and non-icing conditions to be significantly reduced over that required in the prior art and thereby improving the performance of the air conditioning system. Icing conditions, or the likelihood thereof, can be determined by sensing the condition of the refrigerant flow from the evaporator.

Abstract: Cooling operation is performed so as to keep a freezer at a selected temperature. Moreover, if the cooling operation enters a phase where the freezer temperature is higher than the selected temperature by a predetermined deviation or more, not only the deviation temperature but also an accumulated time obtained by accumulating the time periods during which the cooling operation is performed at the deviation temperature or higher are stored. In addition, when an instruction signal to indicate an accumulation is input, the stored accumulated time and deviation temperature are read out and indicated on a segment indicating section (7S).

Abstract: A crossover warm liquid defrost refrigeration system (10) having a medium temperature side (12) for cooling refrigerated goods and a low temperature side (14) for cooling frozen goods. The medium temperature side has a primary refrigeration loop (16) and a secondary refrigeration loop (18). The low temperature side also has a primary refrigeration loop (46) and a secondary refrigeration loop (48). Further included in the refrigeration system is a low temperature defrost heat exchanger (28) that is connected to the primary refrigeration loop of the medium temperature side and the secondary refrigeration loop of the low temperature side such that coolant from the low temperature side secondary refrigeration loop can be heated by the refrigerant of the medium temperature side, and then transported to the low temperature side refrigerated space heat exchanger (64) to melt any frost formed thereon.

Abstract: A novel shape memory alloy electrical switch is disclosed, including both momentary and especially a latching relay. The switch/relay disclosed is particularly useful in low power control of appliances, including i.a. refrigerators. Used with a microprocessor, microcontroller, or like device to control the shape memory alloy switch/relay, an adaptive control routine may be included which facilitates an especially low-power dissipation, highly effective appliance control module, especially suitable for refrigerators. The disclosed refrigerator control module can be manufactured at low cost with high reliability.

Abstract: A control system for mobile air conditioning systems for controlling the rate at which the system compressor or clutch is cycled between operational and decreased refrigerant flow, by selectively controlling the response time of certain system control signals to flow demand changes including de-icing control, from interactions between de-icing control and flow control valves, as well as system overall control. Upon the detection of an icing condition, the response of the control system is delayed to a degree to control the rate at which the capacity of the compressor can be cycled with in design limits. The delay feature allows the differential used in differentiating between icing and non-icing conditions to be significantly reduced over that required in the prior art and thereby improving the performance of the air conditioning system.

Abstract: A reverse cycle refrigeration apparatus for air dehumidification is employed having an evaporator and a condenser and employing first and a second heat transfer coils for this purpose. Both coils are positioned in the air stream. In a first cycle the second coil functions as the evaporator for cooling and dehumidifying the air stream and accumulating frost and the first coil acts as the condenser, warming the cooled and dehumidified air stream and thawing frost having accumulated on it. In a second cycle the first coil acts as the evaporator, cooling and dehumidifying the air and providing the heat for defrost and the second coil acts as the condenser, thereby being defrosted. Dampers are provided for stopping air flow over the defrosting coil.

Abstract: A refrigerator having a shutting device for preventing flow of air between an evaporator and a fresh food compartment is disclosed. The shutting device has a shutting member for shutting a space that the evaporator is installed against a cooling compartment, and a motor for driving the shutting member. During a defrosting operation and when the door is open, cool air discharge ports are closed by the shutting member. Thus, the temperature rise of the fresh food compartment due to the heat from a defrosting heater, and the loss of cool air and the generation of frost on the evaporator due to the opening of the door are prevented.

Abstract: In order to cool a room, a cooling element fitted in the ceiling region is cooled to below the freezing point, preferably to about -40.degree. C., during the cooling phases so that condensate forming thereon freezes immediately. During regeneration phases when the room is not in use, the cooling element is defrosted and the melted condensate is caught in a condensate tray beneath the cooling element and drained via a discharge. The great temperature difference between the room to be cooled and the cooling element also makes it possible to obtain a strong cooling effect with a small cooling element, especially by indirect radiation exchange between the room and the cooling element via an intermediate ceiling. In addition, the air in the room is dehumidified since water vapor is deposited on and bonded to the cooling element in the form of ice.

Abstract: A refrigerator which has a device for opening/closing cool air discharge ports is disclosed. The device includes plates for opening/closing the ports, and a driving device for driving the plates. The heat exchange between an evaporator and the outside warm air is prevented during the defrosting operation when a door is open. Hence the cooling efficiency is enhanced and the frost caused by the outside warm air is not generated on the evaporater.

Abstract: An improved defrost controller is provided for a space cooling system of the type having an evaporator in heat exchange relationship with a space to be cooled, a condenser external to the space, a compressor for circulating heat transfer fluid between the evaporator and condenser, an expansion valve located between an outlet from the condenser and an inlet to the evaporator, and a defroster operatively associated with the evaporator. The expansion valve is positionable in a plurality of positions between a fully open position and a fully closed position to maintain a desired level of superheat across the evaporator. The defrost controller monitors the expansion valve position and activates the defroster in response to the expansion valve being in a more closed position than a predetermined defrost target position.

Abstract: A refrigerator having an apparatus for defrosting. The refrigerator provides an apparatus for defrosting which uses a wasted heat from a compressor. The apparatus has a container placed on an upper surface of the compressor and an antifreezer solution for absorbing and storing the wasted heat from the compressor by performing a heat exchange. A pipe and a pump for circulating the fluid via a space section is provided. In the space section, the pipe is formed with a bending portion so as to transfer a heat to a surrounding air. In addition, a valve for preventing a high temperature air from flowing into a freezer compartment while a defrost operation is being carried out, and a plate for preventing a cabinet from being melted are provided.

Abstract: A new method for defrosting a dehumidifier. The new method minimizes the formation of liquid "slugs" which can occur during normal defrosting and which can damage the compressor, and also makes the operation of the dehumidifier more efficient. In the new method, defrosting takes place with the fan running to draw warm, room air over the condenser to warm the refrigerant passing through it in reverse, to thus minimize the formation of liquid "slugs". The warm air however is prevented by baffles from passing over the evaporator where it would undesirearably pick up moisture from the melting ice on the evaporator. An apparatus for carrying out the above method is also provided.

Abstract: A refrigeration system has a compressor operable to supply relatively hot compressed refrigerant gas, a condenser to liquify the relatively hot compressed refrigerant gas from the compressor, a thermostatic expansion (TX) valve to vaporize liquified refrigerant from the condenser, an evaporator to cool the surrounding atmosphere by vaporized refrigerant from the TX valve, a superheat sensor to improve control of the TX valve, a compressor discharge line to convey relatively hot compressed refrigerant gas from the compressor to the condenser, a liquid line to convey liquified refrigerant from the condenser to the TX valve, and a suction line including the superheat sensor to convey vaporized refrigerant from the evaporator to the compressor.

Abstract: An inexpensive control system for a multiple-type air conditioner makes it possible to automatically and independently detect frosting and conduct defrosting control in an outdoor unit during a reverse cycle heating operation in a two-compressor, multiple-type air conditioner which has an outdoor unit equipped only with a simple ON/OFF control function and which is not provided with a signal conductor for transmitting the information on the state of an outdoor unit to an indoor unit. In this case, the operation of the outdoor unit can be determined, monitored, and controlled from the indoor unit side so as to enable proper action to be taken. The control system is provided with means for independently controlling the operation of the outdoor unit and means for determining the operation of the outdoor unit from the indoor unit side according to the state of an indoor side heat exchanger and for controlling the operation of the air conditioner.

Abstract: An air conditioning system usually referred to as an electric heat pump, which employs reverse cycle refrigeration apparatus to condition air inside a building for heating in the winter months, and for cooling in the summer months, utilizing one heat exchanger coil disposed in heat exchange relation to the flow of conditioned air circulating within a building, and two heat exchanger coils disposed in heat exchange relation to the flow of ambient air circulating outside a building, wherein each said heat exchanger coil comprises a separate and singular component part of a single air conditioning circuit connected to, and served by one single compressor; and wherein, each of the said outside heat exchanger coils are designed to change functions independent of the other, from that of an evaporator, to that of a condenser, for the purpose of inhibiting the accumulation of frost on, and/or removing frost from said outside heat exchanger coil when the heat pump is operating in the heating mode without reversing the

Abstract: A microwave thermal heat pump defroster system, utilizing a magnetron tube, or other microwave energy generating device, for the application of heat to the external surfaces of the outside coil of an electric heat pump, while the heat pump is operating in the heating mode for the following purposes, (1) to defrost the outside coil of the heat pump, (2) to inhibit the accumulation of frost on the external surfaces of the outside coil of the heat pump, and (3) to allow heat so applied to the external surfaces of the outside coil of the heat pump to be absorbed into the heat pump system via the outside coil of the heat pump, in a manner that will improve the efficiency of the heat pump.

Abstract: When a defrosting requiring signal is outputted, the opening of a motor-operated expansion valve (5) is fully closed in a heating cycle so that refrigerant is recovered into a receiver (4). In addition, when the defrosting requiring signal is outputted, an indoor fan (6f) is deactivated so that heat is stored. Further, when the completion of the recovery of refrigerant is determined, defrosting operation is executed. The recovery of refrigerant is completed when an outdoor heat-exchange temperature Tc at the present time drops to or below a specified temperature, when the outdoor heat-exchange temperature Tc at the present time drops to or more than a specified difference from a reference outdoor heat-exchange temperature Tcl at the time before the motor-operated expansion valve (5) is fully closed, when an indoor heat-exchange temperature Te at the present time rises to or above a specified temperature, or when a set time passes.

Abstract: The invention prevents the temperature of supplied air from being decreased by a defrosting operation when a vehicle is in operation. During the heating operation, it is judged whether the vehicle is in operation. When the vehicle is in operation, it is judged whether an external heat exchanger is frosted or not relying upon the external air temperature, temperature of the external heat exchanger (coolant) and the time of heating operation. When it is judged that frost is formed, the rotational speed of the compressor is increased to increase the ability to supplying the coolant, to maintain heating ability and to prevent the drop of temperature of the supplied air. When the frost is formed after the operation of the vehicle has been finished, it is judged whether the secondary batteries are being charged or not, i.e., whether the charging circuit of the secondary batteries is connected to the external power source for charging or not.

Abstract: An electronic refrigeration and defrost control unit includes a compressor relay, a defrost relay, and a fan relay. The compressor relay includes two hot terminals and one neutral terminal, the defrost relay includes three hot terminals and one neutral terminal, and the fan relay includes three hot terminals and one neutral terminal. The terminals are preferably quick connect terminals which eliminate the need for splicing neutral wires together. The electronic refrigeration and defrost control unit preferably includes a processor control circuit for driving an LED display and driving the defrost relay, fan relay and compressor relay. The control circuit is coupled to a power input which includes a super capacitor for storing power in the event of a brown-out or power shortage condition.

Abstract: A self-calibrating defrost controller for use with heat pump. The outdoor heat exchanger coil of a heat pump is defrosted based upon either compressor run-time exceeding 6 hours, or the temperature difference between the coil and ambient air exceeding a value that changes depending upon outdoor coil temperature. A programmable controller mounted to a printed circuit board within a housing executes a control program to monitor temperature sensor produced temperature signals. One sensor that monitors ambient temperature is mounted to the printed circuit board that also supports the programmable controller.

Abstract: An inverter controlling an air conditioner including a brushless motor serving as a compressor motor. A microcomputer detects the rotational position of a rotor of the brushless motor from signals obtained by comparison of each of terminal voltages of the motor windings with a reference voltage in order to determine a commutation time. In a normal operation, the microcomputer forms, according to a normal energization signal forming pattern, energization signals corresponding to every commutation time at every occurrence of the commutation time, so that the motor windings are sequentially energized. When frost forms on an outdoor heat exchanger of a heat pump during a warming operation and a defrosting operation is necessary, the energization signals are formed according to a loss increasing energization signal forming pattern so that loss increasing energization signals for causing the rotor to produce counter torque are added to the respective energization signals formed according to the normal pattern.

Abstract: A heat storage type air conditioner which is free from a difficulty that, when a general cooling and heating circuit and a cold radiating and heat radiating circuit are operated separately or simultaneously, the quantities of refrigerant in those circuits become smaller or larger than required, so that its compressor is damaged or the cooling or heating capacity is lowered. When, in a heat storage type air conditioner, first and second bypass circuits 22 and 23 are closed, a general cooling and heating circuit 18 driven by a compressor 1 and a cold radiating and heat radiating circuit 21 driven by a refrigerant gas pump 13 are made independent of each other, so that a cooling operation or a heating operation is carried out with the aid of a first use-side heat exchanger 4a and a second use-side heat exchanger 4b. Therefore, in the air conditioner, the refrigerant or refrigerating machine oil will never concentrate in any one of the two circuits.

Abstract: A defrost cycle controller for a refrigeration system encompassing a compressor; a defrost heater; a thermostatic switch coupled in series with said compressor to control operation of said compressor; a bimetallic switch coupled in series with said defrost heater to control operation of said defrost heater; and a relay coupled to mutually exclusively couple the compressor or defrost heater to a power supply, the relay having a normally closed contact which is in series with said compressor and a normally open contact coupled in series with said defrost heater.

Abstract: A defrost cycle controller for a refrigerator or freezer having a compressor and a defrost heater, comprising a relay operatively connected to the compressor and the defrost heater via contacts to couple one or the other to a power supply, the relay having a normally closed contact to which said compressor is connected and a normally open contact to which said defrost heater is connected; and a control circuit operatively connected to the compressor, defrost heater and relay and configured to implement the following algorithm: (a) first, energize the relay; (b) second, monitor the relay contacts; (c) third, if the contacts do not change states, de-energize the relay; and (d) fourth, rest for a predetermined period, and then commence the algorithm.

Abstract: Method and apparatus to defrost evaporator coils of a refrigeration system by periodically replacing the refrigerant in the evaporator coils by hot refrigerant gas from the compression side of a compressor. The gas from the compressor is sent through an oil separator, then through a solenoid valve to a vaporizer tank. From the vaporizer tank, a portion of the hot gas is fed constantly during the defrosting cycle through a metering flow control valve to the evaporator coils. As the pressure builds up in the vaporizer tank due to the compressor supplying more gas than the amount flowing through the metering flow control valve, a pressure control senses the pressure increase and opens a vaporizer solenoid valve to allow additional hot gas to flow to the evaporator coils. In the evaporator the gas heats the evaporator coils and melts the frost on the coils and then passes to the suction line of the compressor.

Abstract: Defrosting tool for maintaining the temporarily exposed cold head interface of a cryostat in frost-free condition. A plurality of electrically heated heat exchange surfaces of the tool simultaneously contacts a like plurality of cold head interface surfaces to vaporize frost formed on the latter. The tool further provides a passage for venting the vaporized frost to the surrounding environment.

Abstract: The invention pertains to an auxiliary outside air refrigeration system for use in combination with a conventional refrigeration system to supply refrigeration to an enclosure whereby cold outside air is used as the cooling medium. A differential thermostatic controller monitors the temperature inside the enclosure and in the outside atmosphere and, if the temperature inside the enclosure indicated the need for refrigeration, activates the fans of the auxiliary outside air system whenever the temperature differential between inside and outside indicates adequate potential for refrigeration. The conventional refrigeration system is energized only when the more energy-efficient outside air refrigeration system is not able to maintain adequate refrigeration within the enclosure. The controller can be used for an auxiliary outside air refrigeration system using direct exchange of air between the enclosure and the outside atmosphere or one using an air-to air heat exchanger.