Abstract: An apparatus and a method for conditioning air in a plurality of spaced apart and thermally separated conditioned spaces with a cryogenic temperature control apparatus. The apparatus includes a storage tank housing a cryogen, an evaporator coil being selectively moveable into and out of thermal communication with the plurality of conditioned spaces for alternately conditioning air in the plurality of conditioned spaces, and a flow path fluidly connecting the storage tank and the evaporator coil.

Abstract: An apparatus and a method for conditioning air in a plurality of spaced apart and thermally separated conditioned spaces with a cryogenic temperature control apparatus. The apparatus includes a storage tank housing a cryogen, an evaporator coil being selectively moveable into and out of thermal communication with the plurality of conditioned spaces for alternately conditioning air in the plurality of conditioned spaces, and a flow path fluidly connecting the storage tank and the evaporator coil.

Abstract: A cryogenic temperature control apparatus comprises a storage tank housing a quantity of cryogenic fluid, a housing defining a conditioned space, and a heat exchanger in thermal communication with the conditioned space. A first flow path fluidly connects the storage tank and the heat exchanger. A first valve is positioned along the first flow path to selectively fluidly seal the first flow path between the storage tank and the heat exchanger. A second flow path fluidly connects the storage tank and the heat exchanger. A second valve is positioned along the second flow path to selectively fluidly seal the second flow path between the storage tank and the heat exchanger.

Abstract: A method of temperature control in a cryogenic temperature control apparatus comprises providing a heat exchanger in thermal communication with an air-conditioned space. The heat exchanger includes an air inlet and an evaporator coil having an outlet. The method further comprises providing a first temperature sensor being operatively coupled to a controller, measuring the temperature in the outlet and sending the temperature in the outlet to the controller, providing a second temperature sensor being operatively coupled to the controller, measuring the temperature in the air inlet, and sending the temperature in the air inlet to the controller, and providing a plurality of temperature control values. The flow of cryogen from a storage tank to the evaporator coil is altered each time the temperature in the outlet passes one of a first plurality of temperature control values and each time the temperature in the air inlet passes one of a second plurality of temperature control values.

Abstract: A temperature control system for a motor vehicle includes a housing having an air inlet and an air outlet, both of which are in fluid communication with an air-conditioned space of the vehicle. An evaporator coil is mounted within the housing and provides a pathway for a heat-absorbing fluid between a heat-absorbing fluid tank and the atmosphere. A blower mounted within the housing between the air inlet and the evaporator coil is driven by the motor vehicle engine, and blows air to be conditioned over the evaporator coil. A heating coil is positioned adjacent to the evaporator coil, and provides a heating flow path for engine coolant such that hot engine coolant flows from the engine, through the evaporator coil, and back to the engine. The heating coil is used to thaw out moisture that has frozen onto the outer surface of the evaporator coil.

Abstract: A method of temperature control in a cryogenic system, wherein the system includes a cryogenic tank. The method comprises providing a motor speed sensor which determines a motor speed, providing a pressure sensor which determines a cryogenic pressure, providing a temperature sensor in the conditioned space which measures a temperature within the conditioned space, providing a deprived integral region, and generating an overriding control signal at the proportional-integral-derivative controller when the temperature and the pressure are beyond a temperature set point and a pressure set point.

Abstract: A method of temperature control in a cryogenic temperature control apparatus comprises providing a heat exchanger in thermal communication with an air-conditioned space. The heat exchanger includes an air inlet and an evaporator coil having an outlet. The method further comprises providing a first temperature sensor being operatively coupled to a controller, measuring the temperature in the outlet and sending the temperature in the outlet to the controller, providing a second temperature sensor being operatively coupled to the controller, measuring the temperature in the air inlet, and sending the temperature in the air inlet to the controller, and providing a plurality of temperature control values. The flow of cryogen from a storage tank to the evaporator coil is altered each time the temperature in the outlet passes one of a first plurality of temperature control values and each time the temperature in the air inlet passes one of a second plurality of temperature control values.

Abstract: A method of temperature control in a cryogenic system, wherein the system includes a cryogenic tank. The method comprises providing a motor speed sensor which determines a motor speed, providing a pressure sensor which determines a cryogenic pressure, providing a temperature sensor in the conditioned space which measures a temperature within the conditioned space, providing a deprived integral region, and generating an overriding control signal at the proportional-integral-derivative controller when the temperature and the pressure are beyond a temperature set point and a pressure set point.

Abstract: A cryogenic temperature control apparatus comprises a storage tank housing a quantity of cryogenic fluid, a housing defining a conditioned space, and a heat exchanger in thermal communication with the conditioned space. A first flow path fluidly connects the storage tank and the heat exchanger. A first valve is positioned along the first flow path to selectively fluidly seal the first flow path between the storage tank and the heat exchanger. A second flow path fluidly connects the storage tank and the heat exchanger. A second valve is positioned along the second flow path to selectively fluidly seal the second flow path between the storage tank and the heat exchanger.

Abstract: An apparatus to refrigerate the cargo space of delivery vehicles. It provides an environmentally friendly alternative to conventional mechanical a/c and refrigeration units. Cooling is provided by controlled evaporation of a liquefied gas such as CO2 or nitrogen. Defrost and heating requirements, if needed, are provided by hot engine coolant or by electric heaters powered from the vehicle electrical system. Airflow for the evaporator and for circulation in the temperature controlled space is provided by a blower which is mechanically or electrically driven from vehicle power. This invention can also be applied to multi-temperature control applications. The apparatus is compact and is particularly suited for small inner city delivery vehicles.

Abstract: The invention relates to methods of defrosting an evaporator coil of a transport refrigeration unit which includes microprocessor based electrical control. The electrical control maintains the temperature of a conditioned space at a predetermined set point temperature via hot gas heating and cooling cycles. The evaporator coil is defrosted to remove frost and ice by closing a damper to the served space and initiating a heating cycle. At the termination of defrost, a cooling cycle is initiated, but the damper is maintained in a closed position for a predetermined period of time to remove heat built up during the defrost process. The invention also detects damper malfunctions, including failure to close prior to defrost, and failure to open after defrost. The invention also evaluates manual and timed requests for a defrost operation, overriding the requests in response to predetermined conditions.

Abstract: A method of operating a transport refrigeration system having a compressor driven by a prime mover at a selected one of high and low speeds, an evaporator, and an evaporator blower driven by the prime mover. Refrigeration control provides an error value which controls the temperature of a load space to a predetermined set point via heating and cooling modes. The method includes the steps of driving the compressor at high speed during pull down, and injecting hot gas into the evaporator when the error is reduced to a predetermined value. The prime mover is maintained at high speed, to keep evaporator air flow at a high rate, continuing a relatively rapid temperature pull-down across the entire load space. The speed of the prime mover is reduced to low speed when the error is further reduced to a second value, which also initiates suction line modulation while maintaining hot gas injection.

Abstract: A transport refrigeration system operable in cooling and heating cycles to maintain the temperature of a fresh load in a conditioned space extremely close to a predetermined set point temperature, with the cooling cycle primarily controlling the load temperature in ambients above freezing. The transport refrigeration system includes a compressor driven by a prime mover in one of two selectable speeds, an air delivery system which provides a substantially constant volume of conditioned air for a conditioned load space regardless of prime mover speed, a modulation valve in a suction line of the compressor, and a digital thermostat which senses the temperature of air returning to an evaporator. The digital thermostat controls the modulation valve via modulation control in a predetermined temperature range above and below set point, in both the heating and cooling cycles.

Abstract: A compartmentalized transport refrigeration system, and method of operating same, in which a host refrigeration unit controls the temperature of the air in a front compartment of a trailer, and a remote evaporator unit controls the temperature of the air in a rear compartment. In order to increase the heating capacity of the remote evaporator, the host's hot gas line is selectively controlled to enable all of the hot gas from the compressor to be directed to the remote evaporator when the host unit is in null. The host unit can only heat when the remote unit is in null. In order to increase the cooling capacity of the remote unit, the host's liquid line in selectively controlled to enable the liquid from the receiver to be all directed to the remote evaporator unit when the host unit is in null.

Abstract: A compartmentalized transport refrigeration system, and method of operating same, in which a host refrigeration unit controls the temperature of the air in a front compartment of a trailer, and a remote evaporator unit controls the temperature of the air in a rear compartment. In order to increase the heating and cooling capacity of the remote evaporator, the host unit is prevented from going into a heating mode in response to predetermined conditions, and more, or all in certain instances, of the discharge gas from the host compressor is made available for the remote evaporator.

Abstract: A compartmentalized transport refrigeration system, and method of operating same, in which a host refrigeration unit controls the temperature of the air in a front compartment of a trailer, and a remote evaporator unit controls the temperature of the air in a rear compartment. In order to increase the heating and cooling capacity of the remote evaportor, the host unit is prevented from going into a heating mode in response to predetermined conditions, and more, or all in certain instances, of the discharge gas from the host compressor is made available for the remote evaporator.

Abstract: A compartmentalized transport refrigeration system, and method of operating same, in which a host refrigeration unit controls the temperature of the air in a front compartment of a trailer, and a remote evaporator unit controls the temperature of the air in a rear compartment. In order to increase the heating capacity of the remote evaporator, the host's hot gas line is selectively controlled to enable all of the hot gas from the compressor to be directed to the remote evaporator when the host unit is in null. The host unit can only heat when the remote unit is in null. In order to increase the cooling capacity of the remote unit, the host's liquid line in selectively controlled to enable the liquid from the receiver to be all directed to the remote evaporator unit when the host unit is in null.

Abstract: A transport refrigeration unit of the type which has a single or common refrigerant circuit, and a truck engine driven compressor 22 and a mutually, exclusively operable standby compressor 34 is provided with an arrangement of suction line fitting 46 with a pair of check valves 64 and 66 located physically above the fitting which receives the suction side refrigerant through line 48 from below the fitting and is provided with an inversely related pressure side fitting 54 with associated check valves 68 and 70 and the compressors are of substantially identical pumping capacity and oil capacity, all to the end of preventing an interchange of oil between the compressors during operation, and to migration of refrigerant and oil during periods of inoperation.