Abstract: A mobile refrigeration system that includes an engine that is operable at a first speed greater than zero and a second speed greater than zero. A compressor is operable in response to the engine at a first speed and a second speed. The system also includes an evaporator, a first temperature sensor positioned to measure a first temperature, and a second temperature sensor positioned to measure a second temperature. A controller is operable to transition the engine between the first speed and the second speed in response to the first temperature exceeding a first predetermined value and the second temperature falling below a second predetermined value.

Abstract: A mobile refrigeration system that includes an engine that is operable at a first speed greater than zero and a second speed greater than zero. A compressor is operable in response to the engine at a first speed and a second speed. The system also includes an evaporator, a first temperature sensor positioned to measure a first temperature, and a second temperature sensor positioned to measure a second temperature. A controller is operable to transition the engine between the first speed and the second speed in response to the first temperature exceeding a first predetermined value and the second temperature falling below a second predetermined value.

Abstract: A mobile refrigeration system that includes an engine that is operable at a first speed greater than zero and a second speed greater than zero. A compressor is operable in response to the engine at a first speed and a second speed. The system also includes an evaporator, a first temperature sensor positioned to measure a first temperature, and a second temperature sensor positioned to measure a second temperature. A controller is operable to transition the engine between the first speed and the second speed in response to the first temperature exceeding a first predetermined value and the second temperature falling below a second predetermined value.

Abstract: A method of controlling a heating cycle of a refrigeration system is provided that includes a refrigerant circuit. The refrigerant circuit includes a compressor having a suction port and an outlet having a discharge port with a hot gas compressor discharge line, a condenser for condensing the refrigerant, an evaporator for evaporating the refrigerant and an expansion valve. The method includes using refrigerant from the hot gas compressor discharge line to heat the evaporator during a heating cycle, detecting periodically a discharge superheat of the refrigerant leaving the outlet of the compressor, producing a control signal representing a difference between the detected discharge superheat and a minimum discharge superheat setpoint, adjusting the flow rate of the refrigerant to the suction port of the compressor according to the control signal so as to maintain the discharge superheat of the refrigerant at the outlet of the compressor substantially at the minimum discharge superheat setpoint.

Abstract: A mobile refrigeration system that includes an engine and a compressor that is operable in response to the engine to produce a flow of refrigerant. An evaporator receives the flow of refrigerant and a first temperature sensor is positioned to measure a first temperature. A second temperature sensor is positioned to measure a second temperature and a controller is operable to detect a failure of one of the first temperature sensor and the second temperature sensor by calculating a temperature difference between the measured first temperature and the measured second temperature and comparing the temperature difference to a predetermined value.

Abstract: A temperature control unit and a method of operating a temperature control unit. The temperature control unit including a refrigeration circuit enclosing a refrigerant and having a compressor, a condenser, and an evaporator coil. The method including providing a first flow path extending through the compressor, the condenser, and the evaporator, providing a second flow path extending through the compressor and the evaporator, the second flow path bypassing a section of the refrigeration circuit, directing refrigerant through the first flow path during operation in a cooling mode, directing refrigerant through the second flow path during operation in a heating mode, and recovering refrigerant from the section of the refrigeration circuit during operation in a recovery cycle.