Abstract: A refrigeration system for a transport refrigeration unit and a method of operating the refrigeration system for cooling a temperature controlled cargo space are disclosed. The refrigeration system includes a primary refrigerant circuit including a refrigerant compression device, a motor for driving the compression device; a variable speed drive for varying the speed of operation of the compression device; and a controller operatively associated with the variable speed drive and the compression device. The controller controls the cooling capacity of the refrigeration system by selectively controlling the speed of said compression device in a first continuous run mode of operation and by selectively powering on and powering off said compression device in a first cycling mode of operation.

Abstract: A refrigeration system (10) includes a compressor (20) having a first stage (20a) and a second stage (20b); a heat rejecting heat exchanger (40) having a fan (44) drawing ambient fluid over the heat rejecting heat exchanger, the heat rejecting heat exchanger including an inter-cooler (43) and a gas cooler(41), the intercooler coupled to an outlet of the first stage and the gas cooler coupled to an outlet of the second stage;, an unload valve (93) coupled to an outlet of the intercooler and a suction port of the first stage; a flash tank (70) coupled to an outlet of the gas cooler; a primary expansion device (55) coupled to an outlet of the flash tank; a heat absorbing heat exchanger (50) coupled to an outlet of the primary expansion device, an outlet of the heat absorbing heat exchanger coupled to the suction port of the first stage; and a controller (100) for executing a startup process.

Abstract: A method for determining proper wiring of multiple three-phase motors in a refrigeration system is disclosed. The method may include energizing a plurality of three-phase motors with a first input phase rotation and recording performance data, energizing the plurality of three-phase motors with a second input phase rotation and recording the performance data, evaluating the performance data and determining if each of three-phase motors is properly wired, operating the refrigeration system in a normal mode if all of the three-phase motors are properly wired, or operating the refrigeration system in a less efficient mode if at least one three-phase motor is improperly wired.

Abstract: A refrigerant vapor compression system includes a flash tank economizer defining a separation chamber is disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit in operative association with and upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit in operative association and upstream of the flash tank economizer. A refrigerant vapor injection line establishes refrigerant flow communication between an upper portion of the separation chamber and an intermediate pressure stage of the system's compression device and a suction pressure portion of the refrigerant circuit.

Abstract: A refrigerant vapor compression system includes a compression device having at least a first compression stage and a second compression stage, a refrigerant heat rejection heat exchanger disposed downstream with respect to refrigerant flow of the second compression stage, and a refrigerant intercooler disposed intermediate the first compression stage and the second compression stage. The refrigerant intercooler is disposed downstream of the refrigerant heat rejection heat exchanger with respect to the flow of a secondary fluid. A second refrigerant heat rejection heat exchanger may be disposed downstream with respect to refrigerant flow of the aforesaid refrigerant heat rejection heat exchanger, and a second refrigerant intercooler may be disposed intermediate the first compression stage and the second compression stage and downstream with respect to refrigerant flow of the aforesaid refrigerant intercooler.

Abstract: Embodiments of apparatus, transport refrigeration units, and methods for operating the same can control refrigerant compression device restart for a refrigerant vapor compression system. Embodiments can provide control for transitioning a refrigerant vapor compression system to an economized mode.

Abstract: Embodiments of apparatus, transport refrigeration units, and methods for operating the same can control cooling capacity for a refrigerant vapor compression system. Embodiments can provide use discharge pressure control for modulating cooling capacity for a refrigerant vapor compression system. In one embodiment, discharge pressure control can reduce the cooling capacity without increasing the compressor pressure ratio or discharge temperature. In one embodiment, discharge pressure control can reduce the cooling capacity independently of system superheat. In one embodiment, discharge pressure control can control a compressor discharge temperature; for example, to remain below a threshold temperature.

Abstract: Embodiments of apparatus, transport refrigeration units, and methods for operating the same can control defrost operations for a refrigerant vapor compression system. Embodiments can provide control for transitioning a refrigerant vapor compression system into and out of a defrost mode.

Abstract: Embodiments of transport refrigeration systems, apparatus, and/or methods for the same can provide exemplary verification for operating characteristics thereof. In one embodiment, a calculated compressor mid stage pressure can be verified using a prescribed relationship to other transport refrigeration system characteristics.

Abstract: A method is provided for protecting a refrigerant vapor compression system during a standstill period following shutdown of the refrigerant vapor compression system. A method is provided for detecting a low refrigerant charge level in a refrigerant vapor compression system operating in a transcritical mode. A refrigerant vapor compression system is provided that includes a controller operative to perform a refrigerant charge detection method.

Abstract: An activation indicator for a refrigeration system pressure relief valve is presented. In one embodiment, the indicator comprises a covering that covers an outlet passage of the pressure relief valve. The covering is at least partially displaceable by refrigerant as it exits the refrigeration system through the pressure relief valve. In another embodiment, sensors outputting a signal transmit an altered signal when the relief device releases refrigerant. A notification device is activated to indicate that the pressure relief device has activated.

Abstract: A refrigerant vapor compression system includes a hot gas bypass line establishing refrigerant vapor flow communication between the compression device and the refrigerant heat absorption heat exchanger, and bypassing the refrigerant heat rejection heat exchanger and the primary expansion device. A refrigerant vapor flow control device is interdisposed in the hot gas bypass line. The flow control device has at least a first open position in which refrigerant vapor flow may pass through the hot gas bypass line and a closed position in which refrigerant vapor flow may not pass through the hot gas bypass line.

Abstract: A carbon dioxide refrigerant vapor compression system and method of operating that system are provided. The refrigerant vapor compression system includes a compression device, a flash tank receiver disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger, and a compressor unload circuit including a refrigerant line establishing refrigerant flow communication between an intermediate pressure stage of the compression device and the refrigerant circuit at a location downstream of the refrigerant heat absorption heat exchanger and upstream of a suction inlet to the compression device, and a unload circuit flow control device disposed in said unload circuit refrigerant line. In response to at least one system operating parameter sensed by at least one sensor, the controller selectively positions the unload flow control device to maintain the refrigerant vapor compression system operating below a preselected high pressure limit.

Abstract: A refrigerant vapor compression system using CO2 as the working fluid and operating in a transcritical cycle, compression of the refrigerant is accomplished by use of a digital scroll compressor adapted to a variable duty cycle in a pulse width modulation manner. The compression ratio is maintained at an acceptable level by selective control of various components within the system, depending on the mode of operation.

Abstract: A refrigeration system for a transport refrigeration unit and a method of operating the refrigeration system for cooling a temperature controlled cargo space are disclosed. The refrigeration system includes a primary refrigerant circuit including a refrigerant compression device, a motor for driving the compression device; a variable speed drive for varying the speed of operation of the compression device; and a controller operatively associated with the variable speed drive and the compression device. The controller controls the cooling capacity of the refrigeration system by selectively controlling the speed of said compression device in a first continuous run mode of operation and by selectively powering on and powering off said compression device in a first cycling mode of operation.

Abstract: A refrigerant vapor compression system includes a flash tank economizer defining a separation chamber is disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit in operative association with and upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit in operative association and upstream of the flash tank economizer. A refrigerant vapor injection line establishes refrigerant flow communication between an upper portion of the separation chamber and an intermediate pressure stage of the system's compression device and a suction pressure portion of the refrigerant circuit.