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 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: The present disclosure provides a refrigerant vapor compression system includes a compressor (12) having a suction port and a discharge port, a refrigerant heat rejection heat exchanger (24) operatively coupled downstream to the discharge port of the compressor, a refrigerant heat absorption heat exchanger (42) operatively coupled downstream to the refrigerant heat rejection heat exchanger, a compressor suction inlet line connecting the refrigerant heat absorption heat exchanger to the suction port of the compressor, and an adiabatic expansion device (54) operatively coupled to the suction inlet line. A sensor operatively coupled to the suction inlet line measures a superheat value of the refrigerant. The refrigerant vapor compression system further includes a controller (60) in communication with the sensor.

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: Embodiments of systems, apparatus, and/or methods can control conditions such as temperature within a container of a transport refrigeration system. Embodiments can include a controller for controlling the transport refrigeration system to reduce power consumption. Embodiments of systems, apparatus, and/or methods for operating the same can control cycling of a transport refrigeration unit to conserve power where a subsequent cycle time in a power savings mode is based on at least one previous cycle time. In addition, components can be enabled based on monitored conditions to reduce power consumption.

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 CO2 vapor compression system is provided with at least one pressure relief device which is designed to open when the pressure in the low pressure side exceeds the predetermined level because of exposure to high temperatures during non-operational periods. A pressure relief device is provided near the compressor suction inlet to relieve one section of the circuit and another is provided upstream of an unloading valve to relieve pressure in another section thereof.

Abstract: A refrigerated container having a refrigeration system using CO2 as the refrigerant, includes a sensing and warning system for sensing the CO2 concentration in the container and responsively displaying the sensed condition in a display module so that an operator will be aware of excess levels of concentration which might present a hazardous condition and therefore should not enter the container until the condition is alleviated.

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: CO2 refrigeration circuit (2) for circulating a refrigerant in a predetermined flow direction, comprising in flow direction a heat-rejecting heat exchanger (4), a receiver (10) having a liquid portion (12) and a flash gas portion (14), and subsequent to the receiver (10) a medium temperature loop (20) and a low temperature loop (24), wherein the medium and low temperature loops (24) each comprise in flow direction an expansion device (26, 28), an evaporator (30, 32) and a compressor (46, 38), the refrigeration circuit (2) further comprising a liquid line (16) connecting the liquid portion (12) of the receiver (10) with at least one of the medium and low temperature loops (20, 24) and having an internal heat exchanger (54), and a flash gas line (50) connecting the flash gas portion (14) of the receiver (10) via the internal heat exchanger (54) with the inlet of the low temperature compressor (46), wherein the internal heat exchanger (54) transfers in use heat from the liquid flowing through the liquid line (16

Abstract: CO2 refrigeration circuit (2) for circulating a refrigerant in a predetermined flow direction, comprising in flow direction a hear-rejecting heat exchange, (4), a receiver (10) having a liquid portion (12) and a flash gas portion (14), and subsequent to the receiver (10) a medium temperature loop (20) and a low temperature loop (24), wherein the medium and low temperature loops (24) each comprise in flow direction an expansion device (26, 28), an evaporator (30, 32) and a compressor (46, 38), the refrigeration circuit (2) further comprising a liquid line (16) connecting the liquid portion (12) of the receiver (10) with at least one of the medium and low temperature loops (20, 24) and having an internal heat exchanger (54), and a flash gas line (50) connecting the flash gas portion (14) of the receiver (10) via the internal heat exchanger (54) with the inlet of the low temperature compressor (46), wherein the internal heat exchanger (54) transfers in use heat from the liquid flowing through the liquid line (16

Abstract: Rather than having a frame into which, or upon which, an air conditioning system is mounted, a bus rooftop air conditioning module has a unibody which is formed partially of structural members interconnected to the tube sheets of the evaporator and condenser coils to form a structural body which supports the components of the system. In this way the coil tube sheets combine with other structural members to form the supporting body.

Abstract: A bus rooftop air conditioning system is made up of one or more self-contained modules having one or more evaporator sections and one or more condenser sections, with each extending transversely across the width of the bus, and with the evaporator sections fluidly communicating with both a common return air opening and a common supply air opening of the bus. The modules may be of a single unit configuration with a single condenser section and a single evaporator section or they may be of a double unit configuration having two condenser sections and two evaporator sections. The total capacity requirements are met by combining the use of single units and double unit configuration, with each of the evaporator sections communicating with a single return air opening and a single supply air opening in a bus.