Abstract: A transport climate control system to cost-effectively maintain an ultra-low temperature over an extended period of time is provided. The transport climate control system includes a primary climate control system and a secondary climate control system. The primary climate control system includes a first compressor, a first condenser, a first expander, and a main evaporator that is configured to thermally communicate with a climate controlled space. The secondary climate control system includes an ultra-low temperature phase changing medium packaged inside or outside of an enclosure for a cargo. The secondary climate control system is configured to thermally communicate with the climate controlled space, the primary climate control system, and the cargo to provide additional or backup climate control capacity at the ultra-low temperature.

Abstract: A climate control circuit for a transport climate control system is provided. The circuit includes a compressor, a plurality of evaporators, a suction flow control device, and a controller. The suction flow control device is downstream of the plurality of evaporators and directs the working fluid from each of the evaporators to one of a main suction port and an auxiliary port of the compressor. The controller determines whether each of the evaporators is operating in a fresh temperature range or in a frozen temperature range. For each of the evaporators operating in the fresh temperature range, the controller instructs the suction flow control device to direct the working fluid from the corresponding evaporator to the auxiliary suction port. For each of the plurality of evaporators operating in the frozen temperature range, the controller instructs the suction flow control device to direct the working fluid to the main suction port.

Abstract: A climate control system includes a compressor which includes a compressor housing, a compressor element provided in the compressor housing, a lubricant circuit, and an auxiliary sump. The lubricant circuit includes a lubricant sump provided in the compressor housing. The auxiliary sump is in fluid communication with the lubricant sump. A method for maintaining lubrication supply for a compressor of a climate control system includes transferring lubricant from the auxiliary sump to the lubricant sump of the compressor when a height of the lubricant in the auxiliary sump is greater than a height in the lubricant sump and returning the lubricant from the lubricant sump to the auxiliary sump when a height of the lubricant in the lubricant sump is higher than a height of a predetermined minimum level in the lubricant sump. The lubricant in the auxiliary sump and lubricant sump are equalized by gravity.

Abstract: Systems and methods for simultaneous vapor and liquid injection for a transport climate control system are provided. The system includes a compressor, a condenser having a condensing unit and a sub-cooling unit, a receiver, an economizer having a vapor outlet and a liquid outlet, a controller, and a flow control device. The receiver is disposed downstream of the condensing unit and upstream of the sub-cooling unit. The economizer is disposed downstream of the sub-cooling unit. The compressor includes a suction port, a vapor injection port connected to the vapor outlet of the economizer, and a liquid injection port separated from the vapor injection port. The controller is configured to control the flow control device to adjust an amount of liquid refrigerant into the liquid injection port to maintain a discharge temperature of the compressor at or below a threshold.

Abstract: A method for providing supplemental flow control of working fluid through a transport climate control circuit during a start-stop cooling operation mode is provided. The method includes closing a main liquid suction solenoid valve disposed between a condenser and an evaporator of the transport climate control circuit when the compressor is OFF. The method also includes monitoring a climate controlled space temperature within a climate controlled space. When the climate controlled space temperature is greater than or equal to a setpoint temperature, the method includes turning a compressor ON, and opening the main liquid suction solenoid valve when a suction pressure at the suction port of the compressor is less than or equal to a predetermined suction pressure threshold. When the climate controlled space temperature is less than or equal to the setpoint temperature, the method includes turning the compressor OFF, and closing the main liquid suction solenoid valve.

Abstract: A climate control circuit for a transport climate control system is provided. The circuit includes a compressor, a plurality of evaporators, a suction flow control device, and a controller. The suction flow control device is downstream of the plurality of evaporators and directs the working fluid from each of the evaporators to one of a main suction port and an auxiliary port of the compressor. The controller determines whether each of the evaporators is operating in a fresh temperature range or in a frozen temperature range. For each of the evaporators operating in the fresh temperature range, the controller instructs the suction flow control device to direct the working fluid from the corresponding evaporator to the auxiliary suction port. For each of the plurality of evaporators operating in the frozen temperature range, the controller instructs the suction flow control device to direct the working fluid to the main suction port.

Abstract: A transport climate control system to cost-effectively maintain an ultra-low temperature over an extended period of time is provided. The transport climate control system includes a primary climate control system and a secondary climate control system. The primary climate control system includes a first compressor, a first condenser, a first expander, and a main evaporator that is configured to thermally communicate with a climate controlled space. The secondary climate control system includes an ultra-low temperature phase changing medium packaged inside or outside of an enclosure for a cargo. The secondary climate control system is configured to thermally communicate with the climate controlled space, the primary climate control system, and the cargo to provide additional or backup climate control capacity at the ultra-low temperature.

Abstract: A climate control circuit for a transport climate control system is provided. The circuit includes a compressor, a plurality of evaporators, a suction flow control device, and a controller. The suction flow control device is downstream of the plurality of evaporators and directs the working fluid from each of the evaporators to one of a main suction port and an auxiliary port of the compressor. The controller determines whether each of the evaporators is operating in a fresh temperature range or in a frozen temperature range. For each of the evaporators operating in the fresh temperature range, the controller instructs the suction flow control device to direct the working fluid from the corresponding evaporator to the auxiliary suction port. For each of the plurality of evaporators operating in the frozen temperature range, the controller instructs the suction flow control device to direct the working fluid to the main suction port.

Abstract: A climate control circuit for a transport climate control system is provided. The circuit includes a compressor, a plurality of evaporators, a suction flow control device, and a controller. The suction flow control device is downstream of the plurality of evaporators and directs the working fluid from each of the evaporators to one of a main suction port and an auxiliary port of the compressor. The controller determines whether each of the evaporators is operating in a fresh temperature range or in a frozen temperature range. For each of the evaporators operating in the fresh temperature range, the controller instructs the suction flow control device to direct the working fluid from the corresponding evaporator to the auxiliary suction port. For each of the plurality of evaporators operating in the frozen temperature range, the controller instructs the suction flow control device to direct the working fluid to the main suction port.

Abstract: A method for providing supplemental flow control of working fluid through a transport climate control circuit during a start-stop cooling operation mode is provided. The method includes closing a main liquid suction solenoid valve disposed between a condenser and an evaporator of the transport climate control circuit when the compressor is OFF. The method also includes monitoring a climate controlled space temperature within a climate controlled space. When the climate controlled space temperature is greater than or equal to a predetermined setpoint temperature, the method includes turning a compressor ON, and opening the main liquid suction solenoid valve when a suction pressure at the suction port of the compressor is less than or equal to a predetermined suction pressure threshold. When the climate controlled space temperature is less than or equal to the predetermined setpoint temperature, the method includes turning the compressor OFF, and closing the main liquid suction solenoid valve.

Abstract: A refrigeration system having a cooling circuit, a heating circuit, a pressurizing receiver tank circuit, a pilot circuit and a liquid injection circuit wherein the hot gas line includes a solenoid valve that connects an outlet of a compressor to an outlet of a receiver tank, and wherein the liquid injection circuit includes a liquid injection solenoid that connects the outlet of the receiver tank to an outlet of an economizer.

Abstract: A refrigeration system having a cooling circuit, a heating circuit, a pressurizing receiver tank circuit, a pilot circuit and a liquid injection circuit wherein the hot gas line includes a solenoid valve that connects an outlet of a compressor to an outlet of a receiver tank, and wherein the liquid injection circuit includes a liquid injection solenoid that connects the outlet of the receiver tank to an outlet of an economizer.

Abstract: A refrigeration system having a cooling circuit, a heating circuit, a pressurizing receiver tank circuit, a pilot circuit and a liquid injection circuit wherein the hot gas line includes a solenoid valve that connects an outlet of a compressor to an outlet of a receiver tank, and wherein the liquid injection circuit includes a liquid injection solenoid that connects the outlet of the receiver tank to an outlet of an economizer.

Abstract: A refrigeration system having a cooling circuit, a heating circuit, a pressurizing receiver tank circuit, a pilot circuit and a liquid injection circuit wherein the hot gas line includes a solenoid valve that connects an outlet of a compressor to an outlet of a receiver tank, and wherein the liquid injection circuit includes a liquid injection solenoid that connects the outlet of the receiver tank to an outlet of an economizer.

Abstract: A refrigerant compressor assembly for a refrigeration circuit controls the temperature within a temperature controlled space. The refrigerant compressor assembly includes a first unloading valve, a first valve actuator, and a first valve control system that adjusts the first valve actuator via a pulse-width-modulated signal, a second unloading valve, a second valve actuator, and a second valve control system that adjusts the second valve actuator via a pulse-width-modulated signal. The refrigerant compressor assembly also includes a third unloading valve. The first valve actuator is coupled to the first and third unloading valves and controlled by the first valve control system. The unloading valves selectively allow or resist fluid flow from higher to lower pressure areas within the refrigerant compressor assembly.

Abstract: A refrigerant compressor assembly for a refrigeration circuit controls the temperature within a temperature controlled space. The refrigerant compressor assembly includes a first unloading valve, a first valve actuator, and a first valve control system that adjusts the first valve actuator via a pulse-width-modulated signal, a second unloading valve, a second valve actuator, and a second valve control system that adjusts the second valve actuator via a pulse-width-modulated signal. The refrigerant compressor assembly also includes a third unloading valve. The first valve actuator is coupled to the first and third unloading valves and controlled by the first valve control system. The unloading valves selectively allow or resist fluid flow from higher to lower pressure areas within the refrigerant compressor assembly.

Abstract: A method for controlling at least one electronic expansion valve coupled to an economizer in a refrigeration system in order to dynamically control the refrigeration system operating conditions and in order to accommodate more than one set of operating conditions. The system can also be used to control the capacity of the system. More specifically, the method can include determining the required capacity of the system and adjusting the flow of refrigerant through the electronic expansion valve to adjust the actual capacity of the system toward the required capacity of the system. In another aspect of the invention, the system is operated to maintain the power of the system below a threshold value (e.g., below a max rated horsepower).

Abstract: A method for controlling at least one electronic expansion valve coupled to an economizer in a refrigeration system in order to dynamically control the refrigeration system operating conditions and in order to accommodate more than one set of operating conditions. The system can also be used to control the capacity of the system. More specifically, the method can include determining the required capacity of the system and adjusting the flow of refrigerant through the electronic expansion valve to adjust the actual capacity of the system toward the required capacity of the system. In another aspect of the invention, the system is operated to maintain the power of the system below a threshold value (e.g., below a max rated horsepower).

Abstract: A transport refrigeration system for heating and cooling a conditioned space is provided that includes an improved, combined heat exchanger and economizer for increasing the efficiency of the refrigeration cycle. The system includes a refrigerant compressor driven by an internal combustion engine that includes suction and discharge ports, and an intermediate pressure port; a refrigeration circuit including a heating coil and evaporator assembly thermally connected to the conditioned space, and a mode valve for selectively routing the refrigerant through either the heating coil or the evaporator assembly via a condenser to heat or cool the conditioned space, respectively. The combined heat exchanger and economizer includes a tube connected to the intermediate suction port of the compressor, a shell for conducting refrigerant to the evaporator assembly depending upon the position of the mode valve, and a jacket for circulating engine coolant.

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein.