An HVAC system includes an evaporator coil and a compressor fluidly coupled to the evaporator coil. A condenser coil is fluidly coupled to the compressor. The condenser coil includes at least one condenser circuit fluidly coupled between a discharge line and an exit manifold. A sub-cool circuit is fluidly coupled between the exit manifold and a liquid line. A first temperature sensor is disposed at an entrance to the sub-cool circuit. A second temperature sensor is disposed at an exit to the sub-cool circuit. An HVAC controller is operatively coupled to the first temperature sensor and the second temperature sensor. The HVAC controller is configured to determine a temperature difference across the sub-cool circuit.

A method for directing thermal energy to an evaporator of a transport climate control circuit of a transport climate control system is provided. The method includes a controller determining whether the climate control circuit is operating in a start-stop cooling mode. Also, the method includes the controller determining a thermal energy charge of the thermal storage reservoir when the climate control circuit is operating in the start-stop cooling mode. The method also includes determining whether the thermal energy charge is greater than a charge threshold. Further, the method includes determining whether the climate control circuit is operating in a stop portion of the start-stop cooling mode when the thermal energy charge is greater than the charge threshold. The method further includes transferring thermal energy from the thermal storage reservoir to an evaporator when the climate control circuit is operating in the stop portion of the start-stop cooling mode.

A method for operating a compressor unit (2) comprising one or more compressors (8, 9, 10) is disclosed, the compressor unit (2) being arranged in a vapour compression system (1). Two or more options for distributing the available compressor capacity of the compressor unit (2) between being connected to a high pressure suction line (11) and to a medium pressure suction line (13) are defined. For each option, an expected impact on one or more operating parameters of the vapour compression system (1), resulting from distributing the available compressor capacity according to the option, is predicted. An option is selected, based on the predicted expected impact for the options, and based on current operating demands of the vapour compression system (1), and the available compressor capacity is distributed according to the selected option, e.g. by means of settings of one or more valve arrangements (14, 15).

A cooling system includes a second receiver that receives refrigerant from a low side heat exchanger. A pipe connects the second receiver to a first receiver. A vapor portion of the refrigerant in the first receiver can flow through the pipe to the second receiver. A compressor is used to create a pressure differential in the second receiver relative to the first receiver such that the pressure in the first receiver is greater than the pressure in the second receiver. This pressure differential effectively acts as a pump that pushes the liquid refrigerant in the first receiver towards the low side heat exchanger.

A heating, ventilation, and air conditioning system may include a refrigerant loop to circulate refrigerant, a first valve, a second valve, a sensor to measure parameters of the refrigerant, a refrigerant tank fluidly coupled to the refrigerant loop via the valves, and control circuitry communicatively coupled to the sensor, the first valve, and the second valve. The control circuitry may determine environmental conditions and detect whether an undercharge or overcharge condition is present in the refrigerant loop based at least in part on the environmental conditions and the measured parameters. The control circuitry may also instruct the first valve to open when the undercharge condition is detected to facilitate flowing refrigerant from the refrigerant tank into the refrigerant loop and instruct the second valve to open when the overcharge condition is detected to facilitate flowing refrigerant from the refrigerant loop into the refrigerant tank.

A vapor compression system includes a heat transfer system including an arrangement of components moving a refrigerant through a vapor compression cycle to condition a controlled environment and a refrigerant management system including at least one expansion device regulating an amount of the refrigerant in the vapor compression cycle. The vapor compression system also includes a controller including a processor jointly controlling the expansion device and at least one component of the heat transfer system according to a metric of performance of the vapor compression system.

A system for maximizing the measured efficiency of an HVAC&R system may include the steps of (1) providing a plurality of operating parameters selected from the group consisting of condenser fan speed, evaporator fan speed, inlet solenoid valve position, outlet solenoid valve position, and compressor control to the air conditioner or the heat pump system wherein each of the plurality of operating parameters has a respective operating parameter value; (2) calculating an initial efficiency of the system using signals received from a plurality of components selected from the group consisting of a temperature sensor, a humidity sensor, a pressure sensor, a flow sensor, a voltage sensor, and a current sensor; and (3) proceeding, starting with a first of the plurality of operating parameters, to iteratively adjust values of each of the plurality of operating parameters and accept the new values only if the measured efficiency increases.

A decentralized condenser evaporator system includes a condenser system, a controlled pressure receiver, a subcooler system, and an evaporator system. The condenser system is positioned to receive a compressed gaseous refrigerant from a centralized compressor system. The condenser system is configured to condense the compressed gaseous refrigerant into a liquid refrigerant. The controlled pressure receiver is positioned to receive and store the liquid refrigerant. The subcooler system is positioned to receive the liquid refrigerant from the controlled pressure receiver. The subcooler system is configured to sub-cool the liquid refrigerant into a sub-cooled liquid refrigerant. The evaporator system is positioned to receive the sub-cooled liquid refrigerant from the subcooler system. The evaporator system is configured to facilitate providing a cooling operation to a cooling zone through evaporation of the sub-cooled liquid refrigerant flowing through the evaporator system into an evaporated gaseous refrigerant which is returned to the centralized compressor system.

A condenser and evaporator system includes (i) a condenser system positioned to receive a gaseous refrigerant from a compressor system and configured to condense the gaseous refrigerant into a liquid refrigerant, (ii) a controlled pressure receiver (CPR) positioned to receive and store the liquid refrigerant, (iii) an evaporator system including a conduit, an expansion valve, and a fan, and (iv) a controller. The conduit is positioned to receive the liquid refrigerant from the CPR. The expansion valve is positioned between the CPR and the conduit, and configured to facilitate modulating an amount of the liquid refrigerant that flows into the conduit from the CPR. The fan is positioned to facilitate providing a cooling operation to an arca associated with the evaporator system through evaporation of the liquid refrigerant flowing through the conduit. The controller is configured to control a stage of the condenser system and/or the evaporator system a condenser system, a reservoir, a compressor return conduit, an evaporator system, and a return line. The condenser system is configured to receive a compressed gaseous refrigerant from a compressor system and condense the compressed gaseous refrigerant into a liquid refrigerant. The reservoir is configured to receive the liquid refrigerant. The compressor return conduit is configured to couple the reservoir to the compressor system to direct gaseous refrigerant within the reservoir to the compressor system. The evaporator system is configured to receive the liquid refrigerant from the reservoir and perform a cooling operation where the liquid refrigerant is converted into an evaporated gaseous refrigerant to facilitate thermally regulating a cooling zone associated with the evaporator system. The return line is configured to couple the evaporator system to the reservoir and direct defrost condensate refrigerant to the reservoir from the evaporator system.

A heat exchanger, such as for example, a condenser coil constructed as a fin and microchannel tube is fluidly connected with a volume constructed and configured to store refrigerant in certain operations, such as for example during a pump down operation. The volume is fluidly connected to a fluid port of the heat exchanger, where the fluid port is an inlet (in the cooling mode) to the heat exchanger, such as the high side condensing section of the heat exchanger. The volume receives refrigerant exiting the heat exchanger from the fluid port in a mode other than a cooling mode, e.g., a pump down operation