Disclosed is a CO.sub.2 based refrigeration system including a condenser for transferring heat from a CO.sub.2 refrigerant of the refrigeration system to an air stream. The system further includes a metering device downstream of the condenser and a bypass arrangement. The metering device is configured to create a pressure drop so that part of the refrigerant liquifies, when received in a supercritical state, from the condenser such that a liquid component and a flash gas component are generated. The bypass arrangement includes a valve and a bypass line to allow the refrigerant to bypass the metering device.

Devices, systems, and methods are disclosed for cooling using both air and/or liquid cooling sub circuits. A vapor compression cooling system having both an air and liquid cooling sub circuit designed to service high sensible process heat loads that cannot be solely cooled by either liquid or air is provided.

A refrigeration system for a temperature-controlled storage device includes a refrigeration circuit that circulates a refrigerant, a separate cooling circuit that circulates a coolant, and a controller. The refrigeration circuit includes a compressor, a condenser, an expansion device, and an evaporator. The cooling circuit includes a pump, a control valve, and a heat removing device in fluid communication with the condenser via the coolant. The controller is operatively coupled to the control valve and configured to identify a coolant temperature differential setpoint, monitor a temperature of the coolant provided to the condenser by the cooling circuit, calculate a coolant temperature differential based on the temperature of the coolant provided to the condenser, and operate the control valve to modulate a flow of the coolant through the condenser to drive the coolant temperature differential to the coolant temperature differential setpoint.

An air conditioning system using a predetermined amount of refrigerant includes an evaporator unit, a compressor unit, an evaporative cooling system including at least one multiple-effect evaporative condenser connected to the compressor for effectively cooling the refrigerant. Each of the multiple-effect evaporative condensers includes an air inlet side and an air outlet side which is opposite to the air inlet side, a pumping device adapted for pumping a predetermined amount of cooling water at a predetermined flow rate, a first cooling unit and a second cooling unit. The refrigerant flows through heat exchanging pipes in the first cooling unit and the second cooling unit. The cooling water is arranged to pass through the first cooling unit and the second cooling unit in a sequential order and perform heat exchange with the refrigerant.

A method of operating a refrigeration and heating system (2a, 2b) comprises: circulating a refrigerant through a refrigeration circuit (4) which comprises in the direction of flow of the circulating refrigerant: at least one compressor (6a, 6b, 6c); a refrigeration circuit side (8a) of a coupling heat exchanger (8); at least one gas cooler (10); at least one expansion device (12, 14); and at least one evaporator (16); circulating a heating fluid through a heating circuit (20) which comprises a heating circuit side (8b) of the coupling heat exchanger (8) and at least one heat consumer (22); wherein the coupling heat exchanger (8) is configured for transferring heat from the circulating refrigerant to the circulating heating fluid. The method further includes increasing the temperature of the refrigerant entering the at least one gas cooler (10) in order to meet increased heating demands by allowing at least a portion of the heating fluid to flow directly from an outlet to an inlet of the heating circuit side (8b) of the coupling heat exchanger (8) bypassing the at least one heat consumer (22) or by allowing at least a portion of the refrigerant circulating through the refrigeration circuit (4) to bypass the coupling heat exchanger (8).

Chiller control systems and methods for chiller control use iterative modeling of cooling towers, heat exchangers, and pumps to determine the feasibility of integrated free cooling and the ability to take advantage of free cooling. The control systems and control methods can further include selecting the parameters for operating in the free cooling or integrated free cooling mode to improve efficiency and/or reduce energy consumption when operating in these modes. The models can have inputs and outputs that feed into one another, and converge at a solution over multiple iterations. The feasibility of integrated free cooling can be based on providing cooling to a cooling load process fluid at a heat exchanger. The availability of free cooling can be based on the cooling provided at the heat exchanger achieving a target temperature for the cooling load process fluid.

A refrigerator and a method of controlling a refrigerator are provided. The refrigerator may include a machine room defined in or at one side of a storage compartment, a base that defines a bottom surface of the machine room, a compressor seated on the base to compress a refrigerant, a condenser that condenses a refrigerant compressed in the compressor, the condenser being disposed on or at one side of the compressor, a drain pan disposed on the base to store condensed water generated in the condenser, and a fan assembly coupled to the base to generate an air flow within the machine room. The fan assembly may include a plurality of condensation fans.

A refrigeration system includes an evaporator within which a refrigerant absorbs heat, a gas cooler/condenser within which the refrigerant rejects heat, a compressor operable to circulate the refrigerant between the evaporator and the gas cooler/condenser, a high pressure valve operable to control a pressure of the refrigerant at an outlet of the gas cooler/condenser, and a controller. The controller is configured to automatically generate a setpoint for a measured or calculated variable of the refrigeration system based on a measured temperature of the refrigerant at the outlet of the gas cooler/condenser. The setpoint is generated using a stored relationship between the measured temperature and a maximum estimated coefficient of performance (COP) that can be achieved at the measured temperature. The controller is configured to operate the high pressure valve to drive the measured or calculated variable toward the setpoint.

A refrigeration system includes an evaporator within which a refrigerant absorbs heat, a gas cooler/condenser within which the refrigerant rejects heat, a compressor operable to circulate the refrigerant between the evaporator and the gas cooler/condenser, a high pressure valve operable to control a pressure of the refrigerant at an outlet of the gas cooler/condenser, and a controller. The controller is configured to automatically generate a setpoint for a measured or calculated variable of the refrigeration system based on a measured temperature of the refrigerant at the outlet of the gas cooler/condenser. The setpoint is generated using a stored relationship between the measured temperature and a maximum estimated coefficient of performance (COP) that can be achieved at the measured temperature. The controller is configured to operate the high pressure valve to drive the measured or calculated variable toward the setpoint.

A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.