A packaged, pumped liquid, recirculating refrigeration system with charges of 10 lbs or less of refrigerant per ton of refrigeration capacity. The compressor and related components are situated in a pre-packaged modular machine room, and in which the condenser is mounted on the machine room and the evaporator is close coupled to the pre-packaged modular machine room. Prior art large receiver vessels may be replaced with a single or dual phase cyclonic separator also housed in the pre-packaged modular machine room.

A refrigeration cycle apparatus includes: a refrigerant circuit configured to circulate refrigerant; and a controller configured to control the refrigerant circuit. The refrigerant circuit includes a compressor, a first heat exchanger, a first expansion device, a second expansion device, a third expansion device, a second heat exchanger, and a cooler configured to cool a substrate of the controller. In a first path of the refrigerant circuit, the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger are connected in order of the compressor, the first heat exchanger, the first expansion device, the second expansion device, and the second heat exchanger. In a second path of the refrigerant circuit, the cooler and the third expansion device are connected in order of the cooler and the third expansion device from a first point between the first expansion device and the second expansion device to a second point between the compressor and the second heat exchanger.

A heating, ventilating, and air conditioning (HVAC) system that includes a vapor compression system having a refrigerant, a compressor of the vapor compression system configured to circulate the refrigerant through the vapor compression system, an expansion device of the vapor compression system configured to adjust a flow of the refrigerant through the vapor compression system, and a controller configured to adjust a position of the expansion device based on a measured amount of superheat of the refrigerant entering the compressor, a measured discharge temperature of the refrigerant leaving the compressor, or a combination thereof, such that the measured amount of superheat of the refrigerant entering the compressor reaches a target amount of superheat, the measured discharge temperature of the refrigerant leaving the compressor reaches a target discharge temperature, or a combination thereof.

A system for controlling or optimizing the performance of a vapor compression system by modifying the actuator commands via an output interface, that realizes thermofluid property functions and their derivatives as spline functions which are represented in a coordinate system that is aligned with a fluid saturation curve. The system includes an interface configured to receive measurement data from sensors, a memory configured to store thermofluid property data and computer-executable programs including a B-spline method, and a processor for performing the computer-implemented method. The processor is configured to take as input two thermofluid property variables, and compute a coordinate transformation in which one axis of the coordinates is aligned with the liquid and vapor saturation curves. In the saturation-curve aligned coordinates, a spline function represents the thermofluid property function, with coefficients and knots stored in memory. The spline function is constructed in a manner such that derivatives of the thermofluid property function may be discontinuous across the saturation curve.

A refrigeration system includes a heat exchanger configured to provide superheat control for the low temperature low pressure gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger by transferring heat from the high pressure high temperature superheated gas refrigerant flowing through a second side of the heat exchanger. A modulating solenoid valve is located at the inlet of the second side of the heat exchanger and configured to modulate the flow of high pressure high temperature superheated gas refrigerant flowing through the second side of the heat exchanger. A temperature sensor is located in such a way as to measure the temperature of the gas refrigerant flowing out of the evaporator and through the first side of the heat exchanger. A controller is configured to calculate the superheat of the gas refrigerant based on the measured temperature and measured pressure of the gas refrigerant and may compare the calculated superheat to a superheat threshold. If the calculated superheat is less than the superheat threshold, the controller will modulate the flow the high pressure high temperature gas refrigerant flowing through the second side of the heat exchanger. The refrigeration system may be activated in a variety of methods by appropriate control of the valves and other system components.

A refrigeration cycle device includes a compressor configured to compress and discharge a refrigerant containing oil, a refrigerant radiator configured to heat the ventilation air using the refrigerant discharged from the compressor as a heat source during a room interior heating, a refrigerant decompression unit configured to decompress the refrigerant having passed through the refrigerant radiator, an evaporator configured to evaporate the refrigerant and to function as a heat absorber during the room interior heating; and a controller configured to control the refrigerant decompression unit and to perform a fluctuation operation at least during the room interior heating. In the fluctuation operation, a throttle opening degree of the refrigerant decompression unit is changed such that a refrigerant state on a refrigerant outlet side of the evaporator is alternately changed to a superheated state having a superheat degree and a wet state containing the wet vapor.

An HVAC system includes a unit cooler, which includes a first evaporator coil, a second evaporator coil, and a blower. The HVAC system further includes a first sensor, a second sensor, a first valve, a second valve, and a controller. The controller actuates the blower to direct air to flow over the first evaporator coil and the second evaporator coil, receives measurements from the first sensor and the second sensor, initiates a defrost cycle for the first evaporator coil by transmitting instructions to close the first valve to prevent the flow of refrigerant into the first evaporator coil, transmits instructions to open the first valve when the defrost cycle for the first evaporator coil has terminated, and initiates a defrost cycle for the second evaporator coil by transmitting instructions to close the second valve to prevent the flow of refrigerant into the second evaporator coil.

A refrigeration cycle device includes a compressor, a radiator, an air-conditioning heat exchanger, a cooling heat exchanger, an air-conditioning decompression unit, a cooler-unit decompression unit, a refrigerant flow rate detector, and a controller. The radiator is configured to radiate heat of refrigerant discharged from the compressor. The air-conditioning heat exchanger absorbs heat from air to evaporate the refrigerant. The cooling heat exchanger is arranged in parallel with the air-conditioning heat exchanger in the flow of refrigerant. The air-conditioning decompression unit adjusts a decompression amount of the refrigerant flowing into the air-conditioning heat exchanger. The cooler-unit decompression unit adjusts a decompression amount of the refrigerant flowing into the cooling heat exchanger. The controller controls the operation of the cooler-unit decompression unit so that the flow rate of the refrigerant detected by the refrigerant flow rate detector exceeds a predetermined reference flow rate.

Thermal management systems include an open circuit refrigeration system featuring a first receiver configured to store a gas, a second receiver configured to store a liquid refrigerant fluid, an evaporator configured to extract heat from a heat load that contacts the evaporator, and an exhaust line, where the first receiver, the second receiver, the evaporator, and the exhaust line are connected to provide a refrigerant fluid flow path.

A control system for a cooling system configured to selectively operate one or both of a condenser fan an evaporator fan in a reverse direction RD, measure power draw at the motor against configuration data and fan motor profiles, and determine if a blockage has occurred before the static pressure has reached a critical point static pressure where the efficiency, performance, and cooling capability of the cooling system is hindered and maintenance is required to clear the blockage. By determining if blockage has occurred before the static pressure has reached the critical point static pressure, an alert or corrective action can be taken.