A refrigerator includes a first refrigeration cycle unit that is configured to circulate a first refrigerant and that includes a first compressor, a first condenser, a first expansion device, and a first evaporator, a second refrigeration cycle unit that is configured to circulate a second refrigerant and that includes a second compressor, a second condenser, a second expansion device, and a second evaporator, a first valve unit installed at an outlet side of the first compressor, and a first hot gas path configured to extend from the first valve unit to the second evaporator and configured to supply the first refrigerant to the second evaporator.

A method of controlling a refrigeration system including a medium temperature refrigeration load and a low temperature refrigeration load. The method includes selectively bypassing refrigerant between a medium temperature suction group and a low temperature suction group via a bypass line using an electronic valve positioned in the bypass line. The method also includes controlling flow of refrigerant between the medium temperature suction group and the low temperature suction group via a controller communicatively coupled to the valve, and modulating the valve at any position between a closed position and a full open position to vary an amount of refrigerant flow between the medium temperature suction group and the low temperature suction group in response to determining, via the controller, one or both of a state of the medium temperature suction group and a state of the low temperature suction group.

A compressor system for a cryocooler includes a compressor unit that includes a compressor main body compressing a refrigerant gas of the cryocooler and a liquid-cooled heat exchanger cooling, through heat exchange with a cooling liquid, at least one of the refrigerant gas compressed by the compressor main body and an oil lubricating the compressor main body, a supply line through which the cooling liquid is supplied from a main chiller to the liquid-cooled heat exchanger, a collecting line through which the cooling liquid is collected from the liquid-cooled heat exchanger to the main chiller, and a backup chiller that is provided outside the compressor unit, circulates the cooling liquid to the liquid-cooled heat exchanger in place of or together with the main chiller, and includes a circulation pump and a cooler cooling the cooling liquid on an inlet side or outlet side of the pump

An exemplary system is for a facility including a first heating/cooling zone and a water delivery system configured to deliver domestic water to a point of water use. The system generally includes a facility loop having a facility loop refrigerant flowing therethrough, a first zone heat pump configured to transfer thermal energy between the facility loop refrigerant and the first heating/cooling zone, and a first water-source heat pump configured to transfer thermal energy between domestic water upstream of the point of water use and the facility loop refrigerant.

A gaseous compression system for compressing a gas from an initial pressure to an exit pressure with a first, blower compression bank and a second, mechanical compression bank. Each compression bank has plural stages of gaseous compression with a gaseous fluid compressor and a heat pump intercooler. The heat pump intercooler comprises a cascading heat pump intercooler with a high temperature section, a medium temperature section, and a low temperature section, each temperature section with an intercooler core. Each stage of the blower compression bank has a high-pressure blower, and each stage of the mechanical compressor bank has a mechanical compressor. A final stage of gaseous compression is without a heat pump intercooler. Gas compressed by the gaseous fluid compression system can be injected into a gas-driven generator to generate electric power from movement of a working fluid induced by injection of the compressed gas.

A temperature control system is used for controlling a temperature of a control target. The system includes: a first circulation circuit through which a first heat transfer medium circulates; a second circulation circuit that is independent of the first circulation circuit and through which a second heat transfer medium circulates; and a third circulation circuit that is independent of the first circulation circuit and the second circulation circuit and through which a third heat transfer medium circulates. The third heat transfer medium has a usable temperature range wider than usable temperature ranges of the first heat transfer medium and the second heat transfer medium.

A heat recovery system includes a compressor, a solar panel, and a first heat exchanger and a second heat exchanger in fluid connection to form a closed circuit. The compressor is configured to facilitate fluid movement in the fluid circuit between the solar panel, the first heat exchanger and the second heat exchanger. The solar panel includes a plurality of solar cells connected in parallel, and each solar cell includes a plurality of metal tubes for fluid to pass through. A temperature sensor is mounted within each of the solar cells and configured to measure temperature inside the respective solar cell. Each solar cell is connected to the circuit via a respective pressure valve, and the status of the pressure valve is configured to depend on the measurement of the temperature sensor in the respective solar cell.

The present disclosure relates to a heating, ventilation, and/or air conditioning (HVAC) system that has a first circuit and a second circuit that each have a compressor and a condenser, a conduit extending from the second circuit downstream of the condenser to the first circuit upstream of the compressor, a valve along the conduit that may manage flow therethrough, and a controller that may operate the HVAC system in a first mode such that each circuit separately circulates the refrigerant in each circuit and transition to a second mode such that refrigerant-sharing occurs between the circuits. In response to a request to transition from the second mode to the first mode, the controller may determine an amount of refrigerant subcooling, compare the amount to a threshold value associated with the first mode, and instruct opening of the valve upon a determination that the amount is less than the threshold value.

A heat source device includes a heat medium channel through which a heat medium flows, a plurality of refrigerant circuits through which refrigerant circulates, and a plurality of heat-medium heat exchangers configured to cause heat exchange to be performed between the heat medium in the heat medium channel and the refrigerant in the refrigerant circuits. The plurality of heat-medium heat exchangers include a first heat-medium heat exchanger to which at least one of the refrigerant circuits is connected and a second heat-medium heat exchanger to which a greater number of the refrigerant circuits are connected than to the first heat-medium heat exchanger.

The present invention provides a system and method for an improved multistage, cascade refrigeration system using hot gas defrost to rid the evaporator of ice build-up which accumulates over time, while the air in the evaporator enclosure remains below the freezing point of water. The present invention thus provides greater defrost flexibility with increased ease of design and implementation than current refrigeration systems, which allows for more robust hot gas defrost function for multistage refrigeration systems, such that it is unaffected by temperature changes of the condensing fluid (ambient air temperature for air cooled condensers, water temperature for water cooled condensers), and can be readily adapted to any refrigerant suitable for a selected temperature range.