A cryogenic energy system for cooling and powering an indoor environment includes a cryogenic open loop comprising a cryogen source to supply a cryogen and at least one transfer-expansion stage in fluid connection with the cryogen source, each transfer-expansion stage comprising at least one heat exchanger for heat transfer therein from a hot fluid to the cryogen and a power unit for expansion therein of the cryogen that has been heated in the at least one heat exchanger to generate electricity, the at least one heat exchanger including an evaporator; and a heat supply open loop configured to provide the hot fluid for heat exchange with the cryogen in the at least one heat exchanger; the cryogenic energy system configured to perform heat removal from a first heat transfer loop of a conventional cooling system, the first heat transfer loop transferring heat obtained from air in the indoor environment.

Provided is grease capable of suppressing a decrease in a function as a lubricant even when used in a device installed in a refrigerant circuit in which a refrigerant containing a chlorine atom and an olefin bond in a molecule flows, and a refrigeration cycle apparatus using the grease as a lubricant. Grease that is used in a device installed in a refrigerant circuit in which a refrigerant containing a chlorine atom and an olefin bond in a molecule flows contains fluorine as a component. In a chiller apparatus, the grease is used as a lubricant for at least one of a first radial touchdown bearing and a second radial touchdown bearing of a compressor, a drive portion of an inlet guide vane of the compressor, and a drive portion of an expansion valve.

A refrigeration cycle device includes: a switching valve configured to switch between a battery mode in which refrigerant flows to a battery heat exchanger and a non-battery mode in which the refrigerant bypasses the battery heat exchanger; and a controller controlling a compressor and the switching valve. The controller includes an estimation unit configured to estimate an oil stagnation amount, which is an amount of lubricating oil accumulated in the battery heat exchanger in accordance with execution of the non-battery mode. The controller includes a determination unit configured to determine whether lubricating oil in the battery heat exchanger needs to be recovered on the basis of the oil stagnation amount. The controller includes an execution unit configured to execute an oil recovery mode for recovery of lubricating oil in the battery heat exchanger when the determination unit determines that lubricating oil needs to be recovered.

A free cooling unit including a heat exchanger to allow heat exchange between a first fluid and a second fluid; a first pumping assembly to pump the first fluid through a first hydraulic circuit from a first inlet port of the unit to a first outlet port of the unit; a second pumping assembly to pump the second fluid through a second hydraulic circuit from a second inlet port of the unit to a second outlet port of the module and a control module to control the functioning of the unit. The unit further includes a diverter assembly arranged between the first pumping assembly and the heat exchanger and configured to switch between a first state in which the first fluid is directed through the heat exchanger before reaching the first outlet port and a second state in which the first fluid is directly directed to the first outlet port.

A heat pump system provides at least six modes of heating, cooling, and/or domestic water heating operation, where domestic water heating may occur concurrently with heating or cooling a space in a structure. The heat pump system comprises a desuperheater positioned downstream of the compressor and operable as a desuperheater, a condenser or an evaporator, a source heat exchanger operable as either a condenser or an evaporator, a load heat exchanger operable as either a condenser or an evaporator, a reversing valve positioned downstream of the desuperheater heat exchanger and configured to alternately direct refrigerant flow from the desuperheater heat exchanger to one of the load heat exchanger and the source heat exchanger and to alternately return refrigerant flow from the other of the load heat exchanger and the source heat exchanger to the compressor, and an expansion valve positioned between the load heat exchanger and the source heat exchanger.

A gas turbine engine has a compressor section, a combustor, and a turbine section. An associated fluid is to be cooled and an associated fluid is to be heated. A transcritical vapor cycle heats the fluid to be heated, and cools the fluid to be cooled. The transcritical vapor cycle includes a gas cooler in which the fluid to be heated is heated by a refrigerant in the transcritical vapor cycle. An evaporator heat exchanger at which the fluid to be cooled is cooled by the refrigerant in the transcritical vapor cycle. A compressor upstream of the gas cooler compresses the refrigerant to a pressure above a critical point for the refrigerant. An expansion device expands the refrigerant downstream of the gas cooler, with the evaporator heat exchanger being downstream of the expansion device, and such that the refrigerant passing through the gas cooler to heat the fluid to be heated is generally above the critical point.

A heat transfer system that includes one or more heat exchangers and one or more variable control pumps that control flow through the one or more heat exchangers. At least one variable control pump is on the source side of the heat exchanger for controlling flow of a first circulation medium and at least one flow controlling mechanical device is on the load side of the heat exchanger for controlling flow of a second circulation medium. Sensors are used for detecting variables of the first circulation medium and the second circulation medium. At least one controller is configured to control at least one parameter of the first circulation medium or the second circulation medium by controlling at least one of the variable control pump or the flow controlling mechanical device using a feed forward control loop calculated from the detected variables to achieve control of the at least one parameter.

Methods and apparatuses for expelling heat may be provided. For example, an apparatus may comprise a rotating assembly, a support structure, a condenser water tank, and a control system. The apparatus may rotate the rotating assembly such that tanks of the assembly are rotated into and out of the condenser water tank. The rotation may be self-starting and controlled by a control system.

Disclosed are a carbon dioxide overlapping type heating system and a control method therefor. The heating system comprises a low-temperature stage loop, a high-temperature stage loop and a heat supply loop, wherein a low-temperature stage compressor (3) and a high-temperature stage compressor (7) are both variable-frequency compressors; and a water pump (10) is a variable-frequency water pump.

A method of operating a chiller system includes receiving an input from at least one sensor associated with a compressor of the chiller system, determining that the compressor is experiencing a surge or rotating stall event, adjusting at least one operating parameter associated with a heat rejection heat exchanger of the chiller system in response to determining that the compressor is experiencing the surge or rotating stall event, and reducing a condenser saturation temperature by adjusting the at least one operating parameter.