A heat pump includes an indoor heat exchanger; an outdoor heat exchanger that is connected to the indoor heat exchanger; an accumulator that is connected to the outdoor heat exchanger; an evaporative heat exchanger that is provided between the outdoor heat exchanger and the accumulator; and a bypass circuit that that is configured to enable a refrigerant that has flowed out of the indoor heat exchanger to flow into the evaporative heat exchanger.

A heat pump is provided with a compressor; an oil separator provided on a discharge path of the compressor; an accumulator connected to the compressor via a suction path; and a bypass circuit configured to supply a gas refrigerant separated by the oil separator. The bypass circuit is connected to the suction path.

A refrigeration cycle device includes a third refrigerant passage connecting a utilization heat exchanger to a first expansion valve, a fourth refrigerant passage connecting the first expansion valve to a receiver, a fifth refrigerant passage connecting the receiver to a second expansion valve, a sixth refrigerant passage connecting the second expansion valve to an air heat exchanger, a hot-gas bypass passage connecting a discharge passage to the sixth refrigerant passage, a hot-gas bypass valve, an internal heat exchanger to exchange heat between the liquid refrigerant inside the receiver and the refrigerant passing through the suction passage, a liquid bypass passage including an inlet portion connected to the fourth refrigerant passage, the fifth refrigerant passage, or a lower portion of the receiver, and an outlet portion connected to the suction passage upstream of the internal heat exchanger, and a liquid bypass valve.

A fuel cooling system includes a refrigeration unit configured to circulate a refrigerant, a bypass cooling circuit (132) fluidly coupled to the refrigeration unit, and a power generation system operably coupled to the refrigeration unit. The power generation system includes a fuel tank (34) fluidly coupled to an engine (32), and a fuel cooling circuit (160) is fluidly coupled between the fuel tank and the engine. The fuel cooling circuit is thermally coupled to the bypass cooling circuit and is configured to cool a fuel by thermal exchange with the refrigerant.

A heat pump system comprises a compressor, a first heat exchanger, a second heat exchanger, a mode switching valve, a throttling element and a reservoir, wherein the throttling element is arranged on a flow path between the first heat exchanger and the second heat exchanger; and which further comprises a mode switching flow path in which a first flow path and a second flow path are arranged, the reservoir is arranged on the second flow path and each flow path is controllably opened or closed to realize different functional modes.

Systems and methods for controlled subcooling of working fluid in a heating, ventilation, air conditioning and refrigeration (HVACR) system through a suction line heat exchanger are disclosed. The suction line heat exchanger may receive a first fluid flow travelling to a suction of the compressor in the HVACR system and second flow of working fluid that is travelling from a heat exchanger receiving the discharge of the compressor to an expansion device. Superheating of the first working fluid may be determined based on temperature measurements prior to and following the suction line heat exchanger. The superheating may be used to control the quantity of the second flow of working fluid introduced into the suction line heat exchanger, for example to maintain superheat that is below a threshold value. These systems may include chillers and heat pump systems, and methods may be applied to chillers or heat pump systems.

A flash gas bypass system includes a separation assembly having an inlet configured to receive a refrigerant flow from an expansion valve. A bypass conduit is coupled to a first port of the separation assembly and configured to receive a first portion of the refrigerant flow via the first port, where the first portion of the refrigerant flow includes flash gas. A second port of the separation assembly is coupled to an outlet conduit in fluid communication with an evaporator. The outlet conduit is configured to receive the second portion of the refrigerant flow via the second port and direct the second portion of the refrigerant flow toward the evaporator, where the second portion of the refrigerant flow includes liquid refrigerant. A filter is configured to redirect droplets captured by the filter from the first portion of the refrigerant flow into the second portion of the refrigerant flow.

A method for defrosting an evaporator, includes: (i) closing an outlet part that serves as a refrigerant outlet of the evaporator; (ii) closing an inlet part that serves as a refrigerant inlet of the evaporator; (iii) connecting the outlet part and the inlet part to one another; (iv) heating the evaporator. An evaporator, includes: an inlet part that serves as a refrigerant inlet; a first switching valve that is placed in the inlet part; an outlet part that serves as a refrigerant outlet; a second switching valve that is placed in the outlet part; a bypass pathway that connected the inlet part and the outlet part to one another; a horizontal pipe that is communicated with the inlet part; and a vertical pipe that connects the horizontal pipe and the outlet part to one another. A cooling apparatus can include the evaporator.

A heating, ventilation, and/or air conditioning (HVAC) system includes a first condenser coil of a refrigerant circuit, wherein the first condenser coil is configured to receive a first refrigerant flow from a compressor of the refrigerant circuit, a modulating valve of the refrigerant circuit, and a control circuitry communicatively coupled to the modulating valve. The modulating valve is configured to receive a second refrigerant flow from the compressor and configured to direct the second refrigerant flow to a second condenser coil of the refrigerant circuit and to a reheat coil of the refrigerant circuit in a parallel flow arrangement, and the control circuitry is configured to operate the modulating valve to apportion the second refrigerant flow between the second condenser coil and the reheat coil based on a detected operating parameter of an air flow directed across the reheat coil.

A cooling system has a direct expansion mode and a pumped refrigerant economizer mode and a controller. The controller includes a load estimator that estimates real-time indoor load on the cooling system and uses the estimated real-time indoor load to determine whether to operate the cooling system in the pumped refrigerant economizer mode or in the direct expansion mode.