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.

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.

To provide a refrigeration cycle device that has a refrigerant flow path with a structure to form a counter flow of air and refrigerant not only during cooling, but also during heating, and that allows low-pressure two-phase refrigerant to flow through a liquid pipe and can thereby reduce the amount of refrigerant needed. The refrigeration cycle device includes: an outdoor unit 1 including a compressor 5, a four-way valve 6, an outdoor heat exchanger 7, and an outdoor expansion valve 9, the four-way valve 6 being configured to switch between cooling operation and heating operation; an indoor unit 2 including an indoor heat exchanger 12 and an indoor expansion valve 14; and a gas pipe 3 and a liquid pipe 4 configured to connect the outdoor unit 1 and the indoor unit 2; and at least either one of a first bridge circuit 10 having a configuration including a plurality of flow path opening-closing units 11 to allow the refrigerant to flow through the outdoor heat exchanger 7 in the same direction both during the cooling operation and during the heating operation, and a second bridge circuit 15 having a configuration including a plurality of flow path opening-closing units 16 to allow the refrigerant to flow through the indoor heat exchanger 12 in the same direction both during the cooling operation and during the heating operation.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, an intercooler, and an oil discharge pipe. The intercooler cools the refrigerant discharged by the low-stage compressor before the refrigerant is sucked into the high-stage compressor. The intercooler is disposed between the refrigerant pipes. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on an upstream side of the intercooler.

An outdoor unit according to the present disclosure includes: a compressor that sucks refrigerant, compresses the sucked refrigerant, and discharges the compressed refrigerant; a first refrigerant flow switching device that switches a flow passage for the refrigerant between a flow passage for a cooling operation and a flow passage for a heating operation; a heat-source-side heat exchanger that causes heat exchange to be performed between the refrigerant and external fluid; a heat-source-side backflow prevention device and a connection pipe that are included in a flow passage for the refrigerant in which an outlet from which the refrigerant flows to an outside region and an inlet into which the refrigerant flows from the outside region are unchanged regardless of which of the cooling operation and the heating operation is performed; and a flow passage pipe through which part of the refrigerant having flowed from the inlet passes in the cooling operation.

A heat pump system includes a first unit; a second unit connected to a first flow path of the first unit; and a third unit connected to a second flow path of the first unit and connected to the second unit. The heat pump system can operate in a cooling and water heating mode and a heating and water heating mode, wherein, in the cooling and water heating mode, the heat pump system is configured to switch a switching assembly to a first position and connect the at least one first heat exchangers and the second heat exchanger in series; in the heating and water heating mode, the heat pump system is configured to switch the switching assembly to a second position and connect the second heat exchanger and the at least one third heat exchangers in parallel.

The present invention addresses a problem of providing a mixed refrigerant that combines three kinds of performances of having a refrigeration capacity (this may also be referred to as a cooling capacity) and of having a coefficient of performance (COP) equivalent to those of R410A, and of having a sufficiently small GWP. As a means for solving the problem, provided is a refrigerant-containing composition, wherein the refrigerant contains trans-1,2-difluoroethylene (HFO-1132 (E)), trifluoroethylene (HFO-1123) and 2,3,3,3-tetrafluoro-1-propene (R1234yf), and R32.

A refrigeration cycle apparatus includes a heat source unit configured to supply refrigerant, a first distribution unit and a second distribution unit respectively connected to the heat source unit, and a distribution pipe located between the heat source unit and the first distribution unit and the second distribution unit for distributing the refrigerant flowing from the heat source unit into the first distribution unit and the second distribution unit. Further, the first distribution unit and the second distribution unit individually include a heat exchanger configured to serve as a condenser. Further, if the refrigerant flowing through the distribution pipe is unevenly distributed into the first distribution unit and the second distribution unit, a degree of subcooling at an outlet of the heat exchanger of one of the first distribution unit and the second distribution unit of which the distributed refrigerant is of high quality is increased.

The present application provides an outdoor unit and a heat pump system. The outdoor unit includes a compressor, a valve assembly, an outdoor heat exchanger, a first pipeline port and a second pipeline port; a first branch that connects the valve assembly and the first pipeline port, the first branch being provided with the outdoor heat exchanger and a first switch valve assembly; a second branch that connects the mode switch valve assembly and the first pipeline port, wherein the second branch is provided with a second switch valve assembly; a third branch that connects the second pipeline port and the refrigerant inlet of the outdoor heat exchanger. The first and second switch valve assemblies control the on and off of the first branch and the second branch so that the refrigerant flows through the refrigerant inlet and the refrigerant outlet of the outdoor heat exchanger.

A multistage compression system uses refrigerant and oil. The multistage compression system includes a low-stage compressor that compresses the refrigerant, a high-stage compressor that further compresses the refrigerant compressed by the low-stage compressor, refrigerant pipes that-introduce the refrigerant compressed and discharged by the low-stage compressor into a suction part of the high-stage compressor, a pressure reducing element disposed between the refrigerant pipes, an accumulator disposed between the refrigerant pipes at a downstream side of the pressure reducing element and at an upstream side of the high-stage compressor, and an oil discharge pipe. The oil discharge pipe discharges the oil in the low-stage compressor. The oil discharge pipe connects the low-stage compressor and a portion of the refrigerant pipes. The portion of the refrigerant pipes is on a downstream side of the pressure reducing element and an upstream side of the accumulator.