A refrigeration cycle apparatus includes; a refrigerant circuit in which a compressor, a heat-source-side heat exchanger, a first expansion device, a second expansion device, and a load-side heat exchanger are sequentially connected by refrigerant pipes and in which refrigerant is circulated; a controller that controls the refrigerant circuit; a bypass pipe extending from a liquid pipe between the first expansion device and the second expansion device toward a suction side of the compressor; a third expansion device provided at the bypass pipe to decompress the refrigerant that flows through the bypass pipe; and a refrigerant cooler provided at the bypass pipe and downstream of the third expansion device to cause heat exchange to be performed between the refrigerant decompressed by the third expansion device and heat generated from the controller.

System and methods for OCR sensing with a suction-line accumulator are provided. The accumulator may include a sensor configured to detect the level of oil. The accumulator may further include a valve which opens when oil is at a high-level and closes when oil is at a low-level. The accumulator may measure a mass flow rate of oil in the vapor compression cycle system based on an amount of time taken to fill a portion of the accumulator. The accumulator may further determine an oil circulation ratio based on the measured time taken to fill the portion of the accumulator. The smart accumulator may output the oil circulation ratio.

A liquid level detector includes: a vertically-mounted accumulator configured to store refrigerant; a heater configured to heat the accumulator; a temperature detector configured to detect a surface temperature of the accumulator; a pressure detector configured to detect a pressure of the refrigerant in the accumulator; and a controller configured to detect a position of a liquid surface of the refrigerant in the accumulator based on a surface temperature of the accumulator detected by the temperature detector when the accumulator is heated by the heater, and a pressure of the refrigerant in the accumulator detected by the pressure detector.

An air-conditioning apparatus is able to ensure an appropriate flow rate of refrigerant and an appropriate amount of oil returned to a compressor that match operation conditions regardless of an operating state of a refrigerant circuit and a change in an operation condition. The air-conditioning apparatus includes: a first detector configured to detect a refrigerant temperature within an accumulator; a storage unit configured to store information regarding a two-layer separation temperature of refrigerant and refrigerating machine oil; a determiner configured to compare the refrigerant temperature with the two-layer separation temperature and determine a two-layer separation state of the refrigerant and the refrigerating machine oil; a second detector configured to detect a state of the refrigerant sucked by the compressor; and a control unit configured to adjust an opening degree of a flow control valve on the basis of the two-layer separation state and a state of the sucked refrigerant.

A compressor module for a refrigerant circuit of a motor vehicle air-conditioning system, exhibiting a modular multi-part housing with a low-pressure refrigerant inlet, a high-pressure refrigerant outlet and a compressor, characterized in that an inner heat exchanger of the refrigerant circuit is produced such that it is integrated into the compressor module, wherein the housing of the compressor module fully encloses the inner heat exchanger.

An air-conditioning system includes a plurality of indoor units; a relay unit including an intermediate heat exchanger configured to exchange heat between refrigerant and a heat medium; and a heat source unit configured to supply cooling energy or heating energy to each of the plurality of indoor units via the relay unit. The heat source unit and the relay unit are connected by a heat-source connection pipe through which the refrigerant flows, and the relay unit and the plurality of indoor units are connected by a load connection pipe through which the heat medium flows. The load connection pipe comprises a main pipe connecting between the relay unit and one of the indoor units provided at an end of the load connection pipe opposite to the relay unit. The main pipe has branch parts associated with the indoor units.

A cooling system includes a compressor operable to compress refrigerant, an accumulator upstream from the compressor. The accumulator is operable to collect liquid from the refrigerant. A sensor is located upstream from the accumulator. The sensor is operable to detect information including a temperature and a pressure of the refrigerant. The controller is in communication with the sensor. The controller is operable to determine a rate of accumulation of liquid in the accumulator based on the information from the sensor. A method of operating a cooling system is also disclosed.

Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.

A cooling system includes a compressor operable to compress refrigerant, an accumulator upstream from the compressor. The accumulator is operable to collect liquid from the refrigerant. A sensor is located upstream from the accumulator. The sensor is operable to detect information including a temperature and a pressure of the refrigerant. The controller is in communication with the sensor. The controller is operable to determine a rate of accumulation of liquid in the accumulator based on the information from the sensor. A method of operating a cooling system is also disclosed.

Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.