A refrigeration apparatus, including a main circuit for a loop circulation of a main flow of refrigerant, the main circuit including a compressor, a condenser, an expansion valve and an evaporator. The refrigeration apparatus comprises a lubrication branch, for deriving a lubrication flow from the main flow for feeding the compressor for lubrication. The main circuit includes a low-temperature part, consisting in the evaporator, the compressor inlet, and any part of the main circuit between the evaporator and the compressor inlet. The lubrication branch further includes a subcooling heat exchanger, which is configured for enabling an exchange of heat between the lubrication flow circulating through the lubrication branch and the main flow of refrigerant circulating through the low-temperature part, so that the lubrication flow may be cooled by the main flow of refrigerant circulating through the low-temperature part, within the subcooling heat exchanger.

The present disclosure relates to a heating ventilation and air conditioning (HVAC) system. The system includes a primary heat transfer loop configured to be disposed at least partially outside of a building, and the primary heat transfer loop includes a heat exchanger, a compressor configured to compress a refrigerant, where the refrigerant is reactive, a condenser configured to receive and condense the refrigerant, and an expansion device configured to reduce a temperature of the refrigerant. The system further includes a secondary heat transfer loop configured to circulate a two-phase fluid at least partially inside the building, wherein the two-phase fluid is less reactive than the refrigerant. The secondary heat transfer loop includes the heat exchanger, where the heat exchanger is configured to transfer energy from the two-phase fluid circulating in the secondary heat transfer loop to the refrigerant, and an evaporator configured to evaporate the two-phase fluid by exchanging energy with an air supply stream flowing across the evaporator.

Systems and methods for lubricant management of a compressor in an HVACR system are disclosed. A heat transfer circuit can utilize a working fluid to provide heating or cooling includes a compressor for compressing the working fluid and a heat source configured to increase a suction temperature of the working fluid entering the compressor. One or more lubricant rheological properties in a compressor system based on measurements taken at or near a bearing cavity of the compressor are determinable. A lubricant reservoir can be in thermal communication with a discharge flow path of the compressor. An internal heat exchanger can be disposed within a compressor for improving viscosity of the lubricant to be cycled back into the compressor. A heater can be located on a fluid line between a lubricant separator and a lubricant inlet. Condenser fans can be controlled.

An evaporator header can include a header body having one or more walls that define an inner cavity configured to receive a first flow of refrigerant from a plurality of evaporator flow paths. A liquid line portion can extend through the inner cavity, can define a liquid line flow path that is fluidly separated from the inner cavity, and can be configured to receive a second flow of refrigerant. A plurality of apertures can extend through the one or more walls of the header body. The evaporator head can include a plurality of flow path connectors, and each can be configured to facilitate at least some of the first flow of refrigerant from a corresponding evaporator flow path of the plurality of evaporator flow paths, into the inner cavity via a corresponding aperture of the plurality of apertures, and across at least some of the liquid line portion.

An ice making system includes: a refrigerant circuit that performs a vapor compression refrigeration cycle and that includes a compressor, a condenser that condenses refrigerant discharged from the compressor, a first expansion valve with an adjustable opening degree that decompresses the refrigerant from the condenser, a flooded evaporator that evaporates the refrigerant decompressed by the first expansion valve, and a superheater that imparts a degree of superheating to the refrigerant discharged from the flooded evaporator; a circulation circuit that circulates a medium that is cooled by the flooded evaporator; and a control device that controls the adjustable opening degree of the first expansion valve such that the superheater imparts to the refrigerant discharged from the flooded evaporator a degree of superheating at which dryness of the refrigerant is kept within a predetermined range of less than 1.

Disclosed are a refrigerator cooling system and a method for defrosting a refrigerator. The refrigerator cooling system includes a refrigerant circulation flow path provided with a compressor, a condenser, a throttling device and an evaporator. The throttling device has a throttling working mode for cooling and a defrosting working mode not used for cooling. The throttling working mode and the defrosting working mode are switched with each other. The condenser has a first heat release mode corresponding to the throttling working mode and a second heat release mode corresponding to the defrosting working mode, and a heat release amount of a refrigerant flowing through the condenser in the second heat release mode is lower than a heat release amount of the refrigerant flowing through the condenser in the first heat release mode.

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 heat pump device includes a compressor that compresses refrigerant, a motor that drives the compressor, an inverter that applies a desired voltage to the motor, and an inverter controlling unit that generates a pulse width modulation signal for driving the inverter, has, as operation modes, a heating operation mode performing heating operation of the compressor and a normal operation mode performing normal operation of the compressor to compress the refrigerant, and periodically changes carrier frequency, that is frequency of a carrier signal, in the heating operation mode.

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 heat exchange system is provided with an improved internal heat exchanger (IHX). The system includes a loop configured to circulate refrigerant through a compressor, a condenser downstream of the compressor, an expansion valve downstream of the condenser, and an evaporator downstream of the expansion device and upstream of the compressor. The system also includes an internal heat exchanger (IHX) configured to transfer heat between (i) fluid passing from the condenser to the expansion device and (ii) fluid passing from the evaporator to the compressor. In embodiments, the IHX defines a first flow path configured to transfer the fluid passing from the condenser to the expansion device, and a second flow path configured to transfer the fluid passing from the evaporator to the compressor. The first flow path crosses the second flow path within the interior of the IHX.