A fluid cooling apparatus capable of improving liquefaction efficiency of a fluid by appropriately cooling the fluid in various temperature ranges through a simple process. The fluid cooling apparatus includes an expansion unit including a plurality of expanders, which receive refrigerants through a plurality of paths to expand the refrigerants and discharge the expanded refrigerants having different temperatures, a heat exchanger receiving the refrigerants having different temperatures from the expansion unit to cool the fluid in multistages, a precompression unit including a plurality of precompressors, which receive the refrigerants passing through the heat exchanger to compress the refrigerants and discharge the compressed refrigerants at the same pressure, a mixing tube configured to mix the refrigerants discharged from the precompression unit to supply the mixed refrigerant, and a main compression unit connected to the mixing tube to compress the mixed refrigerant and supply the compressed refrigerant to the expansion unit.

Systems and methods are provided for controlling compressor systems to ensure sufficient pressure differentials to provide cooling. A compressor system includes a compressor, a suction pressure sensor at a suction of the compressor, a discharge pressure sensor, a condenser, an expansion device, a liquid line, a liquid line pressure sensor, an evaporator, a condenser blower and a controller. The method includes determining a pressure target based on an intermediate pressure within the compressor and a threshold cooling differential pressure value, determining a pressure ratio setpoint based on the pressure target and a liquid line pressure measured by the liquid line pressure sensor, controlling the condenser blower to operate based on the determined pressure ratio setpoint, determining a subcooling setpoint based on the pressure target and the liquid line pressure in the compressor system, and controlling the expansion device to operate based on the subcooling setpoint.

To reduce the possibility that temperature of refrigerant discharged from a compressor of a refrigeration apparatus becomes excessively high by controlling torque of a motor built into the compressor, the compressor includes the motor having rotation thereof controlled by inverter control. An inverter controller controls torque of the motor using inverter control when operation frequency of the compressor is at least one value within a range of from 10 Hz to 40 Hz. When at least the operation frequency is within the range of from 10 Hz to 40 Hz, torque of the motor is controlled, and under a predetermined condition in which temperature of refrigerant discharged from the compressor easily becomes excessively high, a device controller controls devices provided in a refrigerant circuit such that refrigerant sucked into the compressor is placed in a wet vapor state.

A method of cooling a motor coupled to a compressor of a chiller includes adjusting a position of a motor cooling valve located fluidly between the motor and a refrigerant source, using a motor temperature control system coupled to the motor cooling valve to regulate an amount of refrigerant introduced into the motor from the condenser according to a temperature control scheme performed as a function of a monitored temperature in the motor, a first temperature threshold, and a second temperature threshold lower than the first temperature threshold. The temperature control scheme includes a motor cooling control process that adjusts the position of the motor cooling valve based on a stator winding temperature set point relating to stator windings of the motor. A proportionally limited close command override associated with a first temperature range above the second temperature threshold proportionally limits a close command provided to the motor cooling valve.

A refrigeration apparatus, including a main circuit (1) for circulation of a main flow (90) of refrigerant, and a lubrication branch (20), comprising a lubrication inlet (21), configured to derive a lubrication flow (91) from the main flow (90) circulating through a supply part (16) of the main circuit; and a lubrication outlet (22), to feed the compressor (2) with the lubrication flow (91) for lubrication. According to the invention, the refrigeration apparatus further includes: a subcooling branch (40), comprising a subcooling inlet (41), connected to an evaporator (8) of the main circuit (1), so as to derive a subcooling flow (92), and a subcooling outlet (42), connected to the evaporator (8), for reintroducing the subcooling flow (92) into the main flow (90); and a subcooling heat exchanger (31).

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.

A refrigeration apparatus (1) includes a main refrigerant circuit (2) including a positive displacement compressor (4), a condenser (6), an expansion valve (8), and an evaporator (10), through which a refrigerant circulates successively in a closed loop circulation, a lubrication refrigerant line (18) connected to the main refrigerant circuit (2) between the condenser (6) and the expansion valve (8) or to the condenser (6), in which circulates a portion of the refrigerant of the main refrigerant circuit (2) and connected to the compressor (4) for lubrication of said compressor (4) with the refrigerant, at least one lubrication refrigerant storing cavity (70) connected to the lubrication refrigerant line (18), the lubrication refrigerant storing cavity (70) being configured to store liquid refrigerant for lubrication of the compressor (4) said at least one lubrication refrigerant storing cavity (70) being provided within the compressor (4).

The present invention relates to a portable water dispenser for dispensing cooling water to an overheated compressor of an ACU. The water dispenser includes a splash guard and a core that is installed inside the splash guard. The core includes a magnet that firmly but temporarily attaches the water dispenser to the outer surface with the compressor. Water flow is controlled to convert the flow exiting a water hose into a uniformly distributed curtain covering the entire outer surface of the compressor. The splash guard prevents water loss because it redirects any splashes towards the compressor.

A cooling device for a frequency converter of a refrigerating or conditioning plant comprises at least one thermal exchange element supplied with a total flow rate of refrigerating fluid; regulating means configured to selectively regulate the total flow rate of refrigerating fluid on the basis of at least one parameter indicative of the temperature of the frequency converter.

A compressor includes a compression mechanism, a motor, a drive shaft, and a motor cooler. The compressor is configured to compress a working fluid. The motor dives the compression mechanism and is housed within a motor housing. The drive shaft is engaged with the motor and the compression mechanism and is configured to drive operation of the compression mechanism. The motor cooler is disposed adjacent the motor and is configured to pump a cooling working fluid around the motor. The motor cooler includes a pump that pumps the cooling working fluid into the motor housing based on a rotational speed of the drive shaft.