Abstract: A refrigeration cycle device includes: a switching valve configured to switch between a battery mode in which refrigerant flows to a battery heat exchanger and a non-battery mode in which the refrigerant bypasses the battery heat exchanger; and a controller controlling a compressor and the switching valve. The controller includes an estimation unit configured to estimate an oil stagnation amount, which is an amount of lubricating oil accumulated in the battery heat exchanger in accordance with execution of the non-battery mode. The controller includes a determination unit configured to determine whether lubricating oil in the battery heat exchanger needs to be recovered on the basis of the oil stagnation amount. The controller includes an execution unit configured to execute an oil recovery mode for recovery of lubricating oil in the battery heat exchanger when the determination unit determines that lubricating oil needs to be recovered.

Abstract: A controller is configured to exchange information with a building automation system and includes various executable programs for determining a real time operating efficiency, simulating a predicted or theoretical operating efficiency, comparing the same, and then adjusting one or more operating parameters on equipment utilized by a building's HVAC system. The controller operates to adjust an operating efficiency of the HVAC system. An adjustment module utilized by the controller may modify the HVAC equipment parameters based on the likelihood that various HVAC equipment operates in parallel and on-line near its natural operating curve. In addition, the adjustment module may include a self-learning aspect that permits the controller to more efficiently make similar, future adjustments as needed.

Abstract: A method for preventing formation of droplets in a heat exchanger, in which a second medium transfers heat to a first. The method is performed by a controller which receives different temperature values (T1, T2, T3) and a pressure (P) value to be used for calculating a boiling point temperature value (TB) and determining a first temperature difference (?T1) and a second temperature difference (?T2). Generating a flow control signal, for controlling the flow of the first medium into the heat exchanger, based on the first temperature difference (?T1), the second temperature difference (?T2) and the first temperature value T1 and sending the flow control signal to a regulator device for controlling the flow of the first medium in the heat exchanger.

Abstract: An analysis method of absolute energy efficiency and relative energy efficiency of the compressed air system. For the compressed air system operating in a form of a single compressor, a gas flow rate and a corresponding operating power of the compressor operating in the single compressor model are measured under a specified flow rate. Meanwhile, influencing factors of the compressor operation are monitored. The absolute energy efficiency of the compressor is defined, and a curve of the absolute energy efficiency of the compressor varying with the operating time versus the above factors are plotted in a same coordinate system. Obtaining absolute energy efficiency data of the compressor in a corresponding state. By analyzing the absolute energy efficiency under corresponding conditions and based on the corresponding chart, the actual unit consumption of a given single compressor and its changing rule under different production and environmental operating conditions can be intuitively analyzed.

Abstract: A compressor 12 for use in a refrigerant circuit 11 using a refrigerating machine oil 60 being free of phosphoric ester and a refrigerant mixture inclusive of 1,1,2-trifluoroetylene includes a rolling piston 32 and a vane 33 in contact with the rolling piston 32 in a slidable manner. The rolling piston 32 and the vane 33 are formed of a base metal, the base metal being steel, and the base metal is exposed at a contact portion between the rolling piston 32 and the vane 33.

Abstract: The present disclosure relates to an oil flow switch, comprising a float device connected to a circulating oil passage and a floating liquid level switch element provided in the float device, wherein the float device comprises an oil inlet, an oil outlet, and a float chamber provided between the oil inlet and the oil outlet, the floating liquid level switch element is provided in the float chamber, and the float device is provided with a channel in communication with the float chamber. The oil flow switch according to the present disclosure may avoid a false alarm of the oil level switch and meanwhile mitigate disturbance to the float caused by liquid level fluctuation to reduce friction between the float and the sleeve rod. Further, a lubrication system with the above oil.

Abstract: A sealing assembly, which is mounted at a rear end of an impeller, and a turbo machine including the sealing assembly is provided, the sealing assembly includes a rotation body having a ring shape that surrounds a shaft coupled with the impeller at the rear end of the impeller; and an extension portion extending from the rotation body to the rear end of the impeller, such that an inner space is formed between the rotation body and the rear end of the impeller, wherein the extension portion is sealingly coupled with the rear end of the impeller.

Abstract: A method for adaptive power engine control of a transport refrigeration unit (TRU) is provided. The method includes determining a current compressor power of a compressor of the TRU. The method also includes determining an adaptive compressor power error of the compressor. Also, the method includes calculating and setting a target compressor power of the compressor based on the current compressor power and the adaptive compressor power error. Further, the method includes determining a suction pressure control point of the compressor based on the target compressor power and a compressor curve map. Moreover, the method includes operating the compressor with the suction pressure control point of the compressor.

Abstract: A system includes a compressor and a controller. The controller operates the compressor in a flooded-start control mode. The flooded start control mode includes operating the compressor according to at least one cycle including a first time period during which the compressor is on, followed by a second time period during which the compressor is off. The controller determines at least one of the first time period, the second time period, and a number of cycles for the flooded-start control mode. At least one of the first time period, the second time period, and the number of cycles is based on received asset data corresponding to at least one of a type and a characteristic of at least one component of the refrigeration system. The controller operates the compressor in the flooded-start control mode after determining the first time period, the second time period, and the number of cycles.

Abstract: Provided are a method and apparatus for verifying or correcting the temperature sensor and compressor pairings within the HVAC system control logic, indicating that a sensor is logically paired with the specific compressor, from amongst a tandem compressor group, to which the sensor is coupled.

Abstract: An oil separator includes a capturing member inside a main body container, which includes a first capturing member portion arranged on a side closer to an inflow pipe and a second capturing member portion being arranged on a side closer to an outflow pipe and having a porosity smaller than that of the first capturing member portion. Therefore, a driving force is generated by the capturing member having the different porosities. Through the driving force, a force of gravity, and a capillary phenomenon, oil inside the main body container is transported to an oil return pipe to prevent re-scattering of the oil, thereby being capable of suppressing reduction in oil separation efficiency. At the same time, oil return efficiency to the compressor is improved.

Abstract: An HVAC system includes a refrigerant liquid-gas separator. The liquid-gas separator is thermally coupled to electronics to transfer heat away from the electronics, and assist in vaporizing liquid refrigerant. The liquid-gas separator device includes a refrigeration section configured to couple to a refrigeration loop, and electronics thermally coupled to the refrigeration section. The refrigeration section includes: (a) a refrigerant inlet configured to receive refrigerant from the refrigeration loop; (b) a refrigerant outlet configured to release vapor refrigerant to the refrigeration loop; and (c) a cavity coupled to the refrigerant inlet and the refrigerant outlet, the cavity configured to separate liquid refrigerant from vapor refrigerant. During use of the HVAC system, heat from the electronics board is transferred to the refrigerant. The liquid-gas separator includes a check valve configured to inhibit flow of refrigerant into the liquid-gas separator device via the refrigerant outlet.

Abstract: Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors, a first heat exchanger disposed downstream of the compressors and a second heat exchanger disposed downstream of the first heat exchanger. The compressors and heat exchangers are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.

Abstract: Provided are a method and apparatus for verifying or correcting the temperature sensor and compressor pairings within the HVAC system control logic, indicating that a sensor is logically paired with the specific compressor, from amongst a tandem compressor group, to which the sensor is coupled.

Abstract: An oil separator includes a container having an inner circumferential surface of a cylindrical shape; an inlet pipe that penetrates through from an outside of the container to an inside of the container, comprises an inlet port through which the oil-containing refrigerant is introduced to the container; and a refrigerant discharge pipe that is provided coaxially with a central axis of the container in a top of the container, projects from the top of the container toward a bottom of the container, and comprises a discharge port which is disposed below the inlet port and allows oil removed refrigerant to be discharged. The oil-containing refrigerant flowing out of the inlet port of the inlet pipe is not branched by the refrigerant discharge pipe, and forms a single flow flowing in one direction along an outer circumferential surface of the refrigerant discharge pipe and the inner circumferential surface of the container.

Abstract: A heat pump device includes a compressor including a motor, a heat exchanger, an inverter, and an inverter control unit. The inverter control unit generates a drive signal for the inverter. When the compressor is heated, the inverter control unit applies, to the motor, a high-frequency voltage with which the motor cannot be rotationally driven; estimates a magnetic pole position indicating a stop position of a rotor of the motor; determines an amplitude and a phase of a voltage command based on an estimation result of the magnetic pole position and a necessary amount of heat, and generates a drive signal.

Abstract: In an air conditioning device (10) to which an outdoor unit (20) and indoor units (40) are connected, when a flow rate of a gaseous refrigerant in a gas main pipe (72a) is lower than a lower limit flow rate in main pipe, an amount of refrigerating machine oil accumulated in the gas main pipe (72a) is calculated. When gas branch pipes (72b) include a gas branch pipe (72b) having a flow rate lower than a lower limit flow rate in branch pipe even though the flow rate of the gaseous refrigerant in the gas main pipe (72a) is higher than the lower limit flow rate in main pipe, an amount of the machine oil accumulated in the gas branch pipe (72b) is calculated. When the amounts are integrated and the integrated value exceeds a set amount, oil collecting operation is performed.

Abstract: A method for controlling an air conditioner compressor includes: driving the air conditioner compressor for a first time at a first revolutions per minute (RPM) smaller than a minimum lubrication demand RPM when a lubrication demand RPM of the air conditioner compressor is smaller than the minimum lubrication demand RPM; and driving the air conditioner compressor for a second time at the minimum lubrication demand RPM when the lubrication demand RPM of the air conditioner compressor is smaller than the minimum lubrication demand RPM after the first time elapse.

Abstract: A heat pump apparatus includes a compressor compressing a refrigerant, a motor driving the compressor, an inverter device, and an inverter control unit controlling the inverter device. The inverter device includes the same number of bridge circuits as those of phases of the motor, and each of the bridge circuits includes plural pairs of series-connected switching elements. The pairs of switching elements are connected in parallel. The inverter device applies to the motor a high-frequency voltage of a frequency at which the motor does not rotate.

Abstract: A heat pump apparatus includes a compressor compressing a refrigerant, a motor driving the compressor, an inverter device, and an inverter control unit controlling the inverter device. The inverter device includes the same number of bridge circuits as those of phases of the motor, and each of the bridge circuits includes plural pairs of series-connected switching elements. The pairs of switching elements are connected in parallel. The inverter device applies to the motor a high-frequency voltage of a frequency at which the motor does not rotate.

Abstract: In a screw compressor (20), a male rotor suction end bearing (96) and discharge end bearing (90 1, 90 2, 90 3) mount the male rotor suction end shaft portion (39) and discharge end shaft portion (40). A female rotor suction end bearing (98) and discharge end bearing (92 1, 92 2) mount the female rotor suction end shaft portion (41) and discharge end shaft portion (42). At least one valve (182; 282; 382 1,382 2,382 3; 82; 582-1,582-2; 682-1,682-2; 782-1,782-2) is along a lubricant flowpath and has an energized condition and a de-energized condition. At least one restriction (184; 84-1,84-2; 84-1, 84-2,84-3; 484 1,484-2,84-3; 84 1,84 2,584; 84-1,84-2,684; 84-1,84-2,784) is along the lubricant flowpath. The at least one valve and the at least one restriction are positioned to create a lubricant pressure difference biasing the rotors away from a discharge end of the case.

Abstract: A system and method for flooded start control of a compressor are provided. An ambient temperature sensor generates ambient temperature data and a compressor temperature sensor generates compressor temperature data.

Abstract: Methods and system for managing lubricant within a vapor compression heat pump are presented. In one example, lubricant may be flushed from selected areas of a heat pump to other areas of the heat pump where lubricant is desired. The lubricant may be flushed in full flushing mode or in a partial flushing mode.

Abstract: A refrigeration apparatus includes a compressor and a controller. The compressor has a casing and a compression element. Compressed refrigerant is sent out of the casing after being discharged into an internal space of the casing. An oil sump formed in the casing collects refrigerator oil. A heater heats the refrigerator oil collected. The controller controls the heater while the refrigeration apparatus is stopped so that a temperature of the refrigerator oil collected in the oil sump reaches a first oil temperature target value. The first oil temperature target value is set in order to keep a refrigerant condensation amount of the refrigerant equal to or less than an allowable condensation amount at which the concentration or viscosity of the refrigerator oil needed to lubricate the compressor can be maintained. The refrigerant condensation amount is caused by in-dome condensation at the start of operation of the refrigeration apparatus.

Abstract: In a thermodynamic cycle with at least one first heat exchanger for creating a first heated or partially evaporated working medium flow by heating or partially evaporating a liquid working medium flow by heat transmission from an expanded working medium flow; a second heat exchanger for creating a second at least partially evaporated working medium flow; a separator for separating a liquid from a vaporous phase of the second flow; and an expansion device for creating an expanded vaporous phase, pressure pulsations are prevented during the start-up of the cycle in that the vaporous phase separated by the separator is conducted past the expansion device and the first heat exchanger. The liquid phase separated by the separator is cooled in the first heat exchanger by heat transfer to the liquid flow. After the first heat exchanger, the cooled, separated, liquid phase and the separated vaporous phase are brought together.

Abstract: Provided is an air conditioner which comprises multiple outdoor units, the air conditioner being configured so that, with the use of a low cost configuration, required refrigeration machine oil is supplied to all the outdoor units through refrigerant piping and so that the air conditioner has increased reliability. An air conditioner is provided with multiple indoor units and with four outdoor units which are connected to the multiple indoor units through refrigerant piping. A line of first refrigerant piping leading from the multiple indoor units is branched into two lines of second refrigerant piping, each of the two lines of second refrigerant piping is branched into two lines of third refrigerant piping, and the four lines of third refrigerant piping are respectively connected to the four outdoor units.

Abstract: A climate control system is provided and may include a compressor, a first heat exchanger in fluid communication with the compressor, a second heat exchanger in fluid communication with the compressor and the first heat exchanger, and a third heat exchanger disposed between the first heat exchanger and the second heat exchanger and including an inlet and an outlet. A conduit may be fluidly coupled to the third heat exchanger and the compressor and may selectively supply fluid to the compressor. A valve may control a volume of fluid supplied to the compressor via the conduit. A controller may control the valve based on a temperature difference between the outlet of the third heat exchanger and the inlet of the third heat exchanger.

Abstract: Provided is an air conditioner. The air conditioner including a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion device includes a supercooling device for supercooling a refrigerant condensed in the outdoor heat exchanger or the indoor heat exchanger, an injection passage through which the refrigerant passing through the supercooling device is introduced into an injection inflow part of the compressor, a bypass passage extending from the injection passage to a suction part of the compressor to bypass the refrigerant, and a passage opening/closing part disposed in at least one of the injection passage and the bypass passage to selectively block a flow of the refrigerant.

Abstract: A refrigerant system is provided with a pulse width modulation suction valve and a second valve on a line that bypasses the pulse width modulation suction valve. This second valve has a variable opening. In this manner, the pressure within the compressor shell is maintained at the lowest possible level regardless of the system operating conditions, when the pulse width modulation suction valve is cycled to a closed position. Further, the second valve can continue providing capacity control, should the pulse width modulation suction valve fail.

Abstract: A heat pump system includes: a heat-source-side refrigerant circuit having a heat-source-side compressor, a first usage-side heat exchanger operable as a radiator of heat-source-side refrigerant, and a heat-source-side heat exchanger operable as an evaporator of heat-source-side refrigerant; and a usage-side refrigerant circuit having a usage-side compressor arranged to compress usage-side refrigerant with a pressure of the usage-side refrigerant corresponding to a saturated gas temperature of 65° C. that is 2.8 MPa or less at gauge pressure, a refrigerant-water heat exchanger operable as a radiator of usage-side refrigerant to heat an aqueous medium, and a first usage-side heat exchanger operable as an evaporator of usage-side refrigerant by the radiation of heat-source-side refrigerant. The weight of usage-side refrigerant enclosed in the usage-side refrigerant circuit is one to three times the weight of refrigeration machine oil enclosed to lubricate the usage-side compressor.

Abstract: An air-conditioning apparatus includes an outdoor air temperature sensor detecting an outdoor temperature; a compressor temperature sensor detecting a temperature of an outer wall of a compressor; a liquid-level and concentration detection sensor detecting a liquid surface level in the compressor and a concentration of a lubricant oil in a liquid in the compressor; an electric heater heating the compressor; and a controller that carries out preheating to the compressor by driving the electric heater when a detection value of the outdoor air temperature sensor is higher than or equal to a detection value of the compressor temperature sensor and, further, when the liquid surface level detected by the liquid-level and concentration detection sensor is higher than or equal to a predetermined level and the concentration of the lubricant oil in the liquid is lower than a preset minimum required concentration.

Abstract: Methods of removing moisture from a compressor using a sorbent technology are provided. A dehydration device incorporating the sorbent technology is disposed in a system that contains a hygroscopic fluid. By passing the hygroscopic fluid over the sorbent technology, moisture is removed from the hygroscopic fluid. The systems include sealed devices and integral components for heating, ventilation, and air conditioning (HVAC) systems and refrigeration devices.

Abstract: Systems and methods are described with respect to refrigerant recovery techniques. In one example, a system for recovering a refrigerant from an appliance includes a valve module, a separator, a degasser, and a system controller. The valve modules include a valve and a valve controller configured to control the valve and transmit data. The separator separates the refrigerant from an oil and is in fluid communication with the valve. The degasser further separates the refrigerant from the oil and is in fluid communication with the separator. The system controller is configured to receive data from the valve controller.

Abstract: A refrigeration chiller employs a centrifugal compressor the impellers of which are mounted on a shaft which is itself mounted for rotation using rolling element bearings lubricated only by the refrigerant which constitutes the working fluid of the chiller system. Apparatus is taught for providing liquid refrigerant to (1.) the bearings immediately upon chiller start-up, during chiller operation and during a coastdown period subsequent to shutdown of the chiller and (2.) the drive motor of the chiller's compressor for motor cooling purposes. By use of a variable speed-driven motor to drive the compressor, optimized part load chiller performance is achieved in a chiller which does not require or employ an oil-based lubrication system.

Abstract: A refrigeration cycle apparatus includes a refrigerant circuit of a refrigeration cycle through which a refrigerant that transits in a supercritical state is allowed to flow, and a flow dividing device that divides the flow of a high-pressure liquid refrigerant in a subcritical state into two or more parts. The flow dividing device is configured such that the device is oriented substantially in the horizontal direction or substantially upward in the vertical direction relative to the direction of flow of the refrigerant in a liquid state. With such a configuration, the flow of refrigerating machine oil is equally divided, thus offering high energy saving while keeping heat-medium conveyance power at a low level without reducing the heat exchanging performance.

Abstract: An air conditioner includes a plurality of compressors, an intake passageway, a bypass unit, and an expansion valve. The intake passageway distributes a fluid to each of the compressors. The bypass unit includes a plurality of bypass pipes connected respectively to the compressors and a common bypass pipe to discharge the fluids from the compressors to the intake passageway. The expansion valve is provided to the bypass unit to control a flow of fluid from the common bypass pipe to the intake unit.

Abstract: A refrigeration device includes a radiator, an evaporator, a compressor, a heater and a control device. The radiator causes a refrigerant to radiate heat. The evaporator causes the refrigerant to evaporate. The compressor compresses the refrigerant circulating between the radiator and the evaporator. The heater heats lubricating oil in the compressor. The control device controls the heater so that an oil temperature of the lubricating oil in the compressor reaches an oil temperature target value obtained by adding a predetermined temperature to saturation temperature of the refrigerant in the compressor.

Abstract: An air conditioner (10) composed of a refrigerating apparatus includes a controller (90). A heating control section (91) of the controller (90) feeds electric current in an open phase state to an electric motor (62) of a compressor (30) to heat the compressor (30) in operation stop of the air conditioner (10). The heating control section (91) monitors the detection value of an outdoor air temperature sensor (72) during the operation stop of the air conditioner (10) and keeps on stopping feeding the electric current to the electric motor (62) during the time when the detection value decreases.

Abstract: A refrigeration system (2) comprises a condenser/gas cooler (4), an intermediate expansion device (6) and a refrigerant collecting container (8); a normal refrigeration branch (10) connecting the refrigerant collecting container (8) to the condenser/gas cooler (4) said normal refrigeration branch (12) comprising a first expansion device (12), a first evaporator (14) and a compressor unit (16) of the normal refrigeration branch (10); a freezing branch (18) connecting the refrigerant collecting container (8) to the condenser/gas cooler (4), said freezing branch (18) comprising a second expansion device (20), a second evaporator (22), and a first compressor unit (24) and a second compressor unit (26) of said freezing branch (18), the first and second compressor units (24, 26) of the freezing branch (18) being connected in series.

Abstract: A cooling system for a motor powering a compressor in a vapor compression system includes a housing enclosing the motor and a cavity located within the housing. A fluid circuit circulates a cooling fluid in the motor, and includes a first connection in the housing to receive cooling fluid and a second connection in the housing to remove cooling fluid. The fluid circuit includes a passageway for cooling fluid positioned in an internal chamber formed in a motor shaft.

Abstract: A heating/cooling system design enabling one to maintain a superheat level of more than 1 degree F. and up to 10 degrees F., incorporating a specially designed accumulator, optional special oil return means, a specially designed receiver, and, when utilized in a DX geothermal system application, a preferable sub-surface liquid refrigerant transport line insulation design, as well as a design enabling the utilization of at least two compressors to increase heat transfer temperature differentials together with special oil separators.

Abstract: The present invention relates to a method for increasing the solubility of oils in refrigerant compositions within a system using a refrigerant compressed with a mechanical device by adding polyolester directly to the refrigerant followed by charging a mixture of the polyolester and refrigerant into the system (air conditioner, refrigerator, etc.). The present invention also relates to a method of optimizing mineral oil return in a system using a refrigerant compressed with a mechanical device and a method of cleansing heat exchange tubes of a system using a refrigerant compressed with a mechanical device by adding polyolesters directly to a refrigerant composition followed by charging a mixture of the polyolester and refrigerant into the system.

Abstract: Overhung axial compressor, chemical reactor and method for compressing a fluid. The overhung axial compressor includes a casing configured to be vertically split along a vertical axis for access to an inside of the casing and a removable cartridge. The removable cartridge is configured to fit inside the casing and to be detachably attached to the casing. The removable cartridge includes a shaft disposed along a horizontal axis, the shaft being configured to rotate about the horizontal axis, a bearing system attached to the removable cartridge and configured to rotationally support a first end of the shaft, and plural blades disposed toward a second end of the shaft such that the second end is overhung inside the casing. The compressor also includes a guide vane mechanism configured to connect to the removable cartridge, the guide vane mechanism being configured to adjust a flow of a fluid to the plural blades.

Abstract: In an air-conditioning apparatus that uses a refrigerant, which operates in a transcritical cycle, and refrigerating machine oil, which has low miscibility with the refrigerant, in a refrigerant circuit for a refrigeration cycle connected to a compressor, a radiator, an expansion mechanism, and an evaporator, the air-conditioning apparatus includes a flow regulating mechanism provided in the refrigerant circuit, and flow control means that controls the flow regulating mechanism. If a refrigerant flow velocity at an outlet side of the radiator is lower than a predetermined threshold value, the refrigerant flow velocity at the outlet side of the radiator is increased by the flow control means so that oil-return operation that returns the refrigerating machine oil discharged from the compressor to the compressor is performed for at least a predetermined time period.

Abstract: In an air conditioner provided with an oil-return-operation control portion that performs an oil-return operation, when oil-return conditions are satisfied, by controlling the rotational speed of a compressor, the degree of opening of an expansion valve, etc., with a predetermined refrigerant cycle and provided with high-outdoor-air-temperature oil-return operation means for performing a forced oil-return operation via the oil-return-operation control portion when an outdoor temperature increases and a state in which a detection value of an outdoor air temperature sensor is higher than a set value continues for a predetermined period of time, the oil-return operation is prohibited for a certain period of time after performing the forced oil-return operation via the high-outdoor-air-temperature oil-return operation means.

Abstract: A heat transfer device, including an evaporator, a condenser, a compressor fluidly coupled to the evaporator and the condenser. A refrigerant/oil mixture is routed to the compressor, the evaporator, and the condenser. An apparatus for moisture detection in the refrigerant/oil mixture includes the apparatus being in fluid communication with the mixture. The apparatus includes a refractive index determining device, a dielectric constant determining device, and a controller. The refractive index determining device produces a first signal representative of a refractive index of the mixture. The dielectric constant determining device produces a second signal representative of a dielectric constant of the mixture. The controller receives the first signal and the second signal. The controller determines a moisture content of the mixture dependent upon the first signal and the second signal.

Abstract: A cascade refrigeration system includes an upper portion having at least one modular chiller unit that provides cooling to at least one of a low temperature subsystem having a plurality of low temperature loads, and a medium temperature subsystem having a plurality of medium temperature loads. The modular chiller unit includes a refrigerant circuit having at least a compressor, a condenser, an expansion device, and an evaporator. An ammonia refrigerant mixed with a soluble oil circulates within the refrigerant circuit. A control device may be programmed to modulate the position of the expansion device so that a superheat temperature of the ammonia refrigerant near an outlet of the evaporator fluctuates within a substantially predetermined superheat temperature range to positively return soluble oil from the evaporator to the compressor.

Abstract: A refrigerant circuit (11) of an air conditioner (10) includes a compressor (20) and an expander (30). In the compressor (20), refrigerator oil is supplied from an oil reservoir (27) to a compression mechanism (21). In the expander (30), the refrigerator oil is supplied from an oil reservoir (37) to an expansion mechanism (31). The inner pressures of the compressor casing (24) and the expander casing (34) are the high pressure and the low pressure of the refrigeration cycle, respectively. An oil adjusting valve (52) is provided in an oil pipe (42) connecting the compressor casing (24) and the expander casing (34). The oil amount adjusting valve (52) is operated on the basis of an output signal of an oil level sensor (51). When the oil amount adjusting valve (52) is opened, the refrigerator oil flows from the oil reservoir (27) in the compressor casing (24) toward the oil reservoir (37) in the expander casing (34) through the oil pipe (42).

Abstract: A refrigeration air conditioner includes a first equalizer pipe connecting a bottom portion of a first hermetic vessel, which contains a main compression mechanism and lubricating oil, to a bottom portion of a second hermetic vessel, which contains an expansion mechanism, a sub-compression mechanism, and lubricating oil. A second equalizer pipe connects a side of the second hermetic vessel at a position higher than a minimum oil level to a suction side of the main compression mechanism. The space within the second hermetic vessel is isolated from the expansion mechanism and the sub-compression mechanism, and the pressure within the second hermetic vessel is not dependent upon the pressure within the expansion mechanism and the pressure within the sub-compression mechanism.

Abstract: A refrigerant system has a refrigerant circuit comprising a compressor for compressing a refrigerant and delivering it downstream to a condenser. A bypass line is provided around the condenser for selectively allowing at least a portion of refrigerant to bypass the condenser. Valves are provided on a line leading to the condenser and on the bypass line to individually control the flow of refrigerant. An expansion device is located downstream of the condenser, and an evaporator is located downstream of the expansion device. A reheat cycle is incorporated into the system. The reheat cycle includes a valve for selectively delivering at least a portion of refrigerant through a reheat heat exchanger, which is positioned in the path of air downstream of the evaporator. A control is provided for the system to achieve a desired level of dehumidification and temperature control to air being delivered into the environment to be conditioned.