4325results about "Compression machines with non-reversible cycle" patented technology

The invention provides a magnetic suspension centrifugal water chilling unit, and belongs to the field of refrigeration equipment. The magnetic suspension centrifugal water chilling unit comprises a magnetic suspension compressor, a condenser and an evaporator, the magnetic suspension compressor is connected with the condenser through an exhaust pipeline, and the condenser is connected with the magnetic suspension compressor and the evaporator through a liquid supply pipeline assembly; the system further comprises a natural process control module, the natural process control module is used for dynamically adjusting the starting sequence of a plurality of magnetic suspension compressors in the water chilling unit by determining the energy efficiency health index of the water chilling unit and calculating the energy efficiency health index, and the natural process control module is electrically connected with the central controller. And a natural process control module is arranged, a multi-dimensional energy efficiency health index model is constructed, and the starting sequence of the compressors is dynamically adjusted by integrating the actual energy efficiency ratio, the evaporation efficiency, the compressor aging coefficient, the pressure fluctuation and the environment humidity correction term.

A refrigeration cycle device includes: a compressor; a heat radiating unit that causes refrigerant to heat air supplied to a space inside a vehicle cabin; a decompression unit that decompresses the refrigerant; an outside air heat absorbing unit that causes the refrigerant to absorb heat from outside air; a waste heat absorbing unit that causes the refrigerant to absorb waste heat of a waste heat device; a shutter that opens and closes a passage for the outside air introduced into the outside air heat absorbing unit; and a control unit that closes the shutter when it is determined that an amount of waste heat of the waste heat device is larger than an amount of heat absorbed by the refrigerant in the outside air heat absorbing unit and the waste heat absorbing unit.

The invention relates to the technical field of intelligent control of refrigeration equipment, in particular to an artificial intelligence-based screw compressor running state control system and method, which comprises a signal acquisition unit, a disturbance identification unit and a compressor control unit, the signal acquisition unit acquires a refrigeration house door opening and closing state time sequence signal and three-dimensional temperature field change data, the disturbance identification unit synchronously locks the door opening moment through a timestamp, divides a core influence area and a stable conduction area, analyzes the correlation between the temperature change rate and the door opening angle and the temperature fluctuation amplitude, and determines the temperature change rate of the door opening angle. And the door opening disturbance or equipment abnormity identification factor is output, and the compressor control unit executes differential regulation according to the door opening disturbance or equipment abnormity identification factor, so that the problems of disturbance misjudgment and regulation rigidity in traditional control are solved, and the operation stability and energy consumption control precision of the compressor are improved.

The invention relates to the technical field of unit detection, and discloses an intelligent fault self-diagnosis method for an evaporative condensation integrated screw water chilling unit, which comprises the following steps of: decoupling operation data of a compressor through a blind source separation algorithm, performing image processing on operation data of a condenser in combination with a morphological analysis method, and performing fault diagnosis on the operation data of the condenser; the operation characteristics of the compressor and the operation characteristics of the condenser can be extracted respectively, effective decoupling and clear expression of coupling signals are realized, and by constructing a dual-channel LSTM network comprising a gating fusion unit and introducing a cross-channel coupling gating mechanism, the system reliability is improved. The dynamic coupling relation between the compressor and the condenser can be modeled and regulated in the time dimension, the coupling mechanism between the compressor and the condenser is truly reflected, the time sequence parameter sequence is input into the pre-trained deep LSTM network, the fault types such as control lag and performance degradation can be accurately recognized, and the fault diagnosis accuracy is improved. Therefore, the accuracy and real-time performance of fault diagnosis are improved, and the requirement for intelligent fault management of the water chilling unit is met.

The invention discloses an energy-saving type magnetic suspension centrifugal water chilling unit, and relates to the technical field of refrigeration, the energy-saving type magnetic suspension centrifugal water chilling unit comprises a magnetic suspension compressor, a variable-diameter throttling mechanism and a heat exchange system, the heat exchange system is fixedly installed on the side face of the outer wall of the magnetic suspension compressor, and the variable-diameter throttling mechanism is fixedly installed on the side face of the outer wall of the heat exchange system; an outlet of the magnetic suspension compressor is directly connected with the heat exchange system through a pipeline, and the reducing throttling mechanism is connected with the heat exchange system through a pipeline. The front-stage closed impeller and the rear-stage semi-open impeller are coaxially connected in series, efficient compression without mechanical contact and oil lubrication is achieved, the problems that a centrifugal compressor is high in energy consumption and large in vibration due to mechanical friction are solved, and the energy efficiency ratio of a unit is effectively increased.

The invention provides a two-phase refrigerator control system and method applied to electrochemical energy storage, the system comprises a two-phase refrigerator, a sensor and a controller, the two-phase refrigerator is composed of a cooling circulation pipeline, a refrigeration circulation pipeline, a plate heat exchanger and a liquid storage tank, the sensor is used for monitoring temperature and pressure, and the controller is used for controlling the temperature and the pressure. The controller accurately controls the system through the electromagnetic valve, the circulating pump, the compressor and the centrifugal fan. The control method is divided into a self-circulation mode and a refrigeration mode, automatic switching can be achieved according to temperature changes, and the cooling efficiency and stability are ensured. Through dual-mode intelligent and frequency conversion control switching, the cooling efficiency and the energy efficiency ratio are remarkably improved, and the problem that in the prior art, the cooling power of a two-phase liquid cooling machine is difficult to effectively control is effectively solved.

The invention relates to the technical field of automatic control, in particular to a low-temperature control system of a centrifugal variable-frequency magnetic suspension water chilling unit, which comprises an environment heat parameter detection module, a condensation pressure deviation identification module, a condensate water flow rate regulation and control module, a refrigerant flow evaporation linkage module and an energy consumption curve dynamic construction module. According to the method, the inlet and outlet water temperature of the condenser and the external air temperature are collected, and synchronous filing and water temperature difference rate normalization processing are combined, so that when the external temperature changes drastically, the abnormal trend of water temperature change lag can be captured in time, and the condensation instability risk is pre-judged in advance; based on local pressure change rate gradient density analysis, abnormal fluctuation of condensation pressure is precisely discriminated, the problem that the local instability risk is covered by a global mean value is avoided, and the early warning timeliness is improved; the flow speed of condensate water is dynamically adjusted according to condensation instability characteristics, PID dynamic correction is conducted by extracting the rotating speed and flow speed error of a water pump, it is ensured that the heat exchange performance of a condenser continuously meets the low-temperature change requirement, and the condensation pressure stability is remarkably improved.

A refrigeration circuit comprising one first compressor (1), a first gas-cooler (7), connected to the first compressor through a common discharge line (41), a medium temperature expansion valve (19), a medium temperature heat exchanger (20), a liquid receiver (17) that is connected to an outlet liquid line (80) that splits in a first liquid line (81) that connects with the medium temperature heat exchanger and a second liquid line (82) that comprises a first expansion valve (28), to a first pressure reduction valve (14) and to a first heat exchanger (18), wherein the refrigerant flowing through the second liquid line is also mixed with the refrigerant from the first liquid line leaving the medium temperature heat exchanger and the mixture enters the first heat exchanger to exchange heat with the refrigerant in the first liquid line to be directed to the first compressor through a suction line (59).

The invention discloses a defrosting control method and device, refrigeration equipment and a storage medium, and belongs to the technical field of defrosting. According to the defrosting control method, in the first stage, the heater is controlled to defrost the evaporator; entering a second stage when the defrosting state of the first stage meets a first condition; and in the second stage, a compressor exhaust pipe of the refrigerating system is controlled to communicate with the evaporator to conduct hot gas defrosting, and when hot gas defrosting is conducted under the first condition, the heat exchange medium flowing out of the evaporator is in a gaseous state. According to the defrosting control method disclosed by the invention, the heater is firstly controlled to defrost, and then the compressor is controlled to defrost by hot gas, so that staged defrosting is realized; the defrosting state of the first stage is controlled, so that the surface temperature of the evaporator is not too low when hot gas defrosting is carried out, heat exchange media flowing out of the evaporator are prevented from being liquefied, and liquid impact is prevented; and meanwhile, the heater is turned off in the second stage, and excessive heat generated by the heater can be prevented from overflowing to the compartment.

The utility model discloses an efficient cooling-water machine which comprises a machine shell, and an installation cavity is formed in the machine shell. The water tank is provided with a water return connector and a water outlet connector. The heat exchanger is provided with a first heat exchange pipe and a second heat exchange pipe, one end of the first heat exchange pipe is communicated with the water return connector, and the other end of the first heat exchange pipe is communicated with a pipeline of external equipment; the refrigeration assembly comprises a compressor, a condenser, a drying filter and a capillary tube, an outlet of the compressor communicates with an inlet of the condenser, an outlet of the condenser communicates with an inlet of the drying filter, an outlet of the drying filter communicates with one end of the capillary tube, and the other end of the capillary tube communicates with one end of the second heat exchange tube. The other end of the second heat exchange pipe communicates with an inlet of the compressor. Heat exchange between water in the water tank and a refrigerant is achieved through the first heat exchange pipe and the second heat exchange pipe of the heat exchanger, cooling is conducted through cold water in the water tank, and the cooling amount and the cooling efficiency are improved.

The present disclosure relates to a refrigeration system comprising: a compressor (1); an air outlet (2A) of the evaporator (2) is communicated with the air suction port (1A) of the compressor (1) through an air suction pipeline (10); an air inlet (3A) of the oil separator (3) is communicated with an exhaust port (1B) of the compressor (1), an oil outlet (3B) of the oil separator (3) is communicated with the compressor (1) through a first oil return pipeline (20), and a pump (11) is arranged on the first oil return pipeline (20); a liquid inlet (4A) of the automatic oil return device (4) is communicated with the evaporator (2) through a liquid taking pipeline (60) and used for obtaining the liquid refrigerant in the evaporator (2), an oil outlet (4B) of the automatic oil return device (4) is communicated with the air suction pipeline (10) through a second oil return pipeline (30), and at least one of the liquid taking pipeline (60) and the second oil return pipeline (30) is provided with a first on-off valve (18).

To improve the durability of gas bearings. [Solution] The compressor 12 starts when the expansion valve 14 is at the second opening, so the compression ratio of the compressor 12 is small when the compressor 12 starts. Therefore, the pressing load applied from the rotor to the gas bearing is small. The expansion valve 14 is switched to the first opening after the compressor 12 starts. Therefore, the compression ratio of the compressor 12 after starting returns to the compression ratio before the expansion valve 14 was switched to the second opening, preventing any impact on the compression efficiency of the compressor 12 after starting. The compressor 12 then stops after the expansion valve 14 is switched from the first opening to the second opening. Therefore, even if the rotational speed of the rotor falls below the levitation rotational speed as the compressor 12 tries to stop and the gas bearing supports the rotor in contact with the rotor, the pressing load applied from the rotor to the gas bearing is small.

The invention provides a waste steam source high-temperature steam heat pump testing system based on heat energy cyclic utilization, and belongs to the field of compression heat pumps. The invention aims to solve the problems of unstable heat supply in a high-temperature lift, low energy efficiency of an evaporation end, poor temperature control effect of a low-level heat source side and limited thermal control means of an experimental platform. The system comprises a condenser, an expansion valve, a liquid storage tank, an evaporator, a compressor, a water spraying cooling tank, a steam pressure reducing valve, a circulating pump and a regulating valve, or a water mixing cooling tank and a heat supply liquid storage tank are additionally arranged, so that the dynamic balance and control of the temperature of the hot end of the system are realized; or a steam pressure reducing valve is replaced by a steam-water heat exchanger, so that heat exchange is carried out on condensed steam and working medium water to realize mild cooling, and redundant energy consumption is avoided; or a bypass adjustable shunting loop is arranged, so that partial high-temperature backwater bypass mixing is realized, and the thermal matching property and the operation stability of the system are enhanced. According to the invention, the output temperature of over 100 DEG C is realized, and the universality and debugging flexibility of experimental system design are realized.

A refrigerating system of the novel freeze dryer comprises a low-pressure-stage compressor, a high-pressure-stage compressor, a condenser, an intercooler, a throttling valve, an electromagnetic valve, an auxiliary evaporator and a main evaporator. The waste heat collecting system comprises a main evaporator, a cold oil pump, a condenser, a hot oil pump, a regulating valve, an oil tank and a heat exchanger. The vacuumizing system comprises an oil pump, a drying box, a rotating wheel dehumidification box, a valve and a vacuum pump; the rotating wheel dehumidification system comprises a rotating wheel dehumidification box, a dehumidification rotating wheel, a vacuum pump, a fan and a regeneration heater; the drying efficiency is improved, the energy utilization rate of the system is remarkably improved, energy waste is reduced, the operation cost is reduced, it is ensured that the humidity environment in the freeze-drying process is more uniform and controllable, and the frosting phenomenon caused by low temperature in the dehumidification process is avoided.

The invention provides a soil permeability test device suitable for gradient variable-temperature freeze-thaw cycle test, which comprises a temperature control cylinder formed by axially extending and combining a plurality of annular insulating cylinders with hollow structures, an insulating and heat-conducting soil sample cylinder is mounted in a central chamber formed by the temperature control cylinder, a water storage chamber is arranged on one side of the soil sample cylinder, and a water outlet is formed in the other side of the soil sample cylinder. A porous anode plate is arranged between the water storage chamber and the soil sample cylinder, a water collecting chamber is arranged on the other side of the soil sample cylinder, a porous cathode plate is arranged between the water collecting chamber and the soil sample cylinder, an orifice plate flowmeter is arranged between the water collecting chamber and the porous cathode plate, and the water storage chamber is connected with a water supply system; a pore pressure sensor and a temperature sensor are installed on the side wall of each annular insulating cylinder, and each annular insulating cylinder is connected with a refrigeration module and a heating module. The device can simulate a real environment to perform freezing and thawing and gradient temperature control on the sample, can effectively simulate a real geological environment in an alpine region, and provides a scientific basis for research on permeability of frozen soil under a gradient freezing and thawing cycle condition.

The invention provides an energy storage battery liquid cooling dual-mode heat management and battery storage space heat recovery temperature and humidity coordinated regulation and control system and method. The system is composed of a heat pipe cooling module, a steam compression refrigeration cycle module and a module for waste heat recovery and runner regeneration. The heat pipe cooling module and the circulating pump form a natural cooling loop through the liquid cooling plate and the heat pipe heat exchanger; the vapor compression refrigeration cycle module efficiently and rapidly reduces the temperature of cooling liquid through a phase change refrigeration working medium. And the waste heat recovery module uses condensation waste heat for rotary wheel dehumidification regeneration. The system automatically switches double modes according to the temperature of cooling liquid: heat pipe energy-saving cooling is started when the temperature is lower than or equal to 35 DEG C, steam compression refrigeration is switched when the temperature is higher than 35 DEG C, and condensation waste heat of the two modes preheats regenerated air through a heat pipe heat exchanger, then the temperature is supplemented to the regeneration temperature through an electric heater, a rotating wheel is driven to dehumidify, and dry air is fed into a battery cabin. The method gives consideration to energy efficiency and thermal safety, and is suitable for thermal management and space humidity regulation and control of an energy storage battery system.

The invention relates to the technical field of general control systems, in particular to a water chilling unit energy-saving control method and system.The method comprises the steps that the machining process of a numerical control machine tool is equally divided into a plurality of monitoring time periods, and the demand degree of a water chilling unit in the machining process of the numerical control machine tool in the monitoring time periods is determined to screen out a target monitoring time period; energy consumption of the water chilling unit in the target monitoring time period is determined in combination with the time interval from the moment after the cutting temperature rises to the moment when the rotating speed of the compressor changes, and then the cooling effect of the water chilling unit in the target monitoring time period is determined in combination with rising changes of the cutting temperature and the environment temperature. And determining a regulation and control coefficient of the variable frequency driving control system in the target monitoring time period, and regulating and controlling the running speed of a compressor of the water chilling unit. The regulation and control coefficient for energy-saving control of the water chilling unit in the frequency conversion control system is obtained, and the operation speed of the compressor of the water chilling unit is regulated and controlled, so that the purpose of energy-saving control of the water chilling unit is achieved.

The invention discloses a water chilling unit operating under extreme working conditions, which comprises a fan and a finned condenser at the upper part and a refrigerating unit at the lower part, and the refrigerating unit is provided with a refrigerant circulating system and a chilled water circulating system; the refrigerant circulating system comprises a compressor, a finned condenser, an electronic expansion valve and a shell and tube evaporator which are connected in sequence; the chilled water circulation system comprises a water pipe, a water pump and an evaporator which are connected in sequence; the electronic expansion valve is connected with the drying filter cartridge and the shell and tube evaporator, the drying filter cartridge is connected with the liquid storage tank, and the shell and tube evaporator is connected with the gas-liquid separator. According to the invention, PWM and stepless regulation multi-dimensional cooperative control are used, so that stable operation is realized when the energy efficiency in a wide temperature range is suddenly reduced; on the high-temperature side, the condensation fan adopts a stepless speed regulation technology; and the low-temperature side is switched into a PWM period adjusting mode.

The invention discloses a refrigeration house refrigerating system, a defrosting control method and device of the refrigeration house refrigerating system and a storage medium. The system comprises a medium-temperature heat accumulator filled with a first phase change material; the low-temperature heat accumulator is connected with the medium-temperature heat accumulator and is internally filled with a second phase-change material of which the phase-change temperature is lower than that of the first phase-change material; an air cooler; the evaporator is respectively connected with the air cooler and the low-temperature heat accumulator through a throttle valve; the defrosting heater abuts against the surface of the evaporator and is connected with the medium-temperature heat accumulator and the low-temperature heat accumulator; one end of the compressor is connected with a heat exchange pipeline of the medium-temperature heat accumulator and the air cooler through a three-way reversing valve, the other end of the compressor is connected with the evaporator, and the low-temperature heat accumulator, the medium-temperature heat accumulator, the solution pump and the defrosting heater sequentially form a loop. By means of the two heat accumulators made of the phase change materials with different phase change temperatures, wide-temperature-range exhaust waste heat of the compressor is absorbed, meanwhile, the evaporator is defrosted in a graded mode through the two stages of heat accumulators, and the energy consumption of the system is reduced.

The application discloses a heat management integrated module, a shunt component and a first heat exchanger connection, the first interface of the shunt component can be in communication with the second interface and the third interface at the same time; the throttling channel of the first heat exchanger has a throttling function, the first flow channel and the second flow channel are isolated from each other in the first heat exchanger, and the throttling channel and the first flow channel can be in communication; the second interface is in communication with the throttling channel, and the third interface can be in communication with the second flow channel. In the application, the shunt component has a shunt function, the first heat exchanger has a throttling channel capable of realizing a throttling function, when the heat management integrated module is in an operating state, two fluid streams shunted through the shunt component realize heat exchange in the first heat exchanger, the first heat exchanger integrates the throttling function and the heat exchange function, part of the pipeline can be shortened or cancelled, and thus the occupied space of the heat management integrated module can be reduced. The application also provides a heat management system capable of reducing the occupied space.

The refrigeration house condenser waste heat recovery energy-saving system comprises a refrigeration module, the refrigeration module is connected with a first heat energy recovery module, and the first heat energy recovery module is connected with a user side; the refrigeration module comprises a compressor, a first condenser, a first expansion valve and a first evaporator, the compressor is communicated with the first condenser, the first condenser is communicated with the first expansion valve, the first expansion valve is communicated with the first evaporator, and the first evaporator is communicated with the compressor; the first heat energy recovery module comprises a first water pump and a first adjusting valve connected with the first water pump in parallel, and the first adjusting valve and the first water pump are connected with a water supply source and communicate with the first condenser. The first condenser is connected with a second regulating valve, the second regulating valve is respectively communicated with one end port of a third regulating valve and one end port of a fourth regulating valve, the third regulating valve is communicated with the first condenser, and the fourth regulating valve is connected with a user side. The system improves the utilization rate of primary energy in the operation process of the refrigeration house.

The invention discloses a pump body assembly, a compressor and refrigeration equipment, and relates to the technical field of compressors, the pump body assembly comprises an air cylinder, a pump body, a pump body, a pump body, a pump body and a pump body, and the air cylinder is provided with a working cavity and a sliding groove communicated with the working cavity; the piston is eccentrically and rotatably arranged in the working cavity; the sliding piece comprises a sliding piece body and a hinge portion arranged at one end of the sliding piece body, the sliding piece body is arranged in the sliding groove in a sliding mode, the hinge portion is hinged to the piston and provided with a first opposite-grinding face, the piston is provided with a second opposite-grinding face in contact with the first opposite-grinding face, and the second opposite-grinding face is provided with a second opposite-grinding face in contact with the second opposite-grinding face. The surface hardness of the first counter-grinding surface is at least 30% higher than that of the second counter-grinding surface. According to the technical scheme, adhesive abrasion can be effectively reduced, and the problem that abrasion of a hinge structure is aggravated is solved.

A refrigerator including a main body including a storage compartment; a first cooler configured to cool the storage compartment, and including a thermoelectric element, a heat dissipation fan, and a cooling fan; a second cooler configured to cool the storage compartment, and including a compressor, and an evaporator fan; and at least one processor configured to, based on a failure in the first cooler, increase an operating speed of the compressor and the evaporator fan of the second cooler.

Oil lubricated supercritical fluid pumps with oil separators are disclosed herein. An example pump system to pressurize a fluid within a closed loop thermal transport bus disclosed herein includes a pump housing, a duct fluidly coupled to the pump housing, a first portion of the duct to include a mixture of an oil and the supercritical fluid, a second portion of the duct to include the supercritical fluid, and a separator positioned in a third portion of the duct between the first portion of the duct and the second portion of the duct, the separator to separate the oil in the mixture from the supercritical fluid.

To shorten the time until a start of a heating operation from when a command of the heating operation is received again after stopping the heating operation.SOLUTION: If a heating operation or a defrost operation in which a coolant in a refrigerant in a refrigerant circuit circulates in the same direction as in a cooling operation proceeds immediately before a refrigeration cycle operation is stopped in an air conditioner 100, a position of a valve body 52 after a non-operation is maintained at a second position, or is moved to the second position. As a result, it is possible to shorten the time until the start of the heating operation from a non-operation state.SELECTED DRAWING: Figure 6

An air conditioner includes: a heat pump cycle including a compressor, a heating part and a low-temperature side water-refrigerant heat exchanger; a heat medium circuit; and a blower. In the air conditioner, when a heating capability of the heating part is increased by using the heat generated by the heat generating part, a heating preparation control is executed, in which a refrigerant discharge capability of the compressor is set to be equal to or less than a predetermined reference discharge capability and a blowing capability of the blower is set to be equal to or less than a predetermined reference blowing capability, until an inlet-side heat medium temperature of the heat medium flowing into the heat medium passage of the low-temperature side water-refrigerant heat exchanger becomes equal to or higher than a target heat medium temperature.

According to the refrigeration extractor hood system and the control method thereof, a first three-way valve and a first temperature sensor for detecting the temperature of an exhaust pipe are installed on the exhaust pipe of a refrigeration system, a first heat exchange pipe is installed on the volute annular wall of an oil smoke suction fan, and a first port of the first three-way valve communicates with an outlet of a compressor; a second port of the first three-way valve is communicated with an inlet of the condenser, a third port of the first three-way valve is communicated with an inlet of the first heat exchange pipe, an outlet of the first heat exchange pipe is communicated with an inlet of the condenser, and the controller receives output signals of the first temperature sensor and correspondingly controls the first three-way valve. The controller of the system adjusts the guiding of the three-way valve according to the temperature of the exhaust pipe, and adjusts the amount of refrigerant entering the first heat exchanger on the volute annular wall, so that the temperature of the volute annular wall reaches a grease melting point, grease can smoothly flow into an oil cup, and the volute is self-cleaned. In addition, an oil fume suction fan is used for conducting auxiliary heat dissipation on the heat dissipation module, and oil fume is subjected to grease separation by means of the cooling capacity of the refrigerating system.

The invention belongs to the technical field of refrigeration, and discloses a leakage detection and protection system and method for an oil-containing refrigeration system, which integrates audio frequency acquisition, processing identification, analysis decision and signal output, and realizes real-time detection of leakage of a refrigerant in an air conditioner pipeline. Meanwhile, two pressure relief protection schemes of a negative pressure protection system and a capacity expansion protection system are combined, and the pipeline pressure can be rapidly reduced while the leakage area is blocked. Therefore, quick response can be ensured when leakage occurs, the system is effectively prevented from being damaged, leakage detection and protection are efficiently achieved, the whole process is automatically operated, manual intervention is not needed, and the safety and reliability of the system can be greatly improved.

A compressor includes a diffuser passage configured to receive refrigerant flow from an impeller of the compressor, where the diffuser passage is at least partially defined by a compressor discharge plate of the compressor. The compressor also includes a variable geometry diffuser positioned within the diffuser passage and configured to adjust a dimension of a refrigerant flow path through the diffuser passage, an actuator coupled to the variable geometry diffuser and configured to adjust a position of the variable geometry diffuser within the diffuser passage, and a controller configured to regulate operation of the actuator. The controller is configured to instruct the actuator to adjust the position of the variable geometry diffuser from a first position to a second position using a first force and to adjust the position of the variable geometry diffuser from the second position to a third position using a second force less than the first force, where the variable geometry diffuser abuts the compressor discharge plate in the third position.

Heat pump systems that include vapor injection feature are disclosed. Embodiments may include a heat pump system that has two tandem scroll compressors. Each compressor is paired with a control valve that regulates the flow of vapor to the respective compressor. Both the control valves are in fluid communication with a single or common source for vapor injection and to the controller. During operation, the controller dynamically determines how much vapor injection is needed for each of the compressors based on the operational data of the compressors and, optionally, ambient environment data. The controller then operates the two valves to ensure that the right amount of vapor is injected into each compressor.