Abstract: Methods and systems for surge control in a compressor system. A recirculation valve position may be actuated in response to identified conditions of potential surge, determined from a compressor map. Recirculation valve position may be controlled by calculating distance of current operating state to a surge line and using proportional integral control to manage the distance. Compressor speed command may be derated in response to identified surge, determined from one of speed fluctuations of the compressor speed, or variance of a compressor speed tracking error.

Abstract: A load balancing method for two compressors. The two compressors are used in a refrigeration system and are driven coaxially by the same driving device. The method comprises the steps of obtaining parameters, determining balance, and controlling start/stop states. The parameters in the step of obtaining parameters are parameters related to the two compressors. The step of determining balance comprises determining, on the basis of the obtained parameters related to the two compressors, whether load is balanced between the two compressors. The step of controlling start/top states comprises controlling the start/stop states of the two compressors according to whether the load is balanced.

Abstract: A compressor control apparatus and method includes: a sensor configured to detect air conditioner operation state information necessary to control engagement and disengagement of a clutch of an air conditioner compressor; an electromagnetic coil in the clutch of the air conditioner compressor configured to perform clutch engagement upon receiving battery current; a microcomputer configured to determine whether the current air conditioner operation state satisfies a clutch engagement allowance condition or a clutch disengagement condition based on the air conditioner operation state information detected by the sensor and to output an operation signal based on the result of determination; and a switch configured to be turned on or off according to the operation signal output by the microcomputer and to control supply of the battery current to the electromagnetic coil such that clutch engagement or clutch disengagement is performed.

Abstract: An indoor gardening appliance includes a cabinet defining a grow chamber within the cabinet. The gardening appliance further includes environmental control system configured to adjust atmospheric conditions in the grow chamber. The gardening appliance may be operable to activate a compressor of the environmental control system to circulate a refrigerant through a sealed system of the environmental control system. The refrigerant enters the compressor at a suction side of the compressor and the refrigerant entering the compressor has a pressure that corresponds to a saturation temperature below the freezing point of water. The gardening appliance may be further operable to flow air across a heat exchange surface of the sealed system. The heat exchange surface of the sealed system is upstream of the grow chamber with respect to the air flow direction, and the heat exchange surface has a temperature above the freezing point of water.

Abstract: The present invention provides a control device for detecting an abnormal operation state of a compressor in a parallel refrigerator. The control device is a control device for a refrigerator that includes a plurality of compressors connected in parallel, and detects occurrence of surging and occurrence of droplet suction on the basis of a deviation between values of currents flowing through electric motors that is configured to drive each of the plurality of compressors, and an operation point indicated by the air volume and the compression ratio of the plurality of compressors.

Abstract: A refrigeration cycle device includes a heating unit, an air-heating expansion valve, an outdoor heat exchanger, an air-cooling expansion valve, an indoor evaporator, and a cooler-unit expansion valve, a cooler unit, and a refrigerant circuit switching unit. In a heating series cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, the outdoor heat exchanger, the cooler-unit expansion valve, and the cooler unit. In a heating parallel cooler-unit mode, refrigerant is circulated in order of the heating unit, the air-heating expansion valve, and the outdoor heat exchanger, and refrigerant is circulated in order of the heating unit, the cooler-unit expansion valve, and the cooler unit.

Abstract: A light-weight, high-strength insulating compressor component formed via additive manufacturing is provided. The component may have at least one interior region comprising a lattice structure that comprises a plurality of repeating cells. A solid surface is disposed over the lattice structure. The interior region comprising the lattice structure minimizes or reduces transmission of at least one of thermal energy, sound, or vibrational energy through the component. Methods of making such compressor components via additive manufacturing processes are also provided.

Abstract: A heat transfer device that contains a circulation route enclosing a refrigerant containing a hydrohaloolefin, the heat transfer device being capable of reducing the influence of oxygen entrapped in the circulation route; and a heat transfer method using the heat transfer device. Also, a heat transfer device that contains a circulation route enclosing a refrigerant containing at least one member selected from the group consisting of hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), and hydrochloroolefins (HCOs); and the device containing an oxygen adsorption device between an evaporator and a compressor present in the circulation route; and a heat transfer method using the same.

Abstract: A method for cooling air in an HVAC system includes moving refrigerant through a closed refrigeration circuit having, inter alia, an expansion device subsystem, which includes a full-load pathway and at least one partial-load pathway and a flow selector for directing refrigerant flow from the condenser to either the partial-load pathway or the full-load pathway. The method also involves directing refrigerant flow from the condenser to the full-load pathway when the refrigerant pressure is greater than or equal to a first preselected activation pressure and stepping down a refrigerant pressure with a set orifice and directing refrigerant flow from the condenser to the partial-load pathway when the refrigerant pressure is less than a second preselected activation pressure and stepping down a refrigerant pressure with a variable expansion device configured for partial loads. Refrigerant is delivered from the full-load pathway or partial-load pathway to the evaporator.

Abstract: A control apparatus in a cooling system has an opening schedule of a degree of opening of each of a plurality of outflow ports in a control valve including at least a heater cut mode, a heater passing water mode, a fully closed mode, and a switching mode in which the opening and closing of an air conditioning outflow port is switched in a state in which at least one outflow port of a radiator outflow port and a bypass outflow port is opened and switches the heater cut mode and the heater passing water mode via the switching mode.

Abstract: A fuel pump includes a fuel pump housing made of stainless steel and having a pumping chamber therewithin, a plunger bore extending thereinto, an inlet passage extending thereinto, and an outlet passage extending thereinto. A pumping plunger reciprocates within the plunger bore such that an intake stroke of the pumping plunger increases volume of the pumping chamber and a compression stroke of the pumping plunger decreases volume of the pumping chamber. An outlet valve controls fuel flow from the pumping chamber out of the fuel pump housing. The outlet valve includes an outlet valve seating surface formed by the fuel pump housing within the outlet passage such that a nitrided layer extends from the outlet valve seating surface into the fuel pump housing. The outlet valve also includes an outlet valve member within the outlet passage which is moveable between a seated position and an unseated position.

Abstract: A computer room air conditioner (CRAC) unit includes a housing having an inlet configured to receive IT air and an outlet configured to exhaust treated air. The CRAC unit further includes a heat exchanger supported by the housing and disposed between the inlet and the outlet of the housing and at least one fan module supported by the housing. The at least one fan module is configured to draw IT air into the housing through the inlet, direct IT air through the heat exchanger, and exhaust treated air through the outlet. The CRAC unit further includes an airfoil frame secured to the housing at the inlet of the housing.

Abstract: An oil separator includes a cylindrical first separating section having a first inner space where the refrigerant can swirl; a cylindrical second separating section disposed below the first separating section and having a second inner space where the refrigerant can swirl; an introduction tube sending the refrigerant toward an inner wall of the first separating section so that a swirl flow occurs; a delivery tube delivering the separated refrigerant; and an exhaust pipe discharging the separated refrigerant oil, the second separating section having a surface connecting the inner wall of the first separating section and an upper end of an inner wall of the second separating section and forming a step, and an angle between the surface and the inner wall of the first separating section and an angle between the surface and the inner wall of the second separating section being 90 degrees or smaller.

Abstract: Provided is a cascade heat pump. The cascade heat pump includes a first refrigerant cycle including a first compressor and a first indoor heat exchanger, a second refrigerant cycle including a second compressor and a second indoor heat exchanger, an outdoor heat exchanger in which a refrigerant compressed in the first compressor or the second compressor is condensed, a bypass tube allowing the refrigerant compressed in the second compressor to bypass the first compressor, thereby flowing into a discharge side of the first compressor, and a first flow rate regulating part disposed on a discharge side of the second compressor to introduce the refrigerant discharged from the second compressor into one of the first compressor and the bypass tube.

Abstract: A required-circulated-refrigerant flow-rate calculating portion provided in a chilled-water flow-rate estimation calculation portion calculates an evaporator exchanged heat quantity exchanged between a refrigerant and chilled water at an evaporator based on a planned chilled-water-flow-rate value and a measured value of the temperature of the chilled water flowing in the evaporator, and calculates an evaporator-refrigerant flow rate based on that evaporator exchanged heat quantity.

Abstract: A method for controlling the operation of a transport refrigeration system to limit current drawn by a compressor powered by AC electric current includes the steps of: (a) determining whether an ambient temperature in which the refrigeration unit is operating has been greater than a set point ambient temperature for a first time period; (b) determining whether the refrigeration unit has been operating in a temperature pulldown mode; (c) determining whether the AC electric current is equal to or exceeds a preset maximum current limit; (d) determining whether a time period between a last defrost cycle and a next previous defrost cycle is less than fifteen minutes; and (e) if the determination is YES in both of step (a) and step (b) and is also YES in at least one of step (c) and step (d), reducing the preset maximum current limit to a reset maximum current limit.

Abstract: A cooling system for cooling food on board an aircraft includes a cooling circuit adapted to supply cooling energy to at least one cooling station, a refrigerant circulating in the cooling circuit selected such that it is convertible at least partially from the liquid to the gaseous state of aggregation on releasing its cooling energy to the at least one cooling station and subsequently convertible back at least partially to the liquid state of aggregation again by an appropriate pressure and temperature control in the cooling circuit, and a refrigerant container including a receiving space arranged in an interior space of the refrigerant container which receives the refrigerant circulating in the cooling circuit, the receiving space of the refrigerant container connected to the cooling circuit by a flow line for discharging the refrigerant from the receiving space and by a return line for returning the refrigerant into the receiving space.

Abstract: A glass-to-metal hermetic seal assembly in a sight glass assembly or a hermetic terminal assembly is disclosed and includes a glass component, an intermediate component, and an outer ring. The intermediate component is provided around the glass component. The glass component is fused to the intermediate component. The outer ring, which has a coefficient of thermal expansion that is greater than a coefficient of thermal expansion of the glass component, compresses the intermediate component against the glass component to create a hermetic compression seal.

Abstract: Methods and coolant distribution systems are provided for automated coolant flow control for, for instance, facilitating cooling of multiple different electronic systems. The methods include, for instance, automatically controlling coolant flow to a plurality of coolant circuits, and for a coolant circuit i of the coolant circuits: automatically determining the heat load transferred to coolant flowing through coolant circuit i, and automatically controlling coolant flow through coolant circuit i based on the determined heat load transferred to the coolant. The different coolant circuits may have the same or different coolant flow impedances, and flow through the different coolant circuits may be controlled using different heat load-to-coolant ranges for the different circuits.

Abstract: Methods are provided for automated coolant flow control for, for instance, facilitating cooling of multiple different electronic systems. The methods include, for instance, automatically controlling coolant flow to a plurality of coolant circuits, and for a coolant circuit i of the coolant circuits: automatically determining the heat load transferred to coolant flowing through coolant circuit i, and automatically controlling coolant flow through coolant circuit i based on the determined heat load transferred to the coolant. The different coolant circuits may have the same or different coolant flow impedances, and flow through the different coolant circuits may be controlled using different heat load-to-coolant ranges for the different circuits.

Abstract: A refrigerant cycle device includes a first refrigerant passage for guiding refrigerant from a refrigerant radiator to an inlet side of an outdoor heat exchanger, a first throttle part capable of varying an opening area of the first refrigerant passage, a second refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to a compressor-suction side, a first opening/closing part for opening/closing the second refrigerant passage, a third refrigerant passage for guiding the refrigerant from the outdoor heat exchanger to the compressor-suction side via an evaporator, a second throttle part capable of varying an opening area of the third refrigerant passage, a bypass passage for guiding the refrigerant flowing between the refrigerant radiator and the first throttle part to a position between the outdoor heat exchanger and the second throttle part in the third refrigerant passage, and a second opening/closing part for opening/closing the bypass passage.

Abstract: A pulse width modulation control is provided for a suction valve on a suction line, delivering refrigerant into a housing shell of a compressor. When the suction valve is closed, the pressure within the housing shell can become very low. Thus, a pressure regulator valve is included within the refrigerant system to selectively deliver a limited amount of refrigerant into the housing shell when the suction valve is closed. The delivery of this limited amount of refrigerant ensures that a specified pressure is maintained within the housing shell to achieve the most efficient operation while at the same time preventing problems associated with damage to electrical terminals, motor overheating and excessive discharge temperature.

Abstract: A method for controlling a refrigerant distribution in a vapour compression system, such as a refrigeration system, e.g. an air condition system, comprising at least two evaporators. The refrigerant distribution determines the distribution of the available amount of refrigerant among the evaporators. While monitoring a superheat, SH, at a common outlet for the evaporators, the distribution of refrigerant is modified in such a manner that a mass flow of refrigerant to a first evaporator is altered in a controlled manner. The impact on the monitored SH is then observed, and this is used for deriving information relating to the behaviour of the first evaporator, in the form of a control parameter. This is repeated for each evaporator, and the refrigerant distribution is adjusted on the basis of the control parameters. The impact may be in the form of a significant change in SH.

Abstract: A variable displacement compressor with a compensated suction shutoff valve (SSV). The SSV prevents noise generated by a suction reed valve at low refrigerant flow rates in an internal suction region from propagating to an air conditioner evaporator by moving a piston to obstruct an opening and restrict fluid communication. The degree of restriction is decreased by an opening force generated by refrigerant at an external suction pressure acting over a first area, and increased by refrigerant at a crankcase pressure acting over a second area. The second area is smaller than the first area so that at high refrigerant flow rates, the effect of crankcase pressure is reduced so that the restriction is reduced and the compressor operates at greater efficiency. The piston position is also influenced by refrigerant at a pressure intermediate the external suction pressure and the internal suction pressure acting over a third area.

Abstract: In a method of the application, cooling energy is produced by a refrigerating device. The cooling energy produced by the refrigerating device is supplied to at least one cooling station by a cooling circuit, circulating in which is a refrigerant, which upon release of its cooling energy to the at least one cooling station is converted from the liquid to the gaseous state and is then converted back to the liquid state by corresponding pressure- and temperature control in the cooling circuit. Upon transfer of the cooling system to its state of rest, a control value disposed in the cooling circuit is controlled in such a way that a desired operating pressure (??) arises in the cooling circuit downstream of the control valve. Refrigerant cooled by the refrigerating device is received in a reservoir disposed upstream of the control valve in the cooling circuit.

Abstract: An air conditioning system having an improved internal heat exchanger (IHX) assembly. The IHX assembly includes an elongated cavity for low pressure refrigerant flow from an evaporator and an interior tube disposed within the cavity for high pressure refrigerant flow from a condenser, and a pressure equalization passage between the low and high pressure sides. The passage is large enough to allow pressures to equalize between the condenser and evaporator while the air conditioning system is inactive, so as to prevent the pressure differential that would otherwise enable the loss of refrigerant oil from the compressor, and small enough not to effect the operation of the air conditioning system. The pressure equalization passage may be a by-pass valve assembly having a reed portion that is normally open when the air conditioning system is inactive and closed when the air conditioning system is active for maximum cooling efficiency.

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. 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 and a controller may control the valve based on a discharge temperature of the compressor and a super heat temperature of the third heat exchanger.

Abstract: For cooling operation, a refrigeration apparatus includes a heat-source-side valve opening controller for controlling a degree of opening of a heat-source-side expansion valve so that pressure of a refrigerant flowing into the utilization-side expansion valve in the cooling operation becomes equal to or lower than a predetermined reference pressure value. For heating operation, the refrigeration apparatus includes a utilization-side valve opening controller for performing, when a low-quantity utilization unit in which a quantity of the refrigerant falls below a quantity of the refrigerant required for delivering capacity of the utilization unit is found among a plurality of the utilization units in the heating operation, valve opening reducing operation of reducing a degree of opening of the utilization-side expansion valve of the utilization unit except for the low-quantity utilization unit.

Abstract: Alternative means of inhibiting frosting in the interior heat exchanger of a DX system when switching from the heating mode to the cooling mode, plus an improved insulation and heat transfer means for vertically oriented sub-surface geothermal heat transfer tubing, as well as a means to protectively coat the sub-surface metal tubing of a DX system in a corrosive environment.

Abstract: A refrigerant system is provided with a pulse width modulation valve. A compressor temperature is monitored to prevent potential reliability problems and compressor failures due to an excessive temperature inside the compressor. A control changes the pulse width modulation valve duty cycle rate to maintain temperature within specified limits, while achieving the desired capacity, and complying with design requirements of a conditioned environment, without compromising refrigerant system reliability. As the compressor temperature increases, the pulse width modulation valve duty cycle time is adjusted to ensure that adequate amount of refrigerant is circulated through the compressor to cool the compressor internal components.

Abstract: A refrigerator control method is disclosed which ensures efficient operation of a compressor. To control a refrigerator including a compressor, a first evaporator and a second evaporator connected to the compressor, and a refrigerant control valve that controls introduction of a refrigerant into the first evaporator and the second evaporator, the refrigerator control method includes operating the compressor, and controlling the opening and closing of the refrigerant control valve, to reduce not only consumption of electricity by the compressor, but also a pressure difference between an entrance and an exit of the compressor upon starting of the compressor.

Abstract: A CO2 refrigeration system comprises a refrigeration circuit in which circulates CO2 refrigerant between a compression stage in which the CO2 refrigerant is compressed. A condensation stage is provided in which the CO2 refrigerant releases heat and is accumulated in a condensation reservoir. An evaporation stage is provided in which the CO2 refrigerant is expanded to a gaseous state to absorb heat from a fluid for refrigeration, with at least a portion of CO2 refrigerant exiting the evaporation stage being directed to a supra-compression circuit comprising a supra-compression stage in which the portion of CO2 refrigerant is compressed. A heat exchanger is provided by which the compressed CO2 refrigerant is in a heat-exchange relation with a secondary-refrigerant circuit, such that the compressed CO2 refrigerant releases heat to a secondary refrigerant used for heating purposes. Pressure-regulating means control a pressure of the compressed CO2 refrigerant being returned to the condensation stage.

Abstract: In a refrigeration cycle device for a vehicle, a weak-inflammability refrigerant that does not ignite at a high-temperature heat source mounted in an engine compartment of the vehicle in a refrigerant single state is circulated in a refrigerant cycle. The refrigerant cycle includes a compressor for compressing and discharging the refrigerant. The compressor includes an oil separator that is located at a refrigerant discharge side of the compressor to separate a lubrication oil from the refrigerant and to return the separated lubrication oil to an interior of the compressor, a shutting portion configured to shut a reverse flow of the refrigerant at a refrigerant suction side of the compressor, and a driving portion located to drive the shutting portion. Furthermore, the driving portion causes the shutting portion to shut the reverse flow of the refrigerant when the refrigerant cycle is damaged.

Abstract: An expansion valve for an air conditioning system circulates refrigerant through a fixed-displacement compressor, a condenser, and an evaporator. An inlet is provided for receiving refrigerant liquefied in the condenser. An outlet of the expansion valve supplies refrigerant to the evaporator. A valve element controls flow of refrigerant between the inlet and the outlet, wherein the valve element is normally closed. A control assembly is coupled to the valve element and is responsive to at least one temperature or pressure in the air conditioning system to open the valve element to variably meter the refrigerant to the evaporator. A bleed passage bypasses the valve element to conduct refrigerant between the inlet and the outlet.

Abstract: A pulse width modulation control is provided for a suction modulation valve in a refrigerant system. An intentional small “leakage” path is maintained through the suction modulation valve to ensure that the pressure inside the compressor shell does not decrease below a safe reliability threshold but, at the same time, does not exceed a certain value, which would cause the refrigerant system to operate inefficiently, when the pulse width modulation control has moved the suction modulation valve to a closed position. The size of this minimum “leakage” path is continuously adjusted to ensure that the optimum pressure inside the compressor shell is maintained regardless of the evaporator pressure and other operating conditions.

Abstract: A system includes a compressor temperature sensor that generates a compressor discharge temperature signal corresponding to a compressor of a refrigeration system, a compressor pressure sensor that generates a compressor discharge pressure signal corresponding to the compressor, and a controller processing the signals over a predetermined time period. The processing includes calculating a discharge saturation temperature based on the compressor discharge pressure signal, calculating compressor superheat data based on the compressor discharge temperature signal and the discharge saturation temperature, accumulating the compressor superheat data over the predetermined time period, and comparing the accumulated compressor superheat data to a predetermined threshold. The controller generates an alarm indicating a compressor fault based on the comparing.

Abstract: A high-pressure side discharge port of a two-stage compressor (12A) and a condenser (14A) are connected, condenser (14A) and a PMV (15A) are connected, a refrigerating side exit of PMV (15A) is connected to a medium pressure side suction port of two-stage compressor (12A) via an R capillary tube (16A) and an F evaporator (18A), connected to an F evaporator (26A) via an F capillary tube (24A), F evaporator (26A) is connected to a low-pressure side suction port of two stage compressor (12A) via a low-pressure suction pipe (28A), PMV (15A) can switch a simultaneous cooling mode and a freezing mode, and in the simultaneous cooling mode, a refrigerant flow rate toward R evaporator (18A) is adjusted by PMV (15A), and thereby a temperature difference control is performed so as to make a difference between an entrance temperature and an exit temperature of R evaporator (18A) equal to a preset temperature difference (for example, 4° C.).

Abstract: A system includes a scroll compressor having a first scroll member interleaved with a second scroll member to define at least two moving fluid pockets that decrease in size as they move from a radially outer position to a radially inner position. A valve in fluid communication with the compression chamber is movable between an open state allowing fluid to the compression chamber and a closed state preventing fluid to the compression chamber. A controller continuously cycles the valve between the open state and the closed state at a rate that is faster than a thermal time constant of a load on the system.

Abstract: A pressure control valve includes a valve portion disposed in a passage from a refrigerant radiator to a suction port of a refrigerant compressor in a vapor-compression refrigerant cycle system. The valve portion controls a refrigerant pressure at an outlet of the refrigerant radiator in accordance with a refrigerant temperature at the outlet of the refrigerant radiator, and the valve portion has a control pressure characteristic in which a pressure change relative to a temperature is smaller than that of the refrigerant. Furthermore, the valve portion may have a fluid passage through which refrigerant flows even when a valve port of the valve portion is closed by a valve body. Accordingly, when the refrigerant radiator is used for heating a fluid, heating capacity for heating the fluid can be rapidly increased at a heating start time.

Abstract: A refrigeration cycle device includes a first branch portion with branched first and second refrigerant passages, an ejector located in the first refrigerant passage, a first evaporator located in the first refrigerant passage to evaporate refrigerant flowing out of the ejector, a branch passage through which refrigerant upstream of a nozzle portion of the ejector flows into a refrigerant suction port of the ejector, a first throttle provided in the branch passage, a second evaporator located in the branch passage to evaporate the refrigerant flowing out of the first throttle, a second throttle provided in the second refrigerant passage, and a third evaporator located in the second refrigerant passage to evaporate the refrigerant flowing out of the second throttle. Furthermore, a pressure-loss generation portion is located to generate a pressure loss in the first refrigerant passage, thereby causing the refrigerant to easily flow into the second refrigerant passage.

Abstract: An air conditioning compressor for air conditioning systems in motor vehicles, wherein the air conditioning compressor at the high pressure output comprises a check valve and a pressure control device, for example a pressure control valve or a bursting disk.

Abstract: A cooling apparatus (1) has a compressor (2), a condenser (3), an expansion valve (5), an evaporator (6) and an electric valve (10), all connected to each other in this order by a piping line to form a refrigeration circuit. The apparatus further has a heating section (11) and a bypass (12), and a thermosensitive tube (13) of the expansion valve is disposed between the heating section (11) and the electric valve (10) so that temperature of a refrigerant having left this section is detected before entering this valve (10). The refrigerant remains as a gas-liquid mixture until it leaves the evaporator (6) such that temperature of the refrigerant is uniform within the evaporator and equal to the saturation vapor temperature of this refrigerant, and therefore fluctuation in the refrigerant temperature is diminished.

Abstract: A high-pressure side discharge port of a two-stage compressor (12A) and a condenser (14A) are connected, condenser (14A) and a PMV (15A) are connected, a refrigerating side exit of PMV (15A) is connected to a medium pressure side suction port of two-stage compressor (12A) via an R capillary tube (16A) and an F evaporator (18A), connected to an F evaporator (26A) via an F capillary tube (24A), F evaporator (26A) is connected to a low-pressure side suction port of two-stage compressor (12A) via a low-pressure suction pipe (28A), PMV (15A) can switch a simultaneous cooling mode and a freezing mode, and in the simultaneous cooling mode, a refrigerant flow rate toward R evaporator (18A) is adjusted by PMV (15A), and thereby a temperature difference control is performed so as to make a difference between an entrance temperature and an exit temperature of R evaporator (18A) equal to a preset temperature difference (for example, 4° C.).

Abstract: An apparatus for refrigeration system control includes a plurality of circuits, each circuit having at least one refrigeration case and an electronic evaporator pressure regulator in communication with each circuit. Each electronic evaporator pressure regulator controls a temperature of one of the circuits. A sensor in communication with each circuit measures a parameter from the circuit. A controller associated with each electronic evaporator pressure regulator controls the respective electronic evaporator pressure regulator based upon measured parameters from each of the circuits.

Abstract: A method for regulating a most loaded circuit of a refrigeration system is provided. Each circuit includes at least one case and an EEPR valve. At least one controller communicates with the EEPR valves for receiving signals from the circuits corresponding to operating conditions for each circuit, and for issuing command signals to the EEPR valves and compressor. The operation of each circuit is monitored and a load signal is calculated for each circuit. The load signals for each circuit are compared and the most loaded circuit is determined. The EEPR valve of the most loaded circuit is adjusted to be approximately 100 percent open and a suction pressure of the compressor is adjusted to move a circuit temperature of the most loaded circuit to a target temperature. The process of selecting and regulating the most loaded circuit is repeated after a predetermined period of time.

Abstract: An inventive method of preventing unpowered reverse rotation in a compressor includes the steps of placing a solenoid valve at a location near compressor discharge. The valve is preferably actuated soon after the power to the motor is cut off, blocking the flow of refrigerant from expanding back toward the compression chambers of the compressor. The compressor is disclosed as a scroll compressor, but may also be a screw compressor. These two types of compressors are susceptible to undesirable unpowered reverse rotation when compressed refrigerant re-expands through the compression elements from the compressor discharge into the compressor suction. By blocking the flow of refrigerant, this unpowered reverse rotation is prevented. A high pressure switch can be positioned directly upstream of the solenoid valve to immediately stop the compressor if the valve malfunctions and blocks the flow of refrigerant during normal compressor operation.

Abstract: A method and apparatus for refrigeration system control includes a control system operable to meet cooling demand and control suction pressure for a plurality of refrigeration circuits each including a variable valve and an expansion valve. The controller controls the variable valve independently of the expansion valves to meet cooling demand by determining a change in a measured parameter and controlling at least one of the variable valves based upon the change to an approximately fully open position.

Abstract: A method and apparatus for refrigeration system control includes an evaporator pressure regulator and sensor in communication with one of a plurality of refrigeration circuits. The sensor is operable to measure a parameter of the refrigeration circuit. A controller is operable to adaptively control a suction pressure of the compressor rack based upon the measured parameter, whereby the controller controls a circuit temperature for one of the plurality of circuits. Further, the controller is operable to control the electronic evaporator pressure regulator to control the temperature in the one of a plurality of refrigeration circuits by determining a change in the parameter and updating a set point based upon the change of parameter.

Abstract: Step control in capacity modulation of a refrigeration or air conditioning circuit is achieved by rapidly cycling a solenoid valve in the suction line, economizer circuit or in a bypass with the percent of “open” time for the valve regulating the rate of flow therethrough. A common port in the compressor is used for economizer flow and for bypass.

Abstract: A diagnostic system includes a controller adapted for coupling to a compressor or electronic stepper regulator valve. The controller produces a variable duty cycle control signal to adjust the capacity of the compressor or valve position of the electronic stepper regulator valve as a function of demand for cooling. The diagnostic system further includes a diagnostic module coupled to the controller for monitoring and comparing the duty cycle with at least one predetermined fault value indicative of a system fault condition and an alert module responsive to the diagnostic module for issuing an alert signal when the duty cycle bears a predetermined relationship to the fault value.