Showing papers on "Thermal expansion valve published in 1994"

Automotive air conditioner having condenser and evaporator provided within air duct

Abstract: An automotive air conditioner which conditions air making use of radiation of heat of a condenser and absorption of heat of an evaporator effectively. The evaporator 207 and the condenser 203 are disposed in a duct 100. A bypass passageway 150 is provided sidewardly of the condenser 203 in the duct 100, and a flow rate of air bypassing the condenser 203 is controlled by pivotal motion of an air mixing damper 154. Another bypass passage is provided sidewardly of the evaporator 207 in the duct 100, and a flow rate of air bypassing the evaporator 207 is controlled by pivotal motion of a bypass damper 159. Air is conditioned to an optimum blown out air temperature by varying the cooling rate at the evaporator 207 and the heating rate at the condenser 203 and is blown out to a room of an automobile from spit holes 141, 142 and 143. An outside heat exchanger is provided outside the duct 100, and a flow of refrigerant is changed over suitably among the outside heat exchanger 202, the evaporator 207 and the condenser 203 to perform cooling operation, heating operation, dehumidifying operation, dehumidifying heating operation and defrosting operation.

Heat pump and air conditioning system incorporating thermal storage

Abstract: A heat pump and air conditioning system is provided with a thermal storage device, a variety of distribution devices for blocking or allowing flow of the system working fluid, and a controller for manipulating the distribution devices to control flow of the working fluid through the thermal storage device to allow thermal energy storage or thermal energy discharged depending upon sensed conditions. In addition, a thermal storage device is provided which is suitable for use in a heat pump and air conditioning system. The thermal storage device includes a container through which refrigerant coils pass. The container is filled with an unencapsulated phase change material having a first melt temperature and an encapsulated phase change material having a second melt temperature higher than the first melt temperature. Further disclosed is a method for conditioning a space by use of heat pump and air conditioning systems incorporating thermal storage. The methods involve controlling refrigerant flow through connected heat exchangers such that depending upon the operating mode, a given heat exchanger may operate as condenser or as an evaporator.

Air conditioning apparatus

Abstract: PURPOSE:To enhance dehumidifying capacity in an intermediate term by disposing first, second heat exchangers in an air conditioning duct and a third heat exchanger out of the duct, and controlling a heat exchanging efficiency of the third exchanger in a state that a cycle for dehumidifying and heating is formed CONSTITUTION:At the time of dehumidifying and heating, a four-way valve 5 is switched to a position of solid lines When a temperature of a first heat exchanger 2 is 0 degC or lower based on an output of a temperature detector 11, a solenoid valve 9 is closed to prevent freezing Then, an the valve travel of an electric control type expansion valve 7 is regulated to control a heat absorption quantity of a third heat exchanger 4 That is, the valve travel of the valve 7 is made small in an intermediate term, a heat exchanging efficiency of the exchanger 4 is deteriorated to reduce heat absorption from the outside air and hence an evaporating pressure of the exchanger 4 is reduced Thus, discharge refrigerant from a compressor 6 is condensed to be liquefied by a second heat exchanger 3, reduced under pressure by the valve 7, then sent to the exchanger 4 to reduce the evaporation pressure of the exchanger 2, thereby enhancing dehumidifying capacity of the exchanger 2

In-line incremetally adjustable electronic expansion valve

Abstract: A variable flow rate expansion valve designed for in-line installation in a fluid conveying conduit such as between the high pressure condenser and lower pressure evaporator of a refrigeration system includes an integrally defined restrictor disc and a closure disc for controlling the flow of fluid through the valve. The restrictor disc has a first set of flow apertures and the closure disc a second set of flow apertures. The closure disc is rotatably coupled to the restrictor device in a plane parallel to the plane of the restrictor disc and perpendicular to refrigerant flow. A stepper motor is coupled to the closure disc through a linear actuator. Movement of the linear actuator causes the closure disc to rotate relative to the restrictor disc such that the flow apertures of the closure disc are selectively brought into and out of registry with the apertures of the restrictor disc.

Refrigerant flow rate control based on evaporator dryness

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve (16) in a refrigeration system (10). A first temperature sensor (30) is located near the evaporator inlet, and a second temperature sensor (28) is disposed in a compartment (22) to be cooled. A controller (26) is included for controlling the duty cycle of the pulse width modulated solenoid valve (16). The controller (26) receives inputs from the two temperature sensors (28, 30) and controls the valve duty cycle based on the difference of the two temperatures. The second temperature sensor (28) is preferably located on the back wall of the compartment (22) and can be adjacent to the compartment air inlet, adjacent to the compartment air outlet, or between the air inlet and air outlet.

Refrigerant flow rate control based on liquid level in simple vapor compression refrigeration cycles

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system using a simple vapor compression cycle. The refrigeration cycle includes a phase separator which receives two phase refrigerant from the condenser and supplies liquid refrigerant to the pulse width modulated solenoid valve. A liquid level sensor is disposed in the phase separator, and a controller for controlling the duty cycle of the pulse width modulated solenoid valve is provided to receive input from the liquid level sensor. The liquid level sensor can be of the type which provides a continuously variable signal as a function of liquid level, or it can be a liquid level switch which controls valve duty cycle on the basis of whether the phase separator liquid level is above or below a set level. Alternatively, two liquid level switches can be provided.

Plate heat exchanger with a refrigerant distributor

Abstract: A device is disclosed for distributing a two-phase refrigerating medium mass flow in a plate evaporator (12). The evaporator has a distribution channel (14) at the inlet side which may receive a refrigerating medium mass flow coming from an expansion valve (10) and several mutually spaced exchanger channels (16) which branch off from the distribution channel (14) in a substantially perpendicular direction. In order to ensure a uniform distribution of the refrigerant medium mass flow (28') among the exchanger channels (16), a porous body (38) is arranged in the distribution channel (14) between the refrigerating medium inlet (26) and the branch-off points of the exchanger channels (16). The porous body (38) is advantageously arranged in an outer throttle insert (32) which extends over at least part of the length of the distribution channel and in whose wall are located additional throttle openings (34) that lead to the exchanger channels (16).

Refrigeration system with electrically controlled expansion valve

Abstract: An energy-efficient refrigeration system includes an electrically controlled thermal expansion valve disposed in the refrigerant piping so as to control flow of refrigerant in the refrigeration system, and an expansion valve controller coupled to the expansion valve to provide control signals to the valve. The controller includes a refrigerant temperature sensing device coupled to the refrigeration system so as to sense a flow control temperature corresponding to the refrigeration temperature at a flow measurement site so that the controller generates control signals to control valve position to provide optimum refrigerant flow for a particular operational mode of the system. The thermal expansion valve includes a heating element that is responsive to control signals from the controller and that is thermally coupled to a thermal expansion medium so that the medium expands upon application of heat from the heating element.

A dynamical model adequate for controlling the evaporator of a heat pump

Abstract: We present a dynamical model for the dry evaporator of a heat pump which is suitable for control purposes. We take into account the expansion valve, the compressor and the condenser to model the evaporator and its surroundings. Our model is of the distributed parameter type and consists of partial differential and algebraic equations. For the solution of discretized equations, Newton iteration with a block-Gauss solution of the linearized systems is applied. Numerical results are presented in graphical form and correspond to simulations of almost all control possibilities.

Refrigerant flow rate control based on suction line temperature

Abstract: Pulse width modulation is used to control the flow rate through a solenoid expansion valve in a refrigeration system. A device for sensing suction line temperature is provided, and a controller is included for controlling the duty cycle of the pulse width modulated solenoid valve. The controller receives input from the suction line temperature sensing device as a basis for controlling the duty cycle. The suction line temperature sensing device may be a temperature sensor disposed on the suction line at the midpoint of the heat exchanger between the suction line and the liquid line. Alternatively, the suction line temperature sensing device may include a first temperature sensor disposed on the liquid line at one end of the heat exchanger and a second temperature sensor disposed on the liquid line at another end of the heat exchanger.

Apparatus and method for refrigerant fluid leak prevention

Abstract: Apparatus and method for preventing leakage of refrigerant fluid from a closed air conditioning or refrigeration system having a sealed compressor, an evaporator, a receiver and a condenser, the apparatus including a solenoid-actuated valve for segmenting the refrigerant within the closed system away from the most leak-prone area of the system. A pump is provided for the periodic spraying of lubrication fluid onto a condenser seal to prevent drying of the seal. A containment compartment or trap is provided for catching refrigerant diverted by a diversion valve, the containment compartment having an improved high pressure relief valve, with an indicator for indicating the occurrence of a high pressure exhaust of refrigerant into the atmosphere.

Evaporator water temperature control for a chiller system

Abstract: A method of controlling the capacity of a chiller system, the chiller system including a circularly linked compressor, condenser, expansion device, and evaporator. The method comprises the steps of: measuring a first chiller system parameter; determining a first parameter error as a function of the difference between the first parameter and a first setpoint; measuring a second chiller system parameter; determining a second parameter error as a function of the difference between the second parameter and a second setpoint; providing a first mode of capacity control where the compressor is modulated in response to the first parameter error and the expansion valve is modulated in response to the second parameter error; and providing a second mode of capacity control where the compressor is maintained at a minimum capacity and the expansion valve is modulated in response to the first parameter error.

Device for cooling a traction battery

Abstract: For such battery cooling it is on the one hand known for an air/water heat exchanger to be used as long as the ambient temperature is significantly below the required battery temperature. On the other hand, it is known for the battery to be cooled by a cooling unit of a vehicle air-conditioning system by the battery serpentine cooling coil being connected into the cooling circuit of the air-conditioning system downstream of the evaporator in said air-conditioning system. Devices are proposed in the case of which either the battery serpentine cooling coil is inserted into the vehicle air-conditioning system cooling circuit with an upstream expansion valve in parallel with the evaporator branch of said vehicle air-conditioning system, or a cooling circuit having an air/water heat exchanger is used, a further cooling unit then being provided whose evaporator is in thermal contact with this cooling circuit and can be activated as required. In this way, the desired battery temperature is maintained at a low cost in terms of line and cooling components in all environmental conditions, in particular when the ambient temperature is higher than the required battery temperature, as well. For use, for example, for cooling the traction battery of an electric vehicle.

Fan control system for the evaporator of refrigerating appliances

Abstract: A fan control system for the evaporator of refrigerating appliances, of the type in which the internal air is forced to circulate, by action of a fan (20), through the evaporator (30) of a refrigerating circuit, fed by a compressor (40), the system comprising: a first temperature sensing means (S1), detecting the temperature of the circulating air at the air inlet of the evaporator (30); a second temperature sensing means (S2), detecting the temperature of the evaporator (30); and a control circuit (50), producing: a fan stop control signal, when the difference between the values of the temperatures detected by the first and second sensors (S1, S2) reaches a stop value, below which the heat transfer from the forced circulating air to the evaporator is lower than the heat transfer from the fan (20) to the air; and a fan start control signal, when the difference of temperatures reaches a certain start value corresponding to a temperature of the evaporator (30) substantially lower than the temperature of the air in the internal medium.

Temperature controlled system for printing press

Abstract: The system of the present invention controls the temperature of ink so as to enhance print quality. An ink roller has a circulation path therein. A circulation system circulates fluid, such as water, through the ink roller and through a heat exchanger. The heat exchanger is part of a refrigeration and heating system that selectively cools and heats the circulating water. The refrigeration and heating system uses a compressor, an expansion valve and the heat exchanger. To provide refrigeration, refrigerant fluid is circulated in the refrigeration and heating system through the expansion valve and to the heat exchanger. To provide heating, the expansion valve is bypassed by a conduit, wherein hot fluid from the compressor flows directly to the heat exchanger.

Air-conditioning system

Abstract: PURPOSE:To level out the power consumption relating to a system utilizing cold heat stored by utilizing nighttime power supply, etc., by providing a first refrigerant circuit consisting of a heat pump circuit and a second refrigerant circuit consisting of a natural circulation circuit of refrigerant. CONSTITUTION:For a time zone, such as midnight, when surplus power abounds a control valve 20 is opened to function as an expansion valve, whereas a control valve 55 is closed and a compressor 11 is actuated by utilizing the surplus power and through a first refrigerant circuit 3 operation for storage of heat is effected so that ice is made in an ice type heat storage tank 2 in a manner of storing cold heat. During the cooling operation in the daytime the cold heat stored in the ice type heat storage tank 2 is supplied to a condenser 60 by a cold heat source circuit 7 and the refrigerant condensed at the condenser 60 is supplied by a second refrigerant circuit 6 to a second coil 51 of the indoor apparatus 5 so as to effect cooling. When the indoor load increases and the cold heat in storage falls short of the need during the cooling operation, the control valve 20 is closed and the control valve 55 is opened so that the cooling is effected by utilizing the first refrigerant circuit 3.

Control device for air conditioner

Abstract: PURPOSE:To contrive the conservation of refrigerant and energy and the reduction of costs by a method wherein the optimum control parameter value is determined from the time series data of the future refrigerant behavior and of room temp. obtained based on the time series data and detecting data of predicted future room load and the control subject is manipulated. CONSTITUTION:A computing means 24 expresses in a genotypic form the values of the control parameters in compressor frequency Hz, room expansion valve opening degree Lrk (k stands for room) and room fan speed gk (k stands for room). A plurality of solids consisting of the genotypes having various values are formed and the gene manipulation of these solids is repeated for the selection, multiplication, crossing and mutation thereof. From the time series data of the future refrigerant behavior and of room temperature Tin obtained based on the time series data and detecting data of the predicted future room load, a determination is made as to whether or not a prescribed room temperature is well followed up, whether or not the refrigerant behavior is instable and whether or not the flow amount of refrigerant is insufficient.

Cooling device for switchgear cabinet or other electronic equipment housing

Abstract: The cabinet is cooled by a cold prim. circuit contg. a compressor (1), condenser (2) filter/dryer (3), expansion valve (4) and evaporator (5), and a sec. circuit (22) in which water or brine is pumped (7) through a heat exchanger (8) in the flow of air extracted from the cabinet by a motor-driven fan (15).Excessive pressure and flow in the sec. circuit, which supplies hot water to the prim. evaporator, are prevented by valves (9,10). A power board (17) subject to a controller (16) supplies current to prim. and sec. fan motors (M2,M3), the compressor motor (M1), air thermometers (B1-B3) and a prim. circuit pressure monitor (20).

A quick cooling air conditioning system

Abstract: A quick cooling air conditioning system that preserves high pressure refrigerant, in a portion of the refrigerant path or in a dedicated reservoir, after the shutdown of the air conditioning compressor. The quick air cooling is achieved by the instant application of high pressure refrigerant to the evaporator at the start-up of the air conditioning system.

Refrigeration defrost cycles

Abstract: A hot gas defrost system for a refrigeration cycle, including at least one compressor, condenser, receiver, expansion valve and evaporator. During defrost, a pressure-sensitive valve to the condenser inlet is normally closed, and the flow of refrigerant from the compressor bypasses the condenser and flows to the receiver. However, when the pressure in the system reaches a critical point, the pressure-sensitive condenser inlet valve will open to release the excessive pressure. The condenser inlet valve is also temperature-sensitive and will open if the ambient temperature surrounding the condenser is above a specific point. Opening of the condenser valve permits the utilization of the hot gas in the condenser for defrost and to decrease the thermal shock resulting from the superheated vapor contacting the evaporator coil. The compressor, which needs a constant flow of liquid refrigerant for cooling, is continually supplied with liquid refrigerant. During refrigeration, a conduit connecting the receiver outlet and the compressor provides liquid refrigerant. During defrost, a conduit from the suction line to the compressor provides the required liquid refrigerant. The system also provides complete defrosting and deicing of the evaporator coil. A bypass line between the hot gas inlet of the evaporator and the lower section of the evaporator coil directs a portion of the hot gas directly to the lower section of the coil.

In-line incrementally manually adjustable rotary expansion valve

Abstract: A variable flow rate expansion valve designed for in-line installation in a fluid conveying conduit such as between the high pressure condenser and lower pressure evaporator of a refrigeration system includes an integrally defined restrictor disc and a closure disc for controlling the flow of fluid through the valve. The restrictor disc has a first set of flow apertures and the closure disc a second set of flow apertures. The closure disc is rotatably coupled to the fixed restrictor device in a plane parallel to the plane of the restrictor disc and perpendicular to refrigerant flow. A manual, calibrated, incrementally adjustable actuator permits the positioning of the closure disc with respect to the restrictor disc so as to permit the flow of refrigerant through the valve to be manually adjusted, by a chnage in the registry of the apertures in the closure and restrictor discs, in accordance with varying operating conditions and requirements.

Air conditioner and refrigerant quantity-determining method therefor

Abstract: PURPOSE:To easily determine excess or insufficiency of sealed refrigerant quantity even by an unspilled operator or regarding a refrigerating cycle at the time of installing an air conditioner. CONSTITUTION:A compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an indoor heat exchanger 5, and a vapor-liquid separator 6 are sequentially connected via tubes to constitute a refrigerating cycle. In order to detect the state of the cycle, a temperature sensor 7d is provided in the heat exchanger 3 or 5 to become an evaporator. When the cycle becomes a steady operation, a set expansion valve opening stored in memory means of a controller 40 is read based on the temperature detected by the sensor. A calculator 8 for reading the set expansion valve opening stored in memory means of a controller 40 based on the temperature detected by the sensor when it becomes a steady operation and comparing the value with the integrated value of the command value of the controller or the actual expansion valve opening to judge the excess or the insufficiency of the sealed refrigerant quantity from the ratio is provided in the controller.

Control system for refrigerant metering solenoid valve

Abstract: A system including a control circuit and a sensing circuit controls an expansion valve in a refrigeration system using pulse width modulation. The control circuit includes a ramp generator, a pulse width modulator, and a power switch. In response to input from the sensing circuit, the control circuit produces a control signal which cyclically opens and closes the valve. The average flow rate through the valve is varied in accordance with a condition of the refrigeration system which is detected by the sensing circuit.

Integral evaporator and suction accumulator for air conditioning system utilizing refrigerant recirculation

Abstract: An evaporator of the plate-fin construction has attached a formed housing which together with the evaporator end plate comprises a suction accumulator. A liquid conduit passes through the accumulator and induces fluid from the accumulator into the evaporator via a venturi located in the conduit. A tube inserted into one tank of the evaporator is in direct connection to the accumulator and increases storage capacity of the accumulator. A field removable filter-drier assembly is installed in the exit tank or compartment of the evaporator. A baffle is located in the accumulator section and separates liquid from gas and allows mostly gas with entrained oil to flow to the compressor. A secondary flow path which opens under low charge conditions aids in oil return to the compressor.

Liquid pressure amplification with bypass

Abstract: Liquid pressure amplification with Bypass is used in an air-conditioning or refrigeration system which includes a compressor, a condenser, a pump, an expansion valve, and an evaporator, interconnected by conduits in a closed refrigerant loop. A first conduit coupling an outlet of the compressor to an inlet to the condenser. A centrifugal pump is coupled to the condenser (or receiver) outlet for boosting the pressure of the condensed liquid refrigerant by a substantially constant increment. A second conduit transmits a first portion of the condensed liquid refrigerant from outlet of the pump through the expansion valve into the evaporator to effect cooling. A third conduit transmits a second portion of the condensed liquid refrigerant from the pump outlet into the condenser inlet, which cools the superheated vapor refrigerant entering the condenser, reducing head pressure. A bypass having a valve around is provided to direct refrigerant around the pump in the event the pump is idled while the compressor remains in operation.

Dual refrigerant recovery apparatus with single vacuum pump and control means

Abstract: A refrigerant recovery assembly will recover incompatible refrigerants. The assembly has two separate processing units. Each unit has a pair of hoses which connect to an air conditioning system for recovering refrigerant. Each unit has an expansion valve, an evaporator, a compressor, a condenser and one or more filters. The two units are mounted on a single frame and utilize common electrical controls. The electrical controls will not allow each unit to operate simultaneously. A single vacuum pump is used with each unit.

Freezer evaporator defrost system

Abstract: A freezer system is disclosed comprising a freezing mechanism and an adjacent freezer cabinet. The freezer mechanism has a compressor that produces hot gas refrigerant, a condenser, and an evaporator which accumulates ice on its outside surface. An evaporator condensate pan is mounted beneath the evaporator and a compressor condensate pan is mounted beneath the compressor and connected by a conduit to the evaporator condensate pan. A condensate pan heater coil is attached to the bottom of the evaporator condensate pan. A hot gas valve connected between the compressor and the condensate pan heater coil, when activated, conducts hot gas refrigerant to the condensate pan heater coil to heat it and thereby heat the attached evaporator condensate pan, which in turn heats the outside of the evaporator to help melt accumulated ice. The hot gas refrigerant is then fed from the condensate pan heater coil to the evaporator, heating the inside of the evaporator and fully melting the ice. The water drips into the evaporator condensate pan and flows to the compressor condensate pan. A condenser fan mounted adjacent the condenser moves outside air through the condenser and around the compressor to cool the condenser and compressor while heating the moved air, which is then passed over the water in the compressor condensate pan to evaporate it and expel it from the freezer system.

Method for limiting the hot-gas temperature in a refrigerant circuit and expansion valve

Abstract: A method for limiting the hot-gas temperature by injection of refrigerant in a refrigerant circuit involves controlling the expansion valve (6) as a function of the superheating temperature (T2) of the evaporator (8). In order to improve performance and be able to dispense with an injection valve, the expansion valve (6) is controlled not only as a function of the superheating temperature but also by the hot-gas temperature (T1).

Control system for air-conditioner

Abstract: An improved control system for air conditioners. The control system detects temperatures at various points in the air-conditioner, and determines the model numbers of an indoor and an outdoor sections of the air-conditioner from these temperature data and a set of given status data associated with the air-conditioner. The control system may periodically set optimum control parameters in accordance with the model numbers and current status data of the air-conditioner and, in response to the refrigerant temperature at the outlet of compressor of its heat exchanger, may control the flow rate of the refrigerant passing through a variable expansion valve, thereby providing optimum refrigerating capacity at all times.