WO2019159826A1

WO2019159826A1 - Refrigerator

Info

Publication number: WO2019159826A1
Application number: PCT/JP2019/004524
Authority: WO
Inventors: 堀尾　好正; 境　寿和
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-02-16
Filing date: 2019-02-08
Publication date: 2019-08-22
Also published as: JP2019143819A

Abstract

This refrigerator comprises: a compressor (11); an expansion valve (14); a condenser (12); an evaporator (16); and an air removal unit (24). In a refrigeration cycle (10) configured to include the compressor (11), the expansion valve (14), the condenser (12), the evaporator (16), and the air removal unit (24), the dryness of a refrigerant that flows downstream of the condenser (12) is controlled by a narrowing amount of the expansion valve (14). The air removal unit (24) is disposed upstream or downstream of the expansion valve (14) in the refrigeration cycle (10), and removes air which has mixed with the refrigerant that circulates through the refrigeration cycle (10).

Description

refrigerator

The present disclosure relates to a refrigerator equipped with an expansion valve with a variable throttle amount.

From the viewpoint of energy saving, there are refrigeration systems and refrigerators equipped with expansion valves with variable throttling amounts.

Hereinafter, a conventional refrigeration system will be described with reference to the drawings.

FIG. 8 is a configuration diagram of a conventional refrigeration system 140. FIG. 9 is a diagram illustrating a method for controlling the expansion valve 144 of the conventional refrigeration system 140.

In FIG. 8, the refrigeration system 140 includes a compressor 141, a condenser 142, a receiver 143, an expansion valve 144, a capillary tube 145, an evaporator 146, an intake pipe 147, an internal heat exchange unit 148, And an intake pipe temperature sensor 149.

The receiver 143 stores the refrigerant circulating in the refrigeration system 140 in a liquid state. The amount of the refrigerant in the liquid state in the receiver 143, that is, the amount of the liquid refrigerant fluctuates by changing the throttle of the expansion valve 144. Thereby, the quantity of the refrigerant | coolant inside the condenser 142 and the evaporator 146 is maintained appropriately. Further, the degree of supercooling of the refrigerant flowing into the expansion valve 144 is kept constant (including substantially constant).

The expansion valve 144 and the capillary tube 145 are arranged in series, whereby the throttle of the refrigeration system 140 is configured. Therefore, the internal heat exchanging part 148 for exchanging heat between the capillary tube 145 and the suction pipe 147 is realized. Thereby, the enthalpy of the low-temperature refrigerant | coolant which recirculates the inside of the suction pipe 147 is collect | recovered. Therefore, the efficiency of the refrigeration system 140 is improved.

The suction pipe temperature sensor 149 detects the temperature of the suction pipe 147 after passing through the internal heat exchange unit 148. Based on the temperature detected by the suction pipe temperature sensor 149, the throttle amount of the expansion valve 144 is varied.

The operation of the conventional refrigeration system 140 configured as described above will be described below.

When the refrigeration system 140 is operated and the cooling operation is performed, the compressor 141 operates (operates). The refrigerant compressed in the compressor 141 dissipates heat and condenses in the condenser 142 and is stored in the receiver 143. The liquid refrigerant stored in the receiver 143, that is, the liquid refrigerant is decompressed in the expansion valve 144 and the capillary tube 145. The decompressed liquid refrigerant is supplied to the evaporator 146 to evaporate, and is supplied (refluxed) to the compressor 141 through the suction pipe 147. At this time, cooling is performed by utilizing the cold heat generated in the evaporator 146, that is, latent heat.

When the temperature of an object (not shown) cooled by the refrigeration system 140 decreases and the refrigeration system 140 approaches a stable state, the cold heat generated in the evaporator 146 becomes redundant. When the cold heat generated in the evaporator 146 becomes excessive, the liquid refrigerant that could not be evaporated is mixed in the suction pipe 147. As a result, the temperature of the suction pipe 147 decreases. At this time, even after the enthalpy of the low-temperature refrigerant that circulates in the suction pipe 147 is collected by the internal heat exchange unit 148, the temperature of the suction pipe 147 does not rise sufficiently. Therefore, the temperature of the suction pipe 147 approaches the temperature of the evaporator 146. At this time, surplus cold heat generated in the evaporator 146 is returned to the compressor 141. As a result, the efficiency of the refrigeration system 140 decreases. When the state where the excessive cold heat generated in the evaporator 146 is returned to the compressor 141 continues, the liquid refrigerant is returned to the compressor 141. Therefore, the durability of the compressor 141 may be reduced. In order to suppress the liquid refrigerant from returning to the compressor 141, the throttle amount of the expansion valve 144 is controlled based on the temperature detected by the suction pipe temperature sensor 149.

Next, a method for controlling the expansion valve of the conventional refrigeration system 140 will be described with reference to FIG.

The horizontal axis in FIG. 9 indicates the value of the pressure loss generated according to the throttle amount of the expansion valve 144. The vertical axis in FIG. 9 indicates the value of the temperature R of the suction pipe 147 detected by the suction pipe temperature sensor 149.

As described above, when the temperature of an object (not shown) cooled by the refrigeration system 140 decreases and the refrigeration system 140 approaches a stable state, the cold heat generated in the evaporator 146 becomes redundant. When the cold heat generated in the evaporator 146 becomes excessive, the temperature R of the suction pipe 147 decreases and the temperature R of the suction pipe 147 falls below R1, the throttle amount of the expansion valve 144 is controlled, and the throttle of the expansion valve 144 is controlled. The amount increases by a predetermined amount. Thereby, the evaporation temperature of the refrigerant in the evaporator 146 is lowered, and the circulation amount of the refrigerant is reduced. Therefore, the cold heat generated in the evaporator 146, that is, the refrigerating capacity in the evaporator 146 is reduced. Further, the liquid refrigerant that has flowed out of the receiver 143 to the suction pipe 147 is stored in the receiver 143 as surplus refrigerant. As a result, the temperature R of the suction pipe 147 increases.

On the other hand, when the temperature R of the suction pipe 147 rises and the temperature R of the suction pipe 147 exceeds R2, the throttle amount of the expansion valve 144 is controlled, and the throttle amount of the expansion valve 144 decreases by a predetermined amount. Thereby, the evaporation temperature of the refrigerant in the evaporator 146 rises, and the circulation amount of the refrigerant increases. Therefore, the cold heat generated in the evaporator 146, that is, the refrigerating capacity in the evaporator 146 increases. Further, excess refrigerant stored in the receiver 143 is supplied to the evaporator 146. As a result, the temperature R of the suction pipe 147 decreases.

By controlling the throttle amount of the expansion valve 144, the temperature R of the suction pipe 147 is maintained between the temperature R1 and the temperature R2 in FIG. Thereby, the fall of the efficiency of the refrigerating system 140 and the fall of the durability of the compressor 141 are suppressed.

Japanese Patent Laid-Open No. 5-196321

The expansion valve is desirably controlled so that the degree of dryness of the refrigerant at the outlet of the condenser, that is, the downstream side of the condenser, that is, the degree of supercooling becomes zero. However, a refrigeration system included in a home refrigerator or the like that uses a condenser that dissipates heat by natural convection from the outer casing of the refrigerator has a large change in heat dissipation capacity depending on environmental conditions. For this reason, it is difficult to keep the outlet of the condenser at a predetermined degree of supercooling. When the degree of supercooling at the outlet of the condenser approaches zero, the gas phase component of the refrigerant at the outlet of the condenser is reduced. At this time, the gas phase component of the refrigerant decreases, and the influence of the air actually remaining in the piping of the refrigeration system increases. Therefore, a large temperature slip occurs at the outlet of the condenser, that is, a temperature difference between the boiling point and the dew point occurs.

The present disclosure solves the above-described problem, and provides a refrigerator in which the temperature slip generated at the outlet of the condenser is reduced by reducing the influence of remaining air, and the efficiency and energy saving performance of the refrigeration cycle is improved. The purpose is to do.

In order to achieve the above object, the refrigerator of the present disclosure includes a compressor, an expansion valve, a condenser, an evaporator, and an air removal unit. The dryness of the refrigerant flowing downstream of the condenser in the refrigeration cycle including the compressor, the expansion valve, the condenser, the evaporator, and the air removing unit is controlled by the throttle amount of the expansion valve. The air removal unit is disposed upstream or downstream of the expansion valve in the refrigeration cycle, and removes air mixed in the refrigerant circulating in the refrigeration cycle.

Thus, the air remaining in the refrigeration cycle is removed by the air removal unit, that is, held by the air removal unit. Therefore, the influence of residual air is reduced, and the temperature slip that occurs between the outlet of the condenser, that is, between the condenser and the evaporator, is reduced. Thereby, the efficiency and energy saving performance of the refrigeration cycle are improved.

According to the present disclosure, since the influence of air that affects the refrigeration cycle can be suppressed, the expansion valve is accurately controlled, the efficiency and energy saving performance of the refrigeration cycle are improved, and the deterioration of the durability of the compressor is suppressed. A refrigerator can be provided.

FIG. 1 is a front view of a refrigerator according to an embodiment of the present disclosure. FIG. 2 is a vertical cross-sectional view of the refrigerator in the embodiment of the present disclosure. FIG. 3 is a configuration diagram of the refrigerator refrigeration system according to the embodiment of the present disclosure. FIG. 4 is a diagram illustrating a method for controlling the expansion valve of the refrigeration system according to the embodiment of the present disclosure. FIG. 5 is a diagram illustrating a correlation between the output of the expansion valve control sensor of the refrigeration system and the refrigerant flow rate in the embodiment of the present disclosure. FIG. 6 is a diagram illustrating a method for controlling the expansion valve of the refrigerator in the embodiment of the present disclosure. FIG. 7 is a schematic diagram of the gas receiver of the refrigerator in the embodiment of the present disclosure. FIG. 8 is a configuration diagram of a conventional refrigeration system. FIG. 9 is a diagram illustrating a method for controlling an expansion valve of a conventional refrigeration system.

The refrigerator in the first disclosure includes a compressor, an expansion valve, a condenser, an evaporator, and an air removal unit. The dryness of the refrigerant flowing downstream of the condenser in the refrigeration cycle including the compressor, the expansion valve, the condenser, the evaporator, and the air removing unit is controlled by the throttle amount of the expansion valve. The air removal unit is disposed upstream or downstream of the expansion valve in the refrigeration cycle, and removes air mixed in the refrigerant circulating in the refrigeration cycle.

Thus, the air remaining in the refrigeration cycle is removed (held) by the air removal unit. Thereby, the influence on the temperature slip by the air of the exit of a condenser is suppressed. Therefore, the efficiency of the refrigeration cycle is improved and the energy saving performance is improved.

Also, the influence of air that affects the refrigeration cycle is suppressed. For this reason, an expansion valve is controlled with a sufficient precision and the fall of the durability of a compressor is suppressed.

In the refrigerator according to the second disclosure, in the first disclosure, the air removal unit is arranged upstream of the expansion valve in the refrigeration cycle.

Thus, the air remaining in the refrigeration cycle is removed by the air removal unit. Thereby, the influence on the temperature slip by the air of the exit of a condenser is suppressed. Therefore, the efficiency of the refrigeration cycle is improved and the energy saving performance is improved.

In the refrigerator according to the third disclosure, in the first or second disclosure, the air removing unit is disposed at a position where the refrigerant flowing downstream of the condenser flows from top to bottom in the refrigeration cycle.

Thus, residual air having a low specific gravity with respect to the refrigerant effectively stays in the air removal section. Therefore, it is suppressed that air circulates with the refrigerant in the refrigeration cycle. Therefore, a reduction in efficiency of the refrigeration cycle and a reduction in cooling capacity due to air that is an uncompressed gas are suppressed, and a refrigerator with high energy saving performance can be provided.

In the refrigerator according to the fourth disclosure, in any one of the first to third disclosures, the air removal unit is a gas receiver. The gas receiver includes a hollow closed receiver main body, an inlet pipe inserted from one end of the receiver main body so that the tip is disposed inside the receiver main body, and an outlet pipe arranged at the other end of the receiver main body. Including.

Generally, when air remains in the refrigeration cycle, the air is mixed into the refrigerant compressed by the compressor. When a refrigerant mixed with an incompressible gas such as air is compressed, the input of the compressor, that is, the power consumption of the compressor is smaller than when a refrigerant not mixed with an incompressible gas is compressed. The energy increases, that is, the energy efficiency decreases. In the refrigerator, the refrigerant is sealed after the inside of the refrigeration cycle is evacuated to a predetermined degree of vacuum before the refrigerant is sealed during production in the factory. However, since vacuuming is performed within a limited time and it is difficult to remove air adhering to the inside of the refrigeration cycle piping, air may remain in the refrigeration cycle. is there.

The gas receiver slightly isolates (removes) the air remaining in the refrigeration cycle from the refrigeration cycle. Thereby, the refrigerator operates in a state close to vacuum. Therefore, it becomes possible to cool with high efficiency without consuming unnecessary power. For this reason, a refrigerator with high energy-saving property can be provided.

In the refrigerator according to the fifth disclosure, the gas receiver is arranged in the refrigeration cycle in a state where one end is up and the other end is down.

This makes it possible for the residual air having a low specific gravity with respect to the refrigerant to effectively stay in the upper part of the gas receiver. Therefore, it is suppressed that air circulates with the refrigerant in the refrigeration cycle. Therefore, a reduction in efficiency of the refrigeration cycle and a reduction in cooling capacity due to air that is an uncompressed gas are suppressed, and a refrigerator with high energy saving performance can be provided.

In the refrigerator according to the sixth disclosure, in the fourth or fifth disclosure, the gas receiver exposes the refrigerant flowing out from the front end portion of the inlet pipe and flowing into the refrigerant inlet portion of the outlet pipe inside the receiver body. Then, the air mixed in the refrigerant is separated from the refrigerant, and the separated air is stored inside the receiver body, thereby removing the air mixed in the refrigerant circulating in the refrigeration cycle.

-The gas receiver isolates the air remaining in the refrigeration cycle slightly from the refrigeration cycle. Thereby, the refrigerator operates in a state close to vacuum. Therefore, it becomes possible to cool with high efficiency without consuming unnecessary power. For this reason, a refrigerator with high energy-saving property can be provided.

The refrigerator according to the seventh disclosure is the refrigerator according to the fourth or fifth disclosure, wherein the gas receiver is disposed between the front end portion of the inlet pipe and the refrigerant inflow portion of the outlet pipe and removes air mixed in the refrigerant. Further included.

This separates the liquid refrigerant passing through the mesh and the residual air, and the residual air having a lighter specific gravity than the refrigerant is efficiently retained in the space above the receiver.

In the refrigerator according to the eighth disclosure, in the sixth disclosure, the gas receiver further includes a mesh that is disposed between the front end portion of the inlet pipe and the inlet portion of the refrigerant in the outlet pipe and removes air mixed in the refrigerant. .

A refrigerator according to a ninth disclosure is the refrigerator according to any one of the first to eighth disclosures, wherein the refrigerator is disposed downstream of the condenser and upstream of the minute resistor, and detects the upstream temperature of the minute resistor. An upstream temperature sensor, and a downstream temperature sensor that is arranged downstream of the minute resistor and detects the downstream temperature of the minute resistor. The value of the temperature difference between the temperature detected by the upstream temperature sensor and the temperature detected by the downstream temperature sensor is compared with a predetermined value set in advance, and the expansion valve is controlled so that the temperature difference value approaches the predetermined value. The

When the compressor is started, the expansion valve throttle amount is minimum. Thereafter, the temperature between the temperature detected by the upstream temperature sensor and the temperature detected by the downstream temperature sensor is set to a predetermined value that is set based on the state of the outlet of the condenser that is predicted when the throttle amount of the expansion valve is minimum. The expansion valve is controlled so that the expansion amount of the expansion valve is gradually reduced so that the difference approaches.

Based on the temperature difference detected by the minute resistance, the upstream temperature sensor, and the downstream temperature sensor, the expansion amount of the expansion valve is controlled so that the dryness of the refrigerant, which changes according to the operating state of the refrigerator, approaches zero. The aperture amount changes. For this reason, optimization of the refrigerating capacity of the refrigerator is realized with high accuracy. Therefore, energy saving of the refrigerator is realized, and a decrease in the durability of the compressor is suppressed.

In the refrigerator disclosed in the tenth disclosure, the predetermined value is corrected based on the difference between the temperature difference value and the predetermined value in the ninth disclosure, and the expansion valve is controlled based on the corrected predetermined value.

The difference between the temperature difference, that is, the temperature detected by the upstream temperature sensor and the temperature detected by the downstream temperature sensor is ΔT1, and the target temperature difference, that is, the temperature difference when no air remains in the refrigerant is Δ Let T2. At this time, if no air remains in the refrigeration cycle, ΔT1 = ΔT2. As the throttle amount of the expansion valve increases, the dryness of the refrigerant, that is, the temperature difference approaches zero. On the other hand, when there is air remaining in the refrigerant, ΔT1 is high in advance, and ΔT1> ΔT2. After the dryness reaches zero, the refrigerant is supercooled. Therefore, when the throttle amount of the expansion valve continues to increase, the temperature at the outlet of the condenser decreases. Thereby, the cooling capacity of a refrigerating cycle falls. Furthermore, since the temperature of a condenser falls, the surface temperature of a refrigerator falls and the surface temperature of a refrigerator may become below a dew point temperature. As a result, not only energy increase occurs, but quality deterioration such as surface condensation may occur. Therefore, the temperature difference ΔT1 is compared with the temperature difference ΔT2, and the predetermined temperature difference ΔT2 that is the target value is corrected based on the divergence temperature that is the difference between ΔT1 and ΔT2. Further, the expansion amount of the expansion valve is corrected based on the corrected predetermined temperature difference, so that an excessive increase in the expansion amount of the expansion valve due to the influence of residual air is suppressed, and the refrigerant is overcooled. It is suppressed.

This makes it possible to prevent the refrigerant from being overcooled due to an excessive increase in the amount of expansion of the expansion valve, while taking into consideration the effect of residual air remaining during the production of the refrigerator. For this reason, generation | occurrence | production of quality degradation, such as dew condensation by the fall of the cooling capacity of a refrigerator and the condensation temperature of a refrigerant | coolant, is suppressed. The refrigerator is controlled so that the dryness approaches zero even when air remains. Therefore, optimization of the refrigerating capacity of the refrigerator can be realized with high accuracy, and a refrigerator with high energy saving can be provided.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. This disclosure is not limited by this embodiment.

FIG. 1 is a front view of the refrigerator 30 in the present embodiment. FIG. 2 is a longitudinal sectional view of the refrigerator 30 in the present embodiment. FIG. 3 is a configuration diagram of the refrigeration system 10 of the refrigerator 30 in the present embodiment.

In this configuration, in a state where the refrigerator 30 is installed, a direction relatively close to the installation surface of the refrigerator 30 is a lower side, and a direction relatively far from the installation surface of the refrigerator 30 is an upper side. That is, the vertical direction in the state in FIG. In the state where the refrigerator 30 is installed, the direction in which the door of the refrigerator 30 opens and closes is the front, and the opposite side of the front is the rear. Further, when the refrigerator 30 is viewed from the front, the left is on the left and the right is on the right. That is, it is set as the left-right direction in the state in FIG.

Note that the definitions relating to the vertical direction, the front-rear direction, and the left-right direction described above are merely for convenience provided for those skilled in the art to fully understand the present disclosure, and merely indicate a relative positional relationship. Absent.

As shown in FIG. 1 to FIG. 3, the refrigerator 30 includes a refrigerating room 31 provided in the upper part of the refrigerating machine 30, an upper freezer room 32 provided below the refrigerating room 31, and an upper stage freezing unit below the refrigerating room 31. Between the ice making chamber 33 provided in parallel with the chamber 32 in the left-right direction, the vegetable chamber 35 provided in the lower part of the main body, and the upper freezing chamber 32 and the ice making chamber 33 and the vegetable chamber 35 installed in parallel in the left-right direction. And a lower freezer compartment 34 provided in The refrigerator compartment 31 includes a metal (for example, iron plate) outer box (not shown), a hard resin (for example, ABS) inner box (not shown), an outer box and an inner box, which are opened forward. And a rigid urethane foam (not shown) filled in between. On the front face of the upper freezer compartment 32, the front face of the ice making compartment 33, the front face of the lower freezer compartment 34, and the front face of the vegetable compartment 35, a drawer-type door (not shown) is provided to be openable and closable. On the front surface of the refrigerator compartment 31, for example, a double door (not shown) is provided so that it can be opened and closed.

The refrigerator compartment 31 is set so that, for example, the internal temperature is 1 ° C. to 5 ° C. for refrigerated storage. The vegetable room 35 is set so that the internal temperature is 2 ° C. to 7 ° C., which is the same temperature as the internal temperature of the refrigerator compartment 31 or slightly higher than the internal temperature of the refrigerator 30. By setting the temperature inside the vegetable compartment 35 to a low temperature, the freshness of the leaf vegetables accommodated in the vegetable compartment 35 is maintained for a long time. The upper freezer compartment 32 and the lower freezer compartment 35 are set so that, for example, the internal temperature is −22 ° C. to −18 ° C. for frozen storage. However, in order to improve the frozen storage state, the internal temperatures of the upper freezer chamber 32 and the lower freezer chamber 35 may be set, for example, from −30 ° C. to −25 ° C.

Since the inside of the refrigerator compartment 31 and the inside of the vegetable compartment 35 are set to a positive temperature, it is also called a refrigerator temperature zone. Since the inside of the upper freezing chamber 32, the inside of the lower freezing chamber 34, and the inside of the ice making chamber 33 are set to minus temperatures, they are also called freezing temperature zones. Note that the upper freezer compartment 32 may be a switching room by using a damper mechanism or the like, for example, and a refrigeration temperature zone and a freezing temperature zone may be selectable.

The top surface of the refrigerator 30 is provided with a stepped recess from the front surface of the refrigerator 30 toward the rear surface. A machine room 47 is provided in the stepped recess of the refrigerator 30. The stepped recess of the refrigerator 30 includes a first top surface portion 37 and a second top surface portion 38.

The refrigeration system 10 includes a compressor 11 disposed in a machine room 47, a condenser 12, a dryer 13 that removes moisture from the refrigerant, a heat radiating pipe (not shown), an expansion valve 14, and a capillary. The tube 15, the evaporator 16, the accumulator 17, the suction pipe 18, and the internal heat exchange unit 19 are included. The refrigeration system 10 further includes a minute resistance 20 and an expansion valve control sensor 23 (detection means) including an upstream temperature sensor 21 and a downstream temperature sensor 22. A refrigerant is enclosed in the refrigeration system 10 and a cooling operation is performed. The refrigeration system 10 is also referred to as a refrigeration cycle.

In recent years, a flammable refrigerant is generally used as the refrigerant sealed in the refrigeration system 10 for environmental protection. In the present embodiment, isobutane, which is a flammable refrigerant with a low global warming potential, is used from the viewpoint of global environmental conservation. Isobutane is a hydrocarbon and has a specific gravity (eg, 2.04) that is about twice that at normal temperature (eg, 300 K) and atmospheric pressure (eg, 1013 hPa) compared to air. Thereby, compared with the past, the filling amount of the refrigerant is reduced, the cost is reduced, and the safety is improved.

The dryer 13 dries the refrigerant circulating in the refrigeration system 10. In order for the liquid refrigerant and the dryer 13 to contact efficiently, the dryer 13 is disposed downstream of the condenser 12.

The accumulator 17 stores surplus refrigerant in the stable state of the refrigeration system 10. In order to maintain the same temperature (including substantially the same) as the temperature of the evaporator 16, the accumulator 17 is disposed downstream of the evaporator 16.

When the temperature of an object (not shown) to be cooled by the refrigeration system 10 increases, the amount of excess refrigerant stored in the accumulator 17 decreases, and the amount of refrigerant circulating in the refrigeration system 10 increases. Thereby, the refrigerating capacity of the refrigerating system 10 increases. In general, the refrigeration system 10 included in a home refrigerator or the like that uses a condenser 12 that dissipates heat by natural convection from the outer casing of the refrigerator 30 varies greatly depending on environmental conditions. In this case, excess refrigerant cannot be stored on the high-pressure side of the refrigeration system 10 by the receiver. Therefore, as in the present embodiment, surplus refrigerant is stored on the low-pressure side of the refrigeration system 10 by the accumulator 17. Further, even if the amount of excess refrigerant stored in the accumulator 17 is relatively small, for example, about 10% to 30% of the amount of all refrigerants in the refrigeration system 10, the function of adjusting the refrigeration capacity can be obtained. . Therefore, the accumulator 17 is effective for suppressing the total refrigerant amount, that is, adjusting the refrigerating capacity.

The throttle of the refrigeration system 10 is configured by arranging the expansion valve 14 and the capillary tube 15 in series. As a result, an internal heat exchanging section 19 for exchanging heat between the capillary tube 15 and the suction pipe 18 is realized. Therefore, the enthalpy of the low-temperature refrigerant that circulates in the suction pipe 18 is recovered, and the efficiency of the refrigeration system 10 is improved.

The microresistor 20 constituting the expansion valve control sensor 23 is provided downstream of the condenser 12 and is constituted by, for example, a thin tube having a length of 250 mm. The minute resistance 20 has a resistance corresponding to about 5% of the total resistance of the minute resistance 20, the expansion valve 14 and the capillary tube 15 arranged in series. The ratio of the minute resistance 20 to the total resistance is desirably 1% to 20%. When the resistance of the minute resistance 20 is a resistance corresponding to less than 1% of the total resistance, it is difficult to detect the state change of the refrigerant flowing through the refrigeration system 10. When the resistance of the minute resistance 20 is a resistance corresponding to more than 20% of the total resistance, the heat exchange of the internal heat exchange unit 19 becomes insufficient, and the efficiency of the refrigeration system 10 is reduced. Here, the ratio of the minute resistance 20 to the total resistance is the length of the capillary tube 15 and the capillary when the resistance of the minute resistance 20, the expansion valve 14 and the capillary tube 15 is replaced by the capillary tube 15 having the same inner diameter. The ratio of the length of the tube 15 is shown.

The upstream temperature sensor 21 constituting the expansion valve control sensor 23 is arranged on the upstream side of the minute resistor 20 and detects the pipe temperature on the upstream side of the minute resistor 20. The downstream temperature sensor 22 constituting the expansion valve control sensor 23 is disposed on the downstream side of the minute resistor 20 and detects the pipe temperature on the downstream side of the minute resistor 20. The value of the temperature difference between the temperature detected by the upstream temperature sensor 21 and the temperature detected by the downstream temperature sensor 22, that is, the temperature difference before and after the micro resistance 20 changes according to the state change of the refrigerant flowing inside the micro resistance 20. To do. Based on the value of the temperature difference between the temperature detected by the upstream temperature sensor 21 and the temperature detected by the downstream temperature sensor 22, the throttle amount of the expansion valve 14 is varied. Thereby, the refrigeration system 10 is controlled to a predetermined state.

Note that the expansion valve control sensor 23 desirably avoids the influence of waste heat from the compressor 11 and the condenser 12. In the present embodiment, the expansion valve control sensor 23 is disposed on the upstream side of the air passage.

Next, basic control of the refrigeration system 10 will be described.

When the refrigeration system 10 is operated and the cooling operation is performed, the throttle amount of the expansion valve 14 is minimum, that is, the refrigerant circulation amount in the expansion valve 14 is maximum, and the compressor 11 operates (operates). The refrigerant compressed in the compressor 11 dissipates heat and condenses in the condenser 12 and is then dried in the dryer 13. The refrigerant dried in the dryer 13 passes through the expansion valve control sensor 23, is depressurized in the expansion valve 14 and the capillary tube 15, is supplied to the evaporator 16, is evaporated, and is compressed through the suction pipe 18. Supplied to. At this time, cooling is performed by utilizing the cold heat generated in the evaporator 16, that is, latent heat.

In a state where the throttle amount of the expansion valve 14 is minimized and the compressor 11 is operating, when the temperature of an object (not shown) cooled by the refrigeration system 10 decreases and the refrigeration system 10 approaches a stable state, The refrigerant at the outlet of the condenser 12, that is, the downstream side of the condenser 12 is in a two-phase state (for example, the dryness is 3 wt% to 10 wt%). When the temperature of the object rises, the amount of excess refrigerant stored in the accumulator 17 decreases, and the amount of refrigerant circulating in the refrigeration system 10 increases, the refrigerant at the outlet of the condenser 12 does not become overcooled. As described above, the total resistance of the microresistor 20, the expansion valve 14, and the capillary tube 15 arranged in series and the total amount of refrigerant in the refrigeration system 10 are designed. In general, the refrigeration system 10 included in a home refrigerator or the like that uses a condenser 12 that dissipates heat by natural convection from the outer casing of the refrigerator 30 varies greatly depending on environmental conditions. For this reason, when the refrigerant at the outlet of the condenser 12 is designed to be supercooled, most of the refrigerant in the refrigeration system 10 stays in the condenser 12 when the heat dissipation capacity increases due to environmental conditions. There is a possibility that the circulation amount of the refrigerant will decrease. Further, when the heat radiation capacity is reduced due to environmental conditions, surplus refrigerant that has not been condensed in the condenser 12 is not stored in the accumulator 17 but is returned to the compressor 11 from the suction pipe 18. Thereby, durability of the compressor 11 may fall.

The throttle amount of the expansion valve 14 is controlled so that the temperature difference between the temperature detected by the upstream temperature sensor 21 and the temperature detected by the downstream temperature sensor 22 becomes a predetermined value set in advance. Alternatively, the throttle amount of the expansion valve 14 is controlled so that the throttle amount of the expansion valve 14 changes by a predetermined amount compared to a stable state where the throttle amount of the expansion valve 14 is minimum. Thereby, the dryness of the refrigerant | coolant of the exit of the condenser 12 reduces. Therefore, the refrigeration effect is increased and the efficiency of the refrigeration system 10 is improved.

Next, a method for controlling the expansion valve 14 of the refrigeration system 10 according to the embodiment of the present disclosure will be described with reference to FIGS. 4 and 5.

The horizontal axis in FIG. 4 indicates the value of the pressure loss that occurs according to the throttle amount of the expansion valve 14. The vertical axis in FIG. 4 indicates the output of the expansion valve control sensor 23, that is, the value of the temperature difference S before and after the minute resistance 20 detected by the expansion valve control sensor 23.

As described above, when the amount of throttle of the expansion valve 14 is the minimum and the compressor 11 is operating, the temperature of the object cooled by the refrigeration system 10 decreases, and the refrigeration system 10 approaches the stable state to condense. The refrigerant at the outlet of the vessel 12 is in a two-phase state. At this time, the output of the expansion valve control sensor 23 indicates S0. Then, the throttle amount of the expansion valve 14 is controlled so that the output of the expansion valve control sensor 23 falls below S2, and the throttle amount of the expansion valve 14 increases. Thereby, the dryness of the refrigerant | coolant of the exit of the condenser 12 reduces. Therefore, the refrigeration effect of the refrigeration system 10 is increased, and the efficiency of the refrigeration system 10 is improved.

On the other hand, when the dryness of the refrigerant at the outlet of the condenser 12 decreases and the output of the expansion valve control sensor 23 falls below S1, the throttle amount of the expansion valve 14 is controlled, and the throttle amount of the expansion valve 14 decreases. Thereby, as for the refrigerating system 10, the output of the expansion valve control sensor 23 is stabilized between S1 and S2. When the expansion valve 14 is controlled and the throttle amount of the expansion valve 14 increases too much, the refrigerant at the outlet of the condenser 12 becomes supercooled, and most of the refrigerant in the refrigeration system 10 stays in the condenser 12. There is a possibility that the circulation amount of the refrigerant will decrease. In such a case, the cooling capacity of the refrigeration system 10, that is, the refrigerator 30, may be insufficient. Therefore, the output of the expansion valve control sensor 23 is provided with S1, which is a lower limit value.

5, the horizontal axis indicates the output of the expansion valve control sensor 23, that is, the value of the temperature difference S before and after the minute resistance 20 detected by the expansion valve control sensor 23, similarly to the vertical axis in FIG. 4. The vertical axis in FIG. 5 indicates the value of the flow velocity V of the refrigerant passing through the minute resistor 20.

As described above, when the throttle amount of the expansion valve 14 is controlled from the state in which the output of the expansion valve control sensor 23 indicates S0 and the throttle amount of the expansion valve 14 increases, the dryness of the refrigerant at the outlet of the condenser 12 increases. It decreases and the flow velocity V of the refrigerant | coolant which passes the inside of the micro resistance 20 becomes slow. As a result, the output of the expansion valve control sensor 23 decreases from S0 to S2. Similarly, when the throttle amount of the expansion valve 14 is adjusted and the output of the expansion valve control sensor 23 is stabilized from S1 to S2, the dryness of the refrigerant at the outlet of the condenser 12 is close to zero (for example, the dryness is 0% by weight). To 1 wt%), and the flow velocity V of the refrigerant passing through the minute resistor 20 is stabilized in the vicinity of the minimum value. In the refrigeration system 10, the circulation amount of the refrigerant is constant (including substantially constant) in a stable state. For this reason, when the dryness of the refrigerant at the outlet of the condenser 12 decreases and the refrigerant at the outlet of the condenser 12 becomes a liquid phase, the flow velocity V of the refrigerant passing through the minute resistor 20 is the minimum (substantially minimum). Included). Further, when the dryness of the refrigerant at the outlet of the condenser 12 increases, the flow velocity V of the refrigerant passing through the minute resistor 20 increases.

Generally, the specific volume of the gas phase is about 50 times the specific volume of the liquid phase. Therefore, the amount of change in the flow velocity V of the refrigerant having a dryness of 0 wt% to 10 wt% passing through the minute resistor 20 is large. In particular, when the dryness is in the range of 0 wt% to 10 wt%, the state of the refrigerant at the outlet of the condenser 12 by the expansion valve control sensor 23 is easily detected.

In this embodiment, a highly efficient cooling operation is performed by performing the above control as basic control. In the above control, the expansion valve 14 is controlled based on the detection result of the expansion valve control sensor 23. However, the flow rate of the refrigerant may be controlled based on the temperature difference generated by the pressure difference of the minute resistor 20. For example, the same control is possible for a switching valve for switching the refrigerant flow path. In this case, the flow rate of the refrigerant is controlled by selecting a flow path that is switched according to the output range of the expansion valve control sensor 23. At this time, the refrigerant may be circulated to capillaries having different resistance values due to different inner diameters, lengths, and the like at the end of the switched flow path.

About the refrigerator 30 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

Usually, the refrigerator 30 is shipped in a state where the refrigerant is sealed and the piping is sealed after vacuuming is performed during production in the factory. Generally, the actual age of the refrigerator 30 used by the user is 10 years or more. The usage state of the refrigerator 30 in the market, that is, the usage state of the refrigerator 30 used by the user is a maintenance-free state except for cleaning of dust and the like. In the evacuation of the refrigerator 30 at the factory, the evacuation is performed until the degree of vacuum in the refrigeration system 10 reaches a predetermined degree of vacuum. However, after evacuation at the factory, it is difficult to evacuate within a limited time, and it is difficult to remove the air adsorbed inside the piping before operating the refrigerant. Even so, there is a possibility that the air adsorbed on the pipe remains in the refrigeration system 10. In addition, the performance of the vacuum equipment that realizes evacuation in the factory and the attachment / detachment of the refrigerator 30 and the vacuum equipment affect the amount of air remaining in the refrigeration system 10. The air remaining in the refrigeration system 10 circulates in the cooling pipe together with the refrigerant during operation of the refrigerator 30. When air remains in the refrigeration system 10, the air is mixed into the refrigerant compressed in the compressor 11. When a refrigerant mixed with an incompressible gas such as air is compressed, the input of the compressor increases as compared with the case where a refrigerant not mixed with an incompressible gas is compressed. It becomes. Further, in a condenser in which two phases of a gas phase and a liquid phase are mixed, the flow rate of the refrigerant increases due to air mixed in the refrigerant. For this reason, a pressure loss occurs, and a temperature slip that reduces the temperature of the dryer occurs.

Refrigerator 30 operates based on FIG. 4 and FIG. However, the output value of the expansion valve control sensor 23 depends on the effect of air remaining in the refrigeration system 10 when no air remains in the refrigeration system 10 and when air remains in the refrigeration system 10. In this case, an error occurs in the output value of the expansion valve control sensor 23.

Here, T is the output temperature difference detected by the expansion valve control sensor 23, that is, the output of the temperature difference between the temperature detected by the upstream temperature sensor 21 and the temperature detected by the downstream temperature sensor 22. At this time, the output actually detected by the expansion valve control sensor 23 is T1. A predetermined output to be aimed at, that is, an output detected by the expansion valve control sensor 23 when air does not remain in the refrigerant is T0. When air does not remain in the refrigeration system 10, T1 = T0. As the throttle amount of the expansion valve 14 is controlled and the throttle amount of the expansion valve 14 increases, the output temperature difference detected by the expansion valve control sensor 23 approaches zero. On the other hand, when there is residual air, T1 is high in advance due to temperature slip, and T1> T0. After the output temperature difference detected by the expansion valve control sensor 23 reaches zero, the refrigerant is supercooled. Therefore, when the throttle amount of the expansion valve 14 is controlled and the throttle amount of the expansion valve 14 continues to increase, the temperature at the outlet of the condenser 12 decreases. Thereby, the cooling capacity of the refrigeration system 10 decreases. Furthermore, since the temperature of the condenser 12 falls, the surface temperature of the refrigerator 30 falls and the surface temperature of the refrigerator 30 may become below a dew point temperature. As a result, not only energy increase occurs, but quality deterioration such as surface condensation may occur. In the supercooled state, the refrigerant mainly stays in the condenser 12. For this reason, the amount of the refrigerant circulating in the refrigeration system 10 is insufficient, and the refrigeration system 10 is difficult to cool. Further, the temperature at the inlet of the evaporator 16 is extremely lowered. Therefore, the actual output T1 detected by the expansion valve control sensor 23 is compared with the target predetermined output T0, and the predetermined value T0 that is the target value is obtained based on the deviation temperature that is the difference between T1 and T0. Will be corrected. Further, by correcting the throttle amount of the expansion valve 14, an excessive increase in the throttle amount of the expansion valve 14 due to the influence of residual air is suppressed, and the refrigerant is suppressed from being overcooled.

Here, by using ΔT = T1−T0 and using the value of ΔT as a correction value, S1 / S2 which is the output of the basic control of the expansion valve control sensor 23 is corrected. As a result, as shown in FIG. 6, the lower limit of the control range of S is S1 ′ = S1 + ΔT. Further, as shown in FIG. 6, the upper limit of the S control range is S2 ′ = S2 + ΔT. Thereby, after taking into consideration the influence of the residual air remaining during the production of the refrigerator 30, the refrigerant is prevented from being overcooled due to an excessive increase in the throttle amount of the expansion valve 14. Degradation of quality such as condensation due to a decrease in the cooling capacity of 10 and a decrease in the condensation temperature of the refrigerant is suppressed. Furthermore, even when air remains, the throttle amount of the expansion valve 14 is controlled so that the dryness of the refrigerant approaches zero. Thereby, the refrigerator 30 with high energy-saving property, ie, high energy efficiency, is provided.

In calculating the difference between the output T1 actually detected by the expansion valve control sensor 23 and the target predetermined output T0, for example, during pull-down cooling when the refrigerator 30 is turned on and after defrosting the refrigerator 30 For example, the compressor 11 may be continuously operated such that the rotation speed of the compressor 11 is constant or is known in advance. This is because the state change of the refrigerator 30 is small and the difference between T1 and T0 is easily detected.

In addition, after the inside of the refrigerator 30 is sufficiently cooled and the cooling operation of the refrigerator 30 is stabilized, the temperature at the outlet of the evaporator 16 is rapidly increased and supercooled due to an excessive increase in the amount of expansion of the expansion valve 14. Is detected, the output value of the expansion valve control sensor 23 is further corrected.

Further, in the present embodiment, the gas receiver shown in FIG. 7 is provided so that residual air does not recirculate into the refrigeration system 10.

The gas receiver 24 is disposed in the refrigeration system 10 downstream of the condenser 12 and upstream of the upstream temperature sensor 21. That is, in the refrigeration system 10, the outlet of the condenser 12, the gas receiver 24, the expansion valve control sensor 23, the expansion valve 14, the dryer 13, and the capillary tube 15 are arranged in this order. In other words, the gas receiver 24 is disposed upstream of the expansion valve 14 in the refrigeration system 10.

The gas receiver 24 includes a hollow closed receiver body 25, an inlet pipe 26, an outlet pipe 28, and an internal mesh 29 disposed between the inlet pipe 26 and the outlet pipe 28. The gas receiver 24 is disposed at a position where the refrigerant flowing in the flow direction from top to bottom, that is, the refrigerant flowing downstream of the condenser 12 flows from top to bottom.

The inlet pipe 26 has an inlet pipe tip 27. The inlet pipe 26 is inserted from the upper part of the gas receiver 24, that is, from the upper part of the receiver body 25 so that the inlet pipe distal end portion 27 is disposed inside the receiver body 25. The outlet pipe 28 is disposed below the gas receiver 24, that is, below the receiver body 25. In the gas receiver 24, the refrigerant flows out from the inlet pipe tip portion 27 and flows into the outlet pipe inflow portion 40 of the outlet pipe 28. At this time, the refrigerant is exposed inside the receiver body 25.

In the present embodiment, the internal volume of the gas receiver 24, that is, the receiver body 25 is about 20 mL as a space from the inlet pipe tip 27 to the inner upper end of the receiver body 25. This is about 2% of the internal space of the piping excluding the compressor 11 constituting the refrigeration system 10. Furthermore, when the gas receiver 24 is arranged, it is small and space saving is realized. Furthermore, the amount of residual air at the time of shipment from the factory is generally about 1%, and is considered to be within about 2% even if variation is considered. The internal volume of the receiver body 25 is not limited to about 20 mL, and may be an internal volume of about 50 mL or less, for example.

The refrigerant is exposed inside the receiver body 25. For this reason, residual air having a relatively low specific gravity with respect to the refrigerant is separated from the refrigerant and stored in the upper space of the gas receiver 24. Thereby, the air mixed in the refrigerant circulating in the refrigeration system 10 is removed. That is, the residual air is separated from the refrigerant by the gas receiver 24 being arranged, and is stored in the upper space of the gas receiver 24. Thereby, the refrigeration system 10 can be operated in a state close to a vacuum. Therefore, cooling is performed with high efficiency without consuming unnecessary power. For this reason, the refrigerator 30 with high energy-saving property is provided.

In the present embodiment, the gas receiver 24 is arranged so that the flow direction of the refrigerant is simply from top to bottom. However, the gas receiver 24 may be arranged in the refrigeration system 10 in a state in which the flow direction of the refrigerant is from the top to the bottom in the vertical direction, that is, the inlet pipe tip 27 is the top and the outlet pipe inflow part 40 is the bottom. . Thereby, residual air is effectively stored.

In the gas receiver 24, an internal mesh 29 is provided between the inlet pipe 26 and the outlet pipe 28, that is, between the inlet pipe tip 27 and the outlet pipe inflow portion 40 that is the refrigerant inflow portion of the outlet pipe 28. Has been placed. The internal mesh 29 separates liquid refrigerant passing through the internal mesh 29 and residual air. As a result, the residual air having a lighter specific gravity than the refrigerant is efficiently stored (held) in the space above the receiver body 25. Furthermore, the size of the mesh of the internal mesh 29 is, for example, Φ0.16 mm, which is relatively fine. Therefore, impurities mixed in the refrigerant passing through the gas receiver 24 are removed.

Note that a dryer 13 or a strainer may be used instead of the gas receiver 24. In this case, it is necessary to increase the outer dimensions of the dryer 13 or the strainer in order to secure the internal volume, that is, the space for storing the residual air. In particular, in the case of the dryer 13, it is necessary to consider the amount of the molecular sieve of the desiccant retained inside. However, in this case, the cost of the refrigerator 30 decreases due to the shared use of parts.

In the present embodiment, the gas receiver 24 is disposed on the upstream side of the expansion valve 14. However, the gas receiver 24 may be disposed on the downstream side of the expansion valve 14. In this case, the expansion valve 14 is controlled after the refrigerant circulates to such an extent that the residual air is sufficiently stored, and the residual air is sufficiently stored, as compared with the case where the expansion valve 14 is arranged upstream. It is necessary to ensure the capacity of the gas receiver 24 to the extent.

Further, an accumulator 17 may be used instead of the gas receiver 24. Usually, when the cooling operation is performed and the inside of the refrigerator 30 is sufficiently cooled, the operation of the compressor 11 is stopped. However, during this time, the refrigerant moves from the high pressure condenser 12 to the low pressure evaporator 16. For this reason, the accumulator 17 becomes full. Therefore, it is necessary to increase the capacity of the accumulator 17 so that an excessive amount of refrigerant and residual air can be stored. Further, the accumulator 17 needs to be arranged so that the residual air once stored does not leak out at the inlet and outlet piping positions of the accumulator 17.

In the factory, the refrigerator 30 may be evacuated again after the refrigerator 30 is evacuated and the refrigerant is sealed and the refrigerator 30 is operated. Thereby, the amount of residual air adsorbed on the piping of the refrigerator 30 is reduced. For this reason, the degree of vacuum of the refrigerator 30 is relatively higher than when the evacuation is not performed again. Therefore, the output of the expansion valve control sensor 23 is detected with high accuracy. For this reason, the expansion valve 14 is adjusted more accurately. Therefore, the refrigerator 30 with high energy-saving property is provided.

In the present embodiment, the minute resistor 20 is a thin tube having a length of 250 mm, and has a resistance of about 5% of the total resistance of the minute resistor 20, the expansion valve 14 and the capillary tube 15 arranged in series. A microresistor 20 is used. However, the resistance of the minute resistor 20 may be about 1% to 20% of the total resistance. In this case, the same effect can be obtained even if the minute resistor 20 is constituted by a small diameter tube or a minute orifice.

As described above, the refrigerator 30 according to the present embodiment uses the expansion valve control sensor 23 including the upstream temperature sensor 21 and the downstream temperature sensor 22 that detects the minute resistance 20 and the temperature difference before and after the minute resistor 20. The expansion valve 14 is controlled so as to keep the outlet state substantially constant. In the refrigerator 30 of the present embodiment, the gas receiver 24 is disposed upstream of the expansion valve 14, and the air mixed in the refrigerant circulating in the refrigeration system 10 is removed by the gas receiver 24. Thereby, the influence of the residual air on the temperature slip at the outlet of the condenser 12 is suppressed. Further, the result of the temperature difference detected by the expansion valve control sensor 23 is compared with a target temperature difference that is a predetermined value, and the predetermined value is corrected based on the difference temperature between the detected temperature difference and the predetermined value. The expansion valve 14 is controlled based on the corrected predetermined value.

This suppresses the influence of residual air that affects the refrigeration system 10. Therefore, the optimal control of the expansion valve 14 and the deterioration of the durability of the compressor 11 are suppressed. Moreover, the refrigerator 30 by which the refrigerator 30 drive | operates with the highly efficient refrigerating system 10 from which a dryness becomes zero can provide the refrigerator 30 with high energy saving property.

This disclosure can be applied to all frozen and refrigerated products.

DESCRIPTION OF SYMBOLS 10,140 Refrigeration system 11,141 Compressor 12,142 Condenser 13 Dryer 14,144 Expansion valve 15,145 Capillary tube 16,146 Evaporator 17 Accumulator 18,147 Intake pipe 19,148 Internal heat exchange part 20 Micro resistance 21 Upstream temperature sensor 22 Downstream temperature sensor 23 Expansion valve control sensor 24 Gas receiver 25 Receiver body 26 Inlet pipe 27 Inlet pipe tip 28 Outlet pipe 29 Internal mesh 30 Refrigerator 40 Outlet pipe inflow section 143 Receiver 149 Intake pipe temperature sensor

Claims

A compressor,
An expansion valve;
A condenser,
An evaporator,
An air removal unit,
In the refrigeration cycle configured to include the compressor, the expansion valve, the condenser, the evaporator, and the air removing unit according to the throttle amount of the expansion valve, the dryness of the refrigerant flowing downstream of the condenser Is controlled,
The air removing unit is disposed upstream or downstream of the expansion valve in the refrigeration cycle, and removes air mixed in the refrigerant circulating in the refrigeration cycle.
refrigerator.
The air removal unit is disposed upstream of the expansion valve in the refrigeration cycle.
The refrigerator according to claim 1.
The air removing unit is arranged at a position where the refrigerant flowing downstream of the condenser flows from top to bottom in the refrigeration cycle.
The refrigerator according to claim 1 or 2.
The air removal unit is a gas receiver,
The gas receiver is disposed at a hollow closed receiver body, an inlet pipe inserted from one end of the receiver body so that a tip is disposed inside the receiver body, and the other end of the receiver body. Outlet pipes,
The refrigerator according to any one of claims 1 to 3.
The gas receiver is arranged in the refrigeration cycle with the one end portion on the top and the other end portion on the bottom.
The refrigerator according to claim 4.
The gas receiver exposes the refrigerant flowing out from the tip end portion of the inlet pipe and flowing into an inflow portion of the outlet pipe in the receiver main body, and the air mixed in the refrigerant from the refrigerant. Separating and storing the separated air inside the receiver body to remove the air mixed in the refrigerant circulating in the refrigeration cycle;
The refrigerator according to claim 4 or 5.
The gas receiver further includes a mesh that is disposed between the distal end portion of the inlet pipe and an inflow portion of the outlet pipe and removes the air mixed in the refrigerant.
The refrigerator according to claim 4 or 5.
The gas receiver further includes a mesh that is disposed between the front end portion of the inlet pipe and the inflow portion of the outlet pipe and removes the air mixed in the refrigerant.
The refrigerator according to claim 6.
A microresistor disposed downstream of the condenser;
An upstream temperature sensor disposed upstream of the microresistor to detect the temperature upstream of the microresistor;
A downstream temperature sensor disposed downstream of the microresistor and detecting the downstream temperature of the microresistor; and
The value of the temperature difference between the temperature detected by the upstream temperature sensor and the temperature detected by the downstream temperature sensor is compared with a preset predetermined value so that the value of the temperature difference approaches the predetermined value. The expansion valve is controlled by
The refrigerator according to any one of claims 1 to 8.
The predetermined value is corrected based on the difference between the temperature difference value and the predetermined value, and the expansion valve is controlled based on the corrected predetermined value.
The refrigerator according to claim 9.