JP2022125447A - Refrigeration cycle device - Google Patents

Abstract

To provide a refrigeration cycle device of a refrigerator or the like, which can maximize refrigeration capacity by controlling a refrigerant circulation amount from a refrigerant temperature difference.SOLUTION: A refrigeration cycle device includes a compressor 11, a condenser 12, throttle means 15, an evaporator 16, and a plurality of temperature sensors including an upstream temperature sensor 21 and a downstream temperature sensor 22 detecting a temperature of a refrigerant pipe between the condenser 12 and the throttle means 15. A refrigerant circulation amount, for example, rotation speed of a cooling fan 45 is controlled so that a difference in temperatures detected by the upstream temperature sensor 21 and the downstream temperature sensor 22 comes closer to a set temperature difference. Thereby, refrigeration capacity is maximized and energy saving performance is enhanced.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to a refrigerating cycle device such as a refrigerator that controls a refrigerating cycle using a temperature difference between two points in refrigerant piping.

Conventionally, in a refrigerator, which is one of refrigeration cycle devices, the rotation speed of a compressor and the rotation speed of a cooling fan are controlled based on the difference between the internal temperature of a storeroom and the set temperature (for example, Patent Document 1 reference).

FIG. 6 is a diagram showing a control method for a compressor and a cooling fan of a conventional refrigeration cycle disclosed in Patent Document 1. As shown in FIG.

As shown in FIG. 6, the internal temperature detection circuit 151 detects the internal temperature of the storage compartment by means of an internal temperature sensor 150 installed in the storage compartment, and outputs the temperature data to the control means 152 . be. The control means 152 determines the number of revolutions of the compressor 141 and the number of revolutions of the cooling fan 142 based on the difference between the temperature data of the storage room and the set temperature, and outputs a corresponding control command signal to the compressor drive circuit 153 and the It outputs to the cooling fan drive circuit 154 to control the rotation speed of the compressor 141 and the rotation speed of the cooling fan 142 .

JP-A-1-33485

However, in the above-described conventional configuration, the number of rotations of the compressor and the cooling fan is controlled based on the difference between the air temperature inside the refrigerator and the set temperature. Depending on the usage environment and usage, such as fluctuations in the ambient temperature and the amount of storage inside the refrigerator, and the intrusion of air outside the refrigerator due to the opening and closing of the door, there was a problem that the cooling efficiency of the refrigerant decreased.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a refrigeration cycle apparatus capable of improving the cooling efficiency of a refrigerant.

In order to solve the conventional problem, the refrigerating cycle apparatus of the present invention includes at least a compressor, a condenser, a throttle means, and an evaporator, wherein the condenser and the throttle means It is characterized by comprising a plurality of temperature sensors for detecting the temperature of the refrigerant between and a refrigerant circulation amount control means for controlling the refrigerant circulation amount in accordance with the temperature difference detected by the temperature sensors.

The refrigerating cycle device of the present invention can improve the cooling efficiency of refrigerant and improve energy saving.

1 is a front view of a refrigerator as a refrigerating cycle device according to Embodiment 1 Longitudinal sectional view of the refrigerator in Embodiment 1 Cycle configuration diagram of refrigerator in Embodiment 1 FIG. 2 shows a method of controlling the cooling fan of the refrigeration cycle according to Embodiment 1. FIG. FIG. 4 is a diagram showing the correlation between the output of the refrigerant control sensor of the refrigeration cycle and the amount of refrigerant circulation in Embodiment 1. FIG. Diagram showing the control method of the cooling fan of the conventional refrigeration cycle

A first invention is a refrigeration cycle apparatus having at least a compressor, a condenser, a throttle means, and an evaporator, and a plurality of temperature sensors for detecting the temperature of the refrigerant between the condenser and the throttle means. A refrigerating cycle apparatus comprising a sensor and refrigerant circulation amount control means for controlling a refrigerant circulation amount in accordance with a temperature difference detected by the temperature sensor.

As a result, the dryness of the refrigerant at the condenser outlet can be estimated from the detected temperature difference in the refrigerant piping at the condenser outlet. The dryness of the outlet refrigerant can be brought close to zero. As a result, the cooling efficiency of the refrigeration system is increased, so that the refrigeration capacity can be maximized and energy saving can be enhanced.

A second invention is characterized in that the refrigerant circulation amount control means controls the number of rotations of a cooling fan that circulates the cool air generated by the evaporator in the refrigerator. refrigeration cycle equipment.

As a result, the rotation speed of the cooling fan can be controlled so that the dryness of the refrigerant at the outlet of the condenser approaches zero. As a result, the cooling efficiency of the refrigeration system is increased, so that the refrigeration capacity can be maximized and energy saving can be enhanced.

A third aspect of the invention is characterized in that the refrigerant circulation amount control means controls the number of revolutions of a condenser fan provided for promoting condensation of the refrigerant in the condenser. The refrigeration cycle device according to .

As a result, the rotation speed of the condenser fan can be controlled so that the dryness of the refrigerant at the outlet of the condenser approaches zero. As a result, the cooling efficiency of the refrigeration system is increased, so that the refrigeration capacity can be maximized and energy saving can be enhanced.

A fourth invention is the refrigeration cycle apparatus according to the first invention, wherein the refrigerant circulation amount control means controls the rotational speed of the compressor.

As a result, the rotation speed of the compressor can be controlled so that the dryness of the refrigerant at the outlet of the condenser approaches zero. As a result, the cooling efficiency of the refrigeration system is increased, so that the refrigeration capacity can be maximized and energy saving can be enhanced.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by this embodiment.

(Embodiment 1)
An embodiment of a refrigeration cycle apparatus will be described below with reference to FIGS. 1 to 5, taking a refrigerator as an example.

FIG. 1 is a front view of a refrigerator as a refrigerating cycle device according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the refrigerator according to the first embodiment, and FIG. 3 is a cycle configuration diagram of the refrigerator according to the first embodiment. be. FIG. 4 is a diagram showing a method of controlling the cooling fan of the refrigerating cycle, and FIG. 5 is a diagram showing the correlation between the output of the refrigerant control sensor of the refrigerating cycle and the amount of refrigerant circulation.

As shown in FIGS. 1 to 3, this refrigerator includes an outer box made of metal (e.g., steel plate) opening forward, an inner box made of hard resin (e.g., ABS), and a space between the outer and inner boxes. A heat-insulating refrigerator main body 30 made of a heat-insulating material such as rigid urethane foam filled with foam is provided. Inside the refrigerator main body 30, there are a refrigerating chamber 31, an upper freezing chamber 32 below the refrigerating chamber 31, an ice making chamber 33 arranged side by side, an upper freezing chamber 32 arranged side by side, and a lower freezing chamber below the ice making chamber 33. 34 , a vegetable compartment 35 is provided below the lower freezer compartment 34 . The front of the refrigerating compartment 31 is closed by, for example, a double door so that it can be opened and closed freely. freely blocked.

The refrigerating compartment 31 is normally set at 1 to 5° C. with the lower limit of the non-freezing temperature for cold storage. The temperature of the vegetable compartment 35 is set to 2° C. to 7° C., which is the same as or slightly higher than that of the refrigerator compartment 31. If the temperature is set to a low temperature, the freshness of leaf vegetables can be maintained for a long period of time. The upper freezer compartment 32 and the lower freezer compartment 35 are normally set at −22 to −18° C. for frozen storage, but are set at a low temperature of −30 to −25° C., for example, to improve frozen storage conditions. sometimes

Also, the upper freezer compartment 32 may be a switchable compartment that can be selected from a refrigerating temperature range to a freezing temperature range by using a damper mechanism or the like.

The refrigerator main body 30 includes the refrigerating chamber 31 , upper freezing chamber 32 , ice making chamber 33 , and lower freezing chamber 34 .
, a refrigerating system 10 for cooling the vegetable compartment 35 is provided, and a variable capacity compressor 11 for compressing the refrigerant of the refrigerating system 10 is provided in a machine room 47 at the rear of the top panel, and an evaporator 16 serving as a cooler. are provided in the rear cooling chamber 48 .

As the refrigerant for the refrigeration system 10, isobutane, which is a flammable refrigerant with a small global warming potential, is used from the viewpoint of global environment conservation. Isobutane, which is a hydrocarbon, has a specific gravity about twice that of air at room temperature and atmospheric pressure (at 2.04, 300K). As a result, the amount of refrigerant to be charged can be reduced compared with the conventional one, the cost is low, and the amount of leakage in the unlikely event that the flammable refrigerant leaks is reduced, so that the safety can be further improved.

Next, the configuration of the refrigeration system 10 will be described with reference to FIG.

The refrigeration system 10 is configured by connecting a compressor 11, a condenser 12, a dryer 13, a capillary tube 15 serving as throttle means, an evaporator 16, an accumulator 17, a suction pipe 18, and an internal heat exchange section 19. The refrigeration system 10 is also provided with a refrigerant control sensor 23 consisting of a minute resistance 20, an upstream temperature sensor 21 and a downstream temperature sensor 22. As shown in FIG.

The micro-resistor 20 constituting the refrigerant control sensor 23 is made of a thin tube with a length of 250 mm and has a resistance equivalent to about 5% of the total resistance of the micro-resistor 20 and the capillary tube 15 arranged in series. The ratio of the minute resistance 20 to the total resistance is preferably 1-20%. If it is less than 1%, it becomes difficult to measure the state change of the refrigerant flowing inside. If it exceeds 20%, the heat exchange in the internal heat exchange section 19 becomes insufficient, and the efficiency of the refrigeration system decreases. The ratio of the minute resistance 20 to the total resistance is indicated by the length ratio when each resistance is replaced by the capillary tube 15 having the same inner diameter.

Here, the upstream temperature sensor 21 and the downstream temperature sensor 22, which constitute the refrigerant control sensor 23, detect the temperature on the upstream side and the downstream side of the micro resistance 20, which changes according to the state change of the refrigerant flowing inside the micro resistance 20. The temperature difference is measured, the refrigerant circulation rate is varied so that the temperature difference approaches the set temperature difference, and the refrigeration system 10 is controlled to a predetermined state.

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

The accumulator 17 stores surplus refrigerant in a stable state, and is arranged downstream of the evaporator 16 in order to keep the temperature substantially the same as that of the evaporator 16 . When the temperature of an object (not shown) to be cooled using the refrigeration system 10 rises, the amount of surplus refrigerant stored in the accumulator 17 decreases and the amount of refrigerant circulating in the refrigeration system 10 increases, thereby increasing the refrigeration capacity. increase.

In general, in a refrigeration system such as a home-use refrigerator that dissipates heat from the outer shell of a housing such as the refrigerator body 30 by natural convection, the heat dissipation capacity changes greatly depending on environmental conditions, and a receiver is used to store surplus refrigerant on the high pressure side of the refrigeration system. Therefore, as in the first embodiment, the accumulator 17 is used to store excess refrigerant on the low-pressure side of the refrigeration system. In addition, the amount of surplus refrigerant stored in the accumulator 17 is about 10 to 30% of the total amount of refrigerant in the refrigeration system. It is valid.

In addition, by configuring the aperture of the refrigeration system 10 using the capillary tube 15, it is possible to realize an internal heat exchange section 19 that exchanges heat between the capillary tube 15 and the suction pipe 18. can recover the enthalpy of the refluxing low temperature refrigerant to improve the efficiency of the refrigeration system 10 .

The action and operation of the refrigerator configured as described above will be described below with reference to FIGS. 3 to 5. FIG.

When this refrigerator performs a cooling operation, the refrigerant compressed by the compressor 11 is condensed by releasing heat in the condenser 12 and then dried by the dryer 13 . After passing through the refrigerant control sensor 23 , the pressure is reduced by the capillary tube 15 , then supplied to the evaporator 16 where it evaporates, and returns to the compressor 11 through the suction pipe 18 . At this time, cooling is performed using cold heat generated by the evaporator 16 .

Here, when the temperature of the object (not shown) drops and approaches a stable state while the compressor 11 is in operation, the refrigerant at the outlet of the condenser 12 is in a two-phase state (preferably, dryness of 3 to 10 % by weight). Even if the temperature of the object to be cooled (not shown) rises and the amount of surplus refrigerant stored in the accumulator 17 decreases and the amount of refrigerant circulating in the refrigeration system 10 increases, the outlet of the condenser 12 This is because the total resistance of the micro resistance 20 and the capillary tube 15 arranged in series and the total amount of refrigerant in the refrigeration system 10 are designed so that the refrigerant does not become supercooled.

In general, in a refrigeration system whose heat dissipation capacity varies greatly depending on environmental conditions, such as a home refrigerator that dissipates heat from the outer shell of the housing by natural convection, if the refrigerant at the condenser outlet is designed to be supercooled, the heat dissipation capacity will be affected by the environmental conditions. When it increases, almost all the refrigerant in the refrigeration system stays in the condenser, and there is a concern that the refrigerant circulation amount will drop abnormally.

In addition, when the heat dissipation capacity decreases due to environmental conditions, the surplus refrigerant that could not be condensed in the condenser cannot be stored in the accumulator 17 and flows back to the compressor 11 from the suction pipe 18, thereby improving the durability of the compressor 11. There is concern that it will decline.

Therefore, in the refrigeration system 10 of the present invention, as described above, the total resistance of the micro resistance 20 and the capillary tube 15 arranged in series and the total amount of refrigerant in the refrigeration system 10 are is designed.

When the two-phase refrigerant from the condenser 12 passes through the minute resistance 20 , the upstream temperature sensor 21 and the downstream temperature sensor 22 detect the temperatures on the upstream and downstream sides of the minute resistance 20 . Then, the refrigerant circulation amount is controlled so that the detected temperature difference before and after the minute resistance 20 becomes a predetermined value. As a result, the dryness of the refrigerant at the outlet of the condenser 12 decreases, the refrigeration effect increases, and the efficiency of the refrigeration system 10 can be improved.

Next, a method for controlling the amount of refrigerant circulation will be described with reference to FIGS. 4 and 5. FIG.

The horizontal axis of FIG. 4 is the number of revolutions of the cooling fan 45 that circulates the cool air generated by the evaporator 16 in the refrigerator, and the vertical axis is the temperature difference S across the minute resistance 20 measured by the refrigerant control sensor 23. .

As described above, when the temperature of the object (not shown) to be cooled using the refrigeration system 10 decreases and approaches a stable state while the compressor 11 is in operation, the refrigerant at the outlet of the condenser 12 has two phases. state. At this time, the output of the refrigerant control sensor 23 indicates S0. Then, the rotation speed of cooling fan 45 is increased so that the output of refrigerant control sensor 23 falls below S2. As a result, the dryness of the refrigerant at the outlet of the condenser 12 decreases, the refrigeration effect increases, and the efficiency of the refrigeration system 10 improves.

On the other hand, when the dryness of the refrigerant at the outlet of the condenser 12 continues to decrease and the output of the refrigerant control sensor 23 falls below S1, the rotation speed of the cooling fan 45 is reduced. As a result, the output of the refrigerant control sensor 23 can be stabilized in a state from S1 to S2.

The reason why the output of the refrigerant control sensor 23 is set to the lower limit value S1 is that if the rotation speed of the cooling fan 45 is excessively increased, the refrigerant at the outlet of the condenser 12 will be in a supercooled state, and almost all the refrigerant in the refrigeration system 10 will be condensed. This is because there is a concern that the refrigerant will stay in the vessel 12 and the amount of refrigerant circulation will abnormally decrease. In such a case, the cooling capacity is insufficient, and there is a risk that the refrigerator will cool slowly, so it must be avoided.

The horizontal axis of FIG. 5 is the temperature difference S across the minute resistance 20 measured by the refrigerant control sensor 23, which is the same as the vertical axis of FIG. is Q.

As described above, when the rotation speed of the cooling fan 45 is increased from the state in which the output of the refrigerant control sensor 23 indicates S0, the heat exchange between the air and the refrigerant is promoted in the evaporator 16, and the evaporation temperature of the refrigerant rises. and the amount of refrigerant circulation increases. Along with this, the dryness of the refrigerant at the outlet of the condenser 12 decreases, and the output of the refrigerant control sensor 23 decreases from S0 to S2. Similarly, when the air volume of the cooling fan 45 is adjusted to stabilize the output of the refrigerant control sensor 23 between S1 and S2, the dryness of the refrigerant at the outlet of the condenser 12 is near zero (preferably, the dryness is between 0 and 0). 1% by weight).

As described above, the micro resistance 20 and the total resistance of the capillary tube 15 are designed so that the refrigerant at the outlet of the condenser 12 does not become supercooled even when the refrigerant circulation amount increases, so the refrigerant circulation amount has decreased. In this case, the total resistance of the minute resistance 20 and the capillary tube 15 is insufficient. To compensate for the lack of resistance, the dryness of the outlet refrigerant of the condenser 12 is increased and the flow rate of the refrigerant is increased accordingly.

As a result, the resistance of the coolant passing through the minute resistance 20 and the capillary tube 15 increases, so that the insufficient resistance can be compensated for. When the refrigerant circulation amount is large, the dryness of the refrigerant at the outlet of the condenser 12 is close to zero, and the dryness of the refrigerant at the outlet of the condenser 12 increases as the refrigerant circulation amount decreases.

By controlling the air volume of the cooling fan 45 according to the output of the refrigerant control sensor 23, that is, the detected temperature difference, so that the temperature difference approaches the set temperature difference, the dryness of the refrigerant at the outlet of the condenser 12 is reduced to near zero ( Desirably, the dryness is stabilized at 0-1 wt.

That is, the refrigerator main body 30 described above controls the cooling fan 45 so that the dryness at the outlet of the condenser approaches zero using the refrigerant control sensor 23 consisting of the minute resistance 20 and the temperature sensor that measures the temperature difference between before and after it. As a result, the cooling fan 45 can be used to maximize the refrigeration capacity in a refrigeration system that does not have a receiver at the outlet of the condenser, and a highly efficient cooling operation can be performed.

As described above, Embodiment 1 has been described as an example of the technology disclosed in the present invention. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments with modifications, replacements, additions, omissions, and the like.

Therefore, other embodiments will be exemplified below.

In the first embodiment, the cooling fan 45 is controlled according to the output of the refrigerant control sensor 23 to maximize the refrigerating capacity. A method of controlling the rotational speed of the provided condenser fan 46 may also be used.

When the rotation speed of the condenser fan 46 is increased, the heat exchange between the air and the refrigerant is promoted in the condenser 12, the condensation temperature of the refrigerant is lowered, and the volumetric efficiency of the compressor is improved. increases. Therefore, the same effect as when the rotation speed of the cooling fan 45 is increased can be obtained.

Alternatively, a method of controlling the rotation speed of the compressor 11 according to the output of the refrigerant control sensor 23 may be used. When the rotational speed of the compressor 11 is increased, the amount of refrigerant circulation increases, so the same effect as when the air volume of the cooling fan 45 and the condenser fan 46 is increased can be obtained.

INDUSTRIAL APPLICABILITY As described above, the refrigeration system device according to the present invention can improve the cooling efficiency of the refrigerant and improve the energy saving performance. It can be widely applied as a refrigerating cycle device such as an air conditioner equipped with a refrigerating cycle and kitchen equipment.

11 compressor 12 condenser 15 capillary tube (squeezing means)
16 Evaporator 20 Micro resistance 21 Upstream temperature sensor 22 Downstream temperature sensor 23 Refrigerant control sensor 30 Refrigerator body 45 Cooling fan 46 Condenser fan

Claims (4)

A refrigeration cycle apparatus comprising at least a compressor, a condenser, a throttle means, and an evaporator, comprising a plurality of temperature sensors for detecting the temperature of refrigerant between the condenser and the throttle means, wherein the temperature A refrigerating cycle apparatus comprising refrigerant circulation amount control means for controlling a refrigerant circulation amount according to a temperature difference detected by a sensor. 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant circulation amount control means controls the rotation speed of a cooling fan that circulates the cool air generated by the evaporator inside the refrigerator. 2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant circulation amount control means controls the rotation speed of the condenser blower. 2. The refrigeration cycle apparatus according to claim 1, wherein said refrigerant circulation amount control means controls the rotation speed of said compressor.

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