KR100251567B1 - Cooling cycle and its control method - Google Patents

Abstract

PURPOSE: A refrigeration cycle and method for controlling refrigeration cycle is provided to achieve an improved cooling rate and maintain the temperature of the freezing and refrigerating compartments constant. CONSTITUTION: A refrigeration cycle includes a compressor(1) for compressing the refrigerant into high temperature high pressure state, a condenser(12) for removing heat from the high temperature high pressure refrigerant, a refrigerant pressure reducing unit(13) for lowering high pressure of the refrigerant into evaporating pressure, and an evaporator(14) where the refrigerant having a reduced pressure is heat exchanged. The compressor, condenser, refrigerant pressure reducing unit and the evaporator are connected in serial through the refrigerant pipe, thereby forming a closed cycle. Cooling air circulation fans(15,16) are arranged at the evaporator side so as to promote heat exchange operation of the evaporator. The refrigerant pressure reducing unit controls, in steps, the evaporating pressure of the refrigerant in accordance with the refrigeration load.

Description

Refrigeration cycle

The present invention relates to a refrigerating cycle, and more particularly, to a refrigerating cycle provided with a refrigerant decompression expansion device that can vary the degree of decompression of the refrigerant instead of the conventional capillary.

In general, a refrigeration cycle is a process in which a compression, condensation, expansion, and evaporation process is continuously performed using a refrigerant as a medium, and a product to which the refrigeration cycle is applied is a refrigerator or an air conditioner.

As shown in FIG. 1, the refrigeration cycle includes a compressor 1 for compressing a refrigerant at a high temperature and high pressure, a condenser 2 for removing heat from the refrigerant at a high temperature and high pressure, that is, condensation, and evaporating the high pressure refrigerant. A capillary tube 3 is provided as a refrigerant regulator for reducing pressure. An evaporator 4 is provided to absorb heat by evaporating the refrigerant decompressed through the capillary tube 3, and the refrigerant exchanged with the inside of the chamber through the evaporator 4 flows back into the compressor 1 to the compressor 1. The compressor 1 is connected in series.

That is, the compressor 1, the condenser 2, the capillary tube 3, and the evaporator 4 are all connected in series through the refrigerant pipe, thereby forming a closed circuit.

In the refrigeration cycle configured as described above, when the compressor 1 is driven, the refrigerant becomes high-temperature, high-pressure steam and is sent to the condenser 2, and the condenser 2 discharges heat contained in the refrigerant to the outside to condense the refrigerant. Then, the high-pressure refrigerant from which heat is continuously removed is decompressed as it passes through the capillary tube 3 having a small diameter and is evaporated to an appropriate evaporation pressure. In the evaporator 4, the refrigerant decompressed in the capillary tube 3 is absorbed and vaporized while cooling the inside of the refrigerator and the like, and the heat exchanged refrigerant is circulated to the compressor 1 so as to be compressed again to a high pressure. A refrigeration cycle is achieved.

The general refrigeration cycle composed of such a closed circuit is configured to stop the forced circulation of the refrigerant by turning off the compressor 1 and the cold air circulation fans 5 and 6 when the temperature in the refrigerator or the like is cooled below a predetermined set temperature. .

However, the conventional refrigeration cycle had the following problems.

In other words, the refrigerant stagnated near the evaporator during the initial compressor operation immediately decreases the pressure due to the suction action of the compressor, and the refrigerant on the refrigeration cycle gradually flows to the evaporator through a capillary tube acting as a resistance function. Therefore, the flow of the refrigerant corresponding to the pressure change on the refrigeration cycle is not smooth. Accordingly, the refrigerant that does not sufficiently obtain the cooling force corresponding to the load in the refrigerator refrigerator of the refrigerant is heat-exchanged by the cold air circulation fan in the evaporator, so that the refrigerant is circulated in the compressor in an overheated state and the temperature of the compressor is excessively increased. there was.

In addition, since the heat exchange force in the evaporator due to the overheating of the refrigerant during the initial driving, it takes a lot of time to converge to the set temperature in the high temperature, resulting in increased power consumption.

In addition, due to the difference in the refrigerant pressure in the vicinity of the evaporator and the pressure difference between the capillary tube by the operation of the compressor during the initial drive, there is a problem such as excessive charging of the refrigerant to improve the flow of the refrigerant.

The present invention has been made to solve the above-mentioned problems, the object of the present invention is to reduce the refrigerant to the standard evaporation temperature of the refrigerator as a structure, and to reduce the refrigerant to the standard evaporation temperature of the freezer as the refrigerant pressure expansion device. To provide a refrigeration cycle.

Another object of the present invention is to provide a refrigeration cycle that can be used to vary the degree of decompression of the refrigerant according to the refrigeration load using the refrigerant pressure reduction expansion device.

1 is a conventional refrigeration cycle,

2 is a refrigeration cycle according to the present invention,

Figure 3 is a state diagram showing a reduced pressure state in a conventional capillary,

Figure 4a, b is a schematic diagram of the operation and configuration of the refrigeration decompression device according to the present invention,

5 is a control block diagram of a refrigerator applied to the present invention;

6 is a control flow diagram of a refrigerator applied to the present invention,

* Description of the symbols for the main parts of the drawings *

10: power supply unit 20: function setting unit 30: freezer temperature detection unit

40: fridge temperature detection unit 50: evaporator temperature detection unit 60: freezer compartment circulation fan drive unit

70: refrigerating chamber cooling fan drive unit 80: pressure reduction expansion unit drive unit

90: compression mechanism moving part

The configuration of the present invention for achieving the technical problem, a compressor for compressing the refrigerant, a condenser for condensing the refrigerant, a pressure reducing device for reducing the refrigerant, an evaporator for vaporizing the refrigerant to absorb heat, the compressor, a condenser, a pressure reducing device, In the refrigeration cycle provided with a refrigerant pipe for inducing the flow of the refrigerant by connecting the evaporator in series, the decompression device is characterized in that the pressure of the refrigerant can be varied by controlling the flow of the refrigerant.

Hereinafter, one preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a refrigeration cycle according to the present invention, Figure 3 is a state diagram showing a decompression state in a conventional capillary tube, Figure 4 is a schematic diagram of a refrigeration pressure reduction apparatus according to the present invention, Figure 5 is a control block diagram of a refrigerator applied to the present invention 6 is a control flowchart of a refrigerator applied to the present invention.

First, a refrigeration cycle according to the present invention will be described with reference to FIG. 2.

The constitution includes a compressor 11 for compressing a refrigerant at a high temperature and high pressure, and a condenser 12 for removing heat from the refrigerant at a high temperature and high pressure, that is, condensation 12, and reducing the refrigerant as a refrigerant regulator for reducing the high pressure refrigerant to the evaporation pressure. An expansion device 13 is provided. An evaporator 14 is provided to absorb heat by evaporating the refrigerant decompressed through the refrigerant pressure reducing device 13, and the refrigerant exchanged with the inside of the chamber through the evaporator 14 is connected in series so as to flow into the compressor 11 again. .

That is, the compressor 11, the condenser 12, the refrigerant pressure expansion device 13, and the evaporator 14 are all connected in series through the refrigerant pipe, and forms a closed circuit. Further, cold air circulation fans 15 and 16 for further promoting heat exchange of the evaporator 14 are further provided on the evaporator 14 side.

Among the components described above, a characteristic element of the present invention is provided with a refrigerant pressure reducing device (13), which is to control the evaporation pressure of the refrigerant step by step according to the refrigeration load.

That is, the concept and structure thereof will be described with reference to FIGS. 3 and 4 as follows.

First, FIG. 3 illustrates a change in the depressurization state of a refrigerant occurring in a conventional capillary tube. The refrigerant circulated from the condenser 2 is decompressed while passing through the capillary tube 3, and the freezing chamber reference evaporation temperature ( When the set temperature in the freezer compartment is -18 degrees, the pressure is reduced enough to make an evaporator temperature that can sufficiently cool the freezer compartment. Therefore, the refrigerant passing through the middle of the total length L of the capillary tube 3 can make the decompression degree based on the refrigerating chamber standard evaporation temperature (evaporator temperature which can sufficiently cool the refrigerating chamber when the temperature of the refrigerating chamber is 3 cities). It is decompressed to a degree.

And Figure 4 shows the structure and operation state of the refrigerant pressure expansion device 13 according to the present invention with reference to Figure 3, Figure 4a is a state of the refrigerant pressure expansion device, Figure 4b refrigerant pressure expansion device It shows off state of. First, the configuration of the refrigerant decompression expansion device 13 includes a primary decompression unit 26 for reducing the primary pressure to the refrigerating chamber reference evaporation temperature and a secondary decompression unit for varying the degree of decompression from the refrigerating chamber reference evaporation temperature to the freezing chamber reference evaporation temperature. It is composed. That is, the primary pressure reducing section 26 is made of the same structure as the conventional capillary tube, and its length is half that of the conventional capillary tube. As described above with reference to Figure 3, by taking only 1/2 of the conventional capillary length (L) to obtain a decompression degree of the refrigerant corresponding to the refrigeration chamber reference evaporation temperature in the primary decompression unit 26. In addition, the secondary decompression unit employs a valve 28, which is a kind of flow path resistance unit for controlling the flow of the refrigerant in the refrigerant pipe, and is configured to control the amount of refrigerant flowing in accordance with the refrigeration load. That is, as shown in FIG. 4A, when the valve driving device 27 is turned on, the valve 28 closes a part of the refrigerant pipe to make the refrigerant difficult to flow, thereby increasing the degree of decompression of the refrigerant, as shown in FIG. 4B. Likewise, when the valve driving device 27 is turned off, the valve 28 opens the refrigerant pipe to smooth the flow of the refrigerant, thereby lowering the decompression degree of the refrigerant.

The valve 28 of the refrigerant decompression expansion device may be driven by heat, electricity, motor, constant voltage, piezoelectric, or the like, and may be manually adjusted. In the on / off operation of the refrigerant pressure reducing expansion device 13, the valve 28 is opened and closed gradually so as to avoid a sudden change in pressure of the refrigerant.

And Figure 5 is a control block diagram of a refrigerator to which the present invention is applied, the configuration is as follows. First, a control unit 100 performing an operation related to overall control of the refrigerator system, a power supply unit 10 for supplying driving power to the control unit 100 and each driving unit, and a function setting unit for setting an operation state of the refrigerator 20, a freezer compartment temperature detector 30 for reading the freezer compartment temperature, a freezer compartment temperature detector 40 for reading the refrigerator compartment temperature, an evaporator temperature detector 50 for reading the evaporator temperature, a freezer cold air circulation fan Fan drive unit 60 for driving 15, the fan drive unit 70 for driving the cold air circulation fan 16, the decompression expansion device driver for controlling the flow of the refrigerant to change the pressure of the refrigerant 80 And a valve 28, and a compressor driving unit 90, a compressor (COMP) 5, etc. for compressing the refrigerant at high temperature and high pressure.

Hereinafter, a control flow of the refrigerator to which the present invention is applied will be described with reference to the above-described components and FIG. 6.

First, when the consumer inputs the operation mode and the desired high internal temperature through the function setting unit 20 while the refrigerator is supplied with power, the control unit 100 calculates the internal and external conditions and the load of each load through the calculation of the program. Determine the condition. That is, the freezer compartment and the refrigerating compartment temperature sensing unit 30, 40 detects the freezer compartment and the refrigerator compartment internal temperature, the evaporator temperature sensing unit 50 detects the temperature of the evaporator 14 (S1), each load stage abnormality After checking, the refrigeration cycle will run.

That is, the control unit 100 compares the refrigerator compartment internal temperature and the refrigerator compartment set temperature, and if it is determined that the refrigerator compartment internal temperature is higher (S2), operates the compressor 11 (S3) and determines that the refrigerator compartment set temperature is higher (S2). Step S6 or below is performed without the compressor 11 being operated.

When the compressor 11 is operated in step S3, the controller 100 compares the refrigerator compartment internal temperature and the refrigerator compartment evaporator temperature to determine that the refrigerator compartment internal temperature is higher (S4) and operates the refrigerator compartment cold air circulation fan 16 (S5). When it is determined that the refrigerating chamber evaporator temperature is higher (S4), the refrigerating compartment fan 16 is kept at a stop state (S14). This is because heat exchange is lost when heat exchange occurs when the temperature of the refrigerating chamber evaporator is higher.

When the refrigerating compartment cold air circulation fan is operated in step S5, the controller 100 compares the freezer compartment internal temperature and the freezer compartment set temperature to determine that the freezer compartment internal temperature is higher (S6) to operate the compressor 11. In this case, when the compressor 11 is operated in step S3, the operating state of the compressor 11 is continuously maintained (S7).

When the compressor 11 is operated in step S7, the controller 100 compares the preset refrigerator compartment reference evaporation temperature with the refrigerator compartment evaporator temperature, and when it is determined that the refrigerator compartment reference evaporation temperature is higher, the controller 100 controls the pressure reducing device driver 80 to control the valve 28. ) Is turned on (S9), and if it is determined that the refrigerating chamber evaporator temperature is higher, the valve 28 is kept off. This is for varying the depressurization of the refrigerant, and when the refrigerator compartment reference evaporation temperature is lower than the refrigerator compartment evaporator temperature, the refrigerator compartment can be sufficiently cooled, thereby further reducing the refrigerant by turning on the valve 28 and making the refrigerant difficult to flow. In order to maximize the heat exchange in the case, and the valve 28 is kept off, the refrigerating chamber standard evaporation temperature is higher than the refrigerating chamber evaporator temperature, so that the refrigerating chamber cannot be sufficiently cooled, thereby increasing the heat exchange rate by smoothing the flow of the refrigerant. For sake.

When the valve 28 is turned on in step S9, the control unit 100 compares the freezer compartment internal temperature with the freezer compartment evaporator temperature and determines that the freezer compartment internal temperature is higher (S10) to operate the freezer compartment cold air circulation fan 15 (S11). When it is determined that the freezer compartment evaporator temperature is higher, the freezer compartment cold air circulation fan is kept at a stop state (S15). This is because when the heat exchange is performed due to the higher temperature of the freezer compartment evaporator, a loss of heat exchange is caused.

When the freezer compartment circulation fan 15 is operated in step S11, the control unit 100 compares the freezer compartment internal temperature and the freezer compartment set temperature, and compares the refrigerator compartment internal temperature and the refrigerator compartment set temperature, and the results are all higher than the internal preset temperature. If it is determined, the operation of the compressor 11 is continuously performed, and if it is determined that all of them are lower than the set temperature in the refrigerator, the operation of the compressor 11 and the cold air circulation fans 15 and 16 are stopped (S13), and the control flow is initialized. Returning to step S1, the step is repeated repeatedly.

As described in detail above, according to the present invention, by providing a device capable of varying the depressurization of the refrigerant after the first and second depressurization steps, it is possible to actively respond to the increase and decrease of the load. Therefore, it is possible to improve the cooling rate and maintain the constant temperature of the freezer compartment and the refrigerating compartment, and to cope with the rapid flow of the refrigerant during the initial operation of the compressor to provide an excellent effect of relatively reducing the amount of refrigerant charged.

Claims (4)

A compressor that compresses the refrigerant, a condenser that condenses the refrigerant, a decompression device that depressurizes the refrigerant, an evaporator that vaporizes the refrigerant to absorb heat, and a refrigerant pipe that induces the refrigerant flow by connecting the compressor, the condenser, the decompression device, and the evaporator in series. In this provided refrigeration cycle, The decompression device is a refrigeration cycle, characterized in that for controlling the flow of the refrigerant to vary the pressure of the refrigerant. 2. The pressure reducing device of claim 1, wherein the pressure reducing device comprises a first pressure reducing part which reduces the internal diameter of the refrigerant pipe to make the refrigerant difficult to flow, and a second pressure reducing part provided with means for varying the flow path of the refrigerant pipe. Refrigeration cycle. The refrigerating cycle according to claim 2, wherein the secondary decompression unit is driven over a predetermined time so that the depressurization of the refrigerant can be made gradually in varying the flow path of the refrigerant pipe. The method of claim 1, wherein the refrigerant decompression degree of the primary decompression unit is reduced to sufficiently cool the temperature of the refrigerating chamber, and the refrigerant decompression degree of the on-reduction operation of the secondary decompression unit is depressurized to sufficiently cool the temperature of the freezing chamber. Refrigeration cycle characterized in that.

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