KR0177709B1 - Cooling apparatus for a refrigerator - Google Patents

Abstract

The present invention relates to a refrigerator of a refrigerator, and to improve the efficiency of the refrigerator by controlling the pressure of the evaporator to a desired level by controlling the flow rate of the refrigerant by opening and closing the electronic expansion valve formed between the condenser and the evaporator.

The object of the present invention is to form a temperature sensing means at the evaporator inlet and outlet to detect the temperature of the evaporator inlet and outlet, the evaporator inlet and outlet temperature detected by the temperature sensing means is the ratio of the time that the evaporator outlet temperature is opened and closed so as to be higher than the inlet temperature It was possible to achieve the above object by forming a flow rate adjusting means for controlling the flow rate of the refrigerant by.

Description

Chiller of refrigerator

1 is a refrigerator of a conventional parallel connection refrigeration / refrigeration system,

(a) is a cross-sectional view of the refrigerator.

(b) is a cycle diagram of the refrigerator.

2 is a refrigerator using a conventional freezing / refrigeration independent cold air flow path.

(a) is a cross-sectional view of the refrigerator.

(b) is a cycle diagram of the refrigerator.

3 is a conventional time-division two-stage refrigerator,

(a) is a cross-sectional view of the refrigerator.

(b) is a cycle diagram of the refrigerator.

4 is a refrigerator of the present invention,

(a) is a cross-sectional view of the refrigerator.

(b) is a cycle diagram of the refrigerator.

* Explanation of symbols for main parts of the drawings

101: freezer compartment 102: refrigerator compartment

103: freezer cold air circulation duct inlet 104: cold compartment cold air circulation duct inlet

105: evaporator 106: fan

107: damper 108: plate

109: compressor 110: condenser

111: electromagnetic expansion valve 112: first temperature thermistor

113: second temperature thermistor 114: barrier

The present invention relates to a cooling apparatus of a refrigerator, and in particular, to improve the efficiency of the refrigerator by controlling the flow rate of the refrigerant to a desired level by controlling the flow rate of the refrigerant through opening and closing of the electronic expansion valve formed between the condenser and the evaporator.

The conventional refrigerator comprises a freezing compartment 1 and a refrigerating compartment 2, as shown in FIG. 1, and introduces air cooled by the freezing compartment evaporator 5 formed at the rear side of the freezing compartment 1 into the freezing compartment 1. A freezer compartment fan (6), a refrigerator compartment fan (6) for introducing air cooled by the refrigerating compartment evaporator (7) formed at the rear side of the refrigerating compartment (2) to the refrigerating compartment (2), and circulating inside the freezing compartment (1) A freezer compartment cold air duct inlet 3 for introducing cold air, a barrier 14 formed to allow cold air to flow through the freezer compartment evaporator 5 to exchange cold air introduced through the freezer compartment cold air duct inlet 3, and High pressure subcooling of the compressor (8) in which the high temperature and low pressure discharged from the freezer compartment evaporator (5) and the refrigerator compartment evaporator (7) compresses the high temperature and high pressure into the refrigerant, and the high temperature and high pressure refrigerant discharged from the compressor (8). A condenser 9 for condensing with a liquid refrigerant, and The first and second valves 10 and 11 for opening and closing the inflow of the high pressure subcooled liquid refrigerant condensed in the accumulator 9 and the high pressure subcooled liquid refrigerant introduced through the first valve 10 are stored at a low temperature. A first capillary tube 12 for reducing the pressure with a refrigerant of the first capillary tube, a first capillary tube 13 for reducing the high pressure subcooled refrigerant introduced through the second valve 11 to a low temperature low pressure refrigerant, and the first capillary tube ( The low temperature low pressure refrigerant depressurized in 12) is introduced into the refrigerating chamber evaporator 7 and the low temperature low pressure refrigerant depressurized in the second capillary tube 13 is introduced into the inner chamber evaporator 5.

A conventional refrigerator having such a configuration is a refrigeration / refrigeration system in which the freezer compartment evaporator 5 and the refrigerator compartment evaporator 7 are connected in parallel as shown in FIG. The refrigerant is condensed into a high pressure subcooled refrigerant while passing through the condenser 9, and the high pressure subcooled refrigerant flows into the first capillary tube 13 by opening and closing the first valve 10 and the second valve 11. It is done.

When the first valve 10 is opened, the high-pressure subcooled refrigerant passes through the first valve 10 to be decompressed to the low-temperature low-pressure refrigerant in the first capillary tube 12, and then flows into the refrigerating chamber evaporator 7.

When the second valve 11 is opened, the high-pressure subcooled refrigerant passes through the second valve 11 to be decompressed to the low-temperature low-pressure refrigerant in the second capillary tube 13, and then flows into the freezing chamber evaporator 5.

The low temperature low pressure refrigerant introduced into the refrigerating chamber evaporator 7 is evaporated into the high temperature low pressure refrigerant while circulating inside the refrigerating chamber 2 and exchanges heat with the introduced cold, and the high temperature low pressure refrigerant flows into the compressor 9.

At this time, the cold air heat exchanged in the refrigerating chamber evaporator 7 is cooled again by the refrigerating chamber evaporator 7 and introduced into the refrigerating chamber 2 as the refrigerating chamber fan 6 rotates.

The low temperature and low pressure refrigerant introduced into the freezer compartment evaporator (5) circulates in the freezer compartment (1) and flows through the freezer compartment cold air duct intake port (3) to exchange heat with cold air flowing in the barrier (14) to the low temperature and low pressure refrigerant. Evaporated, the high temperature low pressure refrigerant flows into the compressor (9).

At this time, the cold air heat exchanged in the freezer compartment evaporator (5) is cooled again by the freezer compartment evaporator (5) and flows into the freezer compartment (1) as the freezer compartment fan (4) rotates.

In the conventional refrigerator, since the freezer compartment and the refrigerating compartment must be simultaneously cooled by one evaporator, the evaporator temperature of the evaporator should be lowered to -28 ° C to -30 ° C.

However, the freezer / refrigeration system in which the freezer compartment evaporator (5) and the refrigerator compartment evaporator (7) are connected in parallel increases the efficiency of the refrigerator by increasing the evaporator temperature of the evaporator (7) by about -10 ° C to -15 ° C when the refrigerator is cooled. Can be.

2 illustrates a refrigerator using a freezing / freezing independent cold air flow path, wherein the refrigerator includes a freezing compartment 21 and a refrigerating compartment 22, and a freezing chamber cold air duct inflowing cold air circulating in the freezing compartment 21. Inlet 23, through the refrigerator compartment cold air circulation duct inlet 24 for introducing cold air circulating in the refrigerating compartment 22, the freezer compartment cold air duct inlet 23 and the cold compartment cold air circulation duct inlet 24 The evaporator 25 formed in the barrier 35 so as to exchange heat with the cold, and the plate 28 is operated to open and close the heat exchange in the evaporator 25 so as to flow into the freezing chamber 21 and the refrigerating chamber 22 which are cooled again. The damper 27 for adjusting the amount of cold air through the condenser, Condenser 30 for introducing the high temperature low pressure refrigerant discharged from the evaporator 25 and condensed into a high temperature high pressure refrigerant, and the condenser 30 To open and close the inflow of high-pressure refrigerant First and second valves 31 and 32, a first capillary tube 33 for reducing the high-pressure subcooled refrigerant introduced through the first valve 31 to a low-temperature low-pressure refrigerant, and the second valve. The second capillary tube 34 for depressurizing the high-pressure subcooled liquid refrigerant introduced through the 32 into the low-temperature low-pressure refrigerant, and the low-temperature low-pressure refrigerant depressurized by the first capillary tube 33 and the second capillary tube 34 Inflow to the evaporator 25 and evaporated to form a high temperature low pressure refrigerant.

The refrigerator configured as described above includes a freezing compartment 21 and a refrigerating compartment 22. The cold air circulating in the freezing compartment 21 is introduced into the barrier 35 through the freezing compartment cold air circulation duct inlet 23, and the refrigerating compartment 22. The cold air circulating in the c) is introduced into the barrier 35 through the refrigerating chamber cold air circulation duct inlet 24.

The cold air introduced into the barrier 35 is cooled again by exchanging heat with the evaporator 25 formed in the barrier 35, and the cooled cold air flows by the rotation of the fan 26 to control the amount of cold air. In accordance with the operation of the plate 28 formed in the) is selectively introduced into the freezing chamber 21 or the refrigerating chamber 22.

At this time, when cooling the refrigerating chamber 22, the plate 28 formed in the damper 27 is operated to block the flow path on the freezer compartment 21 to exchange heat with the evaporator 25 so that the cooled chiller flowing in the barrier 35 again It flows into the refrigerating compartment 22 and circulates. When cooling the freezing compartment 21, the freezing compartment 21 is cooled by heat exchange with the evaporator 25 by blocking the flow path on the refrigerating compartment 22 side with a plate 28 formed in the damper 27. Flows into) and circulates.

The refrigerant introduced into the evaporator 25 is evaporated into a refrigerant having a high temperature and low pressure while being heat exchanged with the cold introduced from the freezing compartment 21 and the refrigerating chamber 22, and introduced into the compressor 29 to be compressed into a refrigerant having a high temperature and high pressure. The refrigerant of the heat exchange is made while passing through the condenser 30 is condensed into a high-pressure subcooled refrigerant.

The high-pressure subcooled liquid refrigerant discharged from the condenser 30 is reduced in the first capillary tube 33 and the second capillary tube 34 according to opening and closing of the first valve 31 and the second valve 32.

At this time, in order to cool the refrigerating chamber 22, the first valve 31 is opened and the second valve 32 is closed so that the high-pressure subcooled coolant discharged from the condenser 30 passes through the first valve 31 to allow the first capillary tube ( In step 33), the refrigerant is decompressed to a low temperature low pressure refrigerant, flowed into the evaporator 25, and heat exchanged to evaporate into a high temperature low pressure refrigerant.

In order to cool the freezer compartment 21, the first valve 31 is closed and the second valve 32 is opened to discharge the high-pressure subcooled coolant discharged from the condenser 30 to the second capillary tube ( In step 34), the refrigerant is depressurized to a low temperature low pressure refrigerant and then flows into the evaporator 24 to exchange heat to evaporate into a high temperature low pressure refrigerant.

Here, when the cycle is operated to cool the refrigerating chamber 22, the evaporator 25 has an evaporation temperature of about -10 to -15 ° C. When the cycle is operated to cool the freezer compartment 21, the evaporator temperature of the evaporator 25 is -25 ℃ so you can increase the efficiency of the refrigerator.

3 shows a refrigerator of a time-division two-stage cooling method, wherein the refrigerator includes a freezing compartment 41 and a refrigerating compartment 42, and the air cooled by the freezing compartment evaporator 45 formed at the rear side of the freezing compartment 41. A refrigerating compartment fan 46 for introducing air cooled by the air 47 into the refrigerating compartment 42, a freezing compartment cold air circulation duct inlet 43 for introducing cold air circulating in the freezing compartment 41, and the freezer cold air circulation duct The barrier 55 is formed so that the cool air flows to heat the cold air introduced through the suction port 43 in the freezer compartment evaporator 45, and the high temperature low pressure refrigerant discharged from the freezer compartment evaporator 45 and the refrigerating compartment evaporator 47. A compressor 48 that flows in and compresses into a high temperature and high pressure refrigerant, a condenser 29 for condensing the high temperature and high pressure refrigerant flowing into the high temperature and high pressure refrigerant discharged from the compressor 48 into a high pressure subcooled refrigerant, and condensation The first capillary tube 50 for depressurizing the high-pressure subcooled liquid refrigerant condensed in the gas 29 to the low-temperature low-pressure refrigerant, and the low-temperature low-pressure refrigerant decompressed in the first capillary tube 50 flows into the refrigerating chamber evaporator 47. And a heat exchanger to form a refrigerant having a high temperature and low pressure, and open and close the gas liquid separator 51 for separating the high temperature and low pressure refrigerant into a gas refrigerant and a liquid refrigerant refrigerant, and a gas refrigerant separated from the gas liquid separator 51 to flow into the compressor 48. The valve 53, the second capillary 52 for reducing the liquid refrigerant separated by the gas-liquid separator 51, and the low-temperature low-pressure refrigerant, and the low-temperature low-pressure refrigerant decompressed in the second capillary tube 52 are freezing chambers. After the heat exchange in the evaporator 45 was formed as a refrigerant of high temperature and low pressure, it was configured to flow through the check valve 54 to the compressor (48).

The refrigerator configured as described above includes a freezing compartment 41 and a refrigerating compartment 42. The cold air circulating in the freezing compartment 41 flows into the barrier 55 through the freezing compartment cold air circulation duct inlet 43 and flows into the freezer compartment evaporator ( After the heat exchange at 45) and cooling again, the freezing chamber 41 is introduced into the freezing chamber 41 according to the rotation of the freezing chamber fan 44.

The cold air circulating in the refrigerating compartment 42 is heat-exchanged in the refrigerating compartment evaporator 47, cooled again, and then introduced into the refrigerating compartment 42 according to the rotation of the refrigerating compartment fan 46.

At this time, the high temperature and low pressure refrigerant formed by evaporation in the freezer compartment evaporator 45 and the refrigerator compartment evaporator 47 flows into the compressor 48 to be compressed into a high temperature and high pressure refrigerant, and the high temperature and high pressure refrigerant is condensed in the high pressure subcooled liquid in the condenser 49. It is condensed with refrigerant.

The high pressure subcooled liquid refrigerant discharged from the condenser 49 passes through the first capillary tube 50 and is decompressed to a low temperature low pressure refrigerant to be introduced into the refrigerator compartment evaporator 47 and the low temperature low pressure introduced into the refrigerator compartment evaporator 47. The refrigerant is exchanged with the refrigerant at high temperature and low pressure by heat exchange.

After the high temperature and high pressure refrigerant is separated into a gas refrigerant and a liquid refrigerant in the gas-liquid separator 51, the gas refrigerant flows into the compressor 48 through the valve 53 when the valve 53 is opened and closed, and the liquid refrigerant The pressure is reduced by the low temperature low pressure refrigerant while passing through the second capillary tube 52, the low temperature low pressure refrigerant is introduced into the freezer compartment evaporator 45, and heat exchanged to evaporate the high temperature low pressure refrigerant. The valve 54 is introduced into the compressor 48.

At this time, the valve 53 is opened and closed repeatedly so that the pressure of the refrigerating chamber evaporator 47 is kept constant.

However, such a conventional refrigerator has not only a complicated configuration of a cycle for cooling a freezer compartment or a refrigerating compartment but also has difficulty in cycle control.

In addition, the number of parts, such as evaporator or capillary tube and valve increases the manufacturing cost, as well as the number of parts need to be welded, there was a problem that a lot of welding defects and work time takes a lot of work loss.

However, when the freezer compartment and the refrigerating compartment are cooled, there is a problem in that the contents of the refrigerator are reduced by providing an evaporator separately.

Therefore, the present invention forms a temperature sensing means at the evaporator inlet and outlet to detect the temperature of the evaporator inlet and outlet, and the temperature of the evaporator inlet and outlet detected by the temperature sensing means is opened and closed by the ratio of time that the evaporator outlet temperature is higher than the inlet temperature. The purpose of the present invention is to improve the efficiency of the refrigerator by adjusting the pressure of the evaporator to a desired level by forming a flow rate adjusting means for controlling the flow rate of the refrigerant.

As shown in FIG. 4, the refrigerator includes a freezer compartment 101 and a refrigerating compartment 102, and the refrigerator compartment cold air duct inlet for introducing cold air circulating in the freezer compartment 101 as shown in FIG. 103, a cold air circulation duct inlet 104 for introducing cold air circulating in the refrigerating compartment 102, and the cold air introduced through the freezer cold air circulation duct inlet 103 and the cold compartment cold air circulation duct inlet 104 An evaporator 105 formed in the barrier 114 to exchange heat with the fan, and a fan 106 rotating to introduce cold air, which has been heat-exchanged in the evaporator 105, into the freezer compartment 101 and the refrigerating chamber 102, and Damper 107 for operating the plate 108 so that the cold air flowing in the barrier 114 by the fan 106 flows into the freezer compartment 101 or the refrigerating compartment 102 to control the amount of cold air through opening and closing; Cold of high temperature and low pressure discharged from the evaporator 105 The compressor 109 for introducing the refrigerant into the high temperature and high pressure refrigerant, the condenser 110 for condensing the high temperature and high pressure refrigerant discharged from the compressor 109 into the high pressure subcooled refrigerant, and the evaporator 105 The first temperature thermistor 112 to sense the temperature, the temperature of the evaporator 105, the second temperature thermistor 113 and the high pressure subcooled liquid low temperature low pressure refrigerant discharged from the condenser 110 It is composed of an electronic expansion valve 111 to reduce the pressure, and adjust the flow rate of the refrigerant flowing into the evaporator 105 through the opening and closing of the signal received by the first temperature thermistor 112 and the second temperature thermistor (113). .

The operation and effects of the present invention configured as described above will be described in detail with reference to FIG.

As shown in FIG. 4, the refrigerator includes a freezing compartment 101 and a refrigerating compartment 102, and the cold air circulated in the freezing compartment 101 passes through the freezing compartment cold air circulation duct into the barrier 114 through the suction port 103. The cold air introduced and circulated in the refrigerating compartment 102 is introduced into the barrier 114 through the refrigerating compartment cold air circulation duct inlet 104.

The cold air introduced into the barrier 114 is cooled again by heat exchange with the evaporator 105 formed in the barrier 114, and the cooled cold air flows by the rotation of the fan 106 to control the amount of cold air. Depending on the operation of the plate 108 formed in the 107 is selectively introduced into the freezer compartment 101 or the refrigerating compartment 102.

At this time, the coolant introduced into the evaporator 105, the cold air introduced from the freezer compartment 101 and the refrigerating chamber 102 exchanges heat and is evaporated into the refrigerant of high temperature and low pressure to be introduced into the compressor 109.

The high temperature and low pressure refrigerant introduced into the compressor 109 is compressed in the compressor 109 to form a high temperature and high pressure refrigerant, and the high temperature and high pressure refrigerant passes through the condenser 110 to perform heat exchange, so that the high pressure is a subcooled refrigerant. To condense.

The high-pressure subcooled refrigerant refrigerant condensed in the condenser 110 is decompressed to a low temperature low pressure refrigerant while passing through the electronic expansion valve 111, and the low temperature low pressure refrigerant is heat-exchanged in the evaporator 105 to evaporate into a high temperature low pressure refrigerant. After being made, it is introduced into the compressor 109.

The first temperature thermistor 112 and the second temperature thermistor 113 are formed at the inlet and outlet of the evaporator 105 to sense the temperature of the evaporator 105 inlet and send the detected signal to the electronic expansion valve 111. Open and close the electromagnetic expansion valve (111).

At this time, the electronic expansion valve 111 is controlled by the evaporator 105 and the condenser 110 by adjusting the flow rate of the low-temperature low-pressure refrigerant depressurized by the electronic expansion valve 111 by the ratio of the opening time and the closing time while repeating the opening and closing in a time division manner. Adjust the pressure difference.

The flow rate is always adjusted so that the evaporator 105 exit condition is dryness 1, which is possible by allowing the outlet temperature of the evaporator 105 to be 1 to 3 ° C. above the inlet temperature.

When the refrigerating compartment 102 is cooled, the plate 108 formed in the damper 107 is operated to block the flow path toward the freezing compartment 101 to exchange heat with the evaporator 105 to allow the refrigerating compartment 102 to flow through the barrier 114. The flow rate of the refrigerant flowing into the evaporator 105 is increased by increasing the opening degree of the electronic expansion valve 111 to the circulation of the freezer compartment 101 at the same time as cooling the freezer compartment 101, thereby increasing the pressure and temperature of the evaporator 105. 102) Increase to a level suitable for cooling.

When the freezer compartment 101 is cooled, the plate 108 formed in the damper 107 is operated to block the flow path toward the refrigerating compartment 102 to exchange heat with the evaporator 105 so that the cold air flowing in the barrier 114 flows into the freezer compartment 101. The refrigerant flowing into the evaporator 105 decreases the flow rate of the evaporator 105 by reducing the flow rate of the electronic expansion valve 111 as compared to when the refrigerating chamber 102 is cooled. ) Lower to a level suitable for cooling.

At this time, by adjusting the opening and closing time ratio of the electronic expansion valve 111 to increase the evaporator 105 outlet temperature than the inlet temperature.

After the compressor 109 is stopped periodically, only the air in the refrigerating compartment 102 is passed through the evaporator 105 to remove the frost formed on the surface of the evaporator 105 while cooling the refrigerating compartment 102. If it is not removed, after stopping the fan 106, the electronic expansion valve 111 is completely opened and the extruder 109 is operated to remove the frost formed on the surface of the evaporator 105 with the heated refrigerant of the compressor 109.

Since the refrigerator has a relatively low flow rate compared to an air conditioner, an electronic expansion for controlling the opening and closing of the valve in order to solve a problem that it is difficult to control the flow rate of the refrigerant by adjusting the area of the open part, which is a general flow control method of the valve. The valve 111 is used.

The electronic expansion valve 111 is a valve used for fuel injection of an automobile, and opens and closes the valve at a high speed, and controls the flow rate of the refrigerant by controlling the degree of opening and closing.

At this time, when the voltage is applied, the electronic expansion valve 111 is opened, the refrigerant controls the flow rate in the ratio of the time the voltage is applied to one cycle and the time that is not applied, the electronic expansion valve 111 is a cycle of 2 seconds.

In the case of the refrigerating chamber 102, the evaporator 105 is maintained at 3 ° C. and the freezing chamber 101 at −18 ° C., and in the case of the freezing cycle, the higher the evaporation temperature of the freezing chamber 105 is, the better the efficiency is. .

In the conventional refrigerator, since the freezer compartment 101 and the refrigerating compartment 102 are simultaneously cooled by one evaporator 105, the temperature of the evaporator 105 must be maintained at a temperature lower than −18 ° C., which is the temperature of the lowest freezer compartment 101. Therefore, to cool the refrigerating compartment 102, an evaporator 105 having a lower temperature than necessary is used to completely solve the problem of lowering the efficiency of the refrigerator, thereby completely separating the cold air from the freezer compartment 101 and the refrigerating compartment 102 and freezing compartment 101. Each of the and the refrigerating compartment 102 forms an evaporator 105.

When the refrigerating chamber 102 is cooled, the evaporator 105 is increased to increase the evaporator temperature. However, since the evaporator 105 is added, the refrigerator has a manufacturing cost and a decrease in the contents of the refrigerator.

Therefore, it constitutes an independent flow path in the refrigerator, uses an electronic expansion valve 111, lowers the temperature of the evaporator 105 when cooling the freezer compartment 101, and allows cold air to circulate only into the freezer compartment 101, and when the refrigerator compartment 102 is cooled. In order to increase the temperature of the evaporator 105 and the cold air to circulate only in the refrigerating chamber 102, it is possible to increase the efficiency of the refrigerator with one evaporator 105.

In addition, it is possible to remove the frost formed on the surface of the evaporator 105 by sending cold air of 0 ° C. or higher of the refrigerating chamber 102 to the evaporator 105, and may also use the freezing chamber 101 and the refrigerating chamber 102 interchangeably.

As described in detail above, the capillary tube and the valve are replaced with an electronic expansion valve to depressurize the refrigerant, and by controlling the flow rate of the refrigerant through opening and closing, the configuration of the cycle is simplified, so that the cycle can be easily controlled, There is an effect that the manufacturing cost is reduced.

In addition, the flow rate of the refrigerant flowing into the evaporator is controlled by opening and closing the electronic expansion valve, thereby increasing the cooling rate of cooling the freezing compartment or the refrigerating compartment.

When cooling the refrigerating compartment, the refrigerating chamber is circulated and the frost formed on the surface of the evaporator formed in the barrier is removed to improve defrosting efficiency of the evaporator. Because the moisture is supplied to the refrigerating compartment, the refrigerating compartment is also humidified.

Claims (3)

A freezer compartment cold air duct inlet, comprising a freezer compartment and a refrigerating compartment, for introducing cold air circulating in the freezer compartment; An evaporator formed in the barrier to exchange heat with cold introduced through the circulation duct inlet, a fan that rotates to introduce cold air that has been heat-exchanged in the evaporator to the freezing compartment and the refrigerating compartment, and the cold air flowing in the barrier by the fan is freezing compartment. Or a damper for controlling the amount of cold air by opening and closing the plate to be introduced into the refrigerating chamber, a compressor for introducing a refrigerant having a high temperature and low pressure discharged from the evaporator and compressing it into a refrigerant having a high temperature and high pressure, and being discharged from the compressor. A condenser that condenses the high temperature and high pressure refrigerant into a high pressure subcooled refrigerant, A first temperature thermistor for sensing the temperature of the evaporator inlet, a second temperature thermistor for sensing the temperature of the evaporator outlet, and a high pressure subcooled refrigerant refrigerant discharged from the condenser to reduce the low temperature and low pressure refrigerant, The temperature of the inlet and outlet of the evaporator detected by the first and second temperature thermistors is composed of an electronic expansion valve configured to control the flow rate of the refrigerant flowing into the evaporator by opening and closing the thermistor and the second temperature thermistor. And a flow rate regulating means for regulating the flow rate of the refrigerant by a time ratio of opening and closing so that the temperature is higher than the inlet temperature. According to claim 1, wherein the damper by operating the plate formed in the damper to block the flow path to the freezer compartment, the cold air flowing in the barrier by heat exchange with the evaporator flows into the refrigerating compartment is circulated, and at the same time the degree of opening of the electromagnetic expansion valve to freeze chamber cooling Cooling apparatus of the refrigerator, characterized in that the flow rate adjusting means for controlling the flow rate of the refrigerant flowing into the evaporator to increase than the time. The refrigerator of claim 1, wherein the damper operates a plate formed in the damper to block the flow path toward the refrigerating compartment to exchange heat with the evaporator, and the cold air flowing in the barrier is introduced into the freezing compartment and circulated, and at the same time, the degree of opening of the electromagnetic expansion valve is controlled. Cooling apparatus of the refrigerator characterized in that the flow rate control means for controlling the flow rate of the refrigerant during cooling of the freezer compartment to reduce the flow rate of the refrigerant flowing into the evaporator to reduce the pressure and temperature of the evaporator.