JP4684067B2 - Cooling storage - Google Patents

Description

The present invention relates to a cooling storage such as a refrigerator-freezer that employs CO ₂ as a refrigerant.

  Conventionally, in a refrigerator-freezer for home use, a main body is constituted by a heat insulating box, a machine room is formed at the back lower part (or upper part of the back) of the main body, and a part of the refrigeration circuit is formed inside the machine room. A machine is installed.

  A condenser, a pressure reducing device (generally a capillary tube), an evaporator (cooler), and the like are sequentially connected in an annular manner on the discharge side of the compressor to constitute a known refrigeration circuit.

  When the compressor is operated, the high-temperature and high-pressure refrigerant discharged from the compressor flows into the condenser, where it dissipates heat and is condensed and liquefied. The condensed and liquefied refrigerant is decompressed by the capillary tube and then flows into the evaporator, where it evaporates and absorbs heat from the surroundings to exert a cooling action, and the refrigerant exiting the evaporator is the original compressor Repeated circulation inhaled.

  A plurality of doors are attached to the main body opening edge of the refrigerator, and when the inside of the refrigerator is cooled, the main body opening edge is also cooled, so that condensation occurs when it comes into contact with the outside air.

  Therefore, heating means for preventing condensation is provided at the opening edge of the refrigerator-freezer.

  As the heating means for the opening edge, a high-temperature high-pressure refrigerant pipe that acts as a part of the condenser is generally provided. That is, the main body opening edge is heated by the high-temperature and high-pressure refrigerant discharged from the compressor to prevent the occurrence of condensation (see Patent Documents 1, 2, and 3). In addition, although it is preferable to arrange | position high pressure side refrigerant | coolant piping to all the main body opening rim | edge parts, the electric heater is arrange | positioned instead of the high pressure side refrigerant | coolant piping in the part where arrangement | positioning is difficult (refer patent document 4). ).

  With such a configuration, the high-temperature high-pressure refrigerant pipe that acts as a part of the condenser also serves as a heating means for preventing condensation, which is advantageous in terms of power consumption, downsizing of the refrigerator-freezer, and the like.

By the way, R134 or R600a (hydrocarbon isobutane) is generally used as a refrigerant in a refrigeration circuit of a refrigerator-freezer, and it has been proposed to employ CO ₂ as this refrigerant (see Patent Document 5).
JP 2002-107044 A Japanese Patent Laid-Open No. 10-300319 JP 2001-12841 A JP-A-10-332249 JP 2004-85106 A

  CO2 is used as a refrigerant, and the high-temperature and high-pressure refrigerant discharged from the compressor of this refrigeration circuit is allowed to flow through a high-pressure side refrigerant pipe that acts as a part of the condenser. As a result, there was a problem that the temperature of the opening edge of the main body varied and could not be heated satisfactorily.

  In the refrigerator / refrigerator employing the conventional refrigerant R600a, the refrigerant in the high-pressure refrigerant pipe is in a gas-liquid two-phase saturated state, and the gas has a lot of latent heat (transition heat, heat of vaporization, heat of evaporation). Even when heat is released to the outside of the high-pressure side refrigerant pipe, the temperature of the refrigerant in the high-pressure side refrigerant pipe does not change so much, and it is assumed that the opening edge of the main body can be uniformly heated.

However, a refrigerator-freezer that employs CO ₂ as a refrigerant is different from this traditional situation. In different situations, first the pressure is different. As an example of R600a, the low pressure side is about 0.05 MPa, and the high pressure side is about 0.5 MPa. As an example of CO ₂ , the low pressure side is about 1.5 MPa, and the high pressure side is about 8 MPa.

  In general, the latent heat of a substance is small in an atmosphere with high pressure.

In the case of a refrigerator-freezer that employs CO ₂ , the high-pressure side refrigerant has a very high pressure and low latent heat, and depending on the state, it may be in a supercritical state. Thus, the latent heat of the refrigerant in the high-pressure side refrigerant pipe is small, and it is very difficult to uniformly warm the periphery of the high-pressure side refrigerant pipe. In actual prototypes of refrigerators and refrigerators, the temperature of the part where the high-pressure refrigerant piping is installed is not uniform, causing too much heat for the user who touches it with hands, or condensation due to insufficient heat. Has occurred.

Thus, in the refrigerator employing the CO ₂ refrigerant in the refrigeration circuit, the use of high-pressure refrigerant pipe of the refrigeration circuit and similarly to the conventional condensation for prevention, could not practically.

The present invention provides a main body constituted by a heat insulating box having an opening on one side, a heat insulating door provided on the one side, a machine room formed on the main body, a part of a refrigeration circuit disposed in the machine room. And a refrigerant pipe for preventing condensation that forms a part of the condenser that condenses the refrigerant discharged from the compressor and is disposed at the opening edge of the one surface of the heat insulating box. In a cooling storage comprising a refrigerant pipe for promoting evaporation disposed in an evaporating dish and forming a part of a condenser for condensing the refrigerant discharged from the compressor, the refrigerant of the refrigeration circuit is CO ₂ . The dew condensation prevention refrigerant pipe is positioned downstream of the evaporation promotion refrigerant pipe, and an electric heater for dew condensation is provided in line with the dew condensation prevention refrigerant pipe. The evaporation from the end of frost The predetermined time for accelerating the evaporation of the defrosted water accumulated in the dish is characterized in that the energization rate is set higher than the subsequent time .

  Further, according to the present invention, the cooling storage is provided with a freezing room and a refrigerating room, and the electric heater is disposed at an opening edge of the freezing room.

  According to the present invention, the cooling storage is provided with a freezing room and a refrigerating room, and the electric heater is provided along the entire circumference of the dew condensation prevention pipe.

According to the present invention, even in a refrigerator (cooling storage) that employs CO ₂ refrigerant in a refrigeration circuit, the opening edge of the main body can be uniformly heated, and condensation can be prevented.

  According to the present invention, the refrigerant pipe for preventing condensation is located at a later stage than the refrigerant pipe for promoting evaporation, and an electric heater for preventing condensation is provided in the refrigerant pipe for preventing condensation. Since the predetermined time for promoting the evaporation of the defrosted water accumulated in the evaporating dish from the end of defrosting is set higher than the time after that, at the end of defrosting, The defrost water that has flowed into the evaporating dish absorbs heat at the refrigerant pipe portion for promoting evaporation, and even if the amount of heat released from the refrigerant pipe portion for preventing condensation is insufficient, Is compensated by increasing the amount of heat generated by the electric heater for preventing condensation, so that the stability of preventing condensation can be improved.

The present invention relates to a main body composed of a heat-insulating box having an opening on one surface, a heat-insulating door provided on the one-surface side, a machine room formed in the main body, and a refrigeration circuit disposed in the machine room. And a refrigerant pipe for preventing condensation that forms a part of the condenser that condenses the refrigerant discharged from the compressor and is disposed at the opening edge of the one surface of the heat insulating box. In the cooling storage comprising a part of a condenser for condensing the refrigerant discharged from the compressor and disposed in the evaporating dish, the refrigerant in the refrigeration circuit is CO _2. And an electric heater for preventing condensation, which is provided side by side on the refrigerant pipe for preventing condensation and has a high energization rate for a predetermined period from the end of defrosting.

  A first embodiment in which the present invention is adopted in a refrigerator-freezer will be described with reference to FIGS. FIG. 1 is a conceptual diagram for explaining a refrigeration circuit and the like of a refrigerator-freezer. FIG. 2 is a diagram for explaining a control circuit of the refrigerator-freezer according to the first embodiment. FIG. 3 is a schematic diagram for explaining the arrangement of the dew condensation preventing means of the refrigerator-freezer of the first embodiment.

  Each part will be described with reference to FIG. In FIG. 1, 1 is a refrigerator-freezer. This refrigerator-freezer 1 is equipped with the main body which consists of a heat insulation box provided with the opening in one surface, and the heat insulation door (not shown) which block | closes this one surface opening. And the heat insulation box is divided | segmented into the upper refrigerator compartment R and the lower freezer compartment F by the partition wall.

  Reference numeral 2 denotes a compressor, which forms part of the refrigeration circuit. This compressor 2 is a two-stage compressor for carbon dioxide refrigerant. This compressor 2 is arrange | positioned in the machine room 15 formed in the lower part of the heat insulation box. The intermediate stage of the compressor 2 is connected to an external condenser 3, and the external condenser 3 cools the intermediate stage refrigerant and returns it to the compressor 2 again.

  The refrigerant from the compressor 2 is condensed by the main condenser 4a. This main condenser 4a is comprised with the heat exchanger provided with the radiation fin. Next, the refrigerant flows into the refrigerant pipe portion 4c routed along the opening edge of the refrigerator-freezer through the refrigerant pipe portion 4b for promoting evaporation of drain water in the evaporating dish 28. The condenser of the refrigerator 1 includes a main condenser 4a and refrigerant pipe portions 4b and 4c. In addition, the refrigerant | coolant pipe part 4c is a pipe for dew condensation prevention of the opening edge of this refrigerator-freezer.

  Thereafter, the refrigerant is branched into the refrigerator compartment R and the freezer compartment F. The decompression means of the refrigerator / freezer employs an electric expansion valve whose opening degree is adjusted by driving a stepping motor, not a capillary tube. As described above, a CO2 refrigerant refrigerator-freezer requires a large pressure reduction as compared with the conventional R600a refrigerant. If this is performed only with a capillary tube, a very long capillary tube is drawn into the insulation of the refrigerator-freezer. That's not realistic. In addition, although the combined use of a capillary tube and an expansion valve has been proposed in the past, in Example 1, the pressure is reduced substantially only by the expansion valve.

  7 is a refrigerator for a refrigerator compartment. The refrigerant for the refrigerating room R flows into the refrigerating room cooler 7 through the refrigerant pipe 5a and the refrigerating room expansion valve 6 (refrigerating room decompression means). The opening degree of the refrigerating room expansion valve 6 is controlled so that the evaporation (cooling) in the refrigerating room cooler 7 is favorably performed.

  Reference numeral 5b denotes a refrigerant pipe that returns the refrigerant from the refrigerator 7 for the refrigerator compartment to the compressor 2. The refrigerant pipe 5b is joined to the refrigerant pipe 5a to form a heat exchanger 5, and performs heat exchange between the two 5a and 5b.

  Reference numeral 10 denotes a freezer cooler. The refrigerant for the freezer compartment F flows into the freezer compartment cooler 10 via the refrigerant pipe 8a and the freezer compartment expansion valve 9 (freezer compartment decompression means). The opening degree of the freezing chamber expansion valve 9 is controlled so that the evaporation (cooling) in the freezing chamber cooler 10 is favorably performed.

  A refrigerant pipe 8 b returns the refrigerant from the freezer cooler 10 to the compressor 2. The refrigerant pipe 8b is joined to the refrigerant pipe 8a to form a heat exchanger 8, and performs heat exchange between the two 8a and 8b.

  Reference numeral 11 denotes a defrosting glass tube heater for the refrigerator 7 for the refrigerator compartment. Reference numeral 12 denotes a defrosting glass tube heater for the freezer cooler 10. The glass tube heaters 11 and 12 are turned ON when the coolers 7 and 10 are defrosted, and melt the frost of the coolers 7 and 10 by heating. The defrost water at this time is each collected in the evaporating dish 28 via a drain hose (not shown) in the heat insulating material. 13 is a check valve. A machine room 15 is formed in the lower part of the main body of the refrigerator-freezer.

  Reference numeral 16 denotes an outside air temperature sensor that measures the ambient temperature of the refrigerator-freezer. Reference numeral 17 denotes a refrigerator temperature sensor that is provided in the refrigerator compartment and measures the temperature of the refrigerator compartment. Reference numeral 18 denotes a freezer temperature sensor that is provided in the freezer and measures the temperature of the freezer.

  Reference numeral 19 denotes an R inlet temperature sensor for measuring the inlet temperature of the refrigerator 7 for the refrigerator compartment. Reference numeral 20 denotes an R outlet temperature sensor for measuring the outlet temperature of the refrigerator 7 for the refrigerator compartment. The detected values from the R inlet / outlet temperature sensors 19 and 20 are used for opening control of the refrigerating chamber expansion valve 6. The R inlet / outlet temperature sensors 19 and 20 are also used as temperature sensors for detecting the completion of defrosting in the refrigerator compartment.

  Reference numeral 21 denotes an F inlet temperature sensor for measuring the inlet temperature of the freezer cooler 10. Reference numeral 22 denotes an F outlet temperature sensor for measuring the outlet temperature of the freezer cooler 10. The detected values from the F inlet / outlet temperature sensors 21 and 22 are used for opening control of the freezing chamber expansion valve 9. The F inlet / outlet temperature sensors 21 and 22 are also used as temperature sensors for detecting the completion of defrosting in the freezer compartment.

  Reference numeral 23 denotes a cold air circulation fan for the refrigerator compartment. It is turned ON when the refrigerator compartment R is cooled, and the cold air in the refrigerator refrigerator 7 is circulated in the refrigerator compartment.

  Reference numeral 24 denotes a cold air circulation fan for the freezer compartment. It is turned ON when the freezer compartment F is cooled, and the cold air of the freezer cooler 10 is circulated in the freezer compartment.

  A machine room fan 25 cools the main condenser 4, the compressor 2, the external condenser 3 and the like in the machine room. When the refrigerator is cooled, it is turned on together with the compressor 1 to cool the machine room.

  Each part will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the same part as FIG. In FIG. 2, 26 is a control circuit for controlling the refrigerator-freezer. 29 is an electric heater routed around the opening edge of the freezer compartment of the refrigerator-freezer.

  Next, the routing of the heating means 4c and 29 for preventing condensation will be described with reference to FIG. The same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals.

In FIG. 3, 4c is a dew condensation prevention pipe. The dew condensation prevention pipe 4c is disposed while turning from the lower side to the upper side of the opening edge of the main body corresponding to the peripheral edge of each door, and is then disposed below the right side above the opening edge of the refrigerator / freezer 1 and is provided at the opening edge. Along the way back to the machine room. The electric heater 29 is arranged alongside the dew condensation prevention pipe 4c around the freezer compartment.

  The operation of this refrigerator-freezer will be described with reference to FIGS. First, the initial operation at the time of pull-down cooling of this refrigerator-freezer will be described.

  When the refrigerator 1 is turned on after the refrigerator is purchased and installed, the refrigerator control unit 26 detects that the power is turned on, detects that the inside temperature of the freezer compartment F is minus 5 ° C. or more, and performs pull-down cooling. Take control.

  That is, the compressor 2, the machine room fan 25, and the cool air circulation fans 23 and 24 are turned on, and the refrigeration circuit is turned on. Then, both the freezing chamber expansion valve 9 and the refrigerating chamber expansion valve 6 are opened to allow the refrigerant to flow through both. The refrigerant discharged from the compressor 2 is condensed by the main condenser 4. Then, it branches for the refrigerator compartment R and the freezer compartment F. The refrigerant for the refrigerating room R flows into the refrigerating room cooler 7 through the refrigerant pipe 5a and the refrigerating room expansion valve 6 (refrigerating room decompression means). And it leaves the refrigerator 7 for refrigerator compartments, merges with the refrigerant | coolant of the freezer compartment side via the refrigerant | coolant pipe 5b, and returns to the compressor 2 via the non-return valve 13. FIG. The refrigerant pipe 5a for allowing the refrigerant to flow into the refrigerator for cold room 7 and the refrigerant pipe 5b for flowing out the refrigerant from the refrigerator for cold room 7 are joined to form the heat exchanger 5, Heat exchange between.

  The refrigerant for the freezer compartment F flows into the freezer compartment cooler 10 through the refrigerant pipe 8a and the freezer compartment expansion valve 9 (freezer compartment decompression means). And it leaves the refrigerator 10 for freezer compartment, merges with the refrigerant | coolant of the refrigerator compartment side via the refrigerant | coolant pipe 8b, and returns to the compressor 2 via the non-return valve 13. The refrigerant pipe 8a for allowing the refrigerant to flow into the freezer cooler 10 and the refrigerant pipe 8b for flowing out the refrigerant from the freezer cooler 10 are joined to form a heat exchanger 8. Heat exchange between.

  The control of the flow rate of the refrigerant becomes severe. In the first embodiment, the degree of opening (opening degree) of the expansion valves 6 and 9 is controlled based on the temperature difference between the refrigerant inlet and outlet of the coolers 7 and 10.

  First, the freezer compartment expansion valve 9 is controlled by measuring the refrigerant inlet and refrigerant outlet temperatures of the freezer compartment cooler 10 from the F inlet temperature sensor 21 and the F outlet temperature sensor 22, and the temperature difference (superheat, superheat). ) When this temperature difference is 7 degrees or less, the freezing chamber expansion valve 9 is closed (squeezed) by one step. When this temperature difference is 7 degrees to 20 degrees, the freezer compartment expansion valve 9 is left as it is. When this temperature difference is 20 degrees or more, the freezing chamber expansion valve 9 is opened by one step.

  Control of the refrigerating room expansion valve 6 is performed by measuring the refrigerant inlet and refrigerant outlet temperatures of the refrigerating room cooler 7 from the R inlet temperature sensor 19 and the R outlet temperature sensor 20, and obtaining the temperature difference. And when this temperature difference is 10 degrees or less, the expansion valve 6 for refrigerator compartments is closed 1 step. When the temperature difference is 10 degrees to 25 degrees, the refrigerator compartment expansion valve 6 is left as it is. When this temperature difference is 25 degrees or more, the refrigerating chamber expansion valve 6 is opened by one step.

  After such control is continued for 90 minutes, the freezer compartment F and the refrigerator compartment R are alternately cooled every 20 minutes.

  First, in order to continue cooling of the freezer compartment F and finish cooling of the refrigerator compartment R, the refrigerator compartment expansion valve 6 is fully closed, the cold air circulation fan 23 is turned off, and the refrigerant is supplied only to the freezer compartment cooler 10 side. Shed. At this time, the freezer compartment expansion valve 9 is controlled by first measuring the refrigerant inlet temperature and the refrigerant outlet temperature of the freezer compartment cooler 10 to obtain the temperature difference. When the temperature difference is 2 degrees or less, the freezing chamber expansion valve 9 is closed by one step. When this temperature difference is 2 degrees to 10 degrees, the freezer compartment expansion valve 9 is left as it is. When this temperature difference is 10 degrees or more, the freezing chamber expansion valve 9 is opened by one step.

  After 20 minutes, in order to cool the refrigerator compartment R, the freezer compartment expansion valve 9 is fully closed, the cold air circulation fan 24 is turned off, the cold air circulation fan 23 is turned on, and the refrigerator compartment expansion valve 6 is opened to a predetermined value. Then, the refrigerant is allowed to flow only to the refrigerator compartment cooler 7 side. At this time, the control of the refrigerating room expansion valve 6 is performed by first measuring the refrigerant inlet and refrigerant outlet temperatures of the refrigerating room cooler 7 to obtain the temperature difference. And when this temperature difference is 2 degrees or less, the expansion valve 6 for refrigerator compartments is closed 1 step. When this temperature difference is 2 degrees to 10 degrees, the refrigerator compartment expansion valve 6 is left as it is. When this temperature difference is 10 degrees or more, the refrigerator compartment expansion valve 6 is opened by one step.

  As described above, the freezer cooling control and the refrigerator cooling control are alternately performed every 20 minutes. And if the temperature in a store | warehouse | chamber falls to target temperature, the compressor 2, the cool air circulation fans 23 and 24, and the machine room fan 25 will be turned off, the expansion valves 6 and 9 will be fully closed, and pull-down control will be complete | finished.

  Next, normal cooling will be described.

  When the temperature of the freezer compartment F rises and rises by 2 ° C. (eg, minus 18 degrees) from the freezer compartment temperature set by the user (eg, minus 20 degrees), the freezer compartment temperature sensor 18 causes the control circuit 26 to Is detected. Then, the control circuit 26 cools the freezer compartment F. The control circuit 26 turns on the compressor 2, the cool air circulation fan 24, and the machine room fan 25, opens the freezer expansion valve 9 to a predetermined value, and allows the refrigerant to flow only to the freezer cooler 10 side. At this time, the freezer compartment expansion valve 9 is controlled by first measuring the refrigerant inlet and refrigerant outlet temperatures of the freezer compartment cooler 10 to obtain the temperature difference. When this temperature difference is 1 degree or less, the freezing chamber expansion valve 9 is closed by one step. When this temperature difference is 1 to 5 degrees, the freezer compartment expansion valve 9 is left as it is. When this temperature difference is 5 degrees or more, the freezing chamber expansion valve 9 is opened by one step. When this temperature difference is 10 degrees or more, the freezing chamber expansion valve 9 is opened by two steps. If the temperature in the freezer compartment F falls to a temperature that is 2 ° C. lower than the freezer compartment temperature set by the user (for example, minus 22 ° C.), the compressor 2, the cold air circulation fan 24, and the machine room fan 25 are turned off to freeze. The chamber expansion valve 9 is fully closed.

  When the temperature of the refrigerator compartment R rises and rises by 1 ° C. (for example, 4 ° C.) from the refrigerator compartment temperature (for example, 3 ° C.) set by the user, the control circuit 26 detects this by the refrigerator compartment temperature sensor 17. To do. Then, the control circuit 26 cools the refrigerator compartment R. The control circuit 26 turns on the compressor 2, the cold air circulation fan 23, and the machine room fan 25, and opens the refrigerating room expansion valve 6 to a predetermined value. Thereby, a refrigerant | coolant is poured only into the refrigerator compartment cooler 7 side. At this time, the control of the refrigerating room expansion valve 7 measures the refrigerant inlet and refrigerant outlet temperatures of the refrigerating room cooler 7, and obtains the temperature difference. And when this temperature difference is 1 degree or less, the expansion valve 6 for refrigerator compartments is closed 1 step. When this temperature difference is 1 to 5 degrees, the refrigerating chamber expansion valve 6 is left as it is. When this temperature difference is 5 degrees or more, the refrigerating chamber expansion valve 6 is opened by one step. When this temperature difference is 10 degrees or more, the refrigerating chamber expansion valve 9 is opened by two steps. If the temperature in the refrigerator compartment R falls to a temperature (for example, 2 ° C.) that is 1 ° C. lower than the freezer compartment temperature set by the user, the compressor 2, the cold air circulation fan 23, and the machine compartment fan 25 are turned off and the refrigerator compartment is turned off. The expansion valve 6 is fully closed.

  Next, the defrosting operation will be described.

The control circuit 26 integrates the operation time of the compressor 2. Then, at the end of the cooling and cooling operation of the refrigerator-freezer 1, the accumulated time is compared with a predetermined time set in advance. And when this integration time exceeds predetermined time, a defrost start check is performed. This check is to check that both the refrigerating room R and the freezing room F are sufficiently cooled. When the room is sufficiently cooled, the defrosting mode is set. If the chamber is not sufficiently cooled (the temperature of one of the chambers is very close to the cooling start temperature), the cooling of this chamber is forcibly started.
And after completion | finish of this cooling, the above-mentioned defrost start check is performed again.

  In the defrost mode, the glass tube heaters 11 and 12 are energized to heat the coolers 7 and 10. Then, when the measured temperatures from the R inlet temperature sensor 19 and the R outlet temperature sensor 20 reach a predetermined temperature at the end of defrosting for refrigeration, the energization of the glass tube heater 11 is stopped. Similarly, energization of the glass tube heater 12 is stopped when the measured temperatures from the F inlet temperature sensor 21 and the F outlet temperature sensor 22 reach a predetermined temperature at which the defrosting for refrigeration is completed. Thereby, a defrost mode is complete | finished.

  The defrost water at this time is collected in the evaporating dish 28 via a drain hose (not shown), and the defrost water in the evaporating dish 28 is accelerated by the heat of the refrigerant pipe 4b of the high-temperature refrigerant. The

  Next, prevention of condensation on the opening edge of the refrigerator 1 will be described.

  As shown in FIG. 3, a dew condensation prevention pipe 4c is disposed at the opening edge of the refrigerator 1 and the high-temperature refrigerant flows through the pipe, thereby preventing the dew condensation by heating the opening edge. Further, the control circuit 26 energizes the electric heater 29 to compensate for the shortage of heating amount. Furthermore, the control circuit 26 controls the energization amount of the electric heater 29 according to the detected outside air temperature. Actually, the energization amount of the electric heater 29 is increased as the outside air temperature increases. Thereby, an opening edge is heated favorably and condensation is prevented.

  By the way, at the end of the defrosting, the defrosting water flows into the evaporating dish 28 and accumulates. Accordingly, the evaporation promoting refrigerant pipe 4b disposed in the evaporating dish 28 releases a large amount of heat in this portion from the end of defrosting to the evaporation promoting period. Therefore, the amount of heat is insufficient in the refrigerant pipe 4c for preventing condensation in the latter stage. Therefore, the control circuit 26 of the first embodiment compensates for this shortage by increasing the energization rate of the electric heater 29 (increasing the heating amount) for a predetermined time from the end of defrosting. The predetermined time may be a fixed time, or may be a time related to (proportional to) this time by measuring the time in the defrost mode (in particular, the defrost time of the freezer cooler). .

  In addition, although the refrigerator-freezer for households was demonstrated in Example 1, this invention is not limited to this. In the first embodiment, the electric heater is provided only around the freezer compartment. However, this may be provided around the entire circumference in the same manner as the dew condensation prevention pipe, or only in the partition portion of the storage compartment. You may follow.

It is a figure for demonstrating the outline of the freezing circuit of the freezer refrigerator of Example 1 of this invention. It is a schematic circuit diagram for demonstrating control of each part of the refrigerator-freezer of Example 1. FIG. It is a figure for demonstrating arrangement | positioning of the heating means for the condensation prevention of the refrigerator-freezer of Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigerating refrigerator R Refrigerating room F Freezing room 2 Compressor 4b A part of condenser (refrigerant pipe for promoting evaporation)
4c Condenser part (condensation prevention pipe, heating means)
6 Expansion valve for refrigerator compartment 7 Cooler for refrigerator compartment 9 Expansion valve for freezer compartment 10 Cooler for freezer compartment 15 Machine room 26 Control circuit 28 Evaporating dish 29 Electric heater (heating means) for preventing dew condensation.

Claims (3)

A main body composed of a heat-insulating box with one side opened, a heat insulating door provided on the one side, a machine room formed in the main body, and a part of the refrigeration circuit disposed in the machine room A compressor, a refrigerant pipe for preventing condensation, which forms part of a condenser that condenses the refrigerant discharged from the compressor and is disposed at an opening edge of the one surface of the heat insulating box, and the compressor In a cooling storage comprising a refrigerant pipe for promoting evaporation that forms part of a condenser that condenses the refrigerant discharged from and is disposed inside the evaporating dish,
Refrigerant of the refrigeration circuit is CO _2,
The dew condensation prevention refrigerant pipe is positioned downstream of the evaporation promotion refrigerant pipe, and an electric heater for dew condensation is provided in line with the dew condensation prevention refrigerant pipe. The cooling storage room characterized in that a predetermined time for promoting the evaporation of the defrosted water accumulated in the evaporating dish from the end is set to have a higher energization rate than the subsequent time . The cooling storage according to claim 1, wherein the cooling storage includes a freezing room and a freezing room, and the electric heater is disposed at an opening edge of the freezing room. The cooling storage according to claim 1, wherein the cooling storage includes a freezing room and a refrigerating room, and the electric heater is disposed over the entire circumference of the dew condensation prevention pipe.

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