JP5267614B2 - refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of causing a fall in cooling performance due to an increase in ventilation resistance although an additional heat exchanger is provided to reduce the amount of frost formation on a cooler of a refrigerator. <P>SOLUTION: The refrigerator includes a refrigerating chamber and a freezing chamber and stores a cooler of a refrigerating cycle. Return air from the refrigerating chamber flows to the cooler from one air duct, and a sub-cooler is disposed on a windward side position of the cooler in the air duct through which return air from the refrigerating chamber passes. A refrigerant flowing to the sub-cooler is allowed to flow in parallel with the cooler through an inlet, an intermediate part, an outlet and a sub-frost formation part of the cooler. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a refrigerator, and more particularly to a refrigerator that operates in a vapor compression refrigeration cycle used in refrigeration equipment.

  In the refrigerator of the conventional refrigerator, since the surface temperature falls to near -30 degreeC, the water vapor | steam in a refrigerator forms frost on the surface of a cooler, and frosts. Due to this frost formation, there is a problem that the ventilation resistance of the cooler is increased, the cooling performance of the refrigerator is lowered, and the power consumption is increased. Therefore, the refrigerator periodically performs a defrosting operation in order to remove the frost from the cooler. However, during the defrosting operation, there is a problem that an extra input such as a defrosting heater is required and power consumption increases.

  In order to solve these problems, to reduce the draft resistance of the cooler due to frost formation, the fin-and-tube heat exchanger that constitutes the cooler, the heat transfer tube in which the refrigerant flows inside, and the outer periphery are spirally wound There has been proposed a heat exchanger unit having a configuration in which the spiral tube heat exchanger is arranged on the wind improving flow side of the fin-and-tube heat exchanger.

  For example, in this heat exchanger unit, it is possible to reduce the amount of frost formation on the cooler, but clogging occurs when the spiral tube heat exchanger forms frost, and the heat exchanger together with clogging of the spiral tube heat exchanger Since the ventilation resistance of the unit is increased, there is a problem that the cooling performance of the cooler is not increased (for example, see Patent Document 1).

  Further, in order to shorten the defrosting operation time and reduce power consumption, the pipe is connected to a refrigerant pipe of the cooler and a heat radiation defrosting heater for defrosting installed at the lower part of the cooler, and the pipe is removed from the heat radiation. There is a proposal to install in the lower part of the frost heater.

  In another configuration, since a pipe connected to the refrigerant pipe of the cooler is installed on the projection surface to the air path of the cooler, when the pipe is blocked by frost, the wind flow to the cooler is inhibited, Although the defrosting time is shortened, there is a problem that the ventilation resistance increases at the time of frost formation (see, for example, Patent Document 2).

JP 2003-314947 A (FIG. 1) JP-A-5-306877 (FIG. 2)

  In the prior art, in order to reduce the draft resistance due to frost formation on the cooler, an additional heat exchanger is installed to reduce the amount of frost formation on the cooler. There was a problem that ventilation resistance increased due to frost formation on the heat exchanger, leading to a decrease in cooling performance. In order to shorten the defrosting time, an attempt has been made to install a pipe connected to the refrigerant pipe of the cooler at the bottom of the defrost heater. However, the flow of air to the cooler is hindered by frost formation on the added pipe, and ventilation resistance is reduced. There was a problem that increased.

In order to solve the above problems, a refrigerator according to the present invention has a refrigerator compartment and a freezer compartment, and a refrigerator in which a refrigerator for a refrigeration cycle is stored. The refrigeration chamber return air circulated through the refrigeration chamber and the refrigeration chamber return air circulated through the refrigeration chamber flow from one air passage to the cooler, and are sent to the refrigerator compartment and the freezer compartment, respectively. A sub-cooler on the upstream side of the refrigerant flow of the cooler of the refrigeration cycle is installed on the windward side of the cooler through which the return air in the refrigerator compartment passes, and the sub-cooler is fin-and-tube heat exchange and vessel, der wherein with the fin pitch of the sub-cooler 2 to 3 times the leeward fin pitch of the cooler, which shape along a fin shape of the sub-cooler to a curved surface of the refrigerator air passage wall .

  The refrigerator of the present invention is a refrigerator having a refrigerator compartment and a freezer compartment, wherein the refrigerator compartment and the refrigerator compartment are cooled by a single cooler, and each return air flows to the cooler through a common air passage by one fan. , A sub-cooler located upstream of the refrigerant flow of the cooler of the refrigeration cycle is installed upstream of the cooler through which the return air of the refrigerator compartment passes, the sub-cooler is a fin-and-tube type, and the sub-cooling The fin pitch of the cooler is widened with respect to the cooler, and the sub-cooler is installed on the refrigerant flow upstream side of the cooler on the refrigerant circuit, thereby improving the cooling performance of the cooler and increasing the efficiency. Get a refrigerator.

It is the figure which showed the whole external shape of the refrigerator in Embodiment 1 of this invention, and the structure of the whole cross section. It is a refrigerant circuit diagram of the refrigerator in Embodiment 1 of this invention. It is the figure which showed the structure of the perspective direction of the refrigerator of the refrigerator in Embodiment 1 of this invention, a cooler front, and a cooler cross section. It is the figure which showed the flow of the refrigerator compartment return air which flows through the inside of the cooler in Embodiment 1 of this invention. It is a figure of the cooler periphery provided with the subcooler in Embodiment 1 of this invention. It is a refrigerant circuit diagram including the subcooler in Embodiment 1 of this invention. It is a figure showing the refrigerant | coolant state in the subcooler in Embodiment 1 of this invention. It is the figure of a cooler periphery provided with the subcooler in Embodiment 2 of this invention, and a refrigerant circuit figure. It is a figure showing the cooler in Embodiment 2 of this invention. It is a figure showing the subcooler aiming at the air path maintenance in Embodiment 2 of this invention. It is a figure of the cooler periphery which has a subcooler which shows Embodiment 2 of this invention. It is the figure of a cooler periphery provided with the subcooler in Embodiment 3 of this invention, and a refrigerant circuit figure. It is the figure of the periphery of the cooler provided with the subcooler in Embodiment 3 of this invention, and the figure showing the state of the refrigerant | coolant during defrosting. It is the figure of a cooler periphery provided with the subcooler in Embodiment 4 of this invention, and a refrigerant circuit figure.

Embodiment 1 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1A and 1B are structural views of a refrigerator according to an embodiment of the present invention. FIG. 1A is a front view of the refrigerator door as viewed from the front, and FIG. 1B is a cross-sectional view illustrating the inside of the refrigerator. The interior 11 of the refrigerator is insulated from the outside (outside air) by the door 12 and the heat insulation wall 13. The refrigerator is provided with a separate room for refrigeration or freezing, and the cooled air from the cooler 15 is sent into the respective compartments by the circulation fan 16 to cool the interiors. The freezer compartment and the refrigerator compartment in the refrigerator 11 are cooled to a target temperature using a vapor compression refrigeration cycle. Since there is some heat intrusion from the opening / closing of the door part of the refrigerator and the heat insulating wall, the cooling operation is performed by the refrigeration cycle of the refrigerator to maintain a predetermined internal temperature.

  A refrigerant circuit diagram of the refrigerator is shown in FIG. A refrigerant such as isobutane is compressed by the compressor 14 to a high temperature and a high pressure, and flows to the pipe group 21 embedded in the heat insulating wall 13 provided in the refrigerator casing. The compressed high-temperature and high-pressure refrigerant dissipates heat in the pipe group 21 to become a liquid refrigerant, and then expands by an expansion means 22 such as a capillary tube to become a gas-liquid two-phase refrigerant. In the cooler 15, the expanded low-temperature refrigerant exchanges heat with the air 23 that has flowed from the inside 11, and heat is transferred to the refrigerant to absorb the heat. And return. The air whose heat has been absorbed by the cooler 15 and whose temperature has been lowered is sent again to the interior 11 by the circulation fan 16. Thus, the refrigeration cycle apparatus of the refrigerator performs a cooling operation for circulating and cooling the air in the interior 11.

  FIG. 3 shows a schematic view around the cooler 15. 3A is a perspective view of the periphery of the cooler 15, FIG. 3B is a cross-sectional view of the cooler, and FIG. 3C is a cross-sectional view AA ′ of the cooler of FIG. As described above, the air whose temperature has risen as a result of cooling the interior flows between the fins 33 of the cooler 15 by the circulation fan 16 (not shown in FIG. 3; only the position is shown). Heat is exchanged with the fins 33, and after cooling, the refrigerant passes through the circulation fan 16 from the outlet of the cooler 15 and is circulated back to the interior again. The cooler 15 is generally a fin-and-tube type having fins 33 and heat transfer tubes 34, but a corrugated fin type or the like may also be used.

In the cooler 15 configured as described above, the air flowing into the cooler 15, that is, the refrigerating chamber return air 31 circulated in the refrigerating chamber and the freezing chamber return air 32 circulated in the refrigerating chamber are in an air inflow state (air temperature). Humidity) varies greatly. In other words, the set temperature of the refrigerator compartment is about 5 ° C, whereas the freezer compartment is about -20 ° C. Compared to the freezer compartment, the refrigerator compartment has a larger volume and a larger surface area, and the amount of heat penetration and outside air entry. This is because the amount is large. The inventors measured the temperature and humidity of the freezer return air 32 and the refrigerator return air 31 and the temperature and humidity of the air blown from the fan 16, and obtained the following results.
Incoming air condition (refrigeration room return air 31) Tin = 5 ° C., φin = 80%
(Freezer return air 32) Tin = −15 ° C., φin = 60%
Outflow air condition Tout = -30 ° C, φout = 80%
When the moisture content of the inflow air was calculated from the above results and the air volume of each return air, it was found that the refrigerating room return air 31 had more than 7 times the moisture of the freezer room return air 32. That is, the cause of frost formation on the cooler 15 is mainly caused by the return air 31 in the refrigerator compartment.

  Next, the result obtained by the visualization test and the numerical fluid analysis of the refrigerator compartment return air 31 and the freezer compartment return air 32 flowing into the cooler 15 is shown in FIG. FIG. 4 shows the periphery 41 of the cooler, and shows only the streamline of the return air 31 of the refrigerator compartment. The inventors have found that the refrigerating room return air 31 passes to the fan 16 through the back side of the cooler 15. Moreover, it turned out that the freezer compartment return air 32 and the refrigerator compartment return air 31 merge in the vicinity of the position A in FIG.

  A sub-cooler 51 is inserted below the cooler 15 with respect to the cooler periphery 41 where the above-described air flow occurs. The sub cooler 51 is installed at a position through which the return air 31 shown in FIG. 4 passes. FIG. 5 shows the periphery of the cooler including the sub cooler 51. FIG. 5A shows a side view around the cooler, and FIG. 5B shows a front view. Although the subcooler is shown as a fin-and-tube heat exchanger in FIG. 5, the following effects can be sufficiently obtained even with corrugated fins or other types of heat exchangers.

  A refrigerant circuit diagram including the sub-cooler 51 is shown in FIG. The refrigerant flow is in the direction of the arrow in FIG. The sub cooler 51 is installed downstream in the refrigerant flow direction of the cooler 15. As described above, the sub-cooler exchanges heat with the refrigerator return air 31. In the cooler in the conventional refrigerator, the refrigerant state at the cooler outlet flows out with a dryness of 1 or less (that is, a two-phase state), but in this embodiment, the refrigerator 15 returns to the refrigerant outlet side of the cooler 15 and By installing the sub cooler 51 that performs heat exchange, the refrigerant flows out with superheated gas at the sub cooler outlet. Because the refrigerating room return air 31 has a high air temperature as described above and a large temperature difference from the refrigerant evaporation temperature in the subcooler 51, the amount of heat exchange is large, and the refrigerant is easily put into a superheated gas state. This is because.

  The refrigerant state in the heat transfer tube 71 of the subcooler 51 is shown in FIG. The refrigerant that flows in at the refrigerant temperature Tetwo (gas-liquid two-phase temperature at low pressure) in the cooler 15 is heated by the refrigerating chamber return air 31 in the heat transfer tube 71, and Teg (superheated gas temperature at low pressure) higher than Tetwo. ) As a result, the surface temperature of the heat transfer tube 71 (the surface temperature of the fin attached to the heat transfer tube 71) becomes higher than the surface temperature of the cooler 15. Depending on the heat exchange amount of the sub cooler 51, the refrigerant temperature at the outlet of the sub cooler 51 rises up to the temperature of the refrigerating room return air 31 (Tin = 5 ° C.).

  The amount of frost formation on the cooling surface is generally determined by the absolute humidity of the incoming air and the absolute humidity of the cooling surface (normally saturated at the surface temperature). Therefore, an increase in the cooling surface temperature leads to a reduction in the amount of frost formation. From the above, the subcooler 51 is installed at a position where the refrigerating room return air 31 passes, so that the water in the high temperature and high humidity refrigerating room return air 31 forms frost on the subcooler 51. After passing through the vessel 51, the amount of moisture decreases, and the amount of frost on the cooler 15 can be reduced. Further, by installing the sub cooler 51 downstream of the refrigerant flow of the cooler 15, the amount of frost formation in the sub cooler 51 can be reduced, and the ventilation resistance including the cooler 15 and the sub cooler 51 can be reduced. It becomes. However, since the surface temperature of the sub-cooler 51 is lower than the dew point temperature of the refrigerating room return air 31 (because the refrigerant temperature Tetwo is included in the sub-cooler 51), the moisture in the refrigerating room return air 31 can be dehumidified by a necessary amount. , Also reduce its temperature. These effects lead to a reduction in the amount of frost on the cooler 15, improving the cooling performance, reducing the power consumption of the refrigerator, and saving energy.

Embodiment 2. FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 8A is a side view around the cooler in which the sub-cooler 51 is installed at a position where the return air 31 passes through the refrigerator as described in the first embodiment, FIG. 8B is a front view thereof, and FIG. Represents a refrigerant circuit diagram in the present embodiment. The present embodiment is different from the first embodiment in that the sub cooler 51 is installed on the upstream side of the cooler 15 on the refrigerant circuit.

  As described in the first embodiment, the high-temperature and high-humidity return air 31 flows into the sub-cooler 51 to exchange heat. As shown in FIG. 8, when the sub-cooler 51 is installed on the upstream side of the refrigerant flow, the surface temperature of the sub-cooler 51 decreases to nearly the same as that of the cooler 15. Therefore, the amount of frost formation in the sub cooler 51 is increased, so that the ventilation resistance is increased, and the cooling capacity of the cooler 15 is not increased. Therefore, in this Embodiment, the increase in ventilation resistance is suppressed by setting it as the form which improves the frosting yield strength of the subcooler 51. FIG. Details are described below.

  The fin structure of the cooler 15 is shown in FIG. As shown in FIG. 9, the refrigerator cooler 15 is composed of fins 33 and heat transfer tubes 34, and the pitch of the fins (hereinafter referred to as fin pitch) varies in the wind flow direction. Generally, the fin pitch is wider on the leeward side than on the leeward side. For example, if the leeward side has a fin pitch of 5 mm, the leeward fin pitch is 7.5 mm to 10 mm, which is 1.5 to 2 times larger. This is because the amount of moisture in the inflowing air decreases due to heat exchange with the fins as it progresses leeward, so that frost formation mainly occurs on the windward side, and therefore clogging due to frost formation on the windward side is delayed.

  In this embodiment, in order to delay clogging due to frost formation in the sub cooler 51, the fin pitch of the sub cooler 51 should be equal to or higher than the above-mentioned windward side. Specifically, if the fin pitch on the leeward side of the cooler 15 is 5 mm, the windward side is 7.5 mm to 10 mm (1.5 to 2 times the leeward), and the subcooler 51 is 10 mm or 15 mm (downwind (2 to 3 times), the frosting resistance of the subcooler 51 can be improved.

However, when the fin pitch is increased, the heat transfer area of the sub-cooler 51 is reduced. As the heat transfer area decreases, the heat exchange amount Q (Q = AKΔT A: heat transfer area, K: heat passage rate, ΔT: temperature difference) of the subcooler 51 decreases (A decreases as the fin pitch increases). K and ΔT are equivalent).
Therefore, for example, by widening the fin pitch and providing slits, the amount of heat exchange can be maintained and the frost resistance can be improved (A decreases but K increases). Further, for example, as shown in FIG. 10, the subcooler 51 is made smaller than the airflow path 102 near the subcooler, and the shape 101 is left to leave the airflow path. It becomes a structure that does not lead to an increase in.

  Further, for example, as a structure for suppressing the ventilation resistance when the sub cooler 51 is frosted, a structure 111 in which the sub cooler 51 is closely attached to the wall surface of the lower portion 112 of the cooler 15 may be installed as shown in FIG. . This is because the refrigerating room return air 31 flows along the wall surface of the lower part 112 as shown in FIG. The fin shape along the curved surface of the wall surface leads to an increase in the heat transfer area of the sub-cooler 111 and further increases the amount of heat exchange.

  As described above, the sub cooler 51 is installed on the upstream side in the refrigerant flow of the cooler 15 to improve the frosting resistance of the sub cooler, thereby reducing the ventilation resistance and improving the rejection performance of the cooler 15. Energy consumption can be reduced by reducing the power consumption of the refrigerator.

Embodiment 3 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 12A is a side view around the cooler in which the sub-cooler 51 is installed at the position where the return air 31 passes through the refrigerator as described in the first embodiment, FIG. 12B is a front view thereof, and FIG. Represents a refrigerant circuit diagram in the present embodiment. In the present embodiment, the sub cooler 51 is installed in the middle of the cooler 15 on the refrigerant circuit. That is, the refrigerant that has passed through the expansion means 22 flows into the cooler 15, flows from the middle of the cooler 15 to the subcooler 51, flows out of the subcooler 51, and then flows into the cooler 15 again.

  A defrosting heater 121 is installed in the lower part of the cooler for the purpose of removing frost from the cooler 15. In a normal refrigerator, a voltage is applied to the defrosting heater to heat the heater, and the air around the heated heater is heated to melt the frost in the cooler 15 by convection or by infrared radiation emitted by the heated heater. . Since convection and radiation are used, the defrosting efficiency (= frost melting heat amount / heater input) of a normal refrigerator is about 20%.

  On the other hand, in the present embodiment in which the sub cooler 51 is installed at the refrigerating room return air position, the position of the sub cooler 51 is installed in the vicinity of the defrosting heater 121. FIG. 13 shows the effect of the subcooler 51 when defrosting is performed with the refrigerant circuit configuration shown in FIG. FIG. 13A is a side view of the periphery of the cooler provided with the sub cooler 51, and FIG. 13B shows the behavior of the refrigerant in the heat transfer tube during defrosting. As shown in FIG. 13, since the sub cooler 51 is installed in the vicinity of the heater 121, frost is melted earlier in the sub cooler 51 than in the cooler 15. When the defrosting of the sub cooler 51 is completed, the refrigerant in the heat transfer tube is warmed in the sub cooler 51. As shown in FIG. 11, the sub cooler 51 and the cooler 15 are installed in the middle of the sub cooler 51 on the refrigerant circuit. That is, the subcooler 51 and the cooler 15 have a loop structure in the refrigerant circuit. Therefore, the refrigerant per unit mass in the sub-cooling 51 becomes a gas by receiving the amount of heat of the latent heat at that pressure from the heater after the completion of the defrosting. The unit mass refrigerant that has become a gas rises upward due to the density change. There is a cooler 15 in the upper part of the loop, and frost is present in the cooler 15 even after the frost of the sub-cooler 51 is melted, and defrosting continues. At this time, the unit mass of the gaseous refrigerant rising from the subcooler 51 is heated by the heater and is at 0 ° C. or higher or the frost temperature or higher. It becomes. The unit mass refrigerant that has dissipated heat due to the density change returns to the lower part and is heated again by the heater. As described above, the refrigerant circuit configuration according to the present embodiment can provide a heat pipe effect using the refrigerant at the time of defrosting, leading to an improvement in defrosting efficiency. In order to actually confirm this effect, the inventors compared the defrosting time with and without the subcooler 51 with respect to the cooler having the same frost amount, and installing the subcooler 51. It was confirmed that the defrosting time was reduced from 25 minutes to 23 minutes. From the above, this embodiment improves the defrosting efficiency, shortens the defrosting time, and reduces the power consumption of the refrigerator.

Embodiment 4 FIG.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 14A is a side view around the cooler in which the sub-cooler 51 is installed at the position where the refrigeration room return air 31 passes as described in the first embodiment, FIG. 14B is a front view thereof, and FIG. Represents a refrigerant circuit diagram in the present embodiment. In the present embodiment, the sub cooler 51 is installed in parallel with the cooler 15 on the refrigerant circuit. Along with this, a flow path switching unit 141 such as a three-way valve is installed at the upper part of the expansion means 22, and between the flow path switching unit 141, the cooler 15 and the sub cooler 51, The expansion means 22 is installed upstream of the refrigerant flow, and the new expansion means 142 is installed upstream of the refrigerant flow of the subcooler 51.

  These functions are described below. First, the cooler 15 and the subcooler 51 are installed at a position through which the refrigerating room return air 31 passes as described above, and the subcooler 51 has the refrigerating room return air 31 and the heat. Exchange.

Next, the flow path switching unit 141 performs an operation of flowing or switching the refrigerant to the expansion means 22 and the new expansion means 142 installed downstream in the refrigerant flow direction. The opening configuration is as follows. Here, A, B, and C represent flows in the direction in the flow path switching unit 141 shown in FIG.
First switch: A → B open / A → C open (flowing refrigerant to both cooler and sub-cooler)
Second switching: A → B open / A → C closed (coolant flows only in the cooler)
3rd switching: A → B closed / A → C open (only subcooler flows refrigerant)
Fourth switch: A → B closed / A → C closed (refrigerant does not flow to both cooler and sub-cooler)

  The operation of the flow path switching unit 141 will be described below. As described above, the sub cooler 51 exchanges heat with the return air 31 of the refrigerator compartment, but a damper is usually installed in the air passage to the refrigerator compartment, and the refrigerator compartment temperature is equal to or higher than the set temperature. Then, the damper is opened and the air blown from the cooler 15 is blown to the refrigerator compartment, and the temperature is lowered to the target temperature. That is, when the damper to the refrigerating room is closed, the refrigerating room return air 31 does not flow through the sub-cooler 51. Therefore, it is not necessary to supply the refrigerant to the sub cooler 51. From the above, when the damper of the refrigerator compartment is closed, the flow path switching unit 141 operates the second switching. On the other hand, when the refrigerator compartment damper is opened, the flow path switching unit 141 operates the first switching. The open / close state of the damper can be determined by the output from the control panel of the refrigerator.

  Next, when refrigerant recovery is necessary during defrosting or in the refrigerant circuit of the refrigerator, or when it is necessary to maintain high or low refrigerant pressure in the refrigerant circuit (for example, when the compressor 14 is stopped) Operates the fourth switching. When the load on the refrigerating room is large or the damper is also installed in the freezer room, when the freezer room temperature or the like is sufficiently below the target temperature, air is blown only to the refrigerating room, so the flow path switching unit 141 Is operated by the third switching.

  The series of flow path switching units 141 are only opened or closed. For example, if the opening degree can be adjusted, the load can be adjusted by adjusting the flow rate in each direction (for example, B or C in FIG. 14). Therefore, the above-described effect can be further enhanced.

  Next, the expansion means 142 connected to the subcooler 51 will be described. The expansion means 22 connected to the cooler 15 has an appropriate flow path inner diameter and length in order to lower the cooler 15 to the target temperature. On the other hand, the new expansion means 142 installed in this embodiment needs to cool the return air 31 in the refrigerator compartment and suppress clogging due to frost formation as much as possible. Therefore, it is necessary to make the surface temperature of the subcooler 51 higher than the surface temperature of the cooler 15 and dehumidify (or remove frost) the moisture in the return air 31 of the refrigerator compartment. In order to satisfy these, it is necessary to adjust the opening degree appropriately. Each of the refrigerator compartment and the freezer compartment is provided with a temperature sensor for detecting the internal temperature, and a temperature / humidity detection sensor for the refrigerator compartment return air is disposed in the air passage through which the refrigerator compartment return air 31 from the refrigerator compartment flows. It is conceivable to provide an electronic expansion valve such as LEV as a suitable device for the expansion means 142. By using the LEV, the required cooling temperature can be determined by measuring the temperature and humidity of the return air 31 in the refrigerator compartment, and the opening degree of the expansion means 142 can be adjusted based on the required cooling temperature. Moreover, the load of the refrigerator compartment / freezer compartment is judged from each room temperature, and the necessary opening degree is adjusted, whereby the sub-cooler 51 and the cooler 15 can have an appropriate heat exchange amount, which is a desirable mode.

  By installing the sub cooler 51 with the above configuration, ventilation resistance due to frost on the cooler 15 can be suppressed, and power consumption of the refrigerator can be suppressed.

  The subcoolers shown in the first to fourth embodiments can be applied not only to the heat exchanger of the refrigeration air conditioner but also to, for example, a car air conditioner.

  The defrost apparatus for the refrigeration and air-conditioning apparatus shown in the first to fourth embodiments can achieve the same effect even when an external heat source such as a heater is used or a hot gas system using a reverse flow of a refrigerant or a discharge gas.

  11 Chamber, 12 Door, 13 Heat insulation wall, 14 Compressor, 15 Cooler, 16 Fan, 21 Piping group, 22 Expansion means, 23 Return air in the chamber, 31 Return air in the refrigerator compartment, 32 Return air in the freezer compartment, 33 Fin, 34 Heat transfer tube, 41 Around the cooler, 51 Sub-cooler, 71 Sub-cooler heat transfer tube, 101 Sub-cooler leaving the air path, 102 Sub-cooler near air path, 111 Sub close to the lower part of the cooler Cooler, 112 cooler lower position, 121 defrost heater, 141 flow path switching unit, 142 sub-cooler expansion means.

Claims (2)

In a refrigerator having a refrigerator compartment and a freezer compartment, in which a refrigerator for a refrigeration cycle is housed, air cooled by the cooler is sent to each of the refrigerator compartment and the freezer compartment by a circulation fan, and The refrigerating room return air circulated in the refrigerating room and the freezing room return air circulated in the freezing room flow from one air passage to the cooler, and the air flows more than the cooler through which the refrigerating room return air in the air passage passes. A sub-cooler on the upstream side of the refrigerant flow of the cooler of the refrigeration cycle is installed on the upper side, the sub-cooler is a fin-and-tube heat exchanger, and the fin pitch of the sub-cooler is leeward of the cooler The refrigerator is characterized in that the fin shape of the sub-cooler is formed along the curved surface of the wall surface of the refrigerator air passage while being 2 to 3 times the side fin pitch. The refrigerator according to claim 1 , wherein the cooler sets the windward fin pitch in the cooler to 1.5 to 2 times the leeward fin pitch .

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