JP2002213832A - Cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling device useful for energy saving which is able to defrost a heat absorbing heat exchanger and prevent temperature rise. SOLUTION: A cold air return duct 20 and a first cold air carrier duct 17 on the side of a first refrigerating unit 11 are closed, to form a defrost path in which a first defrosting duct 22, a part of the duct 17, a first heat-absorbing heat exchanger 7, a second defrosting duct 24, a third defrosting duct 26 and a machine house 4 are connected in this order, communicatingly with each other. Further, a radiating duct 13 at the unit 11 side is closed by a closing damper 15, and then waste heat from a second radiating heat exchanger 10 is discharged from an outlet 13b to the machine house 4 by the rotation operation of a blowing fan 14. The discharged warm air is mixed with the outside air, followed by quick defrosting, while it flows through the defrosting path. The cold taken out of a second heat-absorbing heat exchanger 8 is discharged to first and second cooling chambers 2, 3, after flowing through a cold air transfer path.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling apparatus provided with a Stirling refrigerator using a reverse Stirling cycle.

[0002]

2. Description of the Related Art At present, refrigerators such as home refrigerators are humid due to the influence of external air entering when opening and closing a door to bring food into and out of a cooling room, and moisture evaporating from stored food in the cooling room. And tends to adhere as frost, particularly to a heat absorbing heat exchanger having a low temperature.

[0003] Once the frost adheres, the surface temperature of the heat-absorbing heat exchanger increases due to the heat insulating effect of the frost, the ventilation resistance increases, the amount of air circulating in the refrigerator decreases, and cooling takes place. Performance decreases. Therefore, it is necessary to periodically defrost the heat absorbing heat exchanger.

[0004] The most common defrosting method is to provide a defrost heater such as a nichrome wire which generates heat by energization in the vicinity of a heat absorbing heat exchanger at a location where frost is likely to adhere, and to energize the defrost heater. Directly heats the heat-absorbing heat exchanger, or melts frost attached to the heat-absorbing heat exchanger using radiant heat from the defrost heater.

[0005]

However, such a defrosting method has the following problems. First
Another problem is the power consumption of the defrost heater. In recent years, the relationship between standby power while going out and electricity bills has been actively discussed, and demand for energy-saving products has been increasing. For this reason, cooling devices such as home refrigerators have been developed with a focus on reducing the power consumption of each component, and the power consumption of the defrost heater, which has been neglected so far, has become conspicuous.

To cope with this, various measures have been taken, such as shortening the defrosting time. However, when using a defrost heater, it is necessary to provide latent heat of melting for melting frost as thermal energy. However, the corresponding power consumption is inevitable.

As a second problem, while the defrosting operation is being performed, the cooling fan and the compressor for blowing cool air into the cooling chamber are stopped. The deterioration of the quality and shortening of the storable period cause deterioration of foods that are particularly sensitive to temperature changes.

FIG. 7 shows an example of a current control method for a home refrigerator, which will be described. When the defrosting operation of the heat absorbing heat exchanger is started, the driving of the cooling fan and the compressor is immediately stopped by O.
As a FF, the cool air duct that connects the heat absorbing heat exchanger to be defrosted and the cooling chamber is closed, and the defrost heater is turned on. After the completion of the defrosting operation, the cooling fan is turned on, the heat absorbing refrigerant having a relatively high temperature and a high pressure is precooled by the heat absorbing heat exchanger, and after the pressure is reduced, the operation returns to the normal freezing operation.

As described above, since the cooling fan and the compressor are stopped during the defrosting operation, when the door is opened and closed or when a food having a relatively high temperature is stored, the temperature inside the cooling chamber rises remarkably. In the next refrigeration operation, before operating the compressor, the refrigerant in the cycle must be cooled through the heat-absorbing heat exchanger and the pressure must be reduced to a level at which the compressor can operate. When finished,
Refrigeration operation cannot be restarted immediately. Therefore, there is a problem that the cooling room whose temperature has increased during the defrosting operation cannot be quickly cooled.

The present invention has been made in view of the above-mentioned conventional problems, and can perform defrosting of an endothermic heat exchanger by utilizing waste heat released from a heat radiating portion of a Stirling refrigerator.
It is an object of the present invention to provide a cooling device that can prevent an extreme rise in temperature in a cooling chamber during a defrosting operation and is advantageous for energy saving.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a Stirling refrigerator having a heat radiating section which becomes high in temperature by the operation of a reverse Stirling cycle, and a heat absorbing section which becomes low in temperature, and attached to the heat absorbing section. Heat-exchanging heat exchanger, and a heat-radiating heat exchanger attached to the heat-radiating section,
In a cooling device equipped with a plurality of refrigeration units including, when performing a defrosting operation of the heat-absorbing heat exchanger of one or some refrigeration units arbitrarily selected from the plurality of refrigeration units or Until a short time before the end of the defrosting operation, the operation of the reverse Stirling cycle of at least one Stirling refrigerator of the other refrigeration units is maintained.

According to this, even when the defrosting operation of the cooling device having a plurality of refrigeration units is started, the reverse Stirling cycle of the Stirling refrigerator of at least one refrigeration unit is performed. Therefore, it is possible to prevent an extreme rise in temperature in the cooling chamber during the defrosting operation.

Further, the present invention further comprises a cool air conveying path for communicating the heat absorbing heat exchanger and the cooling chamber, and a closing means for preventing the communication, wherein the one or a part of the refrigeration unit is provided with the heat absorbing path. After the defrosting operation of the heat exchanger is completed, the pre-cooling of the heat absorbing heat exchanger is performed by operating a reverse Stirling cycle of the Stirling refrigerator in a state where the communication is blocked by the closing means. It is characterized by the following.

According to this, immediately after the defrosting operation, the high-temperature air that has passed through the heat absorbing heat exchanger of the defrosted refrigeration unit does not flow through the cool air transport path and is sent out into the cooling chamber. . Therefore, it is possible to prevent an extreme rise in temperature in the cooling chamber immediately after the defrosting operation.

In this case, by providing means for blowing air outside the plurality of refrigeration units to the heat-absorbing heat exchanger of the one or a part of the refrigeration units, energy can be saved without using a defrost heater. The defrosting operation can be performed.

[0016] The air that has recovered the waste heat released from at least one of the heat radiating heat exchangers of the other refrigeration units is blown to the heat absorbing heat exchangers of the one or some refrigeration units. By providing the means for performing the defrosting operation, the defrosting operation can be promptly performed without using the defrosting heater.

In this case, there is provided means for supplying air passing through the heat absorbing heat exchanger of the one or a part of the refrigeration units to at least one of the heat radiating heat exchangers of the other refrigeration unit. Thus, the defrosting operation can be performed in an energy-saving manner without using a defrost heater, and the ability of at least one heat-radiating heat exchanger of the other refrigeration unit is increased, so that cold heat can be efficiently extracted.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> A first embodiment of the present invention
An embodiment will be described with reference to the drawings. FIG. 1 is a rear cross-sectional view of the refrigerator according to the present embodiment, and FIG. 2 is a rear cross-sectional view of the refrigerator during a defrosting operation.

First, the configuration of the refrigerator according to the present embodiment will be described with reference to FIGS. Inside the refrigerator body 1, first and second cooling chambers 2, 3 surrounded by a heat insulating member 1a.
And a lower machine room 4 defined by the heat insulating member 1a. The first cooling chamber 2 and the second cooling chamber 3 are separated by a partition plate. Cooling air delivery openings 2a, 3a and cold air suction openings 2b, 3b are provided at the back of each of the cooling chambers 2, 3.
Are provided.

On the other hand, inside the machine room 4, a pair of first and second Stirling refrigerators 5 and 6 are provided side by side in a standing position. The heat absorbing sections 5a and 6a at the tips of the Stirling refrigerators 5 and 6 efficiently transfer the cold generated in the heat absorbing sections 5a and 5b by the reverse Stirling cycle operation of the first and second Stirling refrigerators 5 and 6. First and second heat absorbing heat exchangers 7 and 8 for taking out are respectively attached.

A ring-shaped heat radiating portion (not shown) fitted to the cylinder portion of each of the first and second Stirling refrigerators 5 and 6 has the first and second Stirling refrigerators 5 and 6 attached thereto.
The first and second heat-dissipating heat exchangers 9 and 10 for promoting the discharge of waste heat generated in the heat-dissipating portion by the operation of the reverse Stirling cycle of No. 6 are provided around the heat-exchanger. The Stirling refrigerators 5 and 6, the heat exchangers 7 and 8 for absorbing heat, and the heat exchangers 9 and 10 for radiating heat constitute first and second refrigeration units 11 and 12 according to the present invention.

The heat-dissipating heat exchangers 9, 10 are provided in a heat-dissipating duct 13 having suction ports 13a, 13a open at both ends. In addition, an air outlet 13b that opens downward is provided substantially at the center of the heat radiation duct 13.
14 is a blower fan provided on the upstream side of the outlet,
Further, on the upstream side, an opening / closing damper 15 capable of closing one of the air blowing paths from the suction port 13a to the air outlet 13b is arranged. Reference numeral 16 denotes a drain plate for collecting water droplets melted by defrost in the refrigerator.

Behind the first and second cooling chambers 2 and 3, there are first and second heat-absorbing heat exchangers 7 and 8, and ducts serving as passages for cold air or defrost air are symmetrical. It is provided in. Explaining the configuration of this duct, there are first cold air transfer ducts 17 and 18 which are bifurcated on the way downstream of each of the heat absorbing heat exchangers 7 and 8, and the other branch extends in the horizontal direction. Second defrost duct 2
4,25.

Reference numerals 29 and 30 denote second switching dampers provided at a branch portion between the first cool air conveying ducts 17 and 18 and the second defrosting duct.
By closing one duct at 9 and 30, an air flow path is formed on the other duct side.

The right and left first cold air conveying ducts 17 and 18 which extend obliquely upward from the branch portion merge at substantially the center, and stand vertically along the inner wall of the first and second cooling chambers 2 and 3. One second cold air transfer duct 19 is obtained. A cooling fan 31 is provided at the junction of the left and right first cold air transfer ducts 17 and 18. On the other hand, the left and right second defrost ducts 24 and 25 also join at substantially the center, and become the third defrost duct 26 communicating with the inside of the machine room 4. This third defrost duct 26
The defrosting fan 32 is disposed in the opening 26a facing the machine room 4 of FIG.

The second cool air transfer duct 19 communicates with the inside of the first and second cooling chambers 2 and 3 through the cool air delivery openings 2a and 3a. Reference numerals 20 and 21 denote openings 2b and 3 for intake of cold air.
Left and right symmetrical cool air return ducts communicating with the insides of the first and second cooling chambers 2 and 3 via b. The left and right cool air return ducts 20 and 21 are bifurcated on the upstream side of the first and second heat absorbing heat exchangers 7 and 8, and the other of the branched first defrosters communicates with the inside of the machine room 4. Ducts 22 and 23.

Also, 27 and 28 are ducts for returning cold air.
A first switching damper provided at a branch between the first and second defrost ducts 22, 23 and the first switching dampers 27, 28, the first switching dampers 27, 28 close one duct to the other duct side. An air circulation path is formed.

Next, an air flow during a normal freezing operation of the refrigerator having the above-described configuration will be described with reference to FIG. At this time, each of the pair of first and second Stirling refrigerators 5 and 6 is operated in a normal refrigeration operation, and the opening / closing damper 15 is maintained in an open state. The external air taken into the machine room 4 by the blower fan 14 which is driven to rotate in this state is supplied to the left and right suction ports 13 of the heat radiation duct 13.
a, 13a are sucked into the duct 13 and
Waste heat is recovered when passing through the surfaces of the heat exchangers 9 and 10 for heat radiation.

As a result, the air whose temperature has risen merges at substantially the center of the heat radiation duct 13 and is sent out from the outlet 13b into the machine room 4 through an opening (not shown) provided in the heat insulating member 1a. Will be released. Therefore, the heat radiation from the heat radiating portions (not shown) of the first and second Stirling refrigerators 5 and 6 accompanying the refrigeration operation is promoted, and the efficiency of the Stirling refrigerators 5 and 6 is improved.

On the other hand, the first and second cooling chambers 2 and 3 side
The first defrost duct 22,
23 is closed and the second switching dampers 29, 3
0, the second defrost ducts 24 and 25 are closed, so that the first cool air transfer ducts 17 and 18, the second cool air transfer duct 19, the first and second cooling chambers 2 and 3, and the cool air return. Ducts 20, 21 and first and second heat absorbing heat exchangers 7, 8
, A symmetrical cool air circulation path is formed.

The cold generated in the heat absorbing portions 5a and 6a of the first and second Stirling refrigerators 5 and 6 is extracted from the first and second heat absorbing heat exchangers 7 and 8 and is rotated by the rotation of the cooling fan 31. The inside of the second cool air transfer duct 19 is conveyed as cool air via the first cool air transfer ducts 17 and 18, and the first and second cooling chambers 2 and 3 are transmitted from the cool air delivery openings 2 a and 2 b.
Sent out.

This cool air is circulated in the first and second cooling chambers 2 and 3 to cool the stored food, and then is sucked in from the cool air suction openings 2b and 3b in a state where the temperature is increased, and is returned to the cool air. After flowing through the ducts 20 and 21, it returns to the upstream side of the first and second heat absorbing heat exchangers 7 and 8 again.

Further, since the heat is promoted from the first and second heat-exchanging heat exchangers 9 and 10 to efficiently extract cold from the first and second heat-absorbing heat exchangers 7 and 8,
The first and second heat-absorbing heat exchangers 7,
The inside of the first and second cooling chambers 2 and 3 is quickly cooled to the set temperature by the cool air circulating between the first cooling chamber 8 and the first and second cooling chambers 2 and 3.

Next, an example of the air flow and control during the defrosting operation of the refrigerator having the above configuration will be described with reference to FIGS. Here, as an example, a case where it is necessary to defrost the first refrigeration unit 11 first from the state where both the first and second refrigeration units 11 and 12 are performing the freezing operation will be described.

At this time, the operation of the reverse Stirling cycle of the first refrigeration unit 11 for first performing defrosting is stopped,
The second refrigeration unit 12 and the cooling fan 29 are continuously maintained in a normal refrigeration operation. And the heat radiation duct 13
Of the first refrigeration unit 11 is closed by the opening / closing damper 15, and the first switching damper 27 and the second switching damper 29 of the first refrigeration unit 11 form one of the cold air return duct 20 and the first cold air transport duct 17. Each will be closed.

Thus, the first defrost duct 22, a part of the cool air return duct 20, the first heat absorbing heat exchanger 7, the second
Defrost duct 24, third defrost duct 26, and machine room 4
, A defrosting path formed by communication is formed in the following order.

On the other hand, on the second refrigeration unit 12 side, the first defrost duct 23 and the second defrost duct 25 are closed by the first switching damper 28 and the second switching damper 30, respectively. As a result, the first cold air transfer duct 18,
The second cool air duct 19, the first and second cooling chambers 2, 3,
A refrigerant circulation path is formed in which the cool air return duct 21 and the second heat absorbing heat exchanger 8 are connected in this order.

At the same time, the defrost fan 32 is driven and the first
The defrosting operation of the refrigeration unit 11 is started. The air taken into the machine room 4 from outside by the rotation of the blower fan 14 passes through the second heat-radiating heat exchanger 10 through the suction port 13 a of the heat-radiating duct 13 on the side of the second refrigeration unit 12. The waste heat from the heat radiating heat exchanger 10 is recovered and discharged from the outlet 13b in a state where the temperature is raised.

This air is mixed with the external air sucked into the machine room 4 and then flows into the first defrost duct 22 by the defrost fan 32 and adheres to the first heat absorbing heat exchanger 7. After melting the frost, the frost passes through the second defrosting duct 24 and the third defrosting duct 26 in the order of low temperature, and is sent out again into the machine room 4 from the opening 26a.

The water melted by the defrost flows down along a drain hose (not shown) drawn from below the first heat-absorbing heat exchanger 7, and is drained from a drain plate 16 disposed at the bottom in the machine room 4. Will be collected. And this water is drain dish 16
Is heated and evaporated by the high-temperature air blown from the outlet 13b of the heat-radiating duct 13 right above, and is discharged to the outside together with the air. Therefore, the defrost water can be removed maintenance-free.

On the other hand, during the defrosting operation of the first refrigeration unit 11, the second refrigeration unit 12 is maintained in the normal refrigeration operation. The air flows through the cool air circulation path and is sent into the first and second cooling chambers 2 and 3. Therefore, since an extreme rise in temperature in each of the cooling chambers 2 and 3 is suppressed, an adverse effect on the stored food can be prevented.

Eventually, the defrost fan 32 stops and the defrosting of the first heat absorbing heat exchanger 7 ends, and at the same time, the refrigeration operation of the first refrigeration unit 11 is restarted. However, if the closing of the first cool air transfer duct 17 and the cool air return duct 21 by the first switching damper 27 and the second switching damper 29 is released immediately after the defrosting, the heated first heat absorbing heat exchanger 7 is released. The air having a relatively high temperature flows through the cool air circulation path and flows into each of the cooling chambers 2 and 3, thereby increasing the temperature in the cooling chambers 2 and 3.

Therefore, without switching the first switching damper 27 and the second switching damper 29, the first refrigeration unit 1 is not cooled until the first heat absorbing heat exchanger 7 is sufficiently cooled.
The preliminary refrigeration operation of 1 is performed. Thereby, the first defrosted
The heat remaining in the endothermic heat exchanger 7 does not leak into the cooling chambers 2 and 3.

When the first heat absorbing heat exchanger 7 is sufficiently cooled, the first switching damper 27 and the second switching damper 29 are switched, and the first defrost duct 22 and the second defrost duct 24 are switched. The first refrigeration unit 11 is closed to form a cool air circulation path, the second refrigeration unit 12 side of the heat radiation duct 13 is closed by the open / close damper 15, and the operation of the first refrigeration unit 11 in the reverse Stirling cycle is continued to return to the normal refrigeration operation.

At the same time, the first cold air transfer duct 18 and the cold air return duct 21 are closed by the first switching damper 28 and the second switching damper 30 on the second refrigeration unit 12 side, thereby forming a defrosting path and removing the air. The rotation drive of the frost fan 32 is restarted, and the defrosting operation of the second refrigeration unit 12 is started. During the defrosting, the flow of the air flowing through the defrosting route is the same as described above, and thus will not be described in detail here.

Eventually, the defrosting fan 32 stops and the defrosting of the second heat absorbing heat exchanger 8 ends, and at the same time, the refrigeration operation of the second refrigeration unit 12 is restarted. However, if the closing of the first cool air conveying duct 18 and the cool air returning duct 21 by the first switching damper 28 and the second switching damper 30 is released immediately after the defrost, the heated second heat absorbing heat exchanger is used. Air having a relatively high temperature from 8 flows through the cooling air circulation path and flows into each of the cooling chambers 2 and 3, thereby increasing the temperature in the cooling chambers 2 and 3.

Therefore, without switching the first switching damper 28 and the second switching damper 30, the second refrigeration unit 1 is not cooled until the second heat absorbing heat exchanger 8 is sufficiently cooled.
The preliminary refrigeration operation 2 is performed. As a result, the defrosted second
The heat remaining in the endothermic heat exchanger 8 does not leak into the cooling chambers 2 and 3.

Then, after the second heat absorbing heat exchanger 8 is sufficiently cooled, the first switching damper 28 and the second switching damper 30 are switched, and the first defrost duct 23 and the second defrost duct 25 to form a cool air circulation path,
The operation of the reverse Stirling cycle of the second refrigeration unit 12 is continued to return to the normal refrigeration operation.

In this embodiment, a refrigerator using two refrigeration units has been described. However, by applying a similar configuration to a refrigerator using two or more refrigeration units, the cooling chamber during defrosting can be further improved. Refrigerator advantageous in suppressing the temperature rise of the above is obtained. Further, in the present embodiment, a refrigerator has been described as an example, but the present invention is also applicable to other cooling devices such as a showcase. Further, the defrosting operation of the Stirling refrigerator of another refrigeration unit which has been kept in the refrigeration operation may be started from a short time before the end of the defrosting operation.

<Second Embodiment> A second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a rear cross-sectional view of the refrigerator according to the present embodiment, and FIG. 5 is a rear cross-sectional view during the defrosting operation. This embodiment is a modification of the first embodiment. In FIGS. 4 and 5, the same members as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIGS. 4 and 5, a characteristic configuration of the refrigerator according to the present embodiment is that a third defrosting duct 34 extending downward and a heat radiating duct 33 are connected to each other to form a sliding type. An opening 35 that can be opened and closed by the shutter 36 is formed around a part of the third defrost duct 34.

Then, the defrost fan 3 also serving as a blower fan
7 is provided in the third defrost duct 34. Also, 38
Is a first opening / closing damper capable of closing one of the defrosting paths from the suction ports 33a, 33a at both ends of the heat radiation duct 33 to the first defrosting ducts 22, 23, and 39 is a third defrosting duct 3.
4 is a second opening / closing damper disposed above the outlet 35.

Next, the air flow during the normal freezing operation of the refrigerator having the above configuration will be described with reference to FIG. At this time, the pair of first and second Stirling refrigerators 5 and 6 are both operated in a normal refrigeration operation, and the shutter 36 and the first opening / closing damper 38 are in the open state, and the second opening / closing damper 39 is in the closed state. Will be maintained. External air taken into the machine room 4 by the defrosting fan 37 rotated in this state is sucked into the duct 33 from the left and right suction ports 33a of the heat dissipation duct 33, and the first and second heat dissipation are performed. When passing through the surfaces of the heat exchangers 9 and 10, waste heat is recovered.

As a result, the air whose temperature has risen joins at substantially the center of the heat radiation duct 33, flows into the third defrost duct 34, is discharged from the air outlet 35, and then is opened in the heat insulating member 1a. Part (not shown) to the outside. Accordingly, the first and second Stirling refrigerators 5 associated with the refrigeration operation,
Since the heat radiation from the heat radiation part (not shown) of No. 6 is promoted,
The efficiency of the Stirling refrigerators 5, 6 is improved.

On the other hand, the first and second cooling chambers 2 and 3 side
The first defrost duct 22,
23 is closed and the second switching dampers 29, 3
0, the second defrost ducts 24 and 25 are closed, so that the first cool air transfer ducts 17 and 18, the second cool air transfer duct 19, the first and second cooling chambers 2 and 3, and the cool air return. Ducts 20, 21 and first and second heat absorbing heat exchangers 7, 8
, A symmetrical cool air circulation path is formed.

The cold generated in the heat absorbing portions 5a and 6a of the first and second Stirling refrigerators 5 and 6 is taken out of the first and second heat absorbing heat exchangers 7 and 8 and is rotated by the rotation of the cooling fan 31. The inside of the second cool air transfer duct 19 is conveyed as cool air via the first cool air transfer ducts 17 and 18, and the first and second cooling chambers 2 and 3 are transmitted from the cool air delivery openings 2 a and 2 b.
Sent out.

This cool air is circulated in the first and second cooling chambers 2 and 3 to cool the stored food, and then is sucked in from the cool air suction openings 2b and 3b in a state where the temperature is increased, and is returned to the cool air. After flowing through the ducts 20 and 21, it returns to the upstream side of the first and second heat absorbing heat exchangers 7 and 8 again.

Further, since the heat is promoted from the first and second heat-exchanging heat exchangers 9 and 10, the cold heat is efficiently extracted from the first and second heat-absorbing heat exchangers 7 and 8.
The first and second heat-absorbing heat exchangers 7,
The inside of the first and second cooling chambers 2 and 3 is quickly cooled to the set temperature by the cool air circulating between the first cooling chamber 8 and the first and second cooling chambers 2 and 3.

Next, an example of air flow and control during the defrosting operation of the refrigerator having the above configuration will be described with reference to FIGS. Here, as an example, a case will be described in which it is necessary to defrost the first refrigeration unit first from the state where both the first and second refrigeration units 11 and 12 are performing the freezing operation.

At this time, first, the operation of the first refrigeration unit 11 for defrosting is stopped, and the second refrigeration unit 12 and the cooling fan 31 are continuously maintained in the normal refrigeration operation. Then, the first refrigeration unit side of the heat dissipation duct 33 is closed by the first opening / closing damper 38, and the closed second opening / closing damper 39 is opened to open the heat dissipation duct 33.
And the second defrost duct 24 are connected to each other via a third defrost duct 34. Further, the first switching damper 27 on the side of the first refrigeration unit 11 causes one of the cold air return ducts 2 to return.
0 is closed.

Thus, the machine room 4, the third defrost duct 34, the second defrost duct 24, the first heat absorbing heat exchanger 7,
Part of the cool air return duct 20 and the first defrost duct 22
, A defrosting path formed by communication is formed in the following order.

On the other hand, on the second refrigeration unit 12 side, the first defrost duct 23 and the second defrost duct 25 are closed by the first switching damper 28 and the second switching damper 30, respectively. As a result, the first cold air transfer duct 18,
The second cool air duct 19, the first and second cooling chambers 2, 3,
A refrigerant circulation path is formed in which the cool air return duct 21 and the second heat absorbing heat exchanger 8 are connected in this order.

At the same time, the defrost fan 37 is driven, and the first
The defrosting operation of the refrigeration unit 11 is started. The air taken into the machine room 4 from the outside by the rotation of the defrost fan 37 passes through the second heat-radiating heat exchanger 10 through the suction port 13a of the heat-radiating duct 33 on the second refrigeration unit 12 side. The waste heat from the heat radiating heat exchanger 10 is recovered and flows into the third defrost duct 34 in a state where the temperature is raised.

Further, this air flows into the second defrosting duct 22 on the first refrigeration unit 11 side by the defrosting fan 37 and melts the frost adhering to the first heat absorbing heat exchanger 7.
In a state where the temperature is low, the air passes through a part of the cool air return duct 20 and the first defrost duct 22 in this order, and is sent out again into the machine room 4 from the opening 22a.

The water melted by the defrost flows down along a drain hose (not shown) drawn out from below the first heat absorbing heat exchanger 7, and flows into a drain plate 16 disposed at the bottom in the machine room 4. Will be collected. The defrost water can be removed by periodically taking out the drain plate and discarding the accumulated defrost water.

On the other hand, during the defrosting operation of the first refrigeration unit 11, the second refrigeration unit 12 is kept in the normal refrigeration operation. After flowing through the circulation path, it is sent into the first and second cooling chambers 2 and 3. Therefore, since an extreme rise in temperature in each of the cooling chambers 2 and 3 is suppressed, an adverse effect on the stored food can be prevented.

Eventually, the defrosting fan 32 stops and the defrosting of the first heat absorbing heat exchanger 8 ends, and at the same time, the refrigeration operation of the first refrigeration unit 11 is restarted. However, if the closing of the first cool air conveying duct 17 and the cool air returning duct 21 by the first switching damper 27 and the second switching damper 29 is released immediately after the defrosting, the heated first heat absorbing heat exchanger 7 is removed. The air having a relatively high temperature flows through the cool air circulation path and flows into each of the cooling chambers 2 and 3, thereby increasing the temperature in the cooling chambers 2 and 3.

Therefore, without switching the first switching damper 27 and the second switching damper 29, the first refrigeration unit 1 is not cooled until the first heat absorbing heat exchanger 7 is sufficiently cooled.
The preliminary refrigeration operation of 1 is performed. Thereby, the first defrosted
The heat remaining in the endothermic heat exchanger 7 does not leak into the cooling chambers 2 and 3.

After the first heat absorbing heat exchanger 7 is sufficiently cooled, the first switching damper 38 and the second switching damper 39 on the first refrigeration unit 11 side are switched.
The first defrost duct 22 and the second defrost duct 24 are closed to form a cool air circulation path, and the heat radiation duct 33
Is closed by the first opening / closing damper 38, and the operation of the first refrigeration unit 11 in the reverse Stirling cycle is continued to return to the normal refrigeration operation.

At the same time, the first cold air transfer duct 18 and the cold air return duct 21 are closed by the first switching damper 28 and the second switching damper 30 on the second refrigeration unit 12 side to form a defrosting path and The rotation drive of the frost fan 37 is restarted, and the defrosting operation of the second refrigeration unit 12 is started. During the defrosting, the flow of the air flowing through the defrosting route is the same as described above, and thus will not be described in detail here.

Eventually, the defrosting fan 37 stops and the defrosting of the second heat absorbing heat exchanger 8 ends, and at the same time, the refrigeration operation of the second refrigeration unit 12 is restarted. However, if the closing of the first cool air conveying duct 18 and the cool air returning duct 21 by the first switching damper 28 and the second switching damper 30 is released immediately after the defrosting, the heated second heat absorbing heat exchanger. Air having a relatively high temperature from 8 flows through the cooling air circulation path and flows into each of the cooling chambers 2 and 3, thereby increasing the temperature in the cooling chambers 2 and 3.

Therefore, without switching the first switching damper 28 and the second switching damper 30, the second refrigeration unit 1 is not cooled until the second heat absorbing heat exchanger 8 is sufficiently cooled.
The preliminary refrigeration operation 2 is performed. As a result, the defrosted second
The heat remaining in the endothermic heat exchanger 8 does not leak into the cooling chambers 2 and 3.

Then, after the second heat absorbing heat exchanger 8 is sufficiently cooled, the first switching damper 28 and the second switching damper 30 are switched, and the first defrost duct 23 and the second defrost duct 25 to form a cool air circulation path,
The operation of the reverse Stirling cycle of the second refrigeration unit 12 is continued to return to the normal refrigeration operation.

By the way, the outside air temperature is relatively high,
When the first heat absorbing heat exchanger 7 can be quickly defrosted by the outside air, the rotation of the defrost fan 37 is reversed to reverse the direction in which the air flows, as indicated by the dotted arrow in FIG. Is also possible.

As an example, the case of defrosting the first refrigeration unit 11 will be described. As shown in FIG.
The air sucked from the outside flows into the first defrosting duct 22 and passes through the first heat absorbing heat exchanger 7 while being defrosted.

The low-temperature air cooled by this flows into the heat-dissipating duct 33 via the second defrosting duct 24 and the third defrosting duct 34, and the second heat-dissipating heat exchanger When passing through the surface of the heat exchanger 10, the waste heat from the heat radiating heat exchanger 10 is recovered and sent out into the machine room 4 from the suction port 33a.

Accordingly, the cold heat obtained from the defrosting of the first heat absorbing heat exchanger 7 can be used to promote the heat radiation from the second heat radiating heat exchanger 10, and the heat radiating ability of the second heat radiating heat exchanger 10 can be improved. The second refrigeration unit 11 held in refrigeration operation to increase
From the second heat absorbing heat exchanger 8. Therefore, the amount of cooling air required for preventing adverse effects on the stored food in the cooling chambers 2 and 3 can be suppressed, and the output of the cooling fan 31 can be reduced accordingly, thereby saving energy.

As described above, whether the cold air obtained by defrosting the heat absorbing heat exchanger of one of the refrigeration units with external air is used to promote heat radiation from the heat radiating heat exchanger of the other refrigeration unit, Or, by appropriately controlling whether the waste heat recovered from the heat-exchange heat exchanger of one refrigeration unit is used for defrosting the heat-absorption heat exchanger of another refrigeration unit as described above, the external environment An efficient defrosting operation according to the condition can be secured.

In this embodiment, a refrigerator using two refrigeration units has been described. However, by applying a similar configuration to a refrigerator using two or more refrigeration units, the cooling chamber during defrosting can be further improved. Refrigerator advantageous in suppressing the temperature rise of the above is obtained. Further, in the present embodiment, a refrigerator has been described as an example, but the present invention is also applicable to other cooling devices such as a showcase. Further, the defrosting operation of the Stirling refrigerator of another refrigeration unit which has been kept in the refrigeration operation may be started from a short time before the end of the defrosting operation.

[0080]

As described above, according to the present invention, most of the cooling apparatus equipped with a plurality of refrigeration units during the defrosting operation is performed in the reverse Stirling cycle of the Stirling refrigerator of at least one refrigeration unit. Since the operation is being performed, an extreme rise in temperature in the cooling chamber during the defrosting operation is suppressed. Therefore, it is possible to prevent adverse effects such as quality deterioration of the stored food and shortening of the storage period.

Further, by providing means for blowing air outside the refrigeration unit to the heat absorbing heat exchanger for defrosting, the defrosting operation can be performed with energy saving. In particular, by collecting and sending the waste heat released from the Stirling refrigerating machine, which is operated in the reverse Stirling cycle even during the defrosting operation, through the heat radiating heat exchanger, further energy saving and defrosting speed are achieved. Is improved.

Further, a means for sending air passing through the heat-absorbing heat exchanger for defrosting to the heat-radiating heat exchanger of the refrigeration unit provided with the operated Stirling refrigerator is provided. Since the capacity of the exchanger is enhanced and the heat radiation is further promoted, the cold heat can be efficiently extracted from the heat absorbing heat exchanger during the defrosting operation.

[Brief description of the drawings]

FIG. 1 is a rear cross-sectional view of a refrigerator according to a first embodiment of the present invention during normal operation.

FIG. 2 is a rear sectional view of the refrigerator during a defrosting operation.

FIG. 3 is an explanatory diagram of an example of control of the defrosting operation of the refrigerator.

FIG. 4 is a rear cross-sectional view of the refrigerator according to the second embodiment of the present invention during normal operation.

FIG. 5 is a rear sectional view of the refrigerator during a defrosting operation.

FIG. 6 is an explanatory diagram of an example of control of the defrosting operation of the refrigerator.

FIG. 7 is an explanatory diagram illustrating an example of control during a conventional defrosting operation of a refrigerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Refrigerator main body 2 1st cooling room 3 2nd cooling room 4 Machine room 5 1st Stirling refrigerating machine 6 2nd Stirling refrigerating machine 7 1st heat absorption heat exchanger 8 2nd heat absorption heat exchanger 9 1st heat dissipation Exchanger 10 Second heat-dissipating heat exchanger 11 First refrigeration unit 12 Second refrigeration unit 13, 33 Heat-dissipating duct 14 Blower fan 15 Opening / closing damper 16 Drain plate 17, 18 First cold-air transport duct 19 Second cold-air transport Ducts 20, 21 Cold air return ducts 22, 23 First defrosting duct 24, 25 Second defrosting duct 26, 34 Third defrosting duct 27, 28 First switching damper 29, 30 Second switching damper 31 Cooling fans 32, 37 Defrosting fan 36 Shutter 38 First open / close damper 39 Second open / close damper

Claims (5)

[Claims] 1. A Stirling refrigerating machine having a heat-dissipating unit which becomes high in temperature by the operation of the reverse Stirling cycle, and a heat-absorbing unit which becomes low in temperature, a heat-exchanging heat exchanger attached to the heat-absorbing unit, And a cooling unit having a plurality of refrigeration units provided with the heat-dissipating heat exchanger, wherein the heat-exchanging heat exchanger of one or some refrigeration units arbitrarily selected from the plurality of refrigeration units is removed. During the frost operation or until a short time before the end of the defrosting operation, the operation of the reverse Stirling cycle of at least one Stirling refrigerator of the other refrigeration units is maintained. Characterized cooling device. 2. The cooling device according to claim 1, further comprising: a cooling air conveyance path communicating the heat absorbing heat exchanger with the cooling chamber; and closing means for preventing the communication, wherein the heat absorbing heat of one or a part of the refrigeration units is provided. After the defrosting operation of the exchanger is completed, by performing the reverse Stirling cycle operation of the Stirling refrigerator in a state where the communication is blocked by the closing means, the pre-cooling of the heat absorbing heat exchanger is performed. The cooling device according to claim 1, wherein: 3. The apparatus according to claim 1, further comprising means for blowing air outside the plurality of refrigeration units to the heat-absorbing heat exchangers of the one or a part of the refrigeration units. 3. The cooling device according to 2. 4. An air recovered from waste heat released from at least one of the heat radiating heat exchangers of the other refrigeration unit is blown to the heat absorbing heat exchanger of one or a part of the refrigeration units. 2. A method according to claim 1, further comprising the step of:
The cooling device according to claim 3. 5. A means for supplying air passing through the heat absorbing heat exchanger of one or a part of the refrigeration units to at least one heat radiating heat exchanger of the other refrigeration unit. The cooling device according to claim 4, wherein: