US20060144073A1

US20060144073A1 - Hybrid cooling system, and refrigerator and freezer using the same

Info

Publication number: US20060144073A1
Application number: US11/319,453
Authority: US
Inventors: Myung Lee; Seong Kim
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2004-12-30
Filing date: 2005-12-29
Publication date: 2006-07-06
Also published as: CN1796900A; KR20060077396A; EP1677059A2

Abstract

A cooling system includes a cooling cycle which includes an evaporator for cooling air; and a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion, the air cooled by the evaporator being further coolable by the heat absorption portion.

Description

This Nonprovisional Application claims priority under 35 U.S.C. §119(a) on Patent Application No. 10-2004-0116240 filed in Korea on Dec. 30, 2004, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a hybrid cooling system, and, more particularly, to a hybrid cooling system wherein air heat-exchanged in an evaporator is re-cooled using a thermoelectric module having an electrical function to generate a cooling effect, so that the hybrid cooling system can provide a lower temperature, and a refrigerator and a freezer using the hybrid cooling system.
2. Description of the Related Art
Generally, a refrigerator includes a compressor, a condenser, an expansion device, and an evaporator which form a cooling cycle to perform operations for compressing, condensing, and evaporating a refrigerant.
In such a refrigerator, however, it is difficult to lower the temperature of the freezing compartment in the refrigerator to −30° C. or below. In order to cool the freezing compartment to ultra-low temperatures, two cooling cycles are conventionally formed in the refrigerator.
FIG. 1 is a schematic view illustrating a conventional cooling cycle for cooling a refrigerator to ultra-low temperatures. As shown in FIG. 1, the conventional refrigerator cooling cycle includes a first cooling cycle having a first compressor 1, a first condenser 2, a first expansion device 3, and an intermediate heat exchanger 4, and a second cooling cycle having a second compressor 5, an intermediate heat exchanger 6, a second expansion device 7, and an evaporator 8.
In the first cooling cycle, a refrigerant is compressed through the first compressor 1, is condensed through the first condenser 2, expanded to a low-temperature and low-pressure liquid state through the first expansion device 3, and then evaporated through the intermediate heat exchanger 4 to generate a cooling effect.
Meanwhile, in the second cooling cycle, a refrigerant is compressed through the second compressor 5, and then condensed through the intermediate heat exchanger 6 which functions as a second condenser. In the intermediate heat exchanger 6, the refrigerant is cooled to a temperature lower than the cooling temperature of the first condenser 2 in accordance with the cooling effect of the intermediate heat exchanger 4 in the first cycle. The condensed refrigerant is expanded through the second expansion device 7, and then evaporated through the evaporator 8 to generate a cooling effect at an ultra-low temperature of −30 to −80° C.
Thus, the first cooling cycle is driven to enable the intermediate heat exchanger 6 of the second cooling cycle to attain a desired ultra-low condensing temperature. Also, the refrigerant of the second cooling cycle must have a condensing temperature lower than that of the refrigerant of the first cooling cycle.
However, when two cooling cycles are driven to enable the evaporator 8 to attain an ultra-low cooling temperature of −30 to −80° C. under an ambient temperature of 20 to 40° C., as in the above-mentioned case, it is necessary to use additional elements than a single cooling cycle. Furthermore, the thermal efficiency of the system is degraded.
In addition, it is necessary to use two different refrigerants for the two cooling cycles. There is also a problem in that the compressors 1 and 5 of the first and second cycles must be controlled independently of each other.
For these reasons, when two cooling cycles are used, as mentioned above, the cost of a refrigerator are increased, the process for cooling are more complicated, and the interior space of the refrigerator is reduced due to the additional elements.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above-mentioned problems incurred in the related art, and it is an object of the invention to provide a hybrid cooling system for a refrigerator in which a single cooling cycle is formed by using a thermoelectric module to attain an ultra-low cooling temperature, e.g., about −30 to −80° C.
In accordance with one aspect of the present invention, a cooling system comprises: a cooling cycle, the cooling cycle including an evaporator for cooling air; and a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion, the air cooled by the evaporator being further coolable by the heat absorption portion.
In accordance with another aspect of the present invention, a cooling device comprises: a freezing compartment; a cooling system for cooling air within the first compartment; a cryogenic compartment within the freezing compartment; and a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion for cooling air within the cryogenic compartment to a temperature below an air temperature in the freezing compartment.
In accordance with another aspect of the present invention, a cooling device comprises: a first compartment; a cooling system for cooling air within the first compartment to a temperature below an air temperature outside of the first compartment; a second compartment within the first compartment, a temperature in the second compartment being lower than a temperature in the first compartment but outside the second compartment; and a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion for cooling air within the second compartment to a temperature below the temperature of the air in the first compartment.
Further scope of applicability of the present application will become more apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein:
FIG. 1 is a schematic view illustrating a conventional cooling cycle for cooling a refrigerator to ultra-low temperatures;
FIG. 2 is a schematic view illustrating a hybrid cooling system of a refrigerator according to an embodiment of the present invention;
FIG. 3 is a sectional view illustrating a hybrid cooling structure in a refrigerator according to a first embodiment of the present invention;
FIG. 4 is a schematic view illustrating a general thermoelectric module;
FIG. 5 is a sectional view illustrating a hybrid cooling structure of a refrigerator according to a second embodiment of the present invention;
FIG. 6 is a sectional view illustrating a freezer according to a third embodiment of the present invention; and
FIG. 7 is a sectional view illustrating a freezer according to a fourth embodiment of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Hereinafter, exemplary embodiments of a refrigerator according to the present invention will be described with reference to the annexed drawings.
FIG. 2 is a schematic view illustrating a hybrid cooling system of a refrigerator according to an embodiment of the present invention. FIG. 3 is a sectional view illustrating a hybrid cooling structure in a refrigerator according to a first embodiment of the present invention. FIG. 4 is a schematic view illustrating a general thermoelectric module.
As shown in FIG. 2, the refrigerator includes a refrigerant circulation type cooling system using circulation of a refrigerant to generate a cooling effect, and a thermoelectric module type cooling system using an electrical co-operation, namely, a Peltier effect.
The refrigerant circulation type cooling system includes a compressor 10 for compressing a gas refrigerant, a condenser 20 for condensing the refrigerant compressed in the compressor 10 to a liquid state, an expansion device 30 for expanding the refrigerant condensed in the condenser 20 to a fine mist state, and an evaporator 40 for heat-exchanging the expanded refrigerant with ambient air, thereby evaporating the refrigerant. On the other hand, the thermoelectric module type cooling system includes a thermoelectric module 50 for generating a thermoelectric effect to re-cool the air cooled by the evaporator 40.
As shown in FIG. 2 or 3, the refrigerator according to the present invention includes a machine compartment 100 in which the compressor 10, the condenser 20, and the expansion device 30 are installed. The refrigerator also includes a freezing chamber 110 and a refrigerating chamber 120 which are provided in a space defined separately from the machine compartment 100.
In the illustrated embodiment shown in FIG. 3, the evaporator 40 is arranged, but no limited to, between the freezing compartment 110 and the refrigerating compartment 120.
A blower 60 is installed inside the refrigerator to circulate the air heat-exchanged in the evaporator 40 through the freezing compartment 110 and refrigerating compartment 120. A flow path is defined in the refrigerator to allow the air blown by the blower 60 to circulate along the flow path, as shown by arrows in FIG. 3. Meanwhile, a cryogenic compartment 130 is within the freezing compartment 110, independently of the freezing compartment 110.
As shown in FIG. 4, the thermoelectric module 50 is an electric cooling system which does not include a mechanical configuration, contrary to the refrigerant circulation type cooling systems. In the illustrated embodiment, the thermoelectric module 50 has a structure in which at least two P-type thermoelectric semiconductor devices 53 and at least two N-type thermoelectric semiconductor elements 54 are fixed between two ceramic substrates 51 and 52 by means of solder.
When a DC current flows through the P-type and N-type thermoelectric elements 53 and 54, heat absorption and heat discharge phenomena occur at opposite ends of the thermoelectric module 50 because of a Peltier effect. That is, when electrons migrate from the P-type element 53 to the N-type element 54, heat absorption occurs on the upper side of the thermoelectric module 50, and heat discharge occurs on the lower side of the thermoelectric module 50 in FIG. 4.
The Peltier effect was discovered by Jean Peltier in 1834 When a DC voltage is applied across a junction of different materials, heat absorption occurs on one side of the junction, and heat discharge occurs on the other side of the junction. Thermoelectric modules using such a Peltier effect have been developed and made commercially available.
The thermoelectric module 50 is installed at the cryogenic compartment 130 such that the heat absorption portion of the thermoelectric module 50 is directed to the cryogenic compartment 130, and the heat discharge portion of the thermoelectric module 50 is directed to the freezing compartment 110. In one embodiment, each of the heat absorption portion and the heat discharge portion has, but not limited to, one or more surfaces for heat absorption or heat discharge.
In an embodiment, the thermoelectric module 50 may be arranged in a path, along which the air blown by the blower 60 circulates in the refrigerator, in order to directly receive the air. In addition, the thermoelectric module 50 may be mounted to the wall partitioning the cryogenic compartment 130 from the freezing compartment 110 as shown in FIG. 3 such that the heat absorption portion of the thermoelectric module 50 is exposed to the cryogenic compartment 130 and the heat discharge portion of the thermoelectric module 50 is exposed to the freezing compartment 110. Meanwhile, when the direction of the current applied to the thermoelectric module 50 is changed, the positions of the heat absorption portion and heat discharge portion are inverted.
Also, the blowers 70 and 75 may be respectively arranged on both of the heat absorption portion and the heat discharge portion of the thermoelectric module 50 in order to selectively circulate the air cooled by the thermoelectric module 50 through the cryogenic chamber 130 or the freezing compartment 110.
Hereinafter, the operation of the first embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3. First, the refrigerant compressed by the compressor 10 is condensed to a liquid state by the condenser 20. The condensed refrigerant is then changed to a mist state by the expansion device 30. Subsequently, the mist refrigerant is evaporated by the evaporator 40.
Air passing the evaporator 40 during the evaporation of the refrigerant is cooled by the evaporator 40. The cooled air is then fed to the freezing compartment 110 and the refrigerating compartment 120 by the blower 60.
The blower 60 may comprise a centrifugal blower adapted to centrally suck the air and to circumferentially discharge the sucked air, in order to supply the air cooled by the evaporator 40 to both the freezing compartment 110 and the refrigerating compartment 120.
A fraction of the air introduced into the freezing compartment 110 by the blower 60 is fed to the thermoelectric module 50 which is installed to be exposed to the cryogenic compartment 130.
The thermoelectric module 50 is selectively driven in accordance with the user's desire. When the user desires to maintain the interior of the cryogenic compartment 130 at a temperature lower than that of the freezing compartment 110, the user operates a controller (not shown) to operate the thermoelectric module 50.
When the thermoelectric module 50 operates, a heat absorption phenomenon occurs in the cryogenic compartment 130 caused by the thermoelectric module 50. At the same time, a heat discharge phenomenon occurs outside the cryogenic compartment 130 caused by the thermoelectric module 50.
In an embodiment, when the thermoelectric module 50 operates in the above described manner, the freezing compartment 110 is maintained at a temperature of about −18° C., and the cryogenic compartment 130 is maintained at a temperature of about −30 to −40° C.
Since the blowers 70 and 75 are arranged on opposite sides of the thermoelectric module 50, respectively, a convection current of air cooled or heated around the thermoelectric module 50 by the Peltier effect is generated in an associated one of the cryogenic compartment 130 and the freezing compartment 110. Accordingly, an enhanced cooling effect is generated in the cryogenic compartment 130.
Also, it is possible to more actively control the temperature of the freezing compartment 110 or the cryogenic compartment 130 by controlling the thermoelectric module 50. For example, when the temperature of the cryogenic compartment 130 is lower than a temperature desired by the user, a control operation can be performed to change the polarity of the current applied to the thermoelectric module 50, thereby increasing the temperature of the cryogenic compartment 130. In this case, the heat discharge portion of the thermoelectric module 50 is exposed to the cryogenic compartment 130 and the heat absorption portion of the thermoelectric module 50 is exposed to the freezing compartment 110. Of course, a reverse operation is also possible.
FIG. 5 is a sectional view illustrating a hybrid cooling structure of a refrigerator according to a second embodiment of the present invention. The second embodiment of the present invention is similar to the first embodiment, except that the thermoelectric module 50 is attached to the evaporator 40. That is, the evaporator 40 is installed in the freezing compartment 110, and the thermoelectric module 50 is directly attached to the surface of the evaporator 40. In this case, the air cooled by the evaporator 40 is re-cooled by the thermoelectric module 50. In an embodiment, the thermoelectric module 50 is mounted to the wall partitioning the cryogenic compartment 130 from the freezing compartment 110. The evaporator 40 is attached to a surface of the wall exposed to the freezing compartment 110.
In accordance with this arrangement, there is an advantage in that it is possible to directly control the temperature of the evaporator 40 through the thermoelectric module 50.
The remaining configuration according to the second embodiment of the present invention is similar to that of the first embodiment. Accordingly, no detailed description thereof will be given.
FIG. 6 is a sectional view illustrating a freezer according to a third embodiment of the present invention. Although the third embodiment of the present invention is similar to the first embodiment, the third embodiment provides a freezer which does not include the refrigerating compartment 120, but includes only the freezing compartment 110 and the cryogenic compartment 130.
In accordance with this arrangement, the air blown by the blower 60 circulates only through the freezing compartment 110. The blowers 70 and 75 arranged around the thermoelectric module 50 operate on opposite sides of the thermoelectric module 50, respectively, to generate the convection current of cooled air.
A door 135 is mounted to a front side of the cryogenic compartment 130, in order to prevent the cooled air in the cryogenic compartment 130 from leaking into the freezing compartment 110. Accordingly, the temperature of the cryogenic compartment 130 can be maintained at a more uniform temperature.
The remaining configuration according to the third embodiment of the present invention is similar to that of the first embodiment. Accordingly, no detailed description thereof will be given.
FIG. 7 is a sectional view illustrating a freezer according to a fourth embodiment of the present invention. The fourth embodiment of the present invention is similar to the third embodiment, except that the thermoelectric module 50 is attached to the evaporator 40.
In this case, a fraction of air cooled by the evaporator 40 is fed to and circulates through the freezing compartment 110 by the blower 60. The remaining fraction of the cooled air is re-cooled by the thermoelectric module 50, and then circulates through the cryogenic compartment 130 by the blower 70.
In the above-illustrated embodiments, the refrigerator and freezer are configured by a combination of a refrigerant circulation type cooling system and a thermoelectric module type cooling system using a Peltier effect. Accordingly, it is possible to operate only the thermoelectric module, if necessary, to locally cool only the cryogenic compartment.
In the refrigerator and freezer using the illustrated hybrid cooling structures, the air cooled by the cooling cycle, which operates independently, is re-cooled by the thermoelectric module. Accordingly, the refrigerator and freezer have a simple structure, as compared to the conventional cases using two independent cooling cycles.
In the refrigerator and freezer using the illustrated hybrid cooling structures, the thermoelectric module re-cooling the cooled air generates a cooling effect using an electrical co-operation of the P-type and N-type semiconductor elements included in the thermoelectric module with current flowing through the semiconductor elements, namely, a Peltier effect. Accordingly, the noise and vibration can be significantly reduced, as compared to the conventional cases using two independent cooling cycles.
In the refrigerator and freezer using the illustrated hybrid cooling structures, the thermoelectric module operates independently of the refrigerant circulation type cooling system. Accordingly, the thermoelectric module can be installed at a desired position of either the refrigerator or the freezer. Since the thermoelectric module is electrically controlled, it is possible to easily achieve temperature control.
Although the illustrated embodiments of the invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. A cooling system, comprising:

a cooling cycle, the cooling cycle including an evaporator for cooling air;

a compressor for compressing a gas refrigerant;

a condenser for condensing the refrigerant compressed in the compressor to a liquid state; and

an expansion device for expanding the refrigerant condensed in the condenser, the expanded refrigerant being heat-exchanged with air by the evaporator, thereby cooling the air; and

a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion, the air cooled by the evaporator being further coolable by the heat absorption portion.

2. (canceled)

3. The cooling system according to claim 1, wherein the thermoelectric module includes P-type semiconductor devices and N-type semiconductor devices, the Peltier effect being generated in accordance with an electrical co-operation of the P-type and N-type semiconductor devices with current flowing through the P-type and N-type semiconductor devices to provide the heat absorption portion and the heat discharge portion.

4. The cooling system according to claim 1, wherein the thermoelectric module is attached to the evaporator.

5. The cooling system according to claim 1, wherein the thermoelectric module is spaced from the evaporator.

6. The cooling system according to claim 1, further comprising a blower arranged at at least one of the heat absorption portion and the heat discharge portion of the thermoelectric module.

7. The cooling system according to claim 1, wherein the thermoelectric module is arranged at the evaporator, the cooling system further comprising a blower arranged at at least one of the heat absorption portion and the heat discharge portion of the thermoelectric module.

8. The cooling system according to claim 1, further comprising a freezing compartment and a cryogenic compartment within the freezing compartment, the air cooled by the evaporator being within the freezing compartment.

9. The cooling system according to claim 8, wherein the heat absorption portion is selectively exposed to one of the cryogenic compartment and the freezing compartment and the heat discharge portion is selectively exposed to the other of the cryogenic compartment and the freezing compartment.

10. The cooling system according to claim 9, wherein the heat absorption portion is exposed to the cryogenic compartment and the heat discharge portion is exposed to the freezing compartment.

11. The cooling system according to claim 10, wherein the thermoelectric module is mounted to a wall partitioning the cryogenic compartment from the freezing compartment.

12. The cooling system according to claim 8, wherein the thermoelectric module is mounted to a wall partitioning the cryogenic compartment from the freezing compartment.

13. The cooling system according to claim 12, wherein the evaporator is attached to a surface of the wall exposed to the freezing compartment.

14. The cooling system according to claim 8, further comprising a blower arranged in the freezing compartment and in the vicinity of the evaporator to circulate the air cooled by the evaporator through the freezing compartment, wherein the thermoelectric module is arranged in a circulation path of the cooled air such that the cooled air circulated by the blower is directly supplied to the thermoelectric module.

15. The cooling system according to claim 14, wherein the blower arranged in the vicinity of the evaporator is a centrifugal blower.

16. The cooling system according to claim 8, further comprising a refrigerating compartment.

17. A cooling device, comprising:

a freezing compartment;

a cooling system for cooling air within the freezing compartment;

a cryogenic compartment within the freezing compartment; and

a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion for cooling air within the cryogenic compartment to a temperature below an air temperature in the freezing compartment.

18. The cooling device according to claim 17, further comprising a blower arranged at at least one of the heat absorption portion and the heat discharge portion of the thermoelectric module.

19. The cooling device according to claim 17, wherein the heat absorption portion is selectively exposed to one of the cryogenic compartment and the freezing compartment and the heat discharge portion is selectively exposed to the other of the cryogenic compartment and the freezing compartment.

20. The cooling device according to claim 19, wherein the heat absorption portion is exposed to the cryogenic compartment and the heat discharge portion is exposed to the freezing compartment.

21. (canceled)

22. (canceled)

23. (canceled)

24. (canceled)

25. A cooling device, comprising:

a first compartment;

a cooling system for cooling air within the first compartment to a temperature below an air temperature outside of the first compartment;

a second compartment within the first compartment, a temperature in the second compartment being lower than a temperature in the first compartment but outside the second compartment; and

a thermoelectric module using a Peltier effect to provide a heat absorption portion and a heat discharge portion for cooling air within the second compartment to a temperature below the temperature of the air in the first compartment.

23-33. (canceled)