THERMOELECTRIC COOLING SYSTEMS

- Sheetak, Inc.

The present disclosure provides a thermoelectric cooling system with improved performance. The thermoelectric cooling system comprises a thermoelectric cooling unit. The thermoelectric cooling unit comprises a thermoelectric device, heat pipes, condenser fins, a cold sink and a cold fan. The thermoelectric cooling unit can be easily assembled with a chamber which contains a fluid to be cooled. The thermoelectric cooling system comprises screws to attach the thermoelectric cooling unit to the chamber, and sealant rings to prevent heat leakage in the thermoelectric cooling system. Further, the present disclosure provides a thermoelectric cooling system with a freezer part and a refrigerator part. The freezer part encloses the cold sink and the cold fan. The freezer part is cooled by the thermoelectric device, and the refrigerator part is cooled by walls of the freezer part. Further, the present disclosure provides a thermoelectric cooling system for use as a wine cooler.

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Description
BACKGROUND

1. Technical Field of the Invention Disclosure

The present disclosure relates to the field of thermoelectric cooling systems for cooling a fluid. More specifically, the present disclosure relates to compact thermoelectric cooling systems such as thermoelectric refrigerators with optimized positioning of elements.

2. Description of Related Art

The most widely used cooling system is a vapor compression cooling system. The vapor compression system uses chlorofluorocarbon (CFC) refrigerants such as Freon, hydrochloroflourocarbon. (HCFC) refrigerants such as R134, or hydroflourocarbons (HFC) refrigerants such as R410 for cooling. The use of CFC refrigerants in the vapor compression system causes emission of green house gases (GHG), which is an environmental threat. Further, such refrigerants may result in depletion of the ozone layer. Depletion of the ozone layer is an environmental hazard because the ozone layer filters ultraviolet radiation from sunlight. Thus, use of refrigerants that deplete the ozone layer needs to be avoided. Further, the vapor compression system which uses such refrigerants is heavy, creates noise, and produces vibrations when in use.

It is known in the art that the vapor compression systems can be effectively replaced with thermoelectric cooling systems provided the Coefficient of Performance (COP) of the thermoelectric cooling systems is improved. Thermoelectric cooling systems have been developed in the past but they have low Coefficient of Performance (COP). The conventional thermoelectric cooling systems suffer from inefficiencies, for instance in design and placement of various components.

Thus, there exists a need for further contributions for development in the domain of thermoelectric cooling systems.

SUMMARY OF THE INVENTION

The present disclosure provides thermoelectric cooling systems with optimized positioning and design of elements for achieving a high coefficient of performance and ease of operation.

A thermoelectric cooling system comprises one or more thermoelectric devices, heat pipes, a cold sink, a cold sink fan, condenser fins and a fan attached to the condenser fins. Further, a chamber comprises a fluid that needs to be cooled. In an embodiment of the present disclosure, the fluid is air. The fluid is thermally coupled to a cold side of the one or more thermoelectric devices. The one or more thermoelectric devices extract heat from the fluid and transfer it to a hot side of the one or more thermoelectric devices. The heat pipes then transfer the heat to the ambient through the condenser fins and the fan.

In an embodiment of the present disclosure, heat pipes with a cross sectional area and a geometry to optimize heat transfer are provided. Accordingly, the heat pipes are flattened at a first and a second side. In an embodiment of the present disclosure, the heat pipes are attached to a metal block at the first side of the heat pipes. The metal block is made of a thermally conducting material such as copper or aluminum. In another embodiment of the present disclosure, only one side which is exposed to the hot side of the one or more thermoelectric devices of the heat pipes is flattened. This results in a larger cross sectional area, thus improving the dissipation of heat. Further, when the cross sectional area of the heat pipes increases it results in a larger area for heat transfer, thus lowering thermal resistance inside the heat pipes.

In yet another embodiment of the present disclosure, a suitable design of a compact refrigerator with the one or more thermoelectric devices is provided. The heat pipes are attached to each of the one or more thermoelectric devices such that the heat pipes are evenly distributed entirely over a hot side of the one or more thermoelectric devices.

In an embodiment of the present disclosure, the compact refrigerator comprises a freezer part and a refrigerator part. The one or more thermoelectric devices cool the fluid inside the freezer part. Cooled walls of the freezer part cool the fluid inside the refrigerator part through natural convection.

In accordance with another embodiment of the present disclosure, arrangements and a design for assembling the thermoelectric cooling systems are provided. In an embodiment, a collar is used to attach the thermoelectric cooling system to the chamber. The collar comprises a cut section. The collar is made of materials such as plastic. In accordance with another embodiment of the present disclosure, one or more screws and one or more sealant rings are used to attach the thermoelectric cooling system to the chamber to avoid leakage. In another embodiment of the present disclosure, the thermoelectric cooling system is attached to the chamber using an epoxy solution. An insulation material is used to enclose the one or more thermoelectric devices to prevent heat leakage from the hot side of the one or more thermoelectric devices to the cold side.

In another embodiment, slots are provided in the chamber to insert the one or more screws to attach the one or more thermoelectric devices to the chamber. Further, a support is provided to attach the thermoelectric device and the fan to the chamber.

In accordance with another embodiment of the present disclosure, the fan is clamped and ducted to the condenser fins. In another embodiment of the present disclosure, the fan is attached to an extended collar and is positioned between the condenser fins and the exterior walls of the thermoelectric cooling apparatus using one or more stubs. In an embodiment of the present disclosure, the extended collar is made of materials such as plastic.

In an embodiment of the present disclosure, the thermoelectric cooling system is a compact refrigerator with a volume ranging from about 80 liters to about 150 liters. In another embodiment of the present disclosure, the thermoelectric cooling system is a portable refrigerator with a body comprising an inner partition, an outer partition and a thermal insulation. The thermal insulation is present between the outer lining and a wall of the body. In an embodiment of the present disclosure, the inner lining and the outer lining are made of a plastic material. The portable refrigerator is powered by a Direct Current (DC) supply. In another embodiment of the present disclosure, the thermoelectric cooling system is powered by an Alternating Current (AC) supply. In this embodiment, a converter from AC to DC supply is used to power the thermoelectric cooling system. In yet another embodiment of the present disclosure, the thermoelectric cooling system is a wine cooler. The wine cooler operates in a temperature range such as 7° C. to 8° C. for white wines and 10° C. to 16° C. for red wines.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, provided to illustrate and not to limit the present invention, wherein like designations denote like elements, and in which:

FIG. 1 is a schematic cross-sectional diagram of a conventional assembly of heat pipes;

FIG. 2 is a schematic cross-sectional diagram of an assembly of heat pipes, in accordance with an embodiment of the present disclosure;

FIG. 3 is a schematic cross-sectional diagram of an assembly of heat pipes, in accordance with another embodiment of the present disclosure;

FIG. 4 is a schematic cross-sectional diagram of a cross-section of a heat pipe, in accordance with an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of a thermoelectric cooling unit, in accordance with an embodiment of the present disclosure;

FIG. 6 is a cross-sectional view of a thermoelectric cooling system, in accordance with an embodiment of the present disclosure;

FIG. 7 is a cross-sectional view of a thermoelectric cooling system, in accordance with another embodiment of the present disclosure;

FIG. 8 is a cross-sectional view of a thermoelectric cooling system, in accordance with yet another embodiment of the present disclosure;

FIG. 9 is a cross-sectional view of a conventional thermoelectric cooling system;

FIG. 10 is a cross-sectional view of a thermoelectric cooling system, in accordance with an embodiment of the present disclosure;

FIG. 11 is a cross-sectional view of a thermoelectric cooling system, in accordance with another embodiment of the present disclosure;

FIG. 12 is a perspective view of a thermoelectric cooling system, in accordance with an embodiment of the present disclosure;

FIG. 13 is a cross-sectional view of a thermoelectric cooling system, in accordance with another embodiment of the present disclosure;

FIG. 14 is a cross-sectional view of a thermoelectric cooling system, in accordance with yet another embodiment of the present disclosure;

FIG. 15 is a schematic cross-sectional diagram of condenser fins, in accordance with an embodiment of the present disclosure;

FIG. 16 is a schematic cross-sectional diagram of condenser fins, in accordance with an embodiment of the present disclosure; and

FIG. 17 is a schematic diagram of condenser fins, in accordance with an embodiment of the present disclosure.

 DETAILED DESCRIPTION OF THE INVENTION

Before describing the embodiments in detail, in accordance with the present invention, it should be observed that these embodiments reside primarily in the method and apparatus for cooling of fluids. Accordingly, the steps involved in the method and the system components have been represented to show only those specific details that are pertinent for understanding the embodiments of the present invention, and not the details that will be apparent to those with ordinary skill in the art.

FIG. 1 illustrates a conventional assembly of heat pipes. FIGS. 2 to 4 illustrate heat pipes, in accordance with various embodiments of the present disclosure.

FIG. 1 is a schematic cross-sectional diagram of a conventional assembly of heat pipes 100.

The assembly of heat pipes 100 comprises heat pipes 102 having a circular cross sectional area embedded in a metal block 104. Metal block 104 comprises circular cavities in which heat pipes 102 are embedded. Preferably, heat pipes 102 are embedded in metal block 104 using an interference fit. Metal block 104 is configured to hold heat pipes 102. When the assembly of heat pipes 100 is used in a thermoelectric cooling system (described in conjunction with FIG. 6), metal block 104 is attached to a thermoelectric device. Heat extracted by the thermoelectric device flows from a hot side of the thermoelectric device (not shown in the figure) to the assembly of heat pipes 100 as denoted by arrows 106.

FIG. 2 is a schematic cross sectional diagram of an assembly of heat pipes 200, in accordance with an embodiment of the present disclosure.

Heat pipes 202 have flat surfaces to increase contact surface area with a metal block 204. Increased contact surface area between heat pipes 202 and metal block 204 increases heat transfer and reduces thermal resistance. In an embodiment of the present disclosure, heat pipes 102, having a diameter equal to 8 mm, are flattened to produce heat pipes 202. A width of resulting heat pipes 202 is in the range of 9.5 mm to 10 mm. Heat pipes 202 comprise four sides after flattening, out of which two sides are flat and the other two sides are curved. Metal block 204 is attached to a flat side of heat pipes 202, which is in thermal contact with a hot side of the thermoelectric device (not shown in figure). Heat is transferred from the hot side of the thermoelectric devices to the assembly of heat pipes 200 as depicted by arrows 206. In an embodiment of the present disclosure, heat pipes 202 are soldered to metal block 204. In another embodiment of the present disclosure, heat pipes 202 are attached to metal block 204 using an epoxy solution.

FIG. 3 is a schematic cross sectional diagram of an assembly of heat pipes 300, in accordance with another embodiment of the present disclosure. The assembly of heat pipes 300 comprises heat pipes 202 and a metal block 304.

One of the two flat sides of heat pipes 202 is attached to the hot side of the thermoelectric device. Since heat pipes 202 are in direct contact with the thermoelectric device, this results in improved heat transfer to heat pipes 202. Heat is transferred from the hot side of the thermoelectric devices to the assembly of heat pipes 300 as depicted by arrows 306. Metal block 304 is configured to facilitate attachment of heat pipes 300 to the hot side of the thermoelectric device, for example by including a recess in the block for receiving the pipes as shown. In an embodiment of the present disclosure, metal block 304 is made of conducting metal materials such as aluminum and stainless steel.

FIG. 4 is a schematic cross sectional diagram of a heat pipe 400, in accordance with an embodiment of the present disclosure.

According to this embodiment of the present disclosure, heat pipe 400 has a flat side 402. Other sides of heat pipe 400 have a curved shape. Flat side 402 is in contact with the hot side of the thermoelectric device (not shown in figure).

The cross sectional area of heat pipe 400 is greater than that of heat pipes 202 because only one side of heat pipe 400 is flattened, while the other sides have a curved shape. Thus, heat pipe 400 has a higher heat carrying capacity. The increased cross sectional area results in a reduced pressure drop across heat pipe 400, thereby avoiding a temperature drop. This happens because in heat pipe 400, the temperature drop is proportional to the pressure drop as a working fluid is in a saturated state inside the heat pipe. The working fluid follows a P-T curve (known in thermodynamics) and when the pressure drops, the temperature also drops. In an embodiment of the present disclosure, heat pipe 400 is made of a conducting material such as Copper.

As heat carrying capacity of heat pipe 400 is high, it results in improved conduction of heat from the hot side of the thermoelectric device. Hence, the efficiency of the thermoelectric device increases.

FIG. 5 illustrates a thermoelectric cooling unit, in accordance with an embodiment of the present disclosure, and FIGS. 6 to 8 illustrate thermoelectric cooling systems using the thermoelectric cooling unit according to various embodiments. Thermoelectric cooling unit 500 comprises the elements desired for thermoelectric cooling. Thermoelectric cooling unit 500 is assembled with a chamber where cooling needs to be done to form a thermoelectric cooling system.

FIG. 5 illustrates a schematic diagram of a thermoelectric cooling unit 500, in accordance with an embodiment of the present disclosure.

Thermoelectric cooling unit 500 comprises a thermoelectric device 502, a metal standoff 504, a cold sink 506, heat pipes 508 and condenser fins 510.

Thermoelectric device 502 comprises a cold side and a hot side. The cold side of thermoelectric device 502 is connected to cold sink 506 through metal standoff 504. Cold sink 506 is in thermal contact with a fluid (not shown in figure). The hot side of thermoelectric device 502 is attached to an evaporator plate 512. The evaporator plate 512 in turn is attached to a heat dissipation assembly. In an embodiment of the present disclosure, evaporator plate 512 is made of Copper. Evaporator plate 512 collects heat from thermoelectric device 502 and transfers it to heat pipes 508. In an embodiment of the present disclosure, evaporator plate 512 is soldered to heat pipes 508. In another embodiment of the present disclosure, evaporator plate 512 is epoxied to heat pipes 508. The heat dissipation assembly comprises heat pipes 508 and condenser fins 510. Heat pipes 508 comprise a first end and a second end. Heat pipes 508 transfer heat from evaporator plate 512 to condenser fins 510. The first end of heat pipes 508 is thermally connected to the hot side of thermoelectric device 502 through evaporator plate 512. The surface area of evaporator plate 512 in contact with heat pipes 508 is maximized to reduce thermal resistance. The contact area is increased by using heat pipes (described in conjunction with FIGS. 2 to 4), which have a flat surface in contact with evaporator plate 512. Thermal resistance is inversely proportional to contact surface area, thus the increased contact surface area between evaporator plate 512 and heat pipes 508 reduces thermal resistance.

The second end of heat pipes 508 is connected to condenser fins 510. In an embodiment of the present disclosure, condenser fins 510 are made of Aluminum. Further, condenser fins 510 are coated with Nickel to help soldering condenser fins 510 with heat pipes 508. In an embodiment of the present disclosure, condenser fins 510 are attached to heat pipes 508 through interference fit. In another embodiment of the present disclosure condenser fins are attached to heat pipes 508 using an epoxy solution. In yet another embodiment of the present disclosure, condenser fins 510 comprise enhanced design structures such as ridges and dimples to increase turbulence and break the thermal and fluid boundary layers. In an embodiment of the present disclosure, dimensions of condenser fins 510 include height and width to be within a range of 80 to 150 mm and depth (fin length along a direction of flow of air, not shown in figure) to be between 20 to 60 mm.

Further, thermoelectric device 502 and metal standoff 504 are enclosed with an insulation 514 to prevent heat leakage from the hot side to the cold side of thermoelectric device 502. In an embodiment of the present disclosure, insulation 514 is made of foam or aerogel.

Thermoelectric device 502, metal standoff 504 and insulation 514 are preferably wrapped with a foil tape (not shown in figure). For example, a UL 181 foil tape is wound around insulation 514. The foil tape assists in creating an air tight assembly between insulation 514 and the walls of a chamber in which the fluid is present (explained in conjunction with FIG. 6, FIG. 7, and FIG. 8).

A collar 516 is attached to evaporator plate 512. Collar 516 assists in attaching thermoelectric cooling unit 500 to the chamber. Collar 516 comprises a cut section (not shown in the figure) and holes 518. The cut section allows evaporator plate 512 to be attached to collar 516. Screws are inserted through holes 518 to attach thermoelectric cooling unit 500 to the chamber.

Thermoelectric cooling unit 500 is configured to extract heat from the fluid and transfer it to the ambient. When thermoelectric device 502 is switched ON, heat gets transferred from the fluid to a hot side of thermoelectric device 502 through cold sink 506 and metal standoff 504. Evaporator plate 512 collects the heat from the hot side of thermoelectric device 502 and transfers this heat to the heat dissipation assembly. The heat dissipation assembly dissipates heat from evaporator plate 512 to the ambient. In particular, a working fluid present in heat pipes 508 transfers heat from evaporator plate 512 to condenser fins 510, where the heat is dissipated to the ambient.

Heat pipes 508 prevent backflow of heat from condenser fins 510 to evaporator plate 512. Metal standoff 504 also reduces thermal loss by separating cold sink 506 from the hot side of thermoelectric device 502. Metal standoff 504 is made of high conductivity materials. In an embodiment of the present disclosure, metal standoff 504 is made of materials such as Copper and Aluminum. In another embodiment of the present disclosure, metal standoff 504 is bevel shaped to reduce thermal leakage.

FIG. 6 illustrates a thermoelectric cooling system 600, in accordance with an embodiment of the present disclosure.

Thermoelectric cooling system 600 comprises thermoelectric cooling unit 500 and a chamber 602. Chamber 602 comprises a fluid 604 that needs to be cooled. Cold sink 506 of thermoelectric cooling unit 500 is in thermal contact with fluid 604 through a cold sink fan 606. Cold sink fan 606 maintains a uniform temperature inside chamber 602 and assists in heat transfer from fluid 604 to thermoelectric device 502. Thermoelectric cooling unit 500 is inserted into chamber 602 through an opening 608 present in chamber 602. An arrow 610 denotes insertion of thermoelectric cooling unit 500 into chamber 602. Screws 612 along with sealant rings 614 are configured to facilitate attachment of thermoelectric cooling unit 500 to chamber 602. Slots 616 are provided in walls of chamber 602 for insertion of screws 612. Sealant rings 614 are configured to avoid leakage of heat from the ambient to fluid 604. In an embodiment of the present disclosure, sealant rings 614 are O-rings or polyethylene rings or weather strips made of weather stripping materials.

Thermoelectric cooling unit 500 allows easy assembly of thermoelectric cooling system 600. If required, the assembly can be done at the place where thermoelectric cooling system 600 needs to be installed.

FIG. 7 is a cross-sectional view of a thermoelectric cooling system 700, in accordance with another embodiment of the present disclosure.

Thermoelectric cooling system 700 comprises elements, which are the same or similar to those of FIGS. 5 and 6 except for the addition of a fan 702 and a clamp 704.

Thermoelectric cooling unit 500 is attached to chamber 602 using screws 612. At the cold side of thermoelectric device 502 (not shown in the figure), cold sink 506 is in thermal contact with fluid 604. Cold sink fan 606 is attached to cold sink 506. At the hot side of thermoelectric device 502, heat pipes 508 are connected to condenser fins 510. Clamp 704 attaches fan 702 to condenser fins 510 and channelizes the air flow from condenser fins 510 to the ambient.

When thermoelectric cooling system 700 is switched ON, thermoelectric device 502 absorbs heat from fluid 604. Heat from fluid 604 is transferred to thermoelectric device 502 through cold sink fan 606 and cold sink 506. From the hot side of thermoelectric device 502, heat is dissipated to the ambient through the heat dissipation assembly. The heat dissipation assembly comprises heat pipes 508, condenser fins 510 and fan 702. Fan 702 is configured to dissipate heat from condenser fins 510 to the ambient.

FIG. 8 illustrates a cross-sectional view of a thermoelectric cooling system 800, in accordance with yet another embodiment of the present disclosure.

Thermoelectric cooling system 800 comprises elements which are the same or similar to those described in conjunction with FIGS. 5 and 6 except for the addition of a fan 802, an extended collar 804 and stubs 806.

Thermoelectric cooling unit 500 is attached to chamber 602 using screws 612. At the cold side of thermoelectric device 502 (not shown in the figure), cold sink 506 is in thermal contact with fluid 604. Cold sink fan 606 is attached to cold sink 506. At the hot side of thermoelectric device 502, heat pipes 508 are attached to condenser fins 510. Fan 802 is attached to extended collar 804 using stubs 806. Fan 802 is positioned between a wall of chamber 602 and condenser fins 510.

When thermoelectric cooling system 800 is switched ON, thermoelectric device 502 absorbs heat from fluid 604. Heat from fluid 604 is transferred to thermoelectric device 502 through cold sink fan 606 and cold sink 506. From the hot side of thermoelectric device 502, heat is dissipated to the ambient through the heat pipes 508, condenser fins 510, and fan 802. Fan 802 is configured to dissipate heat from condenser fins 510 to the ambient.

An advantage of the embodiments mentioned in FIG. 5, FIG. 6, FIG. 7, and FIG. 8 is flexibility of positioning thermoelectric cooling unit 500 at walls of the chamber. Thermoelectric cooling unit 500 can be positioned at a suitable position in the chamber. In applications such as a cold store, the position of the chamber can not be adjusted using a conventional thermoelectric cooling system. In such applications, thermoelectric cooling unit 500 is particularly advantageous because of its maneuverability i.e., it can be mounted in various positions on the walls of the chamber.

Another advantage of these embodiments is manufacturing flexibility as thermoelectric cooling unit 500 and chamber 602 can be independently fabricated. Further, thermoelectric cooling unit 500 can be easily assembled to chamber 602 to generate the thermoelectric cooling systems 600, 700, and 800. Thermoelectric cooling systems 600, 700, and 800 can be used in compact refrigerators and portable refrigerators.

FIG. 9 illustrates a conventional thermoelectric cooling system. Further, FIGS. 10 to 11 illustrate thermoelectric cooling systems, as per the present disclosure that can be used as compact refrigerators.

FIG. 9 illustrates a cross-sectional view of a conventional thermoelectric cooling system 900.

Conventional thermoelectric cooling system 900 comprises chamber 602, thermoelectric device 502, heat pipes 508, condenser fins 510, fan 802 and cold sink 506.

Chamber 602 comprises a fluid 604 to be cooled. Thermoelectric device 502 is attached at a top portion of chamber 602. The cold side of thermoelectric device 502 is attached to cold sink 506. The hot side of thermoelectric device 502 is thermally attached to a first end of heat pipes 508. A second end of heat pipes 508 is attached to condenser fins 510. Fan 802 is attached to condenser fins 510.

When thermoelectric device 502 is switched ON, cold sink 506 transfers heat from fluid 604 present in chamber 602 to a hot side of thermoelectric device 502. Heat from the hot side of thermoelectric device 502 is dissipated to the ambient by the heat dissipation assembly. A working fluid present in heat pipes 508 transfers heat from the hot side of thermoelectric device 502 to condenser fins 510. The heat from condenser fins 510 is dissipated to the ambient using fan 802.

When fluid 604 is cooled, it gets denser and heavier. Thus, fluid 604 flows downward. Arrows 904 denote the direction of flow of fluid 604 during cooling. The portion of fluid 604 in contact with the walls of chamber 602 absorbs heat leaked in through chamber 602 and becomes less dense. Hence the portion of fluid 604 rises to the top of chamber 602. An arrow 902 denotes the direction of flow of fluid after absorbing heat from walls of chamber 602.

This type of direct cooling of fluid 604 by thermoelectric device 502 through a convective heat transfer is conventional. Distribution of cold air present near cold sink 506 is not uniform throughout chamber 602. Further, heat leakage from the ambient or the influence of temperature from the ambient will be high in this type of direct cooling.

FIG. 10 illustrates a cross-sectional view of a thermoelectric cooling system 1000, in accordance with an embodiment of the present disclosure.

Thermoelectric cooling system 1000 comprises a refrigerator part 1002, a freezer part 1004, a freezer wall 1006, thermoelectric device 502, heat pipes 508, condenser fins 510, fan 802, cold sink 506 and cold sink fan 606.

Fluid 604 present in freezer part 1004 is cooled directly by thermoelectric device 502 through cold sink 506 and cold sink fan 606. Cold sink fan 606 is configured to provide uniform cooling inside freezer wall 1006. Fluid 604 present in refrigerator part 1002 gets cooled when it comes in contact with freezer wall 1006. Freezer wall 1006 provides a large contact surface area to cool fluid 604 uniformly in refrigerator part 1002. Increased contact surface area allows an increase in the amount of fluid 604 in contact with freezer wall 1006, thus resulting in an efficient heat transfer. Thus, cooling of fluid 604 present in refrigerator part 1002 happens through thermoelectric device 502 indirectly. Therefore, the temperature of fluid 604 present in freezer part 1004 is lower as compared to the temperature of fluid 604 present in refrigerator part 1002. The presence of cold sink fan 606 increases the heat transfer coefficient of freezer wall 1006.

An advantage of thermoelectric cooling system 1000 over conventional thermoelectric cooling system 900 is that in thermoelectric cooling system 1000 heat leakage from the ambient into refrigerator part 1002 is less than that into chamber 602 of conventional thermoelectric cooling system 900. This is because refrigerator part 1002 of thermoelectric cooling system 1000 is cooled through freezer wall 1006 while chamber 602 of conventional thermoelectric cooling system 900 is cooled directly by thermoelectric device 502. Hence, the temperature differential between the ambient and refrigerator part 1002 is lower than that between the ambient and chamber 602. Thus, heat leakage through refrigerator part 1002 is low as compared to heat leakage through chamber 602.

The heat dissipation assembly of thermoelectric cooling system 1000 that comprises heat pipes 508, condenser fins 510 and fan 802 prevents heat leakage from the hot side of thermoelectric device 502 to freezer part 1004.

FIG. 11 illustrates a cross-sectional view of a thermoelectric cooling system 1100, in accordance with another embodiment of the present disclosure.

Thermoelectric cooling system 1100 comprises refrigerator part 1002, a freezer part 1102, thermoelectric device 502, heat pipes 508, condenser fins 510 and cold sink 506.

Refrigerator part 1002 and freezer part 1102 contain fluid 604. The cold side of thermoelectric device 502 is attached to cold sink 506. Thermoelectric device 502 cools fluid 604 present in freezer part 1102. Cold sink fan 606 helps in maintaining a constant temperature in freezer part 1102. In an embodiment of the present disclosure, cold sink fan 606 is a blower fan. The hot side of thermoelectric device 502 is attached to heat pipes 508.

In an embodiment of the present disclosure, freezer part 1102 is in a horizontal orientation and is made of a sheet metal. In an embodiment of the present disclosure, freezer part 1102 is a hollow sheet metal block. In an embodiment of the present disclosure, freezer part 1102 has a wall thickness in a range between 2 mm and 8 mm. Since freezer part 1102 encloses a relatively small amount of fluid 604 and has cold sink fan 606, intensive cooling takes place inside freezer part 1102. Freezer part 1102 provides a large contact surface area for efficient cooling of fluid 604. Cooling of fluid 604 inside refrigerator part 1002 takes place at cold walls of freezer part 1102 in a similar manner as described in conjunction with FIG. 10.

Fluid 604 in refrigerator part 1002 comes in contact with the cold walls of freezer part 1102 and gets cooled. Cold fluid 604 moves downward as depicted by arrows 1104. Fluid 604 present at the bottom and lateral walls of refrigerator part 1002 is heated by absorbing heat from the ambient. Further, hot fluid present in refrigerator part 1002 rises as depicted by arrows 1106.

FIGS. 12 to 14 illustrate thermoelectric cooling systems for use such as in wine coolers, in accordance with various embodiments of the present disclosure.

FIG. 12 illustrates a perspective view of a thermoelectric cooling system 1200, in accordance with an embodiment of the present disclosure. In this embodiment, thermoelectric cooling system 1200 is a wine cooler, e.g. an under-counter wine cooler, which is designed to be placed under a counter or desk. In another embodiment of the present disclosure, thermoelectric cooling system 1200 is an under-counter refrigerator.

Thermoelectric cooling system 1200 comprises a chamber 1202, a thermoelectric device (not shown in figure), a metal standoff 1206, a cold sink 1208, a cold sink fan 1210, an evaporator plate 1212, heat pipes 1214, condenser fins 1216 and a fan 1218.

A fluid 1204 is present in chamber 1202. Cold sink fan 1210 and cold sink 1208 are in thermal contact with fluid 1204. The thermoelectric device is present at a rear side of chamber 1202. A cold side of the thermoelectric device is attached to metal standoff 1206. Metal standoff 1206 is attached to cold sink 1208. A hot side of the thermoelectric device is attached to evaporator plate 1212. A first end of heat pipes 1214 is connected to evaporator plate 1212. Further, a second end of heat pipes 1214 is connected to condenser fins 1216. Condenser fins 1216 are present at a bottom side of chamber 1202. Fan 1218 is present adjacent to condenser fins 1216 to improve heat transfer from condenser fins 1216 to the ambient. Arrows 1222 denote the direction of air flow from the ambient to the heat transfer assembly as facilitated by fan 1218. Further, arrows 1224 denote the direction of air flow from the heat transfer assembly to the ambient.

When thermoelectric cooling system 1200 is switched ON, the thermoelectric device cools fluid 1204 and absorbs heat from cold sink 1208 through metal standoff 1206. The thermoelectric device transfers heat from fluid 1204 to evaporator plate 1212. Cold sink fan 1210 facilitates the circulation of fluid 1204 inside chamber 1202 and hence maintains a uniform temperature of fluid 1204. Arrows 1220 denote the direction of flow of fluid 1204 inside chamber 1202 as facilitated by cold sink fan 1210. Thermoelectric cooling system 1200 provides efficient cooling as cold sink fan 1210 is positioned at a middle portion of chamber 1202.

At the hot side of thermoelectric device, heat from evaporator plate 1212 is dissipated to the ambient through a heat transfer assembly. The heat transfer assembly comprises heat pipes 1214, condenser fins 1216 and fan 1218. A fan that can provide a high pressure head in air is desirable to conduct heat from condenser fins 1216. In order to achieve this, a blower fan is used as fan 1218 in an embodiment of the present disclosure. The blower fan has higher efficiency against high pressure head in the air as compared to that of an axial fan. The reason for this is that the blower fan has a characteristic of relatively higher pressure head and relatively lower flow rate. The axial fan, on the other hand, provides a lower pressure head and a higher flow rate. Therefore, a natural choice for a high pressure drop situation in the present embodiment is to use the blower fan.

FIG. 13 illustrates a cross-sectional view of a thermoelectric cooling system 1300, in accordance with another embodiment of the present disclosure.

In an embodiment of the present disclosure, thermoelectric cooling system 1300 is a wine cooler, such as an under-counter wine cooler. In another embodiment of the present disclosure, thermoelectric cooling system 1300 is an under-counter refrigerator.

Thermoelectric cooling system 1300 comprises elements which are the same or similar to those described in conjunction with FIG. 12. Thermoelectric cooling system 1300 further comprises an external partition 1304, an insulation 1305, an internal partition 1306 and a door handle 1310.

When thermoelectric cooling system 1300 is switched ON, a thermoelectric device 1302 present at the rear side of chamber 1202 transfers heat from fluid 1204 to the ambient through cold sink 1208. Cold sink 1208 is in thermal contact with fluid 1204. Cold sink fan 1210 circulates fluid 1204 within chamber 1202 in a direction depicted by arrows 1220. Internal partition 1306 forms a path for circulation of fluid 1204 inside chamber 1202. Arrows 1308 denote the direction of flow of fluid 1204 when fluid 1204 is about to enter the internal partition before passing through cold sink 1208.

Thermoelectric device 1302 transfers heat from cold sink 1208 to a hot side of thermoelectric device 1302 through metal standoff 1206. Evaporator plate 1212 collects heat from the hot side of thermoelectric device 1302. Insulation 1305 encloses metal standoff 1206 and thermoelectric device 1302. Insulation 1305 is configured to prevent a thermal leakage to fluid 1204. The heat transfer assembly, which comprises heat pipes 1214, condenser fins 1216 and fan 1218, transfers heat from evaporator plate 1212 to the ambient. External partition 1304 separates the heat transfer assembly from chamber 1202. Arrows 1222 denote the direction of flow of air in the heat transfer assembly as facilitated by fan 1218. In an embodiment of the present disclosure, condenser fins 1216 are present vertically above evaporator plate 1212 such that the air flow is aided by gravity.

FIG. 14 illustrates a cross-sectional view of a thermoelectric cooling system 1400, in accordance with yet another embodiment of the present disclosure.

In this embodiment of the present disclosure, thermoelectric cooling system 1400 is a wine cooler such as an under-counter wine cooler. In another embodiment of the present disclosure, thermoelectric cooling system 1400 is an under-counter refrigerator.

In addition to the elements described in conjunction with FIG. 12 and FIG. 13, thermoelectric cooling system 1400 comprises an electric motor 1402. In thermoelectric cooling system 1400, cold sink fan 1210 and fan 1218 have electric motor 1402 in common. Electric motor 1402 drives cold sink fan 1210 to circulate fluid 1204 within chamber 1202 and fan 1218 to circulate the air from the ambient to the heat transfer assembly.

FIG. 15 is a schematic cross-sectional diagram of condenser fins 1500, in accordance with an embodiment of the present disclosure.

Condenser fins 1500 are attached to heat pipes 508. Heat pipes 508 transfer heat to condenser fins 1500, which dissipate the heat to the ambient. Condenser fins 1500 comprise ridges and dimples (explained in conjunction with FIG. 16) at parts 1502. The ridges and dimples enhance heat transfer from condenser fins 1500 to the ambient by breaking boundary layers of heat transfer and thus promoting heat transfer coefficient.

FIG. 16 is a schematic cross-sectional diagram of condenser fins 1500 across a cross section marked by line A-A in FIG. 15, in accordance with an embodiment of the present disclosure. Condenser fins 1500 comprise ridges 1602 and dimples 1604.

FIG. 17 is a schematic diagram of condenser fins 1700, in accordance with an embodiment of the present disclosure. Condenser fins 1700 have ridges and dimples at parts 1702. Condenser fins 1700 are attached to heat pipes 508. Heat pipes 508 transfer heat to condenser fins 1700, which dissipate the heat to the ambient.

While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. An assembly of heat pipes for use in a thermoelectric cooling system, the assembly of heat pipes comprising:

one or more heat pipes to transfer heat, wherein at least one side of the one or more heat pipes is flat; and
a metal block attached to the one or more heat pipes, wherein the metal block is configured to conduct heat and to provide support to the one or more heat pipes.

2. The assembly of heat pipes in accordance with claim 1, wherein the one or more heat pipes comprise two flat sides.

3. The assembly of heat pipes in accordance with claim 1, wherein the metal block is made of at least one of Aluminum and Copper.

4. The assembly of heat pipes in accordance with claim 1, wherein the metal block is configured to conduct heat from the one or more heat pipes.

5. The assembly of heat pipes in accordance with claim 1, wherein the metal block is configured to conduct heat to the one or more heat pipes.

6. A thermoelectric cooling unit for use in a thermoelectric cooling system to cool a fluid present in a chamber, the thermoelectric cooling unit comprising:

a thermoelectric device comprising a hot side and a cold side, the thermoelectric device being configured to cool the fluid;
a cold sink thermally connected to the cold side of the thermoelectric device, the cold sink being configured to collect heat from the fluid;
a metal standoff present between the thermoelectric device and the cold sink;
an insulation enclosing the thermoelectric device and the metal standoff;
an evaporator plate attached to the hot side of the thermoelectric device, the evaporator plate being configured to collect heat from the thermoelectric device;
one or more heat pipes comprising a first end and a second end, the first end being attached to the evaporator plate, wherein the one or more heat pipes are configured to conduct heat from the evaporator plate to ambient;
condenser fins attached to the second end of the one or more heat pipes, the condenser fins being configured to provide heat transfer from the one or more heat pipes to the ambient; and
a collar configured to attach the thermoelectric cooling unit to the chamber.

7. The thermoelectric cooling unit in accordance with claim 6, wherein the one or more heat pipes are embedded in the evaporator plate.

8. The thermoelectric cooling unit in accordance with claim 6, wherein the collar comprises one or more holes, wherein the one or more holes are used to attach the thermoelectric cooling unit to the chamber by using one or more screws.

9. The thermoelectric cooling unit in accordance with claim 6, wherein the metal standoff is made of at least one of Copper and Aluminum.

10. The thermoelectric cooling unit in accordance with claim 6, wherein the evaporator plate is made of Copper.

11. The thermoelectric cooling unit in accordance with claim 6, wherein the first end of the one or more heat pipes is soldered to the evaporator plate.

12. The thermoelectric cooling unit in accordance with claim 6, wherein the first end of the one or more heat pipes is epoxied to the evaporator plate.

13. The thermoelectric cooling unit in accordance with claim 6, wherein the second end of the one or more heat pipes is attached to the condenser fins with interference fit.

14. The thermoelectric cooling unit in accordance with claim 6, wherein the condenser fins are made of Aluminum.

15. The thermoelectric cooling unit in accordance with claim 6, wherein the condenser fins comprise ridges and dimples.

16. A thermoelectric cooling system to cool a fluid, the thermoelectric cooling system comprising:

a chamber comprising the fluid, wherein the chamber comprises a wall including an opening therein;
a thermoelectric cooling unit inserted in the opening of the chamber, the thermoelectric cooling unit being configured to cool the fluid, wherein the thermoelectric cooling unit comprises a collar configured to attach the thermoelectric cooling unit to the chamber; and
one or more sealant rings present between the collar of the thermoelectric cooling unit and the wall of the chamber.

17. The thermoelectric cooling system of claim 16, wherein the thermoelectric cooling unit comprises:

a thermoelectric device comprising a hot side and a cold side, the thermoelectric device being configured to cool the fluid;
a cold sink thermally connected to the cold side of the thermoelectric device, the cold sink being configured to collect heat from the fluid;
a metal standoff present between the thermoelectric device and the cold sink;
an insulation enclosing the thermoelectric device and the metal standoff;
an evaporator plate attached to the hot side of the thermoelectric device, the evaporator plate being configured to collect heat from the thermoelectric device;
one or more heat pipes comprising a first end and a second end, the first end being attached to the evaporator plate, wherein the one or more heat pipes are configured to conduct heat from the evaporator plate to the ambient; and
condenser fins attached to the second end of the one or more heat pipes, the condenser fins being configured to provide heat transfer from the one or more heat pipes to the ambient.

18. The thermoelectric cooling system of claim 17, wherein the thermoelectric cooling unit further comprises a fan attached to the condenser fins, the fan being configured to provide dissipation of heat from the condenser fins to the ambient.

19. The thermoelectric cooling system of claim 18, wherein the fan is attached to the condenser fins through a clamp.

20. The thermoelectric cooling system of claim 18, wherein the fan is attached to the collar through one or more stubs.

21. The thermoelectric cooling system of claim 17, wherein the thermoelectric cooling unit further comprises a cold sink fan, the cold sink fan being configured to provide collection of heat from the fluid.

22. The thermoelectric cooling system of claim 16, wherein the wall of the chamber comprises one or more slots, and one or more screws are tightened to the one or more slots and the collar to attach the thermoelectric cooling unit to the chamber.

23. The thermoelectric cooling system of claim 16, wherein the one or more sealant rings are 0-rings.

24. The thermoelectric cooling system of claim 16, wherein the one or more sealant rings are made of polyethylene plastic.

25. The thermoelectric cooling system of claim 16, wherein the one or more sealant rings are made of weather stripping materials.

26. A thermoelectric cooling system to cool a fluid, the thermoelectric cooling system comprising:

a chamber comprising the fluid;
a thermoelectric device attached to the chamber, the thermoelectric device comprising a cold side and a hot side, wherein the thermoelectric device is configured to cool the fluid;
a cold sink thermally connected to the cold side of the thermoelectric device, the cold sink being configured to collect heat from the fluid;
a metal standoff present between the thermoelectric device and the cold sink;
an insulation enclosing the thermoelectric device and the metal standoff;
a cold sink fan attached to the cold sink to provide collection of heat from, the fluid to the cold sink fan;
an evaporator plate attached to the hot side of the thermoelectric device, the evaporator plate being configured to collect heat from the thermoelectric device;
one or more heat pipes comprising a first end and a second end, the first end being attached to the evaporator plate, wherein the one or more heat pipes are configured to conduct heat from the evaporator plate to the ambient;
condenser fins attached to the second end of the one or more heat pipes, the condenser fins being configured to provide heat transfer from the one or more heat pipes to the ambient;
a fan attached to the condenser fins, the fan being configured to provide dissipation of heat from the condenser fins to the ambient;
a collar attached to the evaporator plate, wherein the collar is configured to attach an assembly comprising the thermoelectric device, the cold sink, the metal standoff, the insulation, the evaporator plate, the one or more heat pipes, and the condenser fins to the chamber; and
one or more sealant rings present between the collar and a wall of the chamber.

27. A thermoelectric cooling system to cool a fluid, the thermoelectric cooling system comprising:

a freezer part to cool a fluid present in the freezer part, the freezer part comprising: a thermoelectric device attached to the freezer part, the thermoelectric device comprising a hot side and a cold side, wherein the thermoelectric device is configured to cool the fluid; a cold sink thermally connected to the cold side of the thermoelectric device, the cold sink being configured to collect heat from the fluid; and a cold sink fan attached to the cold sink;
one or more heat pipes comprising a first end and a second end, the first end of the one or more heat pipes being attached to the hot side of the thermoelectric device, wherein the one or more heat pipes are configured to conduct heat from the thermoelectric device to the ambient;
condenser fins connected to the second end of the one or more heat pipes, the condenser fins being configured to provide transfer of heat from the one or more heat pipes to the ambient;
a fan attached to the condenser fins, the fan being configured to provide dissipation of heat from the condenser fins to the ambient; and
a refrigerator part comprising the fluid, the refrigerator part enclosing the freezer part, wherein the fluid in the refrigerator part gets cooled by walls of the freezer part.

28. The thermoelectric cooling system according to claim 27, wherein the thermoelectric cooling system is a compact refrigerator.

29. The thermoelectric cooling system according to claim 27, wherein the freezer part further comprises wails made of a sheet metal.

30. A thermoelectric cooling system to cool a fluid, the fluid being present in a chamber, wherein the thermoelectric cooling system comprises:

a thermoelectric device attached to the chamber, the thermoelectric device comprising a hot side and a cold side, wherein the thermoelectric device is configured to cool the fluid;
a cold sink thermally connected to the cold side of the thermoelectric device, the cold sink being configured to collect heat from the fluid;
a cold sink fan present in the chamber, the cold sink fan being configured to circulate the fluid in the chamber;
a first partition present in the chamber, the first partition providing circulation of the fluid by the cold sink fan inside the chamber;
a metal standoff present between the thermoelectric device and the cold sink;
an insulation present between the chamber and an external partition;
an evaporator plate attached to the hot side of the thermoelectric device, the evaporator plate being configured to collect heat from the thermoelectric device;
one or more heat pipes comprising a first end and a second end, the first end of the one or more heat pipes being attached to the evaporator plate, wherein the one or more heat pipes are configured to transfer heat from the hot side of the thermoelectric device to the ambient;
condenser fins attached to the second end of the one or more heat pipes, wherein the condenser fins are configured to provide heat transfer from the one or more heat pipes to the ambient; and
a fan attached to the external partition, the fan being configured to provide dissipation of heat from the condenser fins to the ambient.

31. The thermoelectric cooling system in accordance with claim 30, wherein the cold sink fan and the fan attached to the external partition are driven by an electric motor.

32. The thermoelectric cooling system in accordance with claim 30, wherein the cold sink fan is a blower fan.

33..The thermoelectric cooling system in accordance with claim 30, wherein the fan is a blower fan.

34. The thermoelectric cooling system in accordance with claim 30, wherein the thermoelectric cooling system is a wine cooler.

Patent History
Publication number: 20130291564
Type: Application
Filed: Jan 13, 2011
Publication Date: Nov 7, 2013
Applicant: Sheetak, Inc. (Austin, TX)
Inventors: Uttam Ghoshal (Austin, TX), Ayan Guha (Austin, TX), Himanshu Pockhama (Saratoga, CA)
Application Number: 13/979,000
Classifications
Current U.S. Class: Interior Of Enclosure Cooled; E.g., Refrigerator (62/3.6); Utilizing Change Of State (165/104.21); Thermoelectric; E.g., Peltier Effect (62/3.2)
International Classification: F25B 21/02 (20060101);