INTEGRATION OF THERMOSIPHON TUBING INTO ACCEPT HEAT EXCHANGER

FIELD OF THE DISCLOSURE

This disclosure generally relates to thermoelectric cooling systems and specifically relates to a system to absorb and transport heat to an accept side of a heat-pumping system, formed by integrating one or more thermosiphons with a heat sink. The resulting effect is analogous to that provided by an evaporation system in traditional vapor compression cooling.

BACKGROUND

Refrigeration is a process of transporting heat from one location to another. For example, household refrigerators are operable to transport (i.e., reject) heat from an enclosed chamber to an external environment, thereby cooling the enclosed chamber.

Vapor compression systems are ordinarily used for refrigeration. In these systems, mechanical components perform the work necessary to transport heat. The components may include a compressor, a condenser, a thermal expansion valve, an evaporator, plumbing that interconnects these components, and a thermostat. These components are operable to circulate a working fluid (e.g., refrigerant) that undergoes forced phase changes to transport heat from a cooling chamber to an external environment.

Thermoelectric cooling systems are less commonly used for refrigeration. These systems may include a passive subsystem (sometimes referred to herein as a heat accept subsystem) that transports heat from a cooling chamber to a thermoelectric heat pump. The thermoelectric heat pump consumes electrical energy to actively transport the heat from the heat accept subsystem to another passive subsystem (sometimes referred to herein as a heat reject subsystem) that rejects the heat to an external environment. An example of a passive heat accept/reject subsystem includes one or more thermosiphons that use passive two-phase heat exchange for transporting heat based on natural convection.

Thermosiphons transport heat via a working fluid using buoyancy and gravitational forces, without the need of a mechanical pump. In particular, as the working fluid is heated, the heated (or gasified) working fluid naturally rises up through the thermosiphon via buoyancy forces due to the decreased density of the heated (or gasified) working fluid. Conversely, when the working fluid is cooled, the cooled (or liquefied) working fluid naturally sinks down through the thermosiphon via gravitational forces due to the increased density of the cooled (or liquefied) working fluid. Another example of a passive heat accept/reject subsystem includes a heat-pipe that contains a wicking medium, whereby capillary forces facilitate movement of a working fluid to transport heat.

Vapor compression systems are historically less expensive and have a higher Coefficient of Performance (COP) compared to thermoelectric cooling systems. The COP is a ratio of cooling to electrical energy consumed. Higher COPs equate to lower operating costs. However, vapor compression systems have known drawbacks such as an inability to handle transient demands. To compensate for this deficiency, these systems include excess cooling capacities that far exceed demands required for steady state operations. This lowers the efficiency of such systems, causes current surges during transient periods, generates excess noise, and requires more expensive electrical components.

Thermoelectric cooling systems are advantageous compared to vapor compression systems because they lack moving mechanical parts, have greater lifespans, and can have smaller sizes and flexible shapes. Although vapor compression systems are far more commonly used for conventional refrigerators due to lower costs and increased COP, advances in thermoelectric cooling systems have improved their efficiencies and reduced their costs.

However, widespread adoption of thermoelectric cooling systems remains hampered by existing designs for vapor compression refrigerators. Specifically, typical refrigerators are designed to house fin structures and plumbing for use by mechanical compressors, condensers, and evaporators. As such, the walls of these refrigerators are structured and insulated (e.g., via foaming) in such a way that the refrigerators cannot physically accommodate thermoelectric cooling systems in an effective way. The foaming process is costly, and modifying these designs to accommodate components of thermoelectric cooling systems would require retooling, which is cost prohibitive for many manufacturers. Accordingly, a need exists for a thermoelectric cooling system design that can be installed into existing refrigerators with minimal structural changes to current refrigerator designs and minimal retooling for production.

SUMMARY

Embodiments of a sealed condensing and evaporating system that is suitable for thermoelectric cooling systems and, in particular, thermoelectric refrigeration systems are disclosed. In some embodiments, a thermoelectric cooling system comprises the sealed condensing and evaporating system that includes a heat sink and one or more thermosiphons integrated with the heat sink. Each thermosiphon includes a first portion integrated with the heat sink and a second portion configured to thermally couple to a cold side heat exchange element of a heat exchanger.

In some embodiments, the thermoelectric cooling system is suitable to install in a refrigerator cabinet that is designed to house a type of cooling system other than a thermoelectric cooling system (e.g., a vapor compression based cooling system). Such installation requires minimal structural changes to existing refrigerator designs and minimal retooling for production. As a result, thermoelectric cooling systems can be used in common refrigerator designs. This promotes a widespread adoption of thermoelectric cooling systems for refrigerators because conventional designs for refrigerators can be maintained. As such, existing designs for common vapor compression refrigerators can readily be retrofit to accommodate the disclosed thermoelectric cooling systems.

In some embodiments, the heat sink is structurally distinct from the first portion of each of the one or more thermosiphons.

In some embodiments, an external surface of the first portion of each of the one or more thermosiphons is in direct thermal contact with a surface of the heat sink.

In some embodiments, the one or more thermosiphons and the heat sink are a continuous structure.

In some embodiments, the heat sink comprises a separate and distinct cavity for each of the one or more thermosiphons, wherein, for each thermosiphon of the one or more thermosiphons, the first portion of the thermosiphon is positioned within the separate and distinct cavity for that thermosiphon.

In some embodiments, each separate and distinct cavity forms a surface area of the heat sink that equals a surface area of the first portion of the thermosiphon positioned within the separate and distinct cavity.

In some embodiments, each separate and distinct cavity is a groove on a surface of the heat sink. In some embodiments, each groove extends continuously along a length of the heat sink.

In some embodiments, each separate and distinct cavity is a channel in an interior of the heat sink.

In some embodiments, for each thermosiphon of the one or more thermosiphons, the first portion of the thermosiphon structurally complements the separate and distinct cavity in which the first portion of the thermosiphon is positioned.

In some embodiments, each of the one or more thermosiphons is a pipe. In some embodiments, each of the one or more pipes has a length that comprises a non-linear portion.

In some embodiments, the one or more thermosiphons are formed of a first type of thermally conductive material and the heat sink is formed of a second type of thermally conductive material, the first type of thermally conductive material being different than the second type of thermally conductive material.

In some embodiments, the thermosiphons and the heat sink are formed of a same thermally conductive material.

In some embodiments, the sealed condensing and evaporating system further comprises one or more forced convection units configured to direct airflow towards the heat sink.

In some embodiments, the one or more forced convection units comprise one or more fans.

In some embodiments, the one or more forced convection units are affixed to the heat sink.

In some embodiments, the heat sink comprises a plurality of fin structures.

In some embodiments, the thermoelectric cooling system further comprises a sealed condensing and evaporating reject subsystem comprising an extended surface area fin assembly or heat sinks, and one or more thermosiphons or heat-pipes. Each of the one or more thermosiphons or heat-pipes comprises a first portion integrated with the fin assembly or the heat sinks, and a second portion configured to thermally couple to a hot side heat exchange element of the heat exchanger.

Embodiments of a thermoelectric refrigeration system are also disclosed. In some embodiments, the thermoelectric refrigeration system comprises a heat exchanger comprising a cold side heat exchange element, a hot side heat exchange element, and a thermoelectric cooler disposed between the cold side heat exchange element and the hot side heat exchange element. The thermoelectric refrigeration system further comprises a cooling chamber insulated from the heat exchanger, a heat sink disposed below the heat exchanger, and one or more thermosiphons shaped so as to continuously slope downward from the heat exchanger to the heat sink. Each thermosiphon comprises a first portion integrated with the heat sink, and a second portion thermally coupled to the cold side heat exchange element of the heat exchanger.

Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure.

FIG. 1A illustrates a refrigerator that includes a vapor compression system for performing a refrigeration process;

FIG. 1B illustrates a cross-sectional view of the refrigerator of FIG. 1A to show regions that includes the vapor compression system;

FIG. 2 illustrates a refrigerator that includes a thermoelectric cooling system for performing a refrigeration process;

FIGS. 3A and 3B illustrate a complete thermoelectric cooling system that includes: heat-pipes integrated into a fin assembly that form a sealed condensing and evaporating system for the purpose of rejecting unwanted heat to the environment from a heat pumping system, and thermosiphons integrated with a heat sink that form a sealed condensing and evaporating system for the purpose of accepting unwanted heat into the heat pumping system according to some embodiments of the present disclosure;

FIG. 4A illustrates grooves of a heat sink that structurally complement thermosiphons according to some embodiments of the present disclosure;

FIG. 4B illustrates fin structures of the heat sink of FIG. 4A according to some embodiments of the present disclosure;

FIG. 4C illustrates a cross-sectional view of the heat sink of FIG. 4A according to some embodiments of the present disclosure;

FIG. 5 illustrates a cross-sectional view of channels in a heat sink that structurally complement thermosiphons according to some embodiments of the present disclosure;

FIG. 6A illustrates the sealed condensing and evaporating system including thermosiphons integrated with the heat sink of FIG. 4A for the purpose of accepting heat into a heat pumping system according to some embodiments of the present disclosure;

FIG. 6B illustrates a cross-sectional view of the sealed condensing and evaporating system including thermosiphons integrated with the heat sink of FIG. 6A for the purpose of accepting heat into a heat pumping system according to some embodiments of the present disclosure;

FIG. 7A illustrates an exploded view of the sealed condensing and evaporating system including the thermosiphons and the heat sink of FIG. 6A for the purpose of accepting heat into a heat pumping system according to some embodiments of the present disclosure;

FIG. 7B illustrates a cross-sectional view of the sealed condensing and evaporating system including the thermosiphons and the heat sink of FIG. 7A for the purpose of accepting heat into a heat pumping system according to some embodiments of the present disclosure; and

FIG. 8 illustrates a cross-sectional view of the refrigerator of FIG. 1A retrofit with the thermoelectric cooling system of FIGS. 3A and 3B according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure.

As used herein, terms such as “first,” “second,” and the like, distinguish one element from another but should not limit the elements. For example, an element can be termed a first element or a second element without departing from the scope of the present disclosure.

As used herein, terms such as “up,” “down,” “above,” “below,” “upper,” “lower,” and the like, refer to an orientation, direction, or altitude relative to a local ground level. For example, a first object that is “above” a second object refers to the first object being in a vertical or “up” direction from the second object relative to a local ground level.

As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

As used herein, terms such as “comprises,” “comprising,” “includes,” and “including,” when used to specify the presence of stated structures, steps, operations, elements, or components, do not preclude the presence or addition of one or more other structures, steps, operations, elements, components, or groups thereof.

Embodiments of a sealed condensing and evaporating system (i.e., a sealed condensing and evaporating circuit) for thermoelectric cooling systems for the purpose of accepting heat into a heat pumping system are disclosed. In some embodiments, the sealed condensing and evaporating system for the purpose of accepting heat into the heat pumping system includes a heat sink and thermosiphon(s) integrated with the heat sink. Each thermosiphon includes a first portion integrated with the heat sink and a second portion configured to thermally couple to a cold side of the heat exchanger.

In some embodiments, thermoelectric cooling systems including embodiments of the sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system are suitable to install in refrigerators that are designed to house cooling systems other than thermoelectric cooling systems (e.g., vapor compression based cooling systems). Such installation requires minimal structural changes to existing refrigerator designs and minimal retooling for production. As a result, the disclosed thermoelectric cooling systems can be used in common refrigeration designs. This promotes widespread adoption of thermoelectric cooling systems because conventional designs for refrigerators can be maintained. As such, existing designs for common vapor compression refrigerators can readily be retrofit to accommodate the disclosed thermoelectric cooling systems.

Before further describing embodiments of the present disclosure, a brief discussion of various refrigeration systems is provided for context. This discussion should not be construed as limiting the scope of the present disclosure for use in any specific type of refrigerator. For example, embodiments of the disclosed sealed condensing and evaporating system may be included in any apparatus that performs a refrigeration or dehydration process such as refrigerators designed to use vapor compression systems, thermal mass systems, conventional thermoelectric cooling systems, or combinations thereof. A discussion of vapor compression refrigerators is provided merely because these are by far the most common type of refrigerators. As such, companies have invested significant capital designing refrigerators that specifically house components of a vapor compression system. Moreover, manufacturers have invested significant capital for tools used to produce vapor compression refrigerators.

FIG. 1A illustrates a rear-view perspective of a vapor compression refrigerator 10. The vapor compression refrigerator 10 includes a cabinet 12 housing a vapor compression system 14 operative to extract heat from, and thereby cool, a cooling chamber 16 within the cabinet 12. The cabinet 12 is formed of walls that contain thermal insulation. The insulated walls act to insulate the cooling chamber 16 from an environment external to the cabinet 12.

The vapor compression system 14 includes various mechanical components such as an evaporator 18, an expansion valve 20, a condenser 22, a compressor 24, and plumbing 26 that interconnects these components. As shown, the cabinet 12 is designed to house these components in particular locations relative to each other and relative to the insulated walls of the cabinet 12. For example, the evaporator 18 and the condenser 22 are shown as including coils with fins positioned on an interior of a side wall or an exterior rear wall of the cabinet 12, respectively. However, the evaporator 18 and the condenser 22 may be located on other walls (or multiple walls) of the cabinet 12. As such, common refrigerators may house these components in other locations different from what is shown in FIG. 1A. Moreover, the vapor compression system 14 may include various other components that are well known to persons skilled in the art but are not shown or described herein for brevity. For example, the vapor compression system 14 may also include a thermostat and fans (not shown).

The following brief overview of the vapor compression refrigeration cycle is provided purely to aid in understanding how the components of the vapor compression system 14 may operate to cool the cooling chamber 16. However, various details about the vapor compression refrigeration cycle are well known to persons skilled in the art and, as such, are omitted for brevity. In general, a working fluid circulates through the plumbing 26 as shown by action of the compressor 24. The working fluid is cycled between liquid and gaseous states by actions of the various components to perform a refrigeration process.

For example, the compressor 24 compresses the working fluid to create a high temperature, high pressure gas. The high temperature, high pressure gas passes through reject coils of the condenser 22. As shown, the condenser 22 is positioned on the outside of the rear wall of the cabinet 12. As the high temperature, high pressure gas passes through the reject coils of the condenser 22, heat is dissipated (rejected) to the environment external to the cabinet 12. As a result, the working fluid is cooled and, therefore, changes to a high pressure liquid.

The high pressure liquid passes through the expansion valve 20 to create a low temperature, low pressure liquid (and in some instances at least partially evaporated cold working fluid). This low temperature, low pressure liquid passes through accept coils of the evaporator 18. As shown, the evaporator 18 may be located inside an insulated wall of the cabinet 12. The low temperature, low pressure liquid evaporates as it passes through the evaporator 18 because it accepts heat from the cooling chamber 16 to thereby cool the cooling chamber 16. As a result, the working fluid changes to a low pressure, heated gas.

The low pressure, heated gas is compressed via the compressor 24, which again raises the pressure and temperature of the gas, and the cycle repeats as necessary to accept heat from the environment internal to the cooling chamber 16 and reject that heat to the environment external to the cabinet 12. A thermostat can be adjusted to a set point temperature that determines when the compressor 24 is turned on or off.

FIG. 1B illustrates a cross-section of the vapor compression refrigerator 10 of FIG. 1A. As shown, the various mechanical components of the vapor compression system 14 are located inside or between insulated walls 28-1 through 28-6 (generally referred to herein collectively as insulated walls 28 and individually as insulated wall 28) of the cabinet 12. For example, the compressor 24 is located in a specially designed compartment 30 of the cabinet 12, which is partially enclosed by the insulated walls 28-2, 28-3, and 28-4. The accept coils of the evaporator 18 may be positioned on the surface of (or interior to) the insulated wall 28-1. The reject coils of the condenser 22 may be positioned on an exterior surface of the insulated wall 28-1. The plumbing 26 interconnects the components by traversing outside, inside, and between the insulated walls 28.

As shown, the insulated walls 28 of the cabinet 12 are insulated with a material that thermally isolates the cooling chamber 16 from the environment external to the cabinet 12. For example, the thermal insulation may include foam. In some designs, the insulated walls 28 are heavily insulated with costly materials to improve energy efficiency of the vapor compression refrigerator 10. As a result, properly insulating the vapor compression refrigerator 10 incurs significant costs.

Although vapor compression refrigeration is far more common, technological advances have increased the efficiencies of thermoelectric cooling systems and reduced their manufacturing and operating costs. Moreover, thermoelectric cooling systems are an environmentally friendly alternative to vapor compressions systems because thermoelectric cooling systems do not require circulating environmentally harsh refrigerant fluids. An example of a thermoelectric refrigerator is disclosed in commonly owned and assigned U.S. Patent Application Publication No. 2013/0291557, entitled THERMOELECTRIC REFRIGERATION SYSTEM CONTROL SCHEME FOR HIGH EFFICIENCY PERFORMANCE, which is hereby incorporated herein by reference in its entirety.

FIG. 2 illustrates one example of a thermoelectric refrigerator 32, as disclosed in U.S. Patent Application Publication No. 2013/0291557. The thermoelectric refrigerator 32 includes a cabinet 34 that houses a thermoelectric cooling system 36 and a cooling chamber 38. As shown, the thermoelectric cooling system 36 includes a heat exchanger 40 (which may also be referred to herein as a thermoelectric heat pump), a controller 42 that controls cooling of the cooling chamber 38, and plumbing that contains a two-phase working fluid. The heat exchanger 40 includes a cartridge 44 disposed between a hot side heat exchange element 46 and a cold side heat exchange element 48. The cartridge 44 includes Thermoelectric Coolers (TECs) (also known as thermoelectric cooling modules), wherein each TEC has a cold side that is thermally coupled with the cold side heat exchange element 48 and a hot side that is thermally coupled with the hot side heat exchange element 46. The TEC(s) are integrated circuits that each include multiple thermoelectric devices, where a thermoelectric device is a device containing a single P-type semiconductor leg and a single N-type semiconductor leg. Thus, a TEC can be viewed as an integrated circuit including multiple connected thermoelectric devices, e.g., in series. The TEC(s) are activated by the controller 42 to consume electrical energy that causes heat transfer from a cold side (accept side) to a hot side (reject side) of the thermoelectric cooling system 36. When the TEC(s) are activated, the hot side heat exchange element 46 is heated to thereby create an evaporator, and the cold side heat exchange element 48 is cooled to thereby create a condenser.

On the cold side of the heat exchanger 40, the illustrated plumbing forms an accept loop 50 that contains a working fluid. The accept loop 50 is thermally coupled to an interior wall 52 of the cooling chamber 38 and acts as an evaporation system for the thermoelectric refrigerator 32. In particular, the accept loop 50 operates according to thermosiphon principles to provide two-phase heat transport from the cooling chamber 38 to the cold side heat exchange element 48. In particular, acting as a condenser for the accept loop 50, the cold side heat change element 48, which is cooled by the TECs, condenses the working fluid in the accept loop 50. The condensed working fluid flows through the accept loop 50 via gravitational forces. As the condensed working fluid flows through the accept loop 50, heat is transferred from the cooling chamber 38 to the working fluid. As a result, the condensed working fluid is evaporated (i.e., the portion of the accept loop 50 along the walls of the cooling chamber 38 operates as an evaporator of the accept loop 50). The evaporated working fluid then flows back through the accept loop 50 toward the cold side heat exchange element 48 via buoyancy forces. The cycle continues in this manner such that the cooling chamber 38 is cooled.

On the hot side of the heat exchanger 40, the illustrated plumbing forms a reject loop 54 that contains a working fluid. The reject loop 54 is thermally coupled to an exterior wall 56 of the thermoelectric refrigerator 32 and acts as a condenser system for the thermoelectric refrigerator 32. In particular, the reject loop 54 operates according to thermosiphon principles to provide two-phase heat transport from the hot side heat exchange element 46 to the external environment. In operation, acting as an evaporator for the reject loop 54, the hot side heat exchange element 46, which is heated by the TECs, evaporates the working fluid in the reject loop 54. The evaporated working fluid flows through the reject loop 54 via buoyancy forces. As the evaporated working fluid flows through the reject loop 54, heat is transferred from the working fluid to the external environment. As a result, the evaporated working fluid is condensed (i.e., the portion of the reject loop 54 along the walls of the thermoelectric refrigerator 32 operates as a condenser of the reject loop 54). The condensed working fluid then flows back through the reject loop 54 toward the hot side heat exchange element 46 via gravitational forces. The cycle continues in this manner such that the heat extracted from the cooling chamber 38 is rejected to the external environment. The exterior wall 56 is thermally isolated from the accept loop 50 and the interior wall 52 (and thus the cooling chamber 38) by, for example, appropriate insulation such as foam. Additional details of the operation of the thermoelectric cooling system 36 can be found in, for example, the aforementioned commonly owned and assigned U.S. Patent Application Publication No. 2013/0291557.

As discussed above, refrigerator cabinets are designed to have structural features that are specific for housing a particular type of refrigeration system. For example, as shown in FIG. 2, the accept loop 50 includes a network of plumbing that is integrated throughout walls of the cabinet 34 of the thermoelectric refrigerator 32. In contrast, the plumbing 26 shown in FIGS. 1A and 1B that is used to extract heat in the vapor compression refrigerator 10 may be integrated into fewer walls of the cabinet 12 or even concentrated only in the rear wall 28-1 of the vapor compression refrigerator 10. As a result, for example, the vapor compression refrigerator 10 of FIGS. 1A and 1B is designed specifically to house components of a vapor compression system 14 and cannot accommodate the existing thermoelectric cooling system 36 of FIG. 2.

This creates structural constraints particularly when attempting to integrate a thermoelectric cooling system (e.g., the thermoelectric cooling system 36) into existing designs for a vapor compression refrigerator (e.g., into the cabinet 12 of the vapor compression refrigerator 10 of FIGS. 1A and 1B). In the majority of cases, these structural differences are vast and complex. The differences include compartments for housing components of one type of refrigeration system. As discussed above, these compartments may include hollow regions bounded by insulated walls of refrigerator cabinets so dimensioned as to accommodate specific components of a specific type of refrigeration system. As a result, a refrigerator cabinet that is designed to house a specific type of refrigeration system cannot readily accommodate a different type of refrigeration system.

Consequently, the vast majority of refrigerator cabinets specifically designed to house structures of vapor compression systems cannot easily accommodate existing thermoelectric cooling systems, particularly those that utilize passive two-phase heat transport. Moreover, the vast majority of manufacturers are tooled for producing refrigerators that exclusively house vapor compression systems. As a result, the vast majority of refrigerator cabinets cannot accommodate thermoelectric cooling systems without major structural modifications that may require redesigning the refrigerator cabinet and retooling by manufacturers. Redesigning and retooling are cost-prohibitive options that have stifled the widespread adoption of existing thermoelectric cooling systems by manufacturers of vapor compression refrigerators. As such, although existing thermoelectric cooling systems have recently experienced significant technological advances, widespread adoption of these systems remains hampered by current designs.

Embodiments of a sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system for a thermoelectric cooling system are disclosed. In some embodiments, the sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system is such that the thermoelectric cooling system can be installed in refrigerators that are designed to house cooling systems other than thermoelectric cooling systems (e.g., vapor compression based cooling systems). For example, embodiments of the disclosed sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system can be installed in refrigerator cabinets designed for vapor compression systems with minimal or no structural modifications to the refrigerator cabinets or retooling by manufacturers. Embodiments of the disclosed sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system can operate efficiently to achieve a desired temperature for a cooling chamber.

Embodiments of the sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system include thermosiphons that are integrated with a heat sink, which improves (i.e., lowers) thermal resistance while simultaneously preventing heat from leaking back into a cooling chamber. The thermosiphons are said to be “integrated with” the heat sink when a portion of each of the thermosiphons and the heat sink are structured such that those portions of the thermosiphons and the heat sink function cooperatively, as further detailed below. The use of thermosiphons allows heat exchangers to be mounted closer to the outside of a refrigerator cabinet compared to conventional thermoelectric cooling systems, which improves heat rejection to an external environment. Specifically, by thermally isolating the warmer heat exchange components from the internal cabinet (e.g., internal environment of a cooling chamber), heat leak-back and thermal loading is further reduced. As such, the use of thermosiphons allows heat exchangers to be mounted further from the inside of a cooling chamber.

FIGS. 3A and 3B illustrate different views of a complete thermoelectric cooling system that includes: heat-pipes integrated into a fin assembly that form a sealed condensing and evaporating system for the purpose of rejecting unwanted heat to the environment from a heat pumping system and thermosiphons integrated with a heat sink that form a sealed condensing and evaporating system for the purpose of accepting unwanted heat into the heat pumping system according to some embodiments of the present disclosure.

In particular, FIG. 3A illustrates a perspective view of the thermoelectric cooling system 58, which shows features of the sealed condensing and evaporating system evaporation system 60 for the purpose of accepting heat into the heat pumping system that would face an interior of a cooling chamber. FIG. 3B illustrates another perspective view of the thermoelectric cooling system 58, which shows features of the sealed condensing and evaporating system 60 that would face away from the interior of the cooling chamber and towards a rear wall of a refrigerator cabinet.

An accept side 62 of the thermoelectric cooling system 58 includes the sealed condensing and evaporating system 60 formed of thermosiphons 64-1 through 64-12 (generally referred to herein collectively as thermosiphons 64 and individually as thermosiphon 64) integrated with a heat sink 66. While not limited thereto, in this example, the heat sink 66 includes one or more fin structures 68, and a forced convection unit 70 (e.g., a fan) affixed to the heat sink 66. A fan is said to be “affixed” to the heat sink 66 when it is attached, fastened, or otherwise physically joined with the heat sink 66. The fin structures 68 and the forced convection unit 70 operate to enhance heat extraction from an interior of a cooling chamber, as detailed further below.

The fin structures 68 and the forced convection unit 70 are optional (i.e., may not be included in all implementations). Further, in some embodiments, the heat sink 66 may include the fin structures 68 but not the forced convection unit 70, or vice versa. Further, while the forced convection unit 70 is affixed to the heat sink 66 in this example, the forced convection unit 70 may alternatively not be affixed to the heat sink 66, but positioned relative to the heat sink 66 so as to direct air toward the heat sink 66.

The thermoelectric cooling system 58 also has a reject side 72 including a sealed condensing and evaporating reject system for the purpose of rejecting unwanted heat to an environment from a heat pumping system. Specifically, heat extracted (e.g., from a cooling chamber) by the accept side 62 is rejected (e.g., to an external environment) via the reject side 72. Heat is pumped from the accept side 62 to the reject side 72 by, in this example, two thermoelectric heat exchangers 74-1 and 74-2 (generally referred to herein collectively as thermoelectric heat exchangers 74 and individually as thermoelectric heat exchanger 74). Each heat exchanger 74 may also be referred to herein as a thermoelectric heat pumping system.

Each thermoelectric heat exchanger 74 includes a cold side heat exchange element 76 and a hot side heat exchange element 78. Each cold side heat exchange element 76 is thermally coupled to a different subset of the thermosiphons 64. Each hot side heat exchange element 78 is thermally coupled to an extended surface area fin assembly or heat sinks 80-1 through 80-4 (generally referred to herein collectively as heat sinks 80 and individually as heat sink 80) via one or more thermosiphons or heat-pipes. Each of the one or more thermosiphons or heat-pipes includes a first portion integrated with the heat sinks 80, and a second portion configured to thermally couple to a hot side heat exchange element of a heat exchanger 74. As shown, the heat sinks 80 may be coupled to one or more forced convection units 82-1 and 82-2 (generally referred to herein collectively as forced convection units 82 and individually as forced convection unit 82) that are used to enhance heat rejection to an external environment.

Each thermoelectric heat exchanger 74 also includes one or more TECs disposed between the cold side heat exchange element 76 and the hot side heat exchange element 78, as similarly detailed above with respect to the thermoelectric cooling system 36 of FIG. 2. The TECs are activated by consuming electrical energy to transport heat from the cold side heat exchange element 76 to the respective hot side heat exchange element 78. As a result, heat absorbed from a cooling chamber by the accept side 62 can be transferred to the reject side 72 via the thermoelectric heat exchangers 74 and dissipated via the heat sinks 80 to an external environment.

In summary, the reject side 72 has a sealed condensing and evaporating reject system that includes an extended surface area fin assembly or heat sink(s) thermally coupled to thermosiphon(s) or heat-pipe(s). Each thermosiphon or heat-pipe includes a first portion integrated with the fin assembly or heat sink(s), and a second portion configured to thermally couple to hot side heat exchange element 78 of the heat exchanger 74 (i.e., heat pumping system). The reject side 72 may include various other components which are known to persons skilled in the art and not shown or described in detail herein for brevity. For more information about the illustrated example of the reject side 72, the interested reader is directed to commonly owned and assigned U.S. Patent Application Publication No. 2015/0075184, entitled ENHANCED HEAT TRANSPORT SYSTEMS FOR COOLING CHAMBERS AND SURFACES, which is hereby incorporated herein by reference in its entirety.

As indicated above, the sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system includes the thermosiphons 64 integrated with the heat sink 66. Although the embodiment of FIGS. 3A and 3B show the sealed condensing and evaporating system 60 as being thermally coupled to each cold side heat exchange element 76-1 and 76-2 of each thermoelectric heat exchanger 74-1 and 74-2, respectively, the disclosure is not limited thereto. For example, in some embodiments, the thermoelectric cooling system 58 may include a single thermoelectric heat exchanger 74. As such, the sealed condensing and evaporating system 60 would be coupled to a single cold side heat exchange element 76 of the single thermoelectric heat exchanger 74.

When installed in a refrigerator cabinet, the thermoelectric cooling system 58 is preferably insulated. In particular, the thermoelectric heat exchangers 74 may be insulated from a cooling chamber and from an environment external to the refrigerator cabinet. The sealed condensing and evaporating system 60 operates as a thermal diode when the TECs of the thermoelectric heat exchangers 74 are deactivated such that the thermal diode combined with the thermal insulation prevents heat from leaking back into the cooling chamber from the external environment.

When installed in a refrigerator cabinet, the sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system is oriented in a direction relative to vertical to enable proper operation of the thermosiphons 64. In particular, the thermoelectric cooling system 58, and thus the sealed condensing and evaporating system 60, is oriented such that the heat sink 66 is disposed below the thermoelectric heat exchangers 74. Further, the thermosiphons 64 are shaped so as to continuously slope downward from the thermoelectric heat exchangers 74 to the heat sink 66. For example, a thermosiphon 64 may be a tube (e.g., circular tube/pipe) with linear and/or non-linear portions that form an overall shape that continuously slopes downward relative to vertical. This enables proper two-phase, one-way, passive heat transport from the heat sink 66 to the cold side heat exchange element 76 of the thermoelectric heat exchangers 74 via the thermosiphons 64.

In this example, the thermosiphons 64 extend along a length of the heat sink 66. Each thermosiphon 64 includes a first portion 84 that is integrated with the heat sink 66 and a second portion 86-1 and 86-2 (hereinafter generally referred to as second portions 86 and individually as second portion 86) that is configured to thermally couple to the cold side heat exchange element 76-1 and 76-2 of the corresponding thermoelectric heat exchanger 74-1 and 74-2, respectively, (and thus not integrated with the heat sink 66). In other words, the second portions 86-1 and 86-2 are individually designed to (i.e., configured to) have at least some physical (e.g., structural) characteristics that allow the second portions 86-1 and 86-2 to thermally couple to the cold side heat exchange element 76-1 and 76-2, respectively. For example, the second portions 86-1 and 86-2 may be round and of a size designed, or configured, to be inserted into corresponding holes in the cold side heat exchange element 76. In addition, each thermosiphon 64 includes a third portion 88 that extends between the first portion 84 and the second portions 86 of that thermosiphon 64. In this example, the thermosiphons 64 include a fourth portion 90 that extends below/beyond the end of the heat sink 66, but is not limited thereto.

The passive heat transport of the thermosiphons 64 beneficially lacks moving parts and is therefore highly reliable and operates silently. However, the thermosiphons 64 typically lack sufficient surface area to effectively extract heat from a cooling chamber. To mitigate these drawbacks, the thermosiphons 64 of the disclosed sealed condensing and evaporating system 60 are integrated with the heat sink 66. The integration of the thermosiphons 64 with the heat sink 66 increases the effective surface area of the thermosiphons 64 which are in thermal contact with the environment inside a cooling chamber. This increases the magnitude and rate of heat exchange between the heat transport medium contained in the thermosiphons 64 and the environment inside the cooling chamber. As a result, the cooling chamber can be cooled more efficiently because more heat is transported from the heat sink 66 to the thermoelectric heat exchangers 74, and ultimately rejected to the environment external to the refrigerator.

As indicated above, the thermosiphons 64 are said to be “integrated with” the heat sink 66 when a portion of each of the thermosiphons 64 and the heat sink 66 are structured such that those portions of the thermosiphons 64 and the heat sink 66 function cooperatively. In other words, a portion of the thermosiphon 64 is said to be “integrated with” the heat sink 66 when that portion of the thermosiphon 64 is either (a) mechanically/physically and thermally connected (directly) to the heat sink 66 (e.g., via a thermal paste/glue) or (b) part of the same continuous structure as the heat sink 66. The thermal contact is constrained by physical contact between the heat sink 66 and the thermosiphons 64. Further, the physical contact is constrained by the physical structures of the heat sink 66 and the thermosiphons 64. As a result, the thermosiphons 64 integrated with the heat sink 66 form a sealed condensing and evaporating system for the purpose of accepting unwanted heat into a heat pumping system.

In some embodiments, the thermosiphons 64 are structurally distinct from the heat sink 66. In other words, the thermosiphons 64 are manufactured separately from the heat sink 66 to form separate and distinct structures. At least some physical structures of the thermosiphons 64 are shaped to complement physical structures of the heat sink 66 such that the thermosiphons 64 can be positioned to physically contact the heat sink 66. The shapes of the physical structures are said to complement each other when the physical structures can be joined to form a continuous physical structure. These physical structures may also be referred to herein as complementary physical structures. At least a portion of each thermosiphon 64 is thus integrated with the heat sink 66 by joining these two distinct structures to form a continuous structure. As detailed below, a variety of processes, substances, materials, or combinations thereof may be used to permanently or temporarily join the thermosiphons 64 and the heat sink 66. As a result, the thermosiphons 64 are “integrated with” the heat sink 66.

In some embodiments, the thermosiphons 64 are structurally indistinct from the heat sink 66. In other words, the thermosiphons 64 and the heat sink 66 are manufactured to form a single continuous structure. As a result, the thermosiphons 64 are “integrated with” the heat sink 66 because they are formed of a single continuous structure. Unless otherwise noted, the disclosed embodiments described herein presume that the thermosiphons 64 are structurally separate and distinct from the heat sink 66, and then joined to form the sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system.

Integrating the thermosiphons 64 with the heat sink 66 requires that the heat sink 66 have at least some physical structures that are shaped to complement physical structures of the thermosiphons 64. As such, the thermosiphons 64 can be positioned to physically contact the complementary structures of the heat sink 66. Specifically, at least some physical structures of the heat sink 66 are shaped to form a continuous structure when joined with complementary physical structures of the thermosiphons 64. Integrating the thermosiphons 64 with the heat sink 66 in this manner provides thermal contact across the complementary physical structures of the thermosiphons 64 and the heat sink 66.

The complementary physical structures of the heat sink 66 may include one or more cavities (generally referred to herein collectively as cavities and individually as cavity) for each of the thermosiphons 64. For example, the heat sink 66 may include a single continuous cavity for each thermosiphon 64. Each cavity may have a shape that defines a volume of space anywhere on a surface or embedded in the heat sink 66. For example, a cavity may be a groove on the surface of the heat sink 66 or form a channel that passes through the heat sink 66.

As shown in FIGS. 3A and 3B, the heat sink 66 may be shaped to roughly form a block. However, the shape of the heat sink 66 is not limited thereto. In some embodiments, the heat sink 66 may be shaped to achieve a desired amount of physical contact with the thermosiphons 64. Specifically, a combination of specific dimensions of the heat sink 66 and physical structures of the heat sink 66 that complement structures of the thermosiphons 64 form a surface area of the heat sink 66 that contacts a surface area of the thermosiphons 64. As shown in FIG. 3B, a side 92 of the heat sink 66 includes a surface with a surface area that is in thermal contact with a corresponding surface area of the thermosiphons 64. In particular, a surface area of a portion of each thermosiphon 64 that is integrated with the heat sink 66 physically contacts a complementary surface area on the heat sink 66.

FIG. 4A illustrates grooves 94 (generally referred to herein collectively as grooves 94 and individually as groove 94) of the heat sink 66 that structurally complement thermosiphons 64 according to some embodiments of the present disclosure. The grooves 94 may be formed on the heat sink 66 according to any process known to persons skilled in the art. For example, the grooves 94 on the heat sink 66 may be formed according to an extrusion process to form extruded grooves. As shown, the heat sink 66 includes several grooves 94 that are each shaped to structurally complement a portion of a thermosiphon 64. Specifically, each groove 94 is a cavity on the heat sink 66 that defines a volume of space that structurally complements a portion of the thermosiphon 64. Moreover, each groove 94 has a surface area that complements a surface area of the portion of the thermosiphon 64.

As shown, the grooves 94 may be formed on the side 92 of the heat sink 66. The grooves 94 may extend along a length of that side 92. This helps spread heat along the length of the heat sink 66, which improves thermal resistance of the thermosiphons 64 while preventing heat from leaking down from the thermoelectric heat exchangers 74 to the interior of a chamber.

The amount of surface area of each thermosiphon 64 in contact with the heat sink 66 is a function of a predetermined, desired, and/or acceptable temperature differential (Δt) at an interface between each thermosiphons 64 and the heat sink 66. Ideally, the amount of surface area defining the interface would be 100% to allow for the least number of thermosiphons 64 to be used for a given load condition. In practice, however, the object may be to reduce or minimize the contact resistance between the thermosiphons 64 and the heat sink 66 in a balance of performance with manufacturing costs. Hence, the “integrated with” configuration where each “tube” of the thermosiphons 64 becomes part of the heat sink 66 may therefore have a negligible amount or no contact resistance. For example, referring back to FIG. 3B, at least a portion of the side 92 of the heat sink 66 may be in physical contact with the thermosiphons 64. As shown, a significant portion of the total surface area of the side 92 of the heat sink 66 (e.g., 50% or more) is in physical contact with a significant portion of the total surface area of the thermosiphons 64 (e.g., the first portion 84 of each thermosiphon 64 integrated with the heat sink 66 may be 20% or more of the length of the thermosiphon 64).

Heat exchange between the heat transfer medium, or working fluid, in the thermosiphons 64 and an interior of a cooling chamber is a function of the surface area of the side 92 of the heat sink 66 that is in physical contact with the thermosiphons 64. The surface area of the heat sink 66 that is in physical contact with the thermosiphons 64 is defined by the number, orientation, and shape of the cavities (e.g., grooves 94) of the heat sink 66. Accordingly, these parameters may be selected to achieve a desired amount of thermal contact between the heat sink 66 and the thermosiphons 64.

As shown, several grooves 94 are formed in parallel and adjacent to each other. In some embodiments, the number of grooves 94 may be the same as the number of thermosiphons 64. The grooves 94 may extend along a length of the side 92 of the heat sink 66 that complements a length of the portions of the thermosiphons 64 to be integrated with the heat sink 66. As indicated above, this orientation provides physical contact between the side 92 of the heat sink 66 and the thermosiphons 64 that improves thermal resistance while preventing heat from leaking back down. Lastly, the shape of each groove 94 complements the shape of each thermosiphon 64 to enable physical contact. In some embodiments, the number, orientation, and shapes of the grooves 94 may be such that the grooves 94 span the entire side 92 of the heat sink 66.

The heat sink 66 may include other physical structures that increase the heat exchange between the heat transport medium contained in the thermosiphons 64 and an interior of a cooling chamber. For example, FIG. 4B illustrates the fin structures 68 on another side of the heat sink 66 of FIG. 4A according to some embodiments of the present disclosure. As shown, the fin structures 68 are located on a side of the heat sink 66 and may extend to the center the heat sink 66. The structural configuration of the fin structures 68 may be determined to achieve a desired heat transfer between an interior of a cooling chamber and the heat transport medium of the thermosiphons 64. In particular, heat transfer is constrained by the shape, spacing, and materials used for the fin structures 68. For example, the fin structures 68 may be pins that are cylindrical, elliptical, or square. Moreover, the fin structures 68 may be oriented in any direction to achieve a desired amount of heat extraction from an interior of a cooling chamber.

FIG. 4C illustrates a cross-section of the heat sink 66 of FIG. 4A according to some embodiments of the present disclosure. As shown, the heat sink 66 includes the grooves 94-1 through 94-12 to integrate the thermosiphons 64 with the heat sink 66, and includes the fin structures 68 to improve thermal coupling between the heat transport medium in the thermosiphons 64 and an interior of a cooling chamber. Specifically, the side 92 of the heat sink 66 includes the grooves 94 that are shaped to structurally complement the portions of the thermosiphons 64 to be integrated with the heat sink 66. A second side, opposite of the side 92, includes the fin structures 68. This structural configuration creates continuous thermal contact between the heat transport medium in the thermosiphons 64 and an interior of a cooling chamber. Moreover, the magnitude of thermal coupling is improved by effectively increasing the surface area of the thermosiphons 64 that is in contact with the heat sink 66.

The specific embodiments detailed above with regard to the heat sink 66 are merely examples and should not limit the scope of the disclosure. For example, FIG. 5 illustrates a cross-section of a heat sink 96 that includes channels 98-1 through 98-12 (generally referred to herein collectively as channels 98 and individually as channel 98) for the thermosiphons 64 according to some embodiments of the present disclosure. As shown, the channels 98 are embedded in the heat sink 96. Moreover, the channels 98 are separate and distinct from each other. Each channel 98 is a cavity that defines a volume of space that complements a portion of a thermosiphon 64 to be integrated with the heat sink 96. Each channel 98 defines a surface area for physical contact with a thermosiphon 64. As such, the thermosiphons 64 can be positioned to physically contact complementary structures of the heat sink 96. Thermal contact between the heat sink 96 and the thermosiphons 64 is thus constrained by the length of each channel 98. As a result, the thermosiphons 64 may be integrated with the heat sink 96 by embedded the thermosiphons 64 internally to the heat sink 96.

Again, the embodiments detailed above with regard to the heat sinks 66 and 96 are merely examples. The cavities used to integrate the thermosiphons 64 with any heat sink may be of any shape and located anywhere relative to the heat sink to provide a desired amount of thermal coupling between the thermosiphons 64 and the heat sink. As a consequence, integrating the thermosiphons 64 with the heat sink provides a desired amount of thermal contact between the heat transport medium contained in the thermosiphons 64 and an interior of a cooling chamber.

FIG. 6A illustrates the thermosiphons 64 integrated with the heat sink 66 according to some embodiments of the present disclosure. Moreover, FIG. 6B illustrates a cross-section of the thermosiphons 64 integrated with the heat sink 66 of FIG. 6A according to some embodiments of the present disclosure. As shown, each thermosiphon 64 includes at least a portion integrated with the heat sink 66. For example, the portion of each thermosiphon 64 integrated with the heat sink 66 may correspond to a portion of a tube (i.e., a pipe) that forms a thermosiphon 64. The portion includes an external surface area that is in physical contact with a cavity (e.g., the grooves 94) of the heat sink 66 that has a complementary shape.

As shown, each thermosiphon 64 includes a portion that extends along the length of the heat sink 66 but that is not integrated with the heat sink 66. Each thermosiphon 64 also includes a portion that extends below the heat sink 66 and a portion that extends above the heat sink 66. The uppermost portion of each thermosiphon 64 is coupled to one of the cold side heat exchange elements 76-1 or 76-2. The lowermost portion of each thermosiphon 64 may contain the heat transport medium in a liquid phase for use to transport heat.

These various portions of a thermosiphon 64 described when referring to FIGS. 6A and 6B are merely representative of some embodiments and should not limit the scope of this disclosure. In some embodiments, the thermosiphons 64 may include additional portions not discussed herein or omit portions that have been discussed. For example, embodiments of a sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system that use embedded channels 98 do not include portions of the thermosiphon 64 that extend along the length of the heat sink 66 but are not in contact with the heat sink 66.

The thermosiphons 64 may be permanently or temporarily integrated with the heat sink 66. A variety of processes, substances, materials, or combinations thereof may be used to join complementary structures of the thermosiphons 64 and the heat sink 66. In some embodiments, the thermosiphons 64 may be affixed to the heat sink 66 by using an adhesive that joins their complementary structures. Examples of adhesives include glue, paste, gum, cement, or combinations thereof. The adhesive may bind complementary structures of the thermosiphons 64 and the heat sink 66 to be in physical contact permanently or temporarily.

In some embodiments, the adhesive may form a layer between the thermosiphons 64 and the heat sink 66. In these embodiments, the thermosiphons 64 and the heat sink 66 are still said to be in “physical contact,” and the adhesive binds this contact. In some embodiments, the adhesive is made of a thermally conductive material. For example, the adhesive may be made of a thermally conductive material sufficient to maintain continuous thermal coupling between the thermosiphons 64 and the heat sink 66 through the layer of the adhesive.

In some embodiments, a process of welding, brazing, soldering, or combinations thereof may be used to permanently integrate the thermosiphons 64 with the heat sink 66. In some embodiments, the complementary shape of the physical structures of the thermosiphons 64 and the heat sink 66 are such that frictional forces affix these complementary structures. For example, the cavities (e.g., the grooves 94) of the heat sink 66 may include areas that are abrasive to hold the thermosiphons 64 in place. Accordingly, the integration of the thermosiphons 64 with the heat sink 66 may be permanent or temporary depending on the processes, substances, and materials used to join complementary structures of the thermosiphons 64 and the heat sink 66.

FIG. 7A illustrates an exploded view of the sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system including the heat sink 66, the thermosiphons 64, and the cold side heat exchange elements 76-1 and 76-2 of FIG. 6A according to some embodiments of the present disclosure. FIG. 7B illustrates a cross-section of the exploded view of the thermosiphons 64 integrated with the heat sink 66 of FIG. 7A according to some embodiments of the present disclosure. As shown, at least a portion of each thermosiphon 64 is shaped to form a continuous structure when physically joined with a respective groove 94 of the heat sink 66. Likewise, each groove 94 is shaped to form the continuous structure when physically joined with the respective thermosiphon 64. As such, at least a portion of each thermosiphon 64 can be integrated with the heat sink 66.

The thermosiphons 64 and the heat sink 66 are formed of materials that have at least some thermally conductive properties. The material composition of the thermosiphons 64 and the heat sink 66 may include any metal, non-metal, synthetic material, or combinations thereof, that provide sufficient thermal conductivity as required in a refrigeration process. In some embodiments, the thermosiphons 64 and the heat sink 66 are made of the same type of thermally conductive material. For example, the thermosiphons 64 and the heat sink 66 may both be made of copper. Copper has well known beneficial properties for heat sinks including thermal conductivity that is roughly twice that of aluminum, and is corrosion resistant.

In some embodiments, the thermosiphons 64 and the heat sink 66 are made of different types of thermally conductive materials. For example, the thermosiphons 64 may be made of copper and the heat sink 66 may be made of aluminum. Aluminum also has well known beneficial properties for heat sinks but is less expensive than copper. In some embodiments, alloys of any thermally conductive material may be used to make the thermosiphons 64 and the heat sink 66. The materials used for the thermosiphons 64 and the heat sink 66 facilitate heat exchange between an internal environment of a cooling chamber and the heat transport medium contained in the thermosiphons 64 via the heat sink 66.

In some embodiments, forced convection may be used to augment passive heat exchange. For example, fans may be used to enhance heat extraction from an inside of a cooling chamber. The embodiments of FIGS. 3A and 3B include the forced convection unit 70 that augments the sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system. Other examples of forced convection units that may be used include blowers, inductors, other draft inducing elements, or combinations thereof.

Referring back to FIG. 3A, the forced convection unit 70 may be affixed to the heat sink 66. The forced convection unit 70 operates to cause airflow in a direction from the inside of the cooling chamber towards the heat sink 66. Operation of the forced convection unit 70 increases thermal coupling between the heat sink 66 and a volume defined by a cooling chamber. Referring back to FIG. 3B, the forced convection units 82 are affixed to heat sinks 80 at the reject side 72 of the thermoelectric cooling system 58. These forced convection units 82 operate to cause airflow to move in a direction towards an exterior environment. Operation of the forced convection units 82 augments the rejection of heat extracted from a cooling chamber. Thus, forced convection augments passive heat exchange to further decrease the temperature of a cooling chamber.

In some embodiments, the forced convection units 70 and/or 82 may be used to intermittently provide additional cooling capacity when passive heat transport alone is insufficient to achieve a desired temperature for a cooling chamber. For example, the forced convection units 70 and/or 82 may be activated during a transient period of high heat loading and deactivated during normal operation. In some embodiments, forced convection may be provided in the cooling chamber by fans that are not affixed to the thermoelectric cooling system 58 but are positioned elsewhere in a refrigerator cabinet to increase airflow towards the heat sink 66 and away from the refrigerator cabinet.

Lastly, FIG. 8 illustrates a cross-section of the cabinet 12 of the vapor compression refrigerator 10 of FIG. 1A that has been retrofit with the disclosed thermoelectric cooling system 58 of FIGS. 3A and 3B according to some embodiments of the present disclosure. As detailed above, the disclosed thermoelectric cooling system 58 has a compact and flexible design such that it can be positioned in a region of the cabinet 12 that would otherwise support components of the vapor compression system 14. As a result, the cabinet 12 can be retrofit with the thermoelectric cooling system 58 with minimal structural modifications. As shown, the rear insulated wall 28-1 of the cabinet 12 of the vapor compression refrigerator 10, which would otherwise support components of the vapor compression system 14, could accommodate the thermoelectric cooling system 58.

As shown, a majority of the accept side 62 of the thermoelectric cooling system 58 is located interior to the rear insulated wall 28-1, and a majority of the reject side 72 of the thermoelectric cooling system 58 is located exterior to the rear insulated wall 28-1. As such, the portion of the heat sink 66 that includes the fin structures 68 (not labeled) and the forced convection unit 70 faces the interior of the cooling chamber 16. The portion of the heat sink 66 that is integrated with the thermosiphons 64 faces the interior of the rear insulated wall 28-1. The thermosiphons 64 extend upward along the rear insulated wall 28-1. The uppermost portions of the thermosiphons 64 traverse the rear insulated wall 28-1 and are coupled to the cold side heat exchange element 76 of the thermoelectric heat exchangers 74, which are mounted closer to the outside of the cabinet 12 compared to existing thermoelectric cooling systems.

As shown, the reject side 72 of the thermoelectric cooling system 58 is located at least partially exterior of the rear insulated wall 28-1 of the cabinet 12. As such, the heat extracted from the inside of the cooling chamber 16 is transported to the thermoelectric heat exchangers 74 and expelled to an environment external to the cabinet 12. As indicated above, the addition of thermosiphon tubes also allows the thermoelectric heat exchangers 74 to be mounted closer to the outside of the cabinet 12 compared to existing thermoelectric cooling systems, without adding heat losses to the system, which improves the overall ability to dissipate the rejected heat away from the cabinet 12. In some embodiments, a shell or wall may be affixed to the cabinet 12 to cover features of the reject side 72 of the thermoelectric cooling system 58.

The embodiment of FIG. 8 is merely representative of a variety of ways to structurally incorporate the thermoelectric cooling system 58 into cabinets of refrigerators that are designed to house refrigeration systems other than thermoelectric cooling systems. However, the disclosure is not limited to the embodiment shown. In some embodiments, the thermoelectric cooling system 58 may be housed in a specially designed compartment of a refrigerator cabinet. In some embodiments, the thermoelectric cooling system 58 may be positioned partially or entirely within an insulated wall or on any surface of any wall of a refrigerator cabinet. Moreover, although described in the context of retrofitting existing refrigerator designs, the disclosed thermoelectric cooling system 58 may be installed in a refrigerator that is specifically designed to house the thermoelectric cooling system 58.

In summary, many current vapor compression refrigeration systems utilize fin and tube heat exchangers for the condenser and evaporator in their existing production machines. Significant cost is involved in, for example, foaming the cabinets in such a way to accept these designs. Tooling costs for changing designs that accommodate a cold wall accept (i.e., sealed condensing and evaporating system for the purpose of accepting heat into a heat pumping system) of a thermoelectric cooling system are prohibitive for many manufacturers. So a need exists for a thermoelectric cooling system design that can be installed into such cabinets with minimal changes.

In some of the disclosed embodiments, by using an aluminum heat sink capable of dissipating the heat necessary to achieve the required temperature differences within the refrigerated space, a thermoelectric device can operate at a higher efficiency. Integrating (e.g., embedding) thermosiphons into the heat sink helps spread the heat along the length of the heat sink, reducing its thermal resistance, thereby improving system performance while at the same time preventing heat leak back from the ambient environment to the chamber interior. The addition of thermosiphon tubes also allows the thermoelectric cartridge (TEC) to be mounted closer to the outside of the refrigerator cabinet compared to conventional thermoelectric cooling systems without adding additional losses to the system, which improves the overall ability to dissipate the rejected heat away from the cabinet.

Although the various embodiments detailed above are described in the context of refrigeration systems, the disclosed embodiments are not so limited. For example, embodiments of the disclosed sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system could be implemented in an apparatus operative to provide a dehydration process. As such, the disclosed sealed condensing and evaporating system 60 for the purpose of accepting heat into a heat pumping system could be used in conventional dehydration apparatuses to extract moisture from an interior of a chamber for rejection to an exterior environment in accordance with this disclosure.

Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.

	Number	Date	Country
Parent	PCT/US15/41346	Jul 2015	US
Child	14817319		US

INTEGRATION OF THERMOSIPHON TUBING INTO ACCEPT HEAT EXCHANGER

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