REFRIGERATION SYSTEM USING A THERMOELECTRIC ASSEMBLY FOR A CHILLER
A thermoelectric assembly for use with a chiller system includes a reservoir for liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly. The thermoelectric assembly includes a thermally conductive block surrounded by a housing and configured to exchange heat with the liquid coolant. Fluid passageways extend between first and second ends of the block with first and second endplates coupled to the respective first and second ends. The first and second endplates enclose respective terminal ends of the fluid passageways to interconnect the fluid passageways at the first and second ends to define a fluid flow loop within the block, with an inlet and an outlet each in fluid communication with the fluid flow loop. A heat sink is thermally coupled to the block and a thermoelectric device is in thermal communication with the block and the heat sink.
This application claims the benefit of U.S. Provisional Application Ser. No. 63/306,587 filed Feb. 4, 2022, the contents of which is hereby incorporated by reference as if set forth in its entirety herein.
TECHNICAL FIELDThis invention relates generally to heat exchangers and, more particularly, to a thermoelectric heating and cooling assembly for use with a benchtop chiller.
BACKGROUNDMany industries require the use of chillers having heat exchangers to regulate the temperature of circulated fluids. For example, chillers are frequently used in laboratories for a variety of applications, including analytical instrumentation and equipment cooling. These types of chillers, which are typically referred to as benchtop or tabletop chillers, often include one or more heat exchangers in the form of thermoelectric devices, or thermoelectric coolers, for adjusting the temperature of the fluid circulated by the chiller. For laboratory applications in particular, the development of solid state heating/cooling systems having thermoelectric devices has permitted small commercial chillers to be developed that are capable of temperature control in a variety of applications where chiller size, weight, performance, and noise are at issue.
In general, thermoelectric devices employ electrical current to absorb heat from one side of the device and dissipate the heat on an opposite side of the device. In this regard, thermoelectric devices, also known as Peltier devices, are solid state heat pumps that utilize the Peltier effect to move heat from one side of the device to the other side.
One conventional design of a solid state heating/cooling system which has thermoelectric devices is a block through which a fluid is circulated. The block may have a heat sink coupled to one side whereby ambient air is used to remove heat from the block via the heat sink. In this regard, the heat sink is coupled to the heat-dissipating side of the thermoelectric device to carry heat away from the thermoelectric device. The block is coupled to the heat absorbing side of the thermoelectric device which is used to lower the temperature of the fluid circulated through the block. To this end, a conventional block design comprises two plate halves formed from a thermally conductive metal, and further includes fluid inserts positioned between the block halves to form a fluid flow path through which the fluid is circulated through the block. The fluid inserts typically comprise tubing made from metal or another conductive material.
Historically, thermoelectric heating/cooling devices have a poor power efficiency and require large amounts of energy to achieve a given cooling capacity, which can lead to increased operating expenses. The type of solid state cooling system described above is no exception. In this regard, the solid state cooling system described above is relatively inefficient in that it is difficult to exhaust large quantities of heat rapidly from the solid state heating/cooling system, and more particularly the thermoelectric device and connected heat sink, to thereby establish a large temperature differential across the thermoelectric device for adequate heat pumping. To this end, the application of power through a thermoelectric device is a function of the desired heat pump effect and the temperature differential across the device.
Furthermore, conventional block designs used with solid state heating/cooling systems allow only minimal fluid contact with the block which is oftentimes insufficient to maintain a temperature differential across the thermoelectric device for effective heating or cooling of the fluid. Further, it can be costly to manufacture blocks with complex fluid passageways, including the fluid inserts used with the passageways, to effectuate additional heat transfer between the fluid and the block.
Therefore, it would be desirable to provide a compact solid state heating/cooling system, otherwise referred to as a thermoelectric assembly, for as a benchtop chiller that is capable of exhausting large quantities of heat rapidly from the assembly to establish a needed temperature differential across the thermoelectric device(s) for improved heating, cooling, and overall power efficiency. It is further desirable to provide a compact thermoelectric assembly that has a block design that is cost-effective to manufacture yet has a complex network of fluid passageways to maintain a temperature differential with the thermoelectric device(s) for effective heating and/or cooling of the liquid coolant circulated through the block.
SUMMARYThe present invention overcomes the foregoing and other shortcomings and drawbacks of solid state cooling systems having thermoelectric devices, particularly those for use with a benchtop chiller. While the present invention will be discussed in connection with certain embodiments, it will be understood that the present invention is not limited to the specific embodiments described herein.
According to one embodiment of the invention, a thermoelectric assembly for use as a chiller in a chiller system is provided. The chiller system includes a reservoir configured to contain a quantity of liquid coolant and a pump configured to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant. The thermoelectric assembly includes a housing and a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough. The block includes a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend, and a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block, and an inlet and an outlet each in fluid communication with the fluid flow loop. The block includes a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink. The thermoelectric assembly further includes a first fan coupled to the housing proximate one of the first end or second end of the block.
According to an aspect of the invention, the block includes a centrally disposed and axially extending bore configured to receive a heating element. In another aspect, a heating element is disposed within the axially extending bore. In a further aspect, the bore extends between the first end and the second end of the block.
According to another aspect of the invention, the plurality of fluid passageways are circumferentially spaced about the bore so as to be positioned between the bore and an outer surface of the block. In one aspect, the plurality of fluid passageways are cylindrical tubes arranged in parallel. In another aspect, each of the plurality of fluid passageways is lined with either a protective coating or a protective liner.
In yet another aspect, heat sink includes a plurality of fins that extend axially along the block.
In another aspect, each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop.
In yet another aspect, the first end and the second end of the block each include channels formed in the first and second ends, with each channel extending between two corresponding fluid passageways at the first and second ends thereof such that the channels define part of the fluid flow loop when the first and second end plates are coupled to the first and second ends of the block.
According to one aspect of the invention, the first fan is configured to move air through the housing in a direction from one of the first or second end toward the other of the first or second ends. In a further aspect, a second fan configured to move air through the housing in a direction from the same one of the first or second end toward the other of the first or second ends.
In another embodiment of the invention, a method of adjusting a temperature of a liquid coolant using a thermoelectric assembly is provided. The method includes providing the thermoelectric assembly having a thermally conductive block configured to exchange heat with the liquid coolant that flows therethrough. The block includes a plurality of fluid passageways that extend axially between a first end and a second end of the block, a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways so as to define a fluid flow loop within the block, an inlet and an outlet each in fluid communication with the fluid flow loop, a heat sink thermally coupled to at least one side of the block, and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink. The method includes receiving the liquid coolant having a first temperature into the fluid flow loop through the inlet opening in the block and circulating the liquid coolant through the fluid flow loop. The method further includes transferring energy between the liquid coolant and the block to adjust the temperature of the liquid coolant to an adjusted second temperature by operating the at least one thermoelectric device as follows: applying a current to the at least one thermoelectric device to transfer heat energy between the block and the heat sink to lower the temperature of the liquid coolant and discharging the liquid coolant from the block at the adjusted second temperature.
According to an aspect of the invention, the step of transferring energy between the liquid coolant and the block to adjust the temperature of the liquid coolant further includes reversing the current to the at least one thermoelectric device to transfer heat energy between the heat sink and the block to raise the temperature of the liquid coolant.
According to another aspect of the invention, the block further includes at least one heating element positioned in a centrally disposed and axially extending bore in the block, and the method further includes applying a current to the at least one heating element to transfer heat energy between the at least one heating element and the block to raise the temperature of the liquid coolant. According to another aspect, the method further includes determining whether current is being applied to the at least one heating element and, if current is being applied to the at least one heating element, reversing the current to the at least one thermoelectric device. In yet another aspect, the method includes delaying the step of reversing the current to the at least one thermoelectric device for a period of time if it is determined that current is being applied to the at least one heating element.
According to one aspect of the invention, the thermoelectric assembly further includes a housing surrounding the block with a first fan coupled to the housing proximate one of the first end or second end of the block, and the method further includes operating the first fan to flow air through the housing in a direction from one of the first or second end toward the other of the first or second ends. In another aspect, the thermoelectric assembly further includes a second fan coupled to the housing proximate to the other one of the first or second end of the block, and the method further includes operating the second fan to flow air through the housing in a direction from one of the first or second end toward the other of the first or second ends.
According to one aspect of the invention, the step of circulating the liquid coolant through the fluid flow loop further includes moving the liquid coolant between the first end and the second end of the block.
In another aspect, the plurality of fluid passageways are cylindrical tubes arranged in parallel. In yet another aspect, the block includes at least one thermoelectric device and heat sink thermally coupled to at least one side of the block. In another aspect, each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop.
According to one aspect of the invention, the first end and the second end of the block each include channels formed in the first and second ends, with each channel extending between two corresponding fluid passageways at the first and second ends thereof such that the channels define part of the fluid flow loop when the first and second end plates are coupled to the first and second ends of the block.
According to another embodiment of the invention, a block for use with a chiller system is provided. The block is configured to control a temperature of a liquid coolant that flows through the block, and includes a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend and a first endplate coupled to the first end and a second endplate coupled to the second such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block. The block also includes an inlet and an outlet each in fluid communication with the fluid flow loop.
According to an aspect of the invention, the block includes a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink.
According to another embodiment of the invention, a thermoelectric assembly for use with a chiller system having a reservoir containing a quantity of liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant is provided. The thermoelectric assembly includes a housing and a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough. The thermally conductive block includes a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend. The block includes a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block. The block further includes an inlet and an outlet each in fluid communication with the fluid flow loop. The first end and the second end of the block each include channels formed in the first and second ends, and each channel extends between two corresponding fluid passageways at the first and second ends thereof such that the channels define part of the fluid flow loop when the first and second end plates are coupled to the first and second ends of the block. The block further includes a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink, and a centrally disposed and axially extending bore configured to receive a heating element. The thermoelectric assembly includes a first fan coupled to the housing proximate one of the first end or second end of the block.
According to another embodiment of the invention, a thermoelectric assembly for use with a chiller system having a reservoir containing a quantity of liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant is provided. The thermoelectric assembly includes a housing and a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough. The thermally conductive block includes a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend. The block includes a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block. The block includes an inlet and an outlet each in fluid communication with the fluid flow loop. Each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop. The block further includes a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink. The thermoelectric assembly includes a first fan coupled to the housing proximate one of the first end or second end of the block.
According to yet another embodiment of the invention, a thermoelectric assembly for use with a chiller system having a reservoir containing a quantity of liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant is provided. The thermoelectric assembly includes a housing and a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough. The block includes a first end and a second end located at opposite longitudinal ends of the block between which a fluid flow loop extends within the block and an inlet and an outlet each in fluid communication with the fluid flow loop. The fluid flow loop includes a helical fluid passageway section that extends helically between the first end and the second end of the block. The block includes a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink. The thermoelectric assembly includes a first fan coupled to the housing proximate one of the first end or second end of the block.
Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of one or more illustrative embodiments taken in conjunction with the accompanying drawings.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the one or more embodiments of the invention.
Aspects of the present invention are directed to a thermoelectric assembly for use with a recirculating chiller system. The recirculating chiller system may have an open-loop or closed-loop configuration and uses a continuous flow of fluid, such as a liquid coolant, circulated through appropriate fluid lines to remove heat from an object in contact with the circulated fluid, either directly or indirectly, such as laboratory equipment, for example. As described in further detail below, the chiller system circulates the fluid through the thermoelectric assembly and, more particularly, a thermally conductive block housed within the thermoelectric assembly used as a chiller to adjust a temperature of the fluid coolant to thereby maintain a desired temperature of the object or application that is in direct or indirect contact with the fluid being circulated by the chiller system. However, while aspects of the thermoelectric assembly are shown and described in the context of a closed-loop benchtop recirculating chiller system, it will be understood that the same inventive concepts related to aspects of the thermoelectric assembly may be implemented with different heating and/or cooling applications and systems without departing from the scope of the invention. More particularly, in its broader aspects, the inventive concepts related to the thermoelectric assembly may be implemented in any application that requires temperature control of a circulated or recirculated fluid. To this end, the drawings are not intended to be limiting.
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In one embodiment, the fluid circuit 30 is configured to circulate water as the fluid coolant 34. In another embodiment, the fluid coolant 34 may be a mixture of water and ethylene glycol or a mixture of polyethylene glycol and water, for example. However, it will be understood that the inventive concepts of the thermoelectric assembly 12 may be implemented with different chiller circuits configured to circulate other types of coolants which may be any liquid or gas used to regulate the temperature of a connected system, object, or application.
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To facilitate airflow into or out from the housing 70, or intermixing of multiple airflows, one or more sidewalls 90 of the housing 70 may include at least one perforated section 96. As shown in
As briefly described above, the first fan 78 and the second fan 82 are configured to move air through the chiller 10 and the housing 70 of the thermoelectric assembly 12. In this regard, as shown in
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While each heat sink 86 is shown and described as having a fin-type heat transfer geometry, it is understood that the fins 118 extending from the base 120 of each heat sink 86 may be replaced with other geometries. For example, the rectangle-shaped fins 118 may be replaced with square-shaped plates, trapezoidal shaped plates, or any other polygonal-shaped plate, for example. In one embodiment, the fins 118 may be replaced with a plurality of pins. The pins may be cylindrical in shape and may extend from the base 120 at any angle within the range of between 20° to 90°, for example. This pins may be aligned in parallel rows along the base 120 or, alternatively, staggered, or in a randomized arrangement. In another embodiment, the pins may have a cross-sectional shape that is oval or non-circular, such as square, triangle, diamond, or other polygonal shape. To this end, it is understood that geometries of the fins 118, the arrangement of the fins 118, and the number of the fins 118 may be changed to maximize heat dissipation. Furthermore, each heat sink 86 may be formed using a three-dimensional printing (3D printing) process such as selective laser melting (SLM), direct metal laser sintering (DMLS), selective laser sintering (SLS), fused deposition modeling (FDM), and stereolithography (SLA). The heat sinks 86 may be formed from 3D printable material selected to maximize thermal conductivity, such as aluminum, copper, or another thermally conductive material.
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The first mount bracket 130 is coupled to the first open end 80 of the housing 70 and between the first fan 78 and the housing 70. More particularly, a proximal end 134 of the first bracket 130 is coupled to the first end 80 of the housing 70 and the first fan 78 is coupled to an opposite, distal end 136 of the first bracket 130. The fan 78 and housing 70 are spaced apart by a width of the bracket 130, which is defined as a distance between the proximal and distal ends 134, 136. The first bracket 130 may be coupled to the housing 70 and fan 78 with suitable hardware, such as with one or more bolts, for example. The first bracket 130 has a generally square-shaped profile and includes four angled sidewalls 138 that extend between the proximal and distal ends 134, 136 of the bracket 130. The sidewalls 138 are angled in a radially inward direction from the proximal end 134 to the distal end 136, as shown in
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In the embodiment shown, the block 76 includes six fluid passageways 186. However, the block 76 may include fewer or more fluid passageways 186 to increase or decrease fluid contact between the block 76 and fluid coolant 34, as desired. As shown, each fluid passageway 186 includes a first terminal end 196 located at the first end 108 of the block 76 and a second terminal end 198 located at the second end 110 of the block 76 between which the fluid passageway extends 186. Thus, each fluid passageway 186 is a tubular bore that extends through the block 76 and along an elongate length of the block 76 (e.g., a length of the block 76 between the first and second opposite longitudinal ends 108, 110 of the block 76). To this end, each fluid passageway 186 is shaped as a cylindrical tube having a diameter and a length, the length being defined as a distance between the first and second terminal ends 196, 198. While each fluid passageway 186 has a circular cross-sectional shape (the cross-sectional area may be defined as a plane disposed transverse to the longitudinal axis of the block 76), it is understood that the fluid passageways 186 may be configured to have other cross-sectional shapes, such as rectangular, elliptical, or any other polygonal shape, for example. In either case, the plurality of fluid passageways 186 are circumferentially spaced apart about a the centrally disposed bore 188 and longitudinal center axis of the block 76, as best shown in
In one embodiment, each fluid passageway 186 may include a protective coating, such as a thin layer of Teflon for chemically isolating the block 76 from the fluid coolant 34. In another embodiment, each fluid passageway 186 may include a liner such as an embedded hollow tube formed from a conductive material such as copper or other suitable material, for example.
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In one embodiment, the heating element 204 may have a diameter that is similar to that of the centrally disposed bore 188 in which the heating element 204 is positioned. That way, the heating element 204 is closely received within the bore 188 such that mutual contact is maintained between the bore 188 and the heating element 204 to best transfer heat energy between the heating element 204 and the block 76. Alternatively, the bore 188 may include several heating elements 204 positioned end-to-end and/or side-by-side within the bore 188 to increase heat transfer, for example. While the bore 188 is shown having a circular cross-sectional shape (the cross-sectional area may be defined as a plane disposed transverse to the longitudinal axis of the block 76), it is understood that the bore 188 may be configured to have other cross-sectional shapes, such as rectangular, elliptical, or any other polygonal shape, for example.
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During operation of the thermoelectric devices 184 the thermally conductive block 76 is configured to exchange heat with the fluid coolant 34 that flows through the block 76. In this regard, the block 76 includes the first endplate 190 the second endplate 192 which are configured to be coupled to corresponding first and second ends 108, 110 of the block 76 to define the fluid flow loop 194 (
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To improve engagement and sealing between the first endplate 190 and the first end 108 of the block 76, a gasket 246 may be located therebetween. In this regard, the gasket 246 is sized to cover the first side 224 of the endplate 190 and the countersunk surface 240. The gasket 246 includes a number of apertures 248 that each correspond to an element of the first endplate 190, such as the channels 238, the centrally disposed bore 234, the mounting bores 236, and the notch 230, example. To this end, the gasket 246 may be formed from any suitable material such as silicone, neoprene, nitrile, ethylene propylene diene monomer (EPDM), or other suitable material, for example.
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The second end 110 of the block 76 also includes a countersunk surface 262 that corresponds to the shape of the second endplate 192, and more particularly the first end 250 of the endplate 192. The countersunk surface 262 is recessed into the block 76 a depth, in an axially inward direction, from an outer surface 264 of the second end 110 of the block 76. In this regard, the depth of the countersunk surface 262 corresponds generally to a thickness of the second endplate 192 (e.g., a distance between the first end 250 and the second end 252 of the endplate 192) such that when the second endplate 192 is coupled to the second end 110 of the block 76, the second end 252 of the endplate 192 is positioned generally flush with the outer surface 264 of the second end 110 of the block 76. Similar to the first endplate 190, a gasket 268 may also be used to improve engagement and sealing between the second endplate 192 and the second end 110 of the block 76. The gasket 268 is sized to cover the first side 250 of the endplate 192 and the countersunk surface 262, and includes a number of apertures 270 that each correspond to an element of the second endplate 192, such as the channels 260, the centrally disposed bore 256, and the mounting bores 258, for example.
In one embodiment, the thermally conductive block 76 is formed as a monolithic piece, and may be formed using known manufacturing methods such as computer numerical control (CNC) machining which employs machining techniques such as turning, milling, surface grinding, electrical discharge milling, cylindrical grinding, and/or optical grinding, for example. In this regard, a single block of thermally conductive material is machined to form the thermally conductive block 76 having fluid passageways 186, a centrally disposed bore 188, projections 210, and the countersunk surfaces 240, 262, for example. To this end, the block 76 may comprise any suitable thermally conductive material such as aluminum, copper, or steel, for example.
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As fluid coolant 34 is circulated through the block 76, the temperature of the fluid coolant 34 is changed through operation of the thermoelectric devices 184 and/or heating element 204. In this regard, the fluid coolant 34 may have a first temperature as it enters the block 76. As the fluid coolant 34 is circulated through the fluid flow loop 194, the temperature of the fluid coolant 34 is adjusted or changed as a result of heat transfer through contact between the fluid coolant 34 and the block 76. The thermoelectric devices 184 and/or heating element 204 are operated to transfer energy between the fluid coolant 34 and the block 76 to adjust the temperature of the fluid coolant 34 to a second temperature. To this end, the fluid coolant 34 exits the block 76 at the second temperature, which may be a higher or lower temperature compared to the first temperature.
To lower the temperature of the fluid coolant 34 as it travels through the block 76 and the fluid flow loop 194, the controller 52 is configured to apply a current to the thermoelectric devices 184 to transfer heat energy between the block 76 and each heat sink 86 to lower the temperature of the block 76 and, as a result, the temperature of the fluid coolant 34 in contact with the block 76. To raise the temperature of the fluid coolant 34 as it travels through the block 76 and the fluid flow loop 194, the controller 52 is configured to reverse the current, or apply a reversed current, to the thermoelectric devices 184 to transfer heat energy between each heat sink 86 and the block 76 to raise the temperature of the block 76 and, as a result, the temperature of the fluid coolant 34 in contact with the block 76.
The heating element 204 may be operated to maintain or raise the temperature of the fluid coolant 34 as it travels through the block 76 and the fluid flow loop 194. In this regard, the controller 52 is configured to apply a current to the heating element 204 to transfer heat energy between the heating element 204 and the block 76 to raise the temperature of the block 76 and, as a result, the temperature of the fluid coolant 34 in contact with the block 76. In one embodiment, the controller 52 may be configured to operate the heating element 204 and the thermoelectric devices 184 at the same time to raise the temperature of the fluid coolant 34. For example, the controller 52 may be configured to simultaneously apply a current to the heating element 204 and to reverse the current to the thermoelectric devices 184. In another embodiment, the controller 52 may be configured to only operate the heating element 204 or the thermoelectric devices 204 to raise the temperature of the fluid coolant 34. To maintain a temperature of the fluid coolant 34, the controller 52 may be configured to apply a current to the thermoelectric devices 184 to lower the temperature of the fluid coolant 34 while simultaneously applying a current to the heating element 204 to raise a temperature of the fluid coolant 34 to thereby achieve a desired temperature of the fluid coolant 34. The controller 52 may be programmed to determine whether current is being applied to the heating element 204 and, if current is being applied to the heating element 204, reversing the current to the thermoelectric devices 184. Further, if it is determined that current is being applied to the heating element 204, the controller 52 may be programmed to delay the step of reversing the current to the thermoelectric devices 184 for a predetermined period of time, such as for a few seconds to a few minutes, for example.
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As shown, the first end 108a of the block 76a includes a countersunk surface 240a that corresponds to the shape of the first endplate 190a, and more particularly the first end 224a of the endplate 190a. The countersunk surface 240a is recessed into the block 76 a depth, in an axially inward direction, from an outer surface 242a of the first end 108a of the block 76a. The depth of the countersunk surface 242a corresponds generally to a thickness of the first endplate 190a such that when the first endplate 190a is coupled to the first end 108a of the block 76, as shown, the second end 226a of the endplate 190a is positioned generally flush with the outer surface 242a of the first end 108a of the block 76. Like the previously described embodiment, a gasket 246 may be located between the first endplate 190a and the block 76a. The countersunk surface 240a also defines a rectangular shaped pad 244a which corresponds to the shape of the notch 230a in the endplate 190a. Similar to the previously described embodiment, two adjacent fluid passageways 186a extend through the pad 244a such that the first terminal end 196a of the two fluid passageways 186a is located in the outer surface 242a of the first end 108a of the block 76a. However, unlike the first endplate 190 of the previously described embodiment, the endplate 190a of this embodiment does not include channels 238. Rather, except for the bores 234a, 236a, the first end 224a of the endplate 190a is a solid surface configured to enclose the terminal ends 196 of the fluid passageways 186a to define part of the fluid flow loop 194a, as described in further detail below.
To direct fluid flow between adjacent fluid passageways 186a, the first end 108a of the block 76a includes three grooves 280 formed in the countersunk surface 240a. Each groove 280 is generally oval, or pill-shaped, and extends between terminal ends 196a of two adjacent fluid passageways 186a so as to fluidly connect the two adjacent fluid passageways 186a. Each groove 280 extends a depth into the block 76a in an axial direction from the countersunk surface 240a. In this regard, when the first endplate 190a is coupled to the first end 108a of the block 76a, each groove 280 is configured to direct fluid coolant flow between corresponding adjacent fluid passageways 186a to form part of the fluid flow loop 194a.
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Similar to the first end 108a of the block 76, the countersunk surface 262a of the second end 110a of the block 76a also includes grooves 282 to direct fluid flow between adjacent fluid passageways 186a. The second end 110a of the block 76a includes four grooves 282 to interconnect the terminal ends 198a of all six fluid passageways 186a. In this regard, each groove 282 is generally oval, or pill-shaped, and extends between terminal ends 198a of two adjacent fluid passageways 186a so as to fluidly connect the two adjacent fluid passageways 186a. Thus, when the second endplate 192a is coupled to the second end 110a of the block 76, each groove 282 is configured to direct fluid coolant flow between corresponding adjacent fluid passageways 186a to form part of the fluid flow loop 194a. To this end, the fluid flow loop 194a is formed once each of the first and second endplates 190a, 192a are coupled to the respective first and second ends 108a, 110a of the block 76a. Fluid coolant may be circulated through the fluid flow loop 194a of this embodiment to be heated and/or cooled in a similar way compared to the fluid flow loop 194 of the previously described embodiment.
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The block 300 of this embodiment may be formed using a three-dimensional printing (3D printing) manufacturing method according to an embodiment of the invention. 3D printing of the block 300 is achieved using an additive process, where successive layers of material are laid down in different shapes to build the structures that define the block 300. The term 3D printing, as used herein, may refer to methods such as, but not limited to, selective laser melting (SLM), direct metal laser sintering (DMLS), selective laser sintering (SLS), fused deposition modeling (FDM), and stereolithography (SLA). Further, any type of 3D printing machine that can print the materials described herein may be used.
Before 3D printing of the block 300 may begin, a 3D printing machine being used to form the block 300 must first receive a dataset corresponding to the block 300. The dataset may be a computer-readable three-dimensional model suitable for use in manufacturing the block 300. In particular, the model includes information regarding the characteristics of the block 300 from which the 3D printing machine can form the block 300. The model may be a 3D printable file such as an Stereolithography file, for example. The dataset may also be in the form of a computer program product embodied on a non-transitory computer readable medium storing executable instructions for forming the block 300 using a 3D printing machine.
Computer-readable storage media, which is inherently non-transitory, may include volatile and non-volatile, and removable and non-removable tangible media implemented in any method or technology for storage of data, such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media may further include RAM, ROM, erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other solid state memory technology, portable compact disc read-only memory (CD-ROM), or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store data and which can be read by a computer. A computer-readable storage medium should not be construed as transitory signals per se (e.g., radio waves or other propagating electromagnetic waves, electromagnetic waves propagating through a transmission media such as a waveguide, or electrical signals transmitted through a wire). Computer-readable program instructions may be downloaded to a computer, another type of programmable data processing apparatus, or another device from a computer-readable storage medium or to an external computer or external storage device or server via a network.
Computer-readable program instructions stored in a computer-readable medium may be used to direct a computer, other types of programmable data processing apparatuses, or other devices to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions that implement the functions, acts, or operations specified in the flowcharts, sequence diagrams, or block diagrams. The computer program instructions may be provided to one or more processors of a general purpose computer, a special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the one or more processors, cause a series of computations to be performed to implement the functions, acts, or operations specified in the text of the specification, flowcharts, sequence diagrams, or block diagrams.
Once the 3D printing machine has been provided with a model or computer-readable program instructions suitable for use in manufacturing the block 300, the 3D printing machine may be operated to lay down successive layers of the desired material to build the block 300. The material used to form the block 300 may be, for example, thermally conductive 3D printable material such as aluminum, copper, or other 3D printable thermally conductive material.
While the invention has been illustrated by the description of various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Thus, the various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.
Claims
1. A thermoelectric assembly for use with a chiller system having a reservoir containing a quantity of liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant, comprising:
- a housing;
- a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough, the block comprising: a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend, and a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block, and an inlet and an outlet each in fluid communication with the fluid flow loop; a heat sink thermally coupled to at least one side of the block; and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink; and
- a first fan coupled to the housing proximate one of the first end or second end of the block.
2. The thermoelectric assembly of claim 1, further comprising a heating element positioned in the block, wherein the block includes a centrally disposed and axially extending bore.
3. The thermoelectric assembly of claim 2, wherein the bore extends between the first end and the second end of the block.
4. The thermoelectric assembly of claim 2, wherein the plurality of fluid passageways are circumferentially spaced about the bore so as to be positioned between the bore and an outer surface of the block.
5. The thermoelectric assembly of claim 1, wherein the heat sink includes a plurality of fins that extend axially along the block.
6. The thermoelectric assembly of claim 1, wherein the plurality of fluid passageways are cylindrical tubes arranged in parallel.
7. The thermoelectric assembly of claim 1, wherein each of the plurality of fluid passageways is lined with either a protective coating or a protective liner.
8. The thermoelectric assembly of claim 1, wherein each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop.
9. The thermoelectric assembly of claim 1, wherein the first end and the second end of the block each include channels formed in the first and second ends, with each channel extending between two corresponding fluid passageways at the first and second ends thereof such that the channels define part of the fluid flow loop when the first and second end plates are coupled to the first and second ends of the block.
10. The thermoelectric assembly of claim 1, wherein the first fan is configured to move air through the housing in a direction from one of the first or second end toward the other of the first or second ends.
11. The thermoelectric assembly of claim 10, further comprising a second fan configured to move air through the housing in a direction from the same one of the first or second end toward the other of the first or second ends.
12. A method of adjusting a temperature of a liquid coolant using a thermoelectric assembly having a thermally conductive block configured to exchange heat with the liquid coolant that flows therethrough, the block comprising a plurality of fluid passageways extending axially between a first end and a second end of the block, a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways so as to define a fluid flow loop within the block, an inlet and an outlet each in fluid communication with the fluid flow loop, a heat sink thermally coupled to at least one side of the block and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat, the method comprising:
- receiving the liquid coolant having a first temperature into the fluid flow loop through the inlet opening in the block;
- circulating the liquid coolant through the fluid flow loop;
- transferring energy between the liquid coolant and the block to adjust the temperature of the liquid coolant to an adjusted second temperature by operating the at least one thermoelectric device as follows: applying a current to the at least one thermoelectric device to transfer heat energy between the block and the heat sink to lower the temperature of the liquid coolant; and
- discharging the liquid coolant from the block at the adjusted second temperature.
13. The method according to claim 12, wherein the step of transferring energy between the liquid coolant and the block to adjust the temperature of the liquid coolant further comprises:
- reversing the current to the at least one thermoelectric device to transfer heat energy between the heat sink and the block to raise the temperature of the liquid coolant.
14. The method according to claim 12, wherein the block further includes at least one heating element positioned in a centrally disposed and axially extending bore in the block, the method further comprising:
- applying a current to the at least one heating element to transfer heat energy between the at least one heating element and the block to raise the temperature of the liquid coolant.
15. The method according to claim 14, further comprising:
- determining whether current is being applied to the at least one heating element; and
- if current is being applied to the at least one heating element, reversing the current to the at least one thermoelectric device.
16. The method according to claim 15, wherein if current is being applied to the at least one heating element, delaying the step of reversing the current to the at least one thermoelectric device for a period of time.
17. The method according to claim 12, wherein the thermoelectric assembly further includes a housing surrounding the block with a first fan coupled to the housing proximate one of the first end or second end of the block, the method further comprising:
- operating the first fan to flow air through the housing in a direction from one of the first or second end toward the other of the first or second ends.
18. The method according to claim 17, wherein the thermoelectric assembly further includes a second fan coupled to the housing proximate to the other one of the first or second end of the block, the method further comprising:
- operating the second fan to flow air through the housing in a direction from one of the first or second end toward the other of the first or second ends.
19. The method according to claim 12, wherein the step of circulating the liquid coolant through the fluid flow loop comprises moving the liquid coolant between the first end and the second end of the block.
20. The method according to claim 13, wherein the plurality of fluid passageways are cylindrical tubes arranged in parallel.
21. The method according to claim 12, wherein the block includes at least one thermoelectric device and heat sink thermally coupled to at least one side of the block.
22. The method according to claim 12, wherein each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop.
23. The method according to claim 12, wherein the first end and the second end of the block each include channels formed in the first and second ends, with each channel extending between two corresponding fluid passageways at the first and second ends thereof such that the channels define part of the fluid flow loop when the first and second end plates are coupled to the first and second ends of the block.
24. A thermoelectric assembly for use with a chiller system having a reservoir containing a quantity of liquid coolant and a pump to circulate the liquid coolant through the thermoelectric assembly to control a temperature of the liquid coolant, comprising:
- a housing;
- a thermally conductive block surrounded by the housing and configured to exchange heat with the liquid coolant that flows therethrough, the block comprising: a first end and a second end located at opposite longitudinal ends of the block between which a plurality of fluid passageways extend, and a first endplate coupled to the first end and a second endplate coupled to the second end such that the first and second endplates enclose respective terminal ends of the plurality of fluid passageways to interconnect the plurality of fluid passageways at the first and second ends to define a fluid flow loop within the block, and an inlet and an outlet each in fluid communication with the fluid flow loop, wherein each of the first and second endplates includes channels formed in the first and second endplates, with each channel being configured to direct flow of the liquid coolant between two corresponding fluid passageways of the fluid loop; a heat sink thermally coupled to at least one side of the block; and at least one thermoelectric device thermally coupled between the side of the block and the heat sink so as to be in thermal communication with the block and the heat sink; and
- a first fan coupled to the housing proximate one of the first end or second end of the block.
Type: Application
Filed: Feb 3, 2023
Publication Date: Aug 10, 2023
Inventors: Warren C Prouty (Danville, NH), Ashok Balakrishnan (Karnataka), Rajsekhar Krapa (Telangana), Vivek Silwal (Uttarakhand)
Application Number: 18/164,047