Abstract:
An apparatus for cooling foodstuffs using a thermoelectric cooling module, which is aided by a heatsink formed from a planer sheet into a corrugated fin. The heatsink has a series of land and grooves, which are spaced apart from each other by a substantially planer intermediate portion. The heatsink further includes indentations on the intermediate portion between the lands and grooves, which create a turbulent airflow through the heatsink. The heatsink further includes a plurality of apertures that are formed into the grooves for allowing water to drain out of the heatsink, if any condenses and collects in the grooves of the heatsink.

Description:
BACKGROUND  
       [0001]     The present invention relates to a cooler for adjusting the temperature of the contents thereof, and more particularly, to a cooler including a thermoelectric cooling apparatus including a heatsink and/or a coldsink formed from a substantially planar sheet material.  
         [0002]     For the sake of convenience and not by way of limitation in any manner, the use of the term “cooler” in this disclosure will refer to any apparatus that is capable of defining a volume to chill or freeze foodstuffs. The volume is preferably insulated from heat exchange with the exterior environment. Further, the term “cooler” is intended to include other common apparatuses, such as a container, thermos, ice box, bottle, box, can, storage tank, or any other suitable receptacle.  
         [0003]     A refrigerator is one common apparatus useful for adjusting the temperature of the contents thereof. However, in certain situations the refrigerator has several disadvantages. A primary disadvantage is that the refrigerator requires a complex system to chill or freeze foodstuffs including a compressor, heat-exchanging pipes, an expansion valve, and a refrigerant. A secondary disadvantage is that the refrigerator requires a motor, and thus can be noisy to operate. A third disadvantage is that the refrigerator is costly to produce and operate.  
         [0004]     Another common apparatus for adjusting the temperature of the contents thereof uses a thermoelectric module, commonly known as a Peltier device. Thermoelectric modules are small solid-state devices that function as a heat pump to either cool or heat a target volume. The modules may be configured with any desired dimensions and are particularly useful in smaller dimensions where complex systems cannot be configured to operate efficiently or are space limited. Generally, in one configuration, for example only and not for limitation, a thermoelectric module includes two electric conductors, two ceramic plates and an array of small bismuth telluride cubes disposed between the ceramic plates. Heat transfer across the plates occurs when a direct current is applied to the two conductors. Further, to increase the rate of heat transfer at least one heat exchanger is commonly added to the thermoelectric module.  
         [0005]     However, the conventional Peltier device including a heat exchanger has several disadvantages. As is well know in the art, a higher heat transfer rate may be achieved by increasing the effective heat transfer area of the heatsink exposed to the surrounding medium. The larger surface area aids in both conduction and convention cooling of the target volume, as desired.  
         [0006]     A common example of a heatsink is a fin-type heatsink that includes a base plate, in thermal contact with one side of the Peltier device. Further, a series of fins, or protrusions, extend perpendicularly away from the base and extend into the volume. Obviously, a pair of such heatsinks is preferred and in this disclosure one side which draws heat, or cools the volume, will be referred to as the “coldsink” and the other side which rejects heat, or heats the volume, will be referred to as the “heatsink.” 
         [0007]     However, conventional heatsink/coldsink design is limited due to the required thickness of the fins, so that the fins will support their own weight and will collapse or come into contact with adjacent fins. Accordingly, conventional fin-type heat exchangers have relatively thick fins, i.e. greater than 0.080 inches. This limitation is the result of the manufacturing processes necessary to produce the heat exchanger. The fins are commonly either extruded or milled, which are both time intensive and costly. Further, the tooling necessary for both processes requires a thicker fin and spacing therebetween. Consequently, the potential surface area of the heat exchanger and spacing of the fins per square inch of base is physically limited.  
         [0008]     Therefore, there is a need in the art for a cooler including a thermoelectric cooling apparatus having a more efficient (i.e. more fins, thinner fins, closer spacing, and more surface area per given square inch of base) and cost effective heatsink, that is easy to manufacture. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Certain embodiments are shown in the drawings. However, it is understood that the present disclosure is not limited to the arrangements and instrumentality shown in the attached drawings, wherein:  
         [0010]      FIG. 1  illustrates a partially exploded, cut-away perspective view of a cooler with a thermoelectric cooling apparatus;  
         [0011]      FIG. 2  is a detailed assembly view of the thermoelectric cooling apparatus;  
         [0012]      FIG. 3  is a detailed, exploded end view of the thermoelectric cooling apparatus of  FIG. 2 ;  
         [0013]      FIG. 4  is a schematic representation of air movement though one of the heat exchangers;  
         [0014]      FIGS. 5A and 5B  are schematic representations of electrical circuits for operation of embodiments of the cooler; and  
         [0015]      FIG. 6  is a schematic representation view of air movement through one of the heat exchangers. 
     
    
     DETAILED DESCRIPTION  
       [0016]     For the purposes of promoting and understanding the principles disclosed herein, reference will now be made to the preferred embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope is thereby intended. Such alterations and further modifications in the illustrated device and such further applications are the principles disclosed as illustrated therein as being contemplated as would normally occur to one skilled in the art to which this disclosure relates.  
         [0017]     In accordance with one principle aspect of the present disclosure, a thermoelectric cooling apparatus comprises a thermoelectric module including a heatsink contiguous with one side of the thermoelectric module and a coldsink contiguous with another side of the thermoelectric module. At least one of the heatsink and the coldsink is configured from a generally continuous planar element and includes a series of lands and opposing grooves, which are each defined about a fold line normal to a longitudinal axis of the continuous planar element. Further, a substantially planar intermediate portion is disposed between each adjacent land and groove. Each groove is contiguous with the thermoelectric module so that heat is transferred by the Peltier effect when direct current is applied to the thermoelectric module.  
         [0018]     In accordance with another principal aspect of the present disclosure, the cooler comprises walls that enclose a volume. A thermoelectric module is connected to one of the walls such that a heatsink, contiguous with one side of the thermoelectric module, is disposed external to the volume and a coldsink, contiguous with another side of the thermoelectric module, is disposed within the volume of the cooler. At least one of the heatsink and the coldsink is configured from a generally continuous planar element and includes a series of lands and opposing grooves, which are each defined about a fold line normal to a longitudinal axis of the continuous planar element. Further, a substantially planar intermediate portion is disposed between each adjacent land and groove. Each groove is contiguous with the thermoelectric module so that heat is transferred by the Peltier effect when direct current is applied to the thermoelectric module.  
         [0019]     In another aspect of the present disclosure, at least one aperture is formed in at least one of the lands and/or grooves adjacent the respective fold line. In another aspect of the present disclosure, at least one offset element is formed in the intermediate portion of the heat exchanger extending along the longitudinal axis.  
         [0020]     In another aspect of the present disclosure, a flange couples at least one of the heatsink and coldsink to the thermoelectric module. In another aspect of the present disclosure, the flange includes a plurality of channels that are complementary to the grooves on the heatsink and/or coldsink.  
         [0021]     In another aspect of the present disclosure, a plurality of offset elements are formed in each intermediate portion of the heat exchanger so that adjacent offset elements each project to an opposite side of the intermediate portion.  
         [0022]      FIG. 1  illustrates a cooler  86  including a pair of thermoelectric apparatuses  20  and a plurality of vertical walls  80  and a mounting wall  81  (collectively, the walls) which define a volume  82 . The walls  80  and mounting wall  81  may be made of any suitable structural product, such as, for example, a preferred material would include, polystyrene which has been injected, extruded or blow molded, or any other suitable product that provides structural support for the cooler  86  and insulation for the volume  82 . Indicia may be provided on the exterior of the walls  80  or on a sheath (not shown) contiguous with the walls  80  to show the contents disposed within the volume  82 . The mounting wall  81  facilitates installation and operation of the thermoelectric apparatuses  20  and fan  84 .  
         [0023]     A lid  28  is configured as the removable top portion of the cooler  86  and includes a hinged door  30  that permits access to the otherwise enclosed volume  82  of the cooler  86 . The lid  28  further includes a bridge portion  83  having a front  102  disposed above the door  30 , opposing ends  104 ,  106  and a top  108 . The bridge portion  83  and the mounting wall  81  cooperatively define a volume that functions as an upper air channel when the cooler  86  is operative. Vents  32  are formed in each of the opposing ends  104 ,  106  and extend onto the top  108  so that the fan  84 , when operative, draws air into the upper air channel and over heatsinks  24  of the thermoelectric apparatus  20  that are disposed in the air channel. A spacer  90  is disposed in the upper air channel to facilitate efficient routing of the air. A vent  33  is formed in the top  108  of the bridge portion  83  to exhaust air drawn into the upper air channel by the fan  84 . Further operation of the cooler  86  will be disclosed in more detail below.  
         [0024]     Equipment (not shown) is disposed in the upper air channel and includes the necessary electrical and electronic components for the operation of the thermoelectric apparatus  20 , which will be recognized by one of skill in the art and is discussed in greater detail in reference to  FIG. 5 .  
         [0025]     The thermoelectric apparatus  20 , in this embodiment, is connected to the mounting wall  81  such that the coldsinks  26  are disposed within the volume  82  in order to facilitate adjustment of the temperature thereof. A deflector plate  54 , connected to the walls  80  and the mounting wall  81 , cooperatively define a lower air channel. The coldsinks  26  and the fan  84  are disposed in the lower air channel. The deflector plate  54 , in this embodiment, is configured as a plastic element that is connected to the mounting wall  81  and rear wall  80  and is spaced, at each end, from opposing side walls so that the fan  84  may exhaust air drawn into the lower air channel through a bottom air vent  34 . A drip hole  42  is configured as an aperture formed in the bottom wall of the cooler  86  that defines a passage from inside the volume  82  to the outside of the volume  82 . A wick  40  is disposed outside of the volume  82  such that condensate, i.e., water, passing through the drip hole  42  must flow over the wick  40  in a convoluted path to a catch pan  52 .  
         [0026]     A rack element  36  is disposed adjacent each of the vertical walls  80  and the bottom wall to support the contents thereof and space the contents from the walls to avoid contact with any condensate. A thermometer  38  may be provided to display a temperature within the volume.  
         [0027]     In one embodiment, a thermometer  38  may be provided that is operatively coupled to appropriate equipment, as will be recognized by one of skill in the art, so that the thermoelectric apparatus  20  may be electronically controlled to adjust the temperature within the volume  82 .  
         [0028]      FIG. 2  illustrates an exploded view of the thermoelectric apparatus  20 . The thermoelectric module  22  is centrally located within the thermoelectric apparatus  20 . As discussed above, the thermoelectric module is of conventional design. For example, it has been discovered that, in one embodiment, a CP Series solid-state thermoelectric cooler from Melcor Corporation of Trenton, N.J. performs in accordance with the present disclosure. Other similar thermoelectric coolers may be specified in accordance with desired results.  
         [0029]     In the preferred embodiment, a heatsink  24  is connected to one side of the thermoelectric module  22  and a coldsink  26  is connected to another, opposite side of the thermoelectric module  22 . At least one of the heatsink  24  and the coldsink  26  is formed from a continuous generally planar element  44 . In the embodiment shown in  FIG. 2 , both such heat exchangers are so formed. The generally planar element  44  is preferably formed of a material that facilitates a high rate of heat transfer capability. For example, one commonly available material is aluminum and alloys thereof. Other materials include iron, copper, steel, and any other suitable materials. The planar element  44  as shown in  FIG. 2  is formed to define a series of lands  46  and opposing grooves  48 , each about a fold line  50  normal to a longitudinal axis  51  of the planar element  44 . A substantially planar intermediate portion  62  is disposed between each adjacent land  46  and groove  48 . The planar element  44  has a thickness that is preferably less than 0.080 inches. More preferably, the planar element has a thickness in the range of 0.05 inches to 0.060 inches.  
         [0030]     In one embodiment, the thermoelectric module  22  is operatively thermally coupled to a spacer  68  which is configured with a specified thickness to facilitate orienting the coldsink  26  within the volume  82  and the heatsink  24  exterior to the volume  82 , substantially as thick as the walls  80 , not shown.  
         [0031]     In another embodiment, the thermoelectric apparatus  20  includes a flange  76  operatively associated with each heatsink  24  and coldsink  26  formed from the generally planar element  44 . Each flange  76 ,  78  has a series of channels  78  that are collectively formed with complementary surfaces to facilitate meshing with the grooves  48 . Such heatsink  24  and/or coldsink  26  is connected to the respective flange  76  to facilitate increased heat transfer by way of greatly increased surface area. The heatsink  24  and/or coldsink  26  may be connected in any suitable manner sufficient to provide the transfer of heat. In one embodiment, threaded fasteners  58  are useful for coupling all the elements of the thermoelectric apparatus  20  together. In another embodiment, a thermal adhesive  56  may be disposed between the heatsink  24  and/or coldsink  26  and the respective flange  76  to facilitate the coupling. Any suitable thermal adhesive may be used to perform the intended functionality. Further, screw holes  60  and the screws  58  can be used to assemble the thermoelectric apparatus  20 . Screw holes  60  are formed in the heatsink  24 , the coldsink  26 , the flange  76 , and the housing element  68 .  
         [0032]     In another embodiment, either the heatsink  24  and/or the coldsink  26  include a plurality of offset elements  66 . The plurality of offset elements  66  are formed in the intermediate portion  62  wherein adjacent offset elements each project to an opposite side of the intermediate portion  62 . Each offset element  66  is formed so that the elongated height of the offset element  66  is generally normal to the fold line  50 . The offset element  66  is preferably formed with a press or stamp punch apparatus (not shown). Further, the offset elements  66  are formed in the generally planar element  44  before the forming of the lands  46  and grooves  48 .  
         [0033]     Further, the offset elements  66  facilitate an improved heat transfer rate in the heatsink/coldsink by way of creating a turbulent airflow in the heatsink/coldsink. The structural configuration of the offset portions  66  strengthens the intermediate portion  62 , keeps adjacent intermediate portions  62  spaced apart and provides turbulence to air flowing there between, thus facilitating an increased rate of heat transfer.  
         [0034]     While the particular preferred embodiment has been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made. For example, changing the profile of the offset element  66 , or modifying the number and/or location of the offset elements  66 .  
         [0035]      FIG. 3  illustrates an exploded end view of a portion of the thermoelectric apparatus  20 . In the preferred embodiment, the planar element  44 , of the heatsink  24  for example, is formed symmetrically about a fold line  50 . The planar element  44  has a thickness that is preferably less than 0.080 inches. More preferably, the planar element has a thickness in the range of 0.05 inches to 0.060 inches. Further, the forming process creates the grooves  48 . In addition, the planar element  44  includes a substantially planar intermediate portion  62 .  
         [0036]     In another embodiment, the planar element  44  includes a plurality of offset elements  66 . Each offset element extends from approximately the fold line  50  to the substantially planar intermediate portion  62 . However, it is possible to have other variations, such as the offset element  66  only being located on the substantially planar intermediate portion  62 . Further, the offset elements  66  overlap, thus forcing the air to follow a convoluted path. This convoluted path creates turbulent airflow in the heatsink  24 .  
         [0037]     In another embodiment, the heatsink  24 , and more specifically the grooves  48 , will couple to the thermal adhesive  56 . Further, the flange  76  has complementary surfaces, the flange channels  78 , to facilitate meshing with the grooves  48  and the thermal adhesive  56 . The flange  76  also thermally couples to the thermoelectric module  22 , and the housing element  68 .  
         [0038]      FIG. 4  illustrates a cut-away view of one section of the cooler. In this embodiment, the two heatsinks  24  are disposed outside the volume  82 , separated therefrom by the mounting wall  81 , which partially encloses the volume  82 . Further, the two corresponding coldsinks  26  are disposed within the volume  82 . A fan  84  moves a fluid, i.e. air in this embodiment, across the heatsinks  24  and coldsinks  26 .  
         [0039]     Further, electrical power is supplied to a motor  91  outside of the volume, that includes a shaft  92  having a first end  93  outside the volume  82  and a second end  94  extending into the volume  82 . A fan blade is connected to each of the first end  93  and the second end  94 .  
         [0040]     During operation of the cooler  86 , ice may form on the coldsink and then may melt and drip from the cold sink, if the lid is opened for a certain period of time, because the warmer outside air flows into the volume  82 . Apertures  64  formed in the coldsinks  26  allow the melted ice to drip out of the coldsink  26 . Thus, the grooves  48  of the heatsink  24  have apertures  64 , which allows the water to flow out of the cold sink  26 .  
         [0041]     The deflector plate  54 , as discussed in  FIG. 1 , directs the water to flow to the back wall  80  of the cooler  86  and prevents water from dripping on the contents. Then the water will flow to the bottom of the cooler  86 , and through the drip hole  42 . The water then can evaporate during passage through the wick  40 . If however, there was insufficient time or improper conditions for the water to have evaporated on the wick  40 , then the water drips into the catch pan  52  and either evaporates out of the catch pan  52 , or is emptied by a user.  
         [0042]      FIG. 5A  illustrates a schematic drawing of the electrical components in one preferred embodiment. Electricity from a normal wall outlet  100  provides the power to the cooler  86 . The electricity from the wall outlet  100  is AC power  96 . The AC power  96  is provided to the cooler  86 , which houses all of the remaining necessary components. The AC power  96  is converted by the converter  97  into DC power  98 . The DC power  98  then connects to the necessary electronics  99 . The necessary electronics  99  will vary depending on the embodiment, however resistors, on/off switches, capacitors, processors, and any other suitable electronic parts may be suitable.  
         [0043]     Further, once the correct voltage and current is set, DC power  98  is provided to the fan motor  91 . On a separate DC power line  98 , two thermoelectric apparatuses  20  electrically connect in series. More specifically, DC power  98  is electrically provided to the thermoelectric modules  22 .  
         [0044]      FIG. 5B  illustrates a schematic drawing of the electrical components in another preferred embodiment. Electricity from a normal wall outlet  100  provides the power to the cooler  86  in the form of AC power  96 . The cooler  86  houses all of the remaining necessary components. AC power  96  is converted into DC power  98  by the converter  97  and then connects to the necessary electronics  99  which will vary depending on the desired embodiment, however resistors, on/off switches, capacitors, processors, and any other suitable electronic parts may be suitable.  
         [0045]     Further, once the correct voltage and current is set, DC power  98  is provided to the fan motor  91 . In this embodiment, four thermoelectric apparatuses  20  electrically connected as two pairs of parallel devices to the DC power  98 . More specifically, DC power  98  is electrically provided to the thermoelectric modules  22 .  
         [0046]     In another embodiment, the thermometer ( 38 , in  FIG. 1 ) may electrically connect to the necessary electronics  99 . Thus allowing the necessary electronics  99  to control the thermoelectric cooling apparatus  20 . Alternatively, the thermometer ( 38 , in  FIG. 1 ) may be a mechanical unit used to save costs in construction and operation of the cooler.  
         [0047]      FIG. 6  illustrates a perspective view of the heatsink  24 , which depicts the flow of air through the heatsink  24 . A portion of the heatsink  24  has been moved for discussion purposes only. In this view, the interior of the groove  48  of the heatsink  24  is visible. Further, this view shows the thickness of the planar element  44 . The planar element  44  has a thickness that is preferably less than 0.080 inches. More preferably, the planar element has a thickness in the range of 0.05 inches to 0.060 inches.  
         [0048]     As briefly mentioned above, a fan draws air in through the vent  32  and then across the heatsinks  24 . The fan blade  95  on the second end  94  draws air in through bottom air vent  34 , which is formed in the deflector plate  54 , and then across the coldsinks  26 .  
         [0049]     As discussed in detail above, a plurality of offset elements  66  are formed in the intermediate portion  62  wherein adjacent offset elements each project to an opposite side of the intermediate portion  62 . The offset elements  66  increase the rigidity of the heatsink  24  and facilitate the use of a thin generally planar element  44 . Accordingly, more grooves  48  and lands  46  may be formed as a heat exchanger. Thereby increasing the surface area and the heat transfer rate.  
         [0050]     In the illustrated embodiment, utilizing four 40 mm.×40 mm. Thermoelectric modules  22  each producing 25 watts of cooling (or 80 Btu per hour) and a door having a 1.8 R factor, a cooler storage volume  80  of 2.5 ft 3  maintains a 35 to 40 degree delta (difference between ambient temperature and mean storage compartment temperature) depending on humidity.  
         [0051]     In the illustrated embodiment, the door  30  is constructed of multiple, slightly spaced plies of plastic sheets to achieve a desired degree of insulation, it being understood that each spacing produces an R factor of approximately 0.6.  
         [0052]     While the particular preferred embodiments have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the teaching of the disclosure. For example, additional Peltier devices may be used in any desired wiring configuration, different materials of construction, controllers and other suitable modification or changes. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as limitation. The actual scope of the disclosure is intended to be defined in the following claims when viewed in their proper perspective based on the related art.