Defrosting system for a cold plate and method for defrosting a cold plate

Abstract

A cooler including a cabinet defining an interior volume for storing perishable products, a cold plate disposed within the cabinet, the cold plate configured to absorb heat within the cabinet, and a defrosting system including a sensor configured to detect the presence of frost on a surface of the cold plate, a heating element affixed to a surface of the cold plate configured to at least partially melt frost on the cold plate, and a control unit configured to selectively activate and deactivate the heating element when the presence of frost is determined by the sensor.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments described herein generally relate to a system for defrosting a cold plate. Specifically, embodiments described herein relate to a system for defrosting a cold plate containing a phase change material by a heating element applied to a surface of the cold plate. [Background technology]

[0002] Perishable products, such as food, beverages, cosmetics, and pharmaceuticals, among other products, are often stored and transported in refrigerated or temperature-controlled compartments, such as refrigerators, coolers, or shipping containers, among others. Perishable products must be maintained at a specific temperature or temperature range to prevent spoilage of the perishable products and to ensure that the products meet quality control requirements.

[0003] To maintain the temperature of a cooler at a desired storage temperature during shipping or transport, phase change material (PCM) cold plates are commonly used to absorb heat as an alternative to mechanical refrigeration systems. For example, a PCM cold plate may be positioned within a refrigerated or temperature-controlled compartment to absorb heat that may enter the compartment, such as when the compartment door is opened. The PCM cold plate may be cooled or "charged" prior to use so that the PCM is frozen and solid. During operation, the PCM can absorb heat while maintaining a constant temperature. In this way, the PCM cold plate helps maintain the interior volume of the refrigerator or cooler at a desired storage temperature. Summary of the Invention

[0004] Some embodiments relate to a cooler that includes a cabinet defining an interior volume for storing perishable products; a cold plate disposed within the cabinet, the cold plate configured to absorb heat within the cabinet; a defrosting system including a sensor configured to detect the presence of frost on a surface of the cold plate; a heating element affixed to a surface of the cold plate configured to at least partially melt frost on the cold plate; and a control unit configured to selectively activate and deactivate the heating element when the presence of frost is detected by the sensor.

[0005] In any of the various embodiments discussed herein, the heating element may include a foil heating element. In some embodiments, the heating element may be attached to the surface of the cold plate by an adhesive. In some embodiments, the heating element may be one of multiple heating elements disposed on the surface of the cold plate.

[0006] In any of the various embodiments discussed herein, the cold plate may include a phase change material. In some embodiments, the phase change material may include a eutectic solution.

[0007] In any of the various embodiments discussed herein, the control unit may be configured to activate the heating element for a predetermined amount of time. In some embodiments, the control unit may be configured to activate the heating element for a predetermined amount of time at predetermined intervals.

[0008] In any of the various embodiments discussed herein, the sensor may be a temperature sensor configured to detect the temperature of the surface of the cold plate, hi some embodiments, the temperature sensor may be a thermistor or a thermocouple.

[0009] Some embodiments relate to a method for defrosting a cold plate of a cooler, including determining the presence of frost on a surface of the cold plate in the cooler with a sensor, and activating a heating element disposed on the surface of the cold plate when the presence of frost is detected by the sensor, such that the heating element at least partially melts the frost.

[0010] In any of the various embodiments discussed herein, activating the heating element may include activating a foil heating element.

[0011] In any of the various embodiments discussed herein, a method for defrosting a cold plate may include deactivating a heating element when the temperature of a surface of the cold plate reaches a predetermined maximum temperature value determined by a secondary sensor.

[0012] In any of the various embodiments discussed herein, the cooler may include a fan configured to circulate air over the cold plate, and the method may further include deactivating the fan before activating the heating element. In some embodiments, the method may further include reactivating the fan after deactivating the heating element. In some embodiments, the method may further include reactivating the fan after a predetermined dwell time has elapsed after deactivating the heating element.

[0013] In any of the various embodiments discussed herein, the sensor may be a temperature sensor, and the heating element may be activated when the temperature of the fluid at the outlet of the cold plate, as determined by the temperature sensor, is below a predetermined minimum temperature value.

[0014] In any of the various embodiments discussed herein, the sensor may be a frost sensor configured to determine an amount of frost on the cold plate, and the heating element may be activated when the amount of frost on the cold plate as determined by the frost sensor is equal to or greater than a predetermined amount.

[0015] Some embodiments relate to a method for defrosting a cold plate, including determining the presence of frost on a surface of the cold plate with a sensor, activating a heating element disposed on the surface of the cold plate for a predetermined amount of time to at least partially melt the frost when the presence of frost is detected by the sensor, and deactivating the heating element after the predetermined amount of time has elapsed.

[0016] In any of the various embodiments discussed herein, the method may include activating a heating element at predetermined intervals for a predetermined amount of time. [Brief explanation of the drawings]

[0017] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate the present disclosure and, together with the description, further explain the principles of the disclosure and enable one skilled in the art to make and use the disclosure.

[0018] [Figure 1] FIG. 1 illustrates a perspective view of a chiller having a cold plate with a defrosting system according to one embodiment.

[0019] [Figure 2] 1 illustrates a diagram of components of a cold plate according to one embodiment.

[0020] [Figure 3] FIG. 1 shows a schematic diagram of components of a defrosting system according to one embodiment.

[0021] [Figure 4] 1 illustrates a foil heating element, according to one embodiment.

[0022] [Figure 5] 1 illustrates an exploded view of a foil heating element, according to one embodiment.

[0023] [Figure 6]1 illustrates a flow diagram of a method for defrosting a cold plate, according to one embodiment.

[0024] [Figure 7] 1 illustrates a flow diagram of a method for defrosting a cold plate, according to one embodiment.

[0025] [Figure 8] 1 shows a schematic block diagram of an exemplary computer system in which embodiments may be implemented. DETAILED DESCRIPTION OF THE INVENTION

[0026] Reference will now be made in detail to the exemplary embodiments, as illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to any one preferred embodiment. On the contrary, the invention is intended to cover alternatives, modifications, and equivalents, which may be included within the spirit and scope of the embodiments as defined by the appended claims.

[0027] Phase change material (PCM) cold plates can be used to absorb heat to help maintain a refrigerated or temperature-controlled compartment, such as a cooler, refrigerator, shipping container, or the like, at a desired temperature. PCM cold plates may be used in refrigerated compartments with dedicated cooling units or to provide cooling within compartments lacking dedicated cooling units. While PCM cold plates can help maintain a desired storage temperature within a compartment, they are susceptible to frost and ice accumulation. Humidity or moisture in the air entering the compartment can condense on the surface of the cold plate when a door providing access to the compartment is opened or when air is vented into the compartment, causing frost or ice to form on the cold plate. Frost accumulation inhibits the cold plate's ability to absorb heat from the compartment. Therefore, frost or ice must be periodically removed from the cold plate to ensure that the cold plate functions optimally and maintains the compartment at the desired temperature.

[0028] Removing frost and ice from cold plates can be time-consuming and inconvenient. When cold plates are used in a cooler, the cooler is typically taken offline and the cold plate is manually cleaned, such as by scraping the frost or ice from the surface of the cold plate. When the cooler is offline and the frost or ice is scraped from the cold plate, the cooler's internal volume may increase in temperature, so that product cannot be stored inside. As a result, it may be necessary to remove the product from the cooler and move it to a separate refrigerated area while the cold plate is defrosted. Once the cold plate is defrosted, additional downtime may be required while the cooler's cooling unit returns the cooler to the desired storage temperature, after which the product must be manually placed back into the cooler.

[0029] Although a cooler's refrigeration or cooling unit may have a dedicated defrosting unit, such a defrosting unit is undesirable when a cold plate is used. The cold plate is configured to absorb heat, which can offset the heating of the cooler by the cooler's defrosting unit, causing the defrosting process to take longer. Furthermore, defrosting a cooler increases the temperature throughout the cooler's internal volume, which is undesirable when the cooler is used to store perishable products. The increased temperature can result in spoilage of the perishable products, which may conflict with food safety storage requirements and / or quality control practices. Therefore, it is desirable to defrost the cold plate without taking the cold plate or cooler offline and without significantly increasing the temperature of the cooler's internal volume.

[0030] Some embodiments described herein relate to a defrosting system for a cold plate configured to at least partially melt frost or ice on the surface of the cold plate. In this manner, the defrosting system helps remove frost from the cold plate to ensure optimal functioning of the cold plate. In some embodiments, the defrosting system for the cold plate is configured to at least partially melt frost or ice on the surface of the cold plate without significantly increasing the temperature of the interior volume of a cooler in which the cold plate is located, such that perishable products stored within the interior volume remain at a desired storage temperature.

[0031] In some embodiments described herein, cold plate 200 is positioned within cooler 100 to absorb heat within interior volume 110 of cooler 100, such as along interior wall 112 of cooler 100. Defrosting system 300 may be coupled to cold plate 200 to remove frost or ice (i.e., defrost) from surface 205 of cold plate 200. Defrosting system 300 may include a sensor 330 (see FIG. 3 ) for detecting the presence of frost on surface 205 of cold plate 200, a heating element 310 positioned on surface 205 of cold plate 200 to melt frost on cold plate 200, and a control unit 350 configured to automatically activate heating element 310 when frost is detected by sensor 330.

[0032] As used herein, the term "cooler" may refer to any container, vessel, or compartment having an interior volume for storing a product. A "cooler" may refer to a refrigerated compartment, such as a refrigerated display case or refrigerator for storing fresh food or beverage products, a temperature-controlled or insulated compartment, or a transport container for transporting perishable products such as food or beverages while maintaining the perishable products at a particular temperature or temperature range to prevent spoilage, deterioration, or deterioration of the products. Thus, a cooler may have a dedicated cooling or refrigeration unit, or the cooler may lack a dedicated cooling unit.

[0033] In some embodiments described herein, a cooler 100 defines an interior volume 110 for storing perishable products, such as food or beverages, as shown in FIG. 1 . The cooler 100 may be in the form of a cabinet. While the cooler 100 is shown as a rectangular prism, the cooler 100 may have any of a variety of shapes and configurations; for example, the cooler may include one or more curved or rounded walls. The cooler 100 may further include a transparent portion 108 constructed from a transparent material, such as glass, such that the interior volume 110 of the cooler 100 is visible from the exterior of the cooler 100. In some embodiments, the cooler 100 may include one or more shelves for storing and organizing perishable products within the interior volume 110.

[0034] A cold plate 200 may be positioned within the cooler 100 to absorb heat within the cooler 100. In some embodiments, the cold plate 200 may be positioned within the interior volume 110 of the cooler 100 on or along a wall of the cooler 100, such as on the rear wall 112 of the cooler 100. In some embodiments, the cooler 100 may include two or more cold plates 200, and the cold plates 200 may be positioned on the same wall or on different walls of the cooler 100. Depending on the size of the cooler 100 and the size of the cold plates 200, two or more cold plates 200 may be used. It is understood that more than one cold plate 200 may be used, but for simplicity, reference will be made herein to a single cold plate 200.

[0035] The cold plate 200 may include one or more tubes or channels 220 for circulating a fluid, such as a coolant or refrigerant, as shown in FIG. 2 . The tubes or channels 220 may be positioned within the jacket 210. The tubes or channels 220 may be arranged in a serpentine pattern within the jacket 210 to maximize the length of the tubes or channels 220 within the jacket 210 and maximize heat transfer. Furthermore, the tubes or channels 220 may be arranged in a single plane. The tubes or channels 220 may be partially exposed or may be completely enclosed or encapsulated by the jacket 210. The jacket 210 may be constructed from a material with high thermal conductivity to facilitate heat transfer. In some embodiments, the jacket 210 may be constructed from a metal such as copper, aluminum, steel, or a combination thereof, among other suitable materials. The cold plate 200 may have a plate-like configuration, whereby the cold plate 200 is generally planar and may have a rectangular configuration with a length and / or width that significantly exceeds the thickness of the cold plate 200.

[0036] Cold plate 200 may further contain a phase change material (PCM) 900. Jacket 210 may contain and store PCM 900 such that PCM 900 surrounds tubes 220 within jacket 210. A PCM is a material that has a high latent heat of fusion such that the material absorbs heat at a constant or near-constant temperature at the phase change temperature at which the material transitions from liquid to solid or from solid to liquid. Any of a variety of PCMs, such as eutectic solutions, may be used within cold plate 200. The PCM may be selected to have a desired melting point (e.g., phase change temperature) to maintain the cooler at a particular temperature. In some embodiments, the melting point of the PCM may be less than 32°F. One skilled in the art will understand that the particular PCM selected may depend, among other considerations, on the desired operating temperature or range of operating temperatures of the cooler.

[0037] When cold plate 200 is in use, the PCM absorbs heat within cooler 100 to maintain the cooler 100 at a desired temperature. However, the PCM must be periodically cooled or “charged” to remove the absorbed heat. To charge the PCM in cold plate 200, cold plate 200 may be placed in communication with heat exchanger 230, as shown in FIG. 2 , for example. A fluid, such as a refrigerant, may be circulated through cold plate 200 to absorb heat from the PCM to cool it. Cold plate 200 may further include pump 240 to facilitate fluid circulation. In some embodiments, cold plate 200 may further include a thermal switch 250 configured to automatically initiate fluid circulation when the fluid temperature reaches a predetermined maximum temperature, such as 27°F. Once the predetermined maximum temperature is reached, fluid is circulated from cold plate 200 to heat exchanger 230 to cool the fluid. When the temperature of the fluid reaches a predetermined operating temperature, such as 20°F, cold plate 200 may stop circulating fluid to heat exchanger 230, and the PCM may be charged and ready for use. In some embodiments, cold plate 200 may be placed in communication with a cooling unit 160 (see FIG. 3 ), such as the cooling unit 160 of a vehicle (e.g., a truck or semi-trailer) in which chiller 100 is located. Cooling unit 160 may include a condenser, a compressor, and an expansion valve, and cold plate 200 may function as an evaporator for cooling unit 160. In some embodiments, cooling unit 160 may further include a fan 165 for circulating air within chiller 100 and over surface 205 of cold plate 200. Thus, cooling unit 160 may circulate refrigerant through tubes 220 of cold plate 200 to charge PCM 900 of cold plate 200.

[0038] The defrosting system 300 is used to remove frost or ice from the cold plate 200. In some embodiments, the defrosting system 300 is configured to remove frost or ice from the surface 205 of the cold plate 200, such as the interior-facing surface of the cold plate 200 in the cooler 100. In some embodiments, the defrosting system 300 may include a heating element 310 in communication with a control unit 350 for selectively activating and deactivating the heating element 310, as shown, for example, in FIG. 3 . In some embodiments, the heating element 310 is disposed on the surface 205 of the cold plate 200. In some embodiments, multiple heating elements 310 are disposed on the surface 205 of the cold plate 200 (see FIG. 1 ). One skilled in the art can readily select a suitable number of heating elements 310 for melting ice or frost on the surface 205 of the cold plate 200 depending on various factors, including, for example, the size and power of the heating element 310 and the size of the cold plate 200.

[0039] The heating elements 310 may be positioned in any of a variety of locations on the surface 205 of the cold plate 200. The heating elements 310 may be arranged in one or more rows and / or columns on the surface 205. In some embodiments, the heating elements 310 may be arranged in a grid pattern. In some embodiments, the heating elements 310 may be positioned on the cold plate 200 in locations most susceptible to frost formation, such as portions of the cold plate 200 with a high density of tubes 220 or portions of the cold plate 200 at the inlet of the tubes 220 into the cold plate 200. The fluid returning to the cold plate 200 from the heat exchanger 230 may be at the lowest temperature because the fluid absorbs heat as it circulates through the cold plate 200, increasing the temperature of the fluid as it flows toward the outlet of the cold plate 200. As a result, frost may be most likely to form in the portions of the cold plate 200 where the tubes 220 and the fluid therein first enter the cold plate 200.

[0040] In some embodiments, the heating element 310 is a foil heating element, as shown in FIGS. 4 and 5 , for example. The foil heating element 310 may include a heating wire 316, such as nichrome wire, positioned on or between metal sheets 312, 314, such as aluminum sheets. However, in other embodiments, different types of heating wire 316 made of different materials and different types of metal sheets 312, 314 may be used. The heating wire 316 may be arranged in a single plane or may have a serpentine pattern to maximize the amount of heating wire 316 in the foil heating element 310. The foil heating element 310 may have a generally planar configuration, such that the foil heating element 310 is an elongated, flat strip or plate. In this way, the planar profile of the heating element 310 does not consume much space within the cooler 100 and therefore does not reduce the amount of storage space within the cooler 100 or require adjustment or reconfiguration of other components of the cooler 100, such as shelves. In some embodiments, the heating element 310 may have a square or rectangular configuration with a length of about 12 cm to about 80 cm, a width of about 12 cm to about 80 cm, and a thickness of about 1 mm or less. However, in alternative embodiments, the foil heating element 310 may have any of a variety of alternative shapes, such as a circular disk shape or a triangular shape, among others.

[0041] Each heating element 310 is configured to provide localized heat to at least partially melt frost or ice accumulated on the surface 205 of the cold plate 200 without heating and increasing the temperature of the entire interior volume 110 of the cooler 100. When the heating element 310 is activated, the temperature of the interior volume 110 of the cooler 100 may increase by 5°F or less, 3°F or less, or 1°F or less. The heating elements 310 may be low-power heating elements 310 or 12V heating elements. In this manner, the heating elements 310 are configured to melt frost on the surface 205 of the cold plate 200 without heating the interior volume 110 of the cooler 100 and the perishable product therein. In some embodiments, the heating elements 310 are configured to only partially melt the frost or ice on the surface 205 rather than completely melting the frost or ice. In this way, the partially melted ice can slide along the surface of the cold plate under the force of gravity, removing the frost and ice surface 205 while minimizing heating of the interior volume 110 of the cooler 100 .

[0042] The heating element 310 may be attached to the surface 205 of the cold plate 200 via any of a variety of fastening methods. In some embodiments, the heating element 310 is attached to the cold plate 200 via an adhesive, such as a pressure-sensitive adhesive. The heating element 310 may include an adhesive on its surface, or an adhesive may be applied to the surface of the heating element 310, and the heating element 310 may be attached to the surface 205 of the cold plate 200 by placing the adhesive-bearing surface of the heating element 310 in face-to-face engagement with the surface 205 of the cold plate 200. In this manner, the heating element 310 can be easily and quickly installed on any of a variety of surfaces. The adhesive may be selected for use at low temperatures, such as temperatures between about 0°F and 40°F. Any of a variety of adhesive types may be used, such as a polymeric adhesive, e.g., a polyester adhesive. In some embodiments, the heating element 310 may be integrally formed with the cold plate 200.

[0043] In some embodiments, defrosting system 300 may further include a sensor 330 configured to detect the presence of frost on cold plate 200, such as frost on surface 205 of cold plate 200. Any of a variety of types of sensors may be used to detect the presence of frost on the surface of cold plate 200. In some embodiments, sensor 330 is a temperature sensor, such as a thermistor or thermocouple, among other suitable temperature sensors, for determining the temperature of the fluid exiting cold plate 200 via tube 220. To measure the temperature of the fluid exiting cold plate 200, temperature sensor 330 may be positioned on a portion of tube 220 of cold plate 200, such as in or on a portion of tube 220 adjacent to the outlet of cold plate 200, as shown in FIG. 2 . Control unit 350 of defrosting system 300 may be configured to activate heating element 310 when the temperature of the fluid exiting cold plate 200, as detected by the temperature sensor, is below a predetermined minimum temperature value. Frost and ice buildup on cold plate 200 inhibits the transfer of heat to the fluid in tubes 220 of cold plate 200, which may cause the fluid in tubes 220 of cold plate 200 to remain cool as it passes through cold plate 200. Thus, a temperature of the fluid below a predetermined temperature minimum may indicate that heat is not being transferred to the fluid due to frost buildup on cold plate 200.

[0044] In some embodiments, sensor 330 may be a frost sensor for determining the amount of frost accumulated on surface 205 of cold plate 200. In some embodiments, frost sensor may be an optical sensor. If the frost sensor is an optical sensor, it may be configured to detect changes in light reflectivity on surface 205 of cold plate 200 due to scattering of light by frost accumulation on surface 205. In some embodiments, frost sensor may be configured to detect the temperature of surface 205 of cold plate 200 such that when there is no frost on cold plate 200, cold plate 200 may be at a low temperature, such as 32°F, and when frost is present, the temperature of surface 205 may increase to, for example, 34°F. In some embodiments, frost sensor may be a capacitive measuring device for detecting a change in a measured signal when ice forms between two points of the sensor. In this manner, a frost sensor positioned on surface 205 of cold plate 200 may determine the thickness of frost accumulated on surface 205 of cold plate 200, measured in a direction perpendicular to surface 205. However, in alternative embodiments, other types of frost sensors may be used to determine the amount of frost accumulated on a surface. In some embodiments, when the frost sensor detects the presence of more than a predetermined amount of frost, such as at least about 2 mm of frost on surface 205, control unit 350 may activate heating element 310 to at least partially melt the frost.

[0045] In some embodiments, the defrosting system 300 further includes a secondary sensor 380 configured to determine the temperature of the surface 205 of the cold plate 200. The secondary sensor 380 may be, for example, an infrared sensor. If the temperature of the surface 205 of the cold plate 200 reaches a predetermined temperature maximum, the heating element 310 is deactivated by the control unit 350. Furthermore, if the temperature of the perishable product in the cooler 100 reaches an override temperature higher than the temperature maximum, such as about 37°F as determined by the secondary sensor 380, the heating element 310 may be automatically deactivated by the control unit 350. This prevents the heating element 310 from getting too hot and heating the perishable product stored in the cooler 100, which could cause spoilage or reduce the shelf life or quality of the perishable product. In some embodiments, the secondary sensor 380 is positioned within the cooler 100 adjacent to the surface 205 of the cold plate 200, such as on an inner wall of the cooler 100 adjacent to the cold plate 200, such that the secondary sensor 380 is positioned to measure the temperature of the surface 205 of the cold plate 200.

[0046] In some embodiments, the defrosting system 300 may include any of a variety of types of power sources, such as a battery, or may be configured to be connected to a power source to provide electrical energy to each of the control unit 350, the sensors 330, 380, and the heating element 310. In some embodiments, the defrosting system 300 may be configured to be powered by the power source of the chiller 100 or the cooling unit 160 of the chiller 100 in which the defrosting system 300 is installed.

[0047] In some embodiments, a method 600 for defrosting a cold plate is shown, for example, in FIG. 6 . The defrosting system detects (610) the presence of frost or ice on the surface of the cold plate. The presence of frost or ice on the cold plate may be detected by a sensor as described herein. When the presence of frost or ice is detected by the sensor, the defrosting system's control unit may activate (620) the heating element. Once the heating element is activated, the defrosting system may again detect (630) the presence of frost to determine whether the frost has been melted or at least partially melted by the heating element. The sensor may continuously detect the presence of frost or may periodically check. When the sensor detects that the frost has melted or at least partially melted (e.g., by an increase in the temperature of the fluid exiting the cold plate as determined by a temperature sensor or by a decreased amount of frost on the surface of the cold plate as detected by a frost sensor), the defrosting system deactivates (640) the heating element. In some embodiments, the heating element may be deactivated without detecting frost 630. In such embodiments, the heating element may instead be activated for a predetermined amount of time, e.g., 5 minutes, 10 minutes, 15 minutes, etc., and once the predetermined amount of time has expired, the heating element may be automatically deactivated by the defrost system control unit. In other embodiments, after activating the heating element (620), the heating element may thereafter be automatically deactivated when the temperature of the surface of the cold plate, as detected by the secondary sensor 380, is equal to or greater than a predetermined maximum temperature value.

[0048] In some embodiments, the defrosting system 300 is in communication with the cooling unit 160 of the chiller 100, as shown in FIG. 3. In such embodiments, a method 700 for defrosting a cold plate may include detecting (710) the presence of frost or ice on the surface of the cold plate via one or more sensors, as shown in FIG. 7. Upon detecting the presence of frost or ice, the defrosting system may be configured to deactivate (720) the cold plate to stop refrigerant circulating through the cold plate and / or deactivate a fan circulating air over the surface of the cold plate. In this way, when the heating element is subsequently activated, the fan does not circulate heat supplied by the heating element throughout the interior volume of the chiller, which may result in an increase in temperature within the chiller. Once the cold plate and / or fan are deactivated, the control unit of the defrosting system may activate (730) the heating element to melt the frost or ice. With the heating element activated, the sensor may again detect the presence of frost (740). When the sensor detects that the frost or ice has melted or partially melted, the heating element is deactivated (750). As described above with respect to method 600, the heating element may operate for a predetermined amount of time and automatically deactivate when the predetermined amount of time expires, or may operate until a secondary sensor determines that the temperature of the surface of the cold plate is equal to or greater than a predetermined maximum temperature. Once the heating element is deactivated, the cold plate and / or fan may be reactivated (760). In some embodiments, the cold plate and / or fan may remain deactivated after deactivating the heating element for a predetermined dwell time, such as 1 minute, 2 minutes, 5 minutes, 10 minutes, or 15 minutes, among other periods, before reactivating. In this way, the heating element may have time to cool down to avoid circulating residual heat from the heating element.

[0049] In some embodiments, a method of defrosting a cold plate may include activating cooling unit 160 and cold plate 200 to cool the interior volume of cooler 100 and the perishable product therein before activating heating element 310 to at least partially melt the frost or ice on cold plate 200. Cooling unit 160 may operate until the temperature of cold plate 200 reaches a predetermined temperature, such as a temperature of approximately 22°F, or until the temperature of the perishable product, as determined by secondary sensor 380, reaches a predetermined storage temperature, such as approximately 34°F. It is understood that the predetermined storage temperature may depend on the particular perishable product being stored. Once the predetermined storage temperature is reached, cooling unit 160 may be deactivated to stop the flow of fluid, e.g., refrigerant, through cooling unit 160, and heating element 310 is activated to at least partially melt the frost on cold plate 200. Activating the cooling unit 160 to cool the interior volume 110 of the cooler 100 before activating the heating element 310 helps ensure that the perishable product is maintained within a desired storage temperature range and is not overheated when the heating element 310 is activated.

[0050] 8 illustrates an exemplary computer system 800 in which embodiments or portions thereof may be implemented as computer-readable code. The control unit 350 discussed herein may be a computer system having all or some of the components of computer system 800 for implementing the processes discussed herein.

[0051] Where programmable logic is used, such logic may be executed on a commercially available processing platform or a special purpose device. Those skilled in the art will appreciate that embodiments of the disclosed subject matter may be practiced with a variety of computer system configurations, including multi-core multiprocessor systems, minicomputers and mainframe computers, computers linked or clustered with distributed functionality, and pervasive or small computers that may be embedded in virtually any device.

[0052] For example, at least one processor device and memory may be used to implement the above-described embodiments. The processor device may be a single processor, multiple processors, or a combination thereof. The processor device may have one or more processor "cores."

[0053] Various embodiments of the present invention may be implemented in terms of this exemplary computer system 800. After reading this description, it will become apparent to one skilled in the art how one or more aspects of the present invention may be implemented using other computer systems and / or computer architectures. While operations may be described as sequential processes, some of the operations may in fact be performed in parallel, concurrently, and / or in a distributed environment, and may be performed by program code stored locally or remotely for access by single or multi-processor machines. Additionally, in some embodiments, the order of operations may be rearranged without departing from the spirit of the disclosed subject matter.

[0054] The processor device 804 may be a special purpose or a general purpose processor device. As will be appreciated by those skilled in the art, the processor device 804 may also be a single processor in a multi-core / multi-processor system, operating singly or in a cluster of computing devices operating in a cluster or server farm. The processor device 804 is connected to a communications infrastructure 806, such as a bus, message queue, network, or multi-core message passing scheme.

[0055] Computer system 800 also includes a main memory 808, e.g., random access memory (RAM), and may also include a secondary memory 810. The secondary memory 810 may include, for example, a hard disk drive 812 or a removable storage drive 814. The removable storage drive 814 may include a floppy disk drive, a magnetic tape drive, an optical disk drive, flash memory, etc. The removable storage drive 814 reads from and / or writes to a removable storage unit 818 in a well-known manner. The removable storage unit 818 may include a floppy disk, magnetic tape, optical disk, universal serial bus (USB) drive, etc., which are read from and written to by the removable storage drive 814. As will be appreciated by those skilled in the art, the removable storage unit 818 includes a computer-usable storage medium having stored thereon computer software and / or data.

[0056] Computer system 800 (optionally) includes a display interface 802 (which may include input and output devices such as a keyboard, mouse, etc.) that transfers graphics, text, and other data from a communications infrastructure 806 (or from a frame buffer, not shown) for display on a display unit 830.

[0057] In alternative implementations, secondary memory 810 may include other similar means for allowing computer programs or other instructions to be loaded into computer system 800. Such means may include, for example, a removable storage unit 822 and interface 820. Examples of such means may include program cartridges and cartridge interfaces (such as those found in video game devices), removable memory chips (such as EPROMs or PROMs) and associated sockets, and other removable storage units 822 and interfaces 820 that can transfer software and data from the removable storage unit 822 to computer system 800.

[0058] Computer system 800 may also include a communications interface 824. Communications interface 824 allows software and data to be transferred between computer system 800 and external devices. Communications interface 824 may include a modem, a network interface (such as an Ethernet card), a communications port, a PCMCIA slot and card, or the like. The software and data transferred via communications interface 824 may be in the form of signals, which may be electronic, electromagnetic, optical, or other signals capable of being received by communications interface 824. These signals may be provided to communications interface 824 via communications path 826. Communications path 826 carries signals and may be implemented using wire or cable, fiber optics, a phone line, a cellular phone link, an RF link, or other communications channel.

[0059] As used herein, the terms "computer program medium" or "computer usable medium" are used generally to refer to media such as removable storage unit 818, removable storage unit 822, and a hard disk installed in hard disk drive 812. Computer program medium and computer usable medium may also refer to memory, such as main memory 808 and secondary memory 810, which may be memory semiconductors (e.g., DRAM, etc.).

[0060] Computer programs (also called computer control logic) are stored in main memory 808 and / or secondary memory 810. Computer programs may also be received via communications interface 824. Such computer programs, when executed, enable computer system 800 to perform the embodiments discussed herein. In particular, when executed, computer programs enable processor device 804 to perform the processes of the embodiments discussed herein. Such computer programs thus represent controllers of computer system 800. If the embodiments are implemented using software, the software may be stored in a computer program product and loaded into computer system 800 using removable storage drive 814, interface 820, and hard disk drive 812, or communications interface 824.

[0061] Embodiments of the present invention may also be directed to computer program products including software stored on any computer-usable medium. Such software, when executed on one or more data processing devices, causes the data processing devices to operate as described herein. Embodiments of the present invention may employ computer-usable or readable media. Examples of computer-usable media include, but are not limited to, primary storage devices (e.g., any type of random access memory), secondary storage devices (e.g., hard drives, floppy disks, CD ROMs, ZIP disks, tapes, magnetic and optical storage devices, MEMS, nanotechnology storage devices, etc.).

[0062] It is understood that the "Detailed Description" section, and not the "Summary" and "Abstract" sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more, but not all, exemplary embodiments of the invention as contemplated by the inventor(s), but are not intended to limit the scope of the invention and the appended claims in any way.

[0063] The present invention has been described above with the aid of functional building blocks that illustrate the performance of certain functions and their relationships. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternative boundaries can be defined so long as the specified functions and their relationships are properly performed.

[0064] The foregoing description of specific embodiments makes the general nature of the present invention fully apparent, and others, by applying the knowledge of those skilled in the art, may readily modify and / or adapt such specific embodiments to various uses without undue experimentation and without departing from the general concept of the present invention. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed embodiments, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology used herein is for the purpose of description and not of limitation, and therefore should be interpreted by those skilled in the art in light of the teaching and guidance provided herein.

[0065] The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A cooler comprising: a cabinet having a door and a plurality of interior walls defining a storage area for storing perishable products, the door being configured to move between an open position and a closed position; a cold plate disposed on a first interior wall of the plurality of interior walls of the cabinet, the cold plate having a jacket including a phase change material and a tube configured to circulate a refrigerant, the cold plate configured to absorb heat within the cabinet; 1. A defrosting system comprising: a sensor configured to detect the presence of frost on a surface of the cold plate; a heating element attached to the surface of the cold plate configured to at least partially melt frost on the cold plate; a control unit configured to activate the heating element when the presence of frost is detected by the sensor and to deactivate the heating element when the cold plate reaches a predetermined temperature; the sensor is disposed on the surface of the cold plate; the surface being an inner facing surface of the first inner wall of the storage area; the door includes a transparent portion through which the cold plate and the heating element are visible when the door is in a closed position; The heating element has heating wires arranged in a serpentine pattern in a single plane. A cooler comprising: a defrosting system.

2. The cooler of claim 1 , wherein the heating element comprises a foil heating element.

3. The cooler of claim 1 , wherein the heating element is attached to the surface of the cold plate by an adhesive.

4. The cooler of claim 1 , wherein the heating element is one of a plurality of heating elements disposed on the surface of the cold plate.

5. The cooler of claim 1 , wherein the phase change material comprises a eutectic solution.

6. The cooler of claim 1 , wherein the control unit is configured to activate the heating element for a predetermined amount of time.

7. The cooler of claim 6 , wherein the control unit is configured to activate the heating element at predetermined intervals for the predetermined amount of time.

8. The cooler of claim 1 , wherein the sensor is a temperature sensor configured to detect a temperature of a surface of the cold plate.

9. The cooler of claim 8 , wherein the temperature sensor is a thermistor or a thermocouple.

10. 1. A method for defrosting a cold plate of a refrigerator, comprising: the cooler has a door and a plurality of interior walls defining a storage area for storing perishable products, the cold plate being disposed along a first of the plurality of interior walls and facing inwardly of the storage area such that the cold plate is visible through a transparent portion of the door when the door is in a closed position; The method comprises: determining the presence of frost on a surface of the cold plate of the cooler with a sensor; activating a heating element disposed on the surface of the cold plate when the presence of the frost is detected by the sensor, such that the heating element at least partially melts the frost; the cold plate includes a phase change material and a tube configured to circulate a refrigerant; the sensor is disposed on a surface of the cold plate facing the storage area; the heating element has a planar profile configured to not reduce the storage volume of the cooler; The method wherein the heating element has a thickness of 1 mm or less.

11. The method of claim 10 , wherein activating the heating element comprises activating a foil heating element.

12. 11. The method of claim 10, further comprising deactivating the heating element when the temperature of the surface of the cold plate reaches a predetermined maximum temperature value determined by a secondary sensor.

13. the cooler comprising a fan configured to circulate air over the cold plate; The method of claim 10, further comprising deactivating the fan before activating the heating element.

14. 14. The method of claim 13, further comprising reactivating the fan after deactivating the heating element.

15. 15. The method of claim 14, further comprising reactivating the fan after a predetermined dwell time has elapsed after deactivating the heating element.

16. The method described in claim 10, wherein the sensor is a frost sensor configured to determine the amount of frost on the cold plate, and the heating element is activated when the amount of frost on the cold plate determined by the frost sensor is equal to or greater than a predetermined amount.

17. A method for defrosting a cold plate of a refrigerator, comprising: the cooler has a door and a plurality of interior walls defining a storage area for storing perishable products, the cold plate being disposed along a first of the plurality of interior walls and facing inward toward the storage area, such that the cold plate is visible through a transparent portion of the door when the door is in a closed state; The method comprises: determining the presence of frost on the inner facing surface of the cold plate with a sensor; activating a heating element including a heating wire disposed on the inner facing surface of the cold plate for a predetermined amount of time to at least partially melt the frost when the presence of the frost is detected by the sensor; deactivating the heating element after the predetermined amount of time has elapsed; the cold plate has a jacket including a phase change material and a tube through which a refrigerant is circulated; the sensor is disposed on the inner facing surface of the cold plate; the heating element is disposed in a portion of the cold plate that includes a plurality of tubes through which the refrigerant circulates, or at the inlet of the tubes into the cold plate; The method wherein the heating wires are arranged in a serpentine pattern within a single plane.

18. The method of claim 17, further comprising activating the heating element at predetermined intervals for the predetermined amount of time.

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