Heating and Cooling Unit with Semiconductor Device and Heat Pipe
Aspects of the invention support the changing of a serving surface temperature in order to cool or heat the serving surface. Heat is transferred to or from the serving surface through at least one Peltier device, a heat pipe, and a heat sink. The mode of operation is determined by changing the electrical power polarity to the at least one Peltier device. A control device may activate the at least one Peltier device from a measured temperature and a temperature setting with a hysteresis. A plurality of Peltier devices may be partitioned into different subsets so that the control device may activate a selected subset during different time intervals. When the measured temperature is outside a temperature range, all of the Peltier devices may be activated, while only a selected subset may be activated when the measured temperature is within the temperature range and until a hysteresis temperature is reached.
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Aspects of the disclosure relate to a hot/cold unit for heating and/or cooling an item on a serving surface. In particular, the hot/cold unit uses a semiconductor device, such as a Peltier device, and a heat pipe.
BACKGROUNDPerishable foods for home, market, catering and restaurant buffets are conventionally chilled by ice or commercially manufactured containers of freezable material, or by refrigeration systems. When the ice melts and the freezable material warms, these cooling media lose their ability to keep foods safe and may render them unsuitable or hazardous for consumption. Refrigeration systems are bulky and costly, requiring condensers, coils and harmful chemicals and, further, must be serviced and maintained. Additionally, they are not easily adapted for portability.
Other foods need to be heated or kept warm for home, market, catering and restaurant buffet service. Conventional sources of heat include flame and electricity, e.g. by use of alcohol-based combustible gels or by electric hot plates. Flame sources often produce local hot spots and uneven heating and may produce fumes, odors, or other combustion products. The indoor pollution and health risks to food service workers and patrons from these combustion products may be viewed with concern by those in the industry.
In the presentation of food and/or beverages such as for a buffet service, it is often desirable to store, transport, and/or present the buffet items in a convenient, presentable fashion. It is often further desirable to provide the items either above or below the ambient temperature of the presentation environment. Moreover, in-home hosting has trended upward, and could benefit from equipment improvement. Further, the costs and convenience of improved buffet service, storage, transportation, and/or presentation means may be improved such that they are more accessible and feasible in the market place.
While traditional servers for heating and/or cooling may not require fuel or ice to achieve a desired temperature of an item, traditional servers may rely on a temperature adjusting element in conjunction with an active exchange device, e.g., a liquid circulation pump, to facilitate energy transfer and thus mitigating the temperature of the temperature adjusting element. This approach may generate noise may typically increases the cost of the traditional server.
SUMMARYAn aspect of the invention provides apparatuses, computer-readable media, and methods for changing the temperature of a serving surface in order to cool or heat an item on the serving surface. Heat is transferred to or from the serving surface through a semiconductor device (e.g., a Peltier device), a heat pipe and a heat sink.
With another aspect of the invention, an apparatus for reducing the temperature of a serving surface includes at least one Peltier device that transfers heat from the serving surface to a heat pipe to a heat exchange device. Alternatively, the apparatus may increase the temperature of the serving surface by reversing the operation of the at least one Peltier device.
With another aspect of the invention, a control device activates the at least one Peltier device from a measured temperature of the serving surface and a temperature setting. The control device activates the at least one Peltier device in order change the serving surface according to the temperature setting. Moreover, hysteresis may be incorporated so that control cycling of the at least one Peltier device may be reduced.
With another aspect of the invention, a plurality of Peltier devices may be partitioned into different subsets so that the control device may activate different subsets during different time intervals. When the measured temperature of the serving surface is outside a temperature range, all of the Peltier devices may be activated, while only a selected subset may be activated when the measured temperature is within the temperature range and until a hysteresis temperature is reached.
Various aspects described herein may be embodied as a method, an apparatus, or as one or more computer-readable media storing computer-executable instructions. Accordingly, those aspects may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Any and/or all of the method steps described herein may be implemented as computer-readable instructions stored on a computer-readable medium, such as a non-transitory computer-readable medium. In addition, various signals representing data or events as described herein may be transferred between a source and a destination in the form of light and/or electromagnetic waves traveling through signal-conducting media such as metal wires, optical fibers, and/or wireless transmission media (e.g., air and/or space).
Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the disclosure will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps illustrated herein may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.
A more complete understanding of the present invention and the advantages thereof may be acquired by referring to the following description in consideration of the accompanying drawings, in which like reference numbers indicate like features and wherein:
In the following description of the various embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.
The measured temperature of serving surface 101 is changed by transferring heat from Peltier devices 102 and 103 through heat pipes 104 and 105 and through heat sinks 106 and 107, respectively.
Control device 108 activates and deactivates Peltier devices 102 and 103 based on an indication from temperature sensor 109 that is indicative of the measured temperature of serving surface 101. Temperature sensor 109 is typically placed against serving surface 101 in order to provide thermal coupling. For example, when the measured temperature is above a cooling temperature setting (i.e., the desired temperature) control device 108 provides electrical power to Peltier devices 102 and 103 through electrical connections 110 and 111 and connections 112 and 113, respectively.
With some embodiments, heat transfer may be enhanced by fans 114 and 115 producing air circulation from heat sinks 106 and 107, respectively, and through vent openings 116 and 117, respectively.
Control device 208 reverses the transfer of heat with respect to block diagram 100 by reversing the electrical polarity of electrical connections 210 and 211 and connections 212 and 213. (As will be discussed, the Peltier effect is a reversible process.) Consequently, heat flows to serving surface 201 to heat it.
Peltier device 300 comprises a plurality of N type and P type semiconductor grains 301-309 that are electrically interconnected through electrical conductor arrangements 310 and 311. Ceramic layers 312 and 313 provide thermal conductivity as well as electrical isolation so that Peltier device 300 is able to cool or heat a serving surface. With some embodiments, the serving surface and heat pipe are thermally coupled to ceramic layers 312 and 313, respectively.
With some embodiments, one or more Peltier devices may be used to exchange heat with the serving surface. For example, with the embodiment shown in
Heat pipe 400 may be a heat-transfer device that combines the principles of both thermal conductivity and phase transition to efficiently manage the transfer of heat between two ends. With traditional systems, a radiator using single-phase convection with a high-speed motor often provides heat transfer. However, heat pipe 400 can transfer the heat efficiently without a high-speed motor.
Heat pipe 400 transports heat from portion 452 to portion 451. Heat pipe 400 comprises casing 401, wick 402, and vapor cavity 403. Casing 401 may comprise a sealed pipe or tube made of a material with high thermal conductivity such as copper or aluminum at both hot and cold ends. Working fluid evaporates to vapor absorbing thermal energy at event 404. Examples of such fluids include water, ethanol, acetone, sodium, or mercury. The vapor migrates along cavity 403 from portion 452 (high temperature end) to portion 451 (low temperature end). The vapor condenses back to fluid and is absorbed by wick 402 at event 406, and the fluid flows back to portion 402 through wick 402.
With some embodiments, referring to
-
- 1. Large capillary action or small effective aperture of wick,
- 2. Smaller fluid flow resistance, which have higher permeability,
- 3. Good thermal conductivity characteristics, and
- 4. Good repeatability and reliability in the manufacturing process.
Referring to
Peltier device 502 is thermally coupled to serving surface 501 and copper block 504, where the top side (corresponding to ceramic layer 312 as shown in
Heat pipe 503 is thermally coupled to Peltier device 502 through copper block 504 so that heat flows along heat flow 509a and 509b. However, with some embodiments, heat pipe 503 may be directly placed against Peltier device 502. Heat pipe 502 transports heat along heat flow 509b by traversing through copper block 504 via branches 507a-507c and heat sink 505. Heat is thus transported along heat flow 509c and into the surrounding environment of serving apparatus 500.
With some embodiments, heat sink 505 may be constructed from copper and/or aluminum in order to achieve performance, size, and cost objectives.
With some embodiments, fan 506 operates when apparatus is operating in the cooling mode. However, with some embodiments, fan 506 may operate in the heating and/or cooling modes. Fan 506 assists in the transfer of heat by drawing in cool air 510a and 510b so that heat sink 505 may be kept to a smaller size than without fan 506. With some embodiments, the speed of fan 506 may be changed based on the temperature of serving surface 501. For example, the speed may be increased when the difference of measured temperature of serving surface 501 and the desired temperature increases. However, with some embodiments, the speed of fan 506 may be fixed when fan 506 is activated and may operate during the entire duration of operation.
With some embodiments, while not explicitly shown in
With some embodiments, processing system 601 may correspond to one or more processors and storage device 604 may correspond to one or more memories.
Control device 600 may be implemented as one or more ASICs or other integrated circuits (e.g., a single chip computer) having instructions for performing operations as described in connection with one or more of any of the embodiments described herein. Said instructions may be software and/or firmware instructions stored in a machine-readable medium and/or may be hard-coded as a series of logic gates and/or state machine circuits in one or more integrated circuits and/or in one or more integrated circuits in combination with other circuit elements.
With some embodiments, control device 600 supports different control capabilities for heating and/or cooling. For example, device 600 may obtain a temperature setting (desired temperature) from a user through an input device and control one or more Peltier devices (e.g., Peltier devices 802-805 as shown in
Some embodiments may support a greater number of Peltier devices. However, the number of Peltier devices may be limited by physical constraints and/or electrical power limitations.
With some embodiments, the same Peltier devices may be used for different modes of operation. For example, referring to
With some embodiments, different Peltier devices may be used for different modes of operation. For example, Peltier devices 802 and 805 may be used for cooling while Peltier devices 803 and 804 may be used for heating. As another example, Peltier devices 802-805 may be used for cooling while only Peltier devices 502 and 805 are used for heating.
At block 1004, the control device determines whether to activate one or more fans (e.g., fans 114 and 115). For example, with some embodiments the fans may be activated at block 1005 only when the measured temperature is outside a temperature range to assist transferring heat with the environment of the serving apparatus. However, with some embodiments, a fan may be activated only for specific operating modes, e.g., a cooling mode or a heating mode.
At block 1103, the control device operates in the cooling mode and determines whether the measured temperature exceeds the cooling temperature setting. If so, the control device activates the Peltier devices until the measured temperature is less than or equal to the cooling hysteresis temperature at block 1104. Otherwise (i.e., the measured temperature does not exceed the cooling temperature setting), the control device deactivates the Peltier devices at block 1105.
At block 1106, the control device operates in the heating mode and determines whether the measured temperature is less than the heating temperature setting. If so, the control device activates the Peltier devices until the measured temperature is greater than or equal to the heating hysteresis temperature at block 1107. Otherwise (i.e., the measured temperature does not exceed the cooling temperature setting), the control device deactivates the Peltier devices at block 1108.
As can be appreciated by one skilled in the art, a computer system with an associated computer-readable medium containing instructions for controlling the computer system may be utilized to implement the exemplary embodiments that are disclosed herein. The computer system may include at least one computer such as a microprocessor, digital signal processor, and associated peripheral electronic circuitry.
While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.
Claims
1. An apparatus for changing a measured temperature of a serving surface, the apparatus comprising:
- a first Peltier device transferring heat between a top side and a bottom side of the first Peltier device;
- the serving surface thermally coupled with the top side of the first Peltier device;
- a heat pipe comprising a first portion and a second portion, the first portion thermally coupled with the bottom side of the first Peltier device, the heat pipe transferring the heat with the bottom side of the first Peltier device, the heat flowing between the first portion and the second portion; and
- a heat exchange device thermally coupled to the second portion of the heat pipe to exchange the heat with the second portion.
2. The apparatus of claim 1, wherein:
- the serving surface is thermally coupled to the top side of the first Peltier device to decrease the measured temperature;
- the heat pipe extracting the heat from the bottom side of the first Peltier device, the heat flowing from the first portion to the second portion; and
- the heat exchange device thermally coupled to the second portion of the heat pipe to extract the heat from the second portion.
3. The apparatus of claim 1, wherein:
- the serving surface is thermally coupled to the top side of the first Peltier device to increase the measured temperature;
- the heat pipe transferring the heat to the bottom side of the first Peltier device, the heat flowing from the second portion to the first portion; and
- the heat exchange device thermally coupled to the second portion of the heat pipe to transfer the heat to the second portion.
4. The apparatus of claim 1, further comprising a plurality of Peltier devices.
5. The apparatus of claim 4, further comprising:
- a temperature sensor providing an indication of the measure temperature of the serving surface; and
- a control device activating selected Peltier devices from the plurality of Peltier devices based on the indication.
6. The apparatus of claim 5, wherein the control device selects different Peltier devices to activate from the plurality of Peltier devices.
7. The apparatus of claim 5, wherein the control device activates all of the plurality of Peltier devices when the measured temperature is outside a temperature range.
8. The apparatus of claim 7, wherein the temperature range is between a temperature setting and a hysteresis temperature.
9. The apparatus of claim 7, wherein the control device activates a first proper subset of the plurality of Peltier devices when the measured temperature is within the temperature range.
10. The apparatus of claim 9, wherein the control device deactivates all of the plurality of Peltier devices when the measured temperature reaches a hysteresis temperature.
11. The apparatus of claim 9 wherein the control device activates a second proper subset during a subsequent time interval.
12. The apparatus of claim 5 further comprising:
- a fan; and
- the control device varying a speed of the fan based on the measured temperature.
13. The apparatus of claim 5, wherein the control device changes polarity of electrical power to the plurality of Peltier devices to change a mode of operation of the apparatus.
14. The apparatus of claim 13, further comprising:
- a fan; and
- the control device activating the fan based on the mode of operation.
15. A method for controlling a measured temperature of a serving surface, the method comprising:
- transporting heat between the a top side and a bottom side of a first Peltier device that is thermally coupled with the serving surface;
- transferring the heat between the bottom side of the first Peltier device and a first portion of a heat pipe that is thermally coupled with the bottom side of the first Peltier device;
- moving the heat between the first portion and a second portion of the heat pipe; and
- exchanging the heat between the second portion of the heat pipe and a heat exchange device that is thermally coupled with the second portion.
16. The method of claim 15, wherein:
- the transporting comprises transporting the heat from the top side to the bottom side of the first Peltier device to decrease the measured temperature;
- the transferring comprises transferring the heat from the bottom side of the first Peltier device to the first portion of the heat pipe;
- the moving comprises moving the heat from the first portion to the second portion of the heat pipe; and
- the exchanging comprises exchanging the heat from the second portion of the heat pipe to the heat exchange device.
17. The method of claim 15, wherein:
- the transporting comprises transporting the heat from the bottom side to the top side of the first Peltier device to increase the measured temperature;
- the transferring comprises transferring the heat from the first potion of the heat pipe to the bottom side of the first Peltier device;
- the moving comprises moving the heat from the second portion to the first portion of the heat pipe; and
- the exchanging comprises exchanging the heat from the heat exchange device to the second portion of the heat pipe.
18. The method of claim 15, further comprising:
- activating selected Peltier devices from a plurality of Peltier devices based on the measured temperature of the serving surface, wherein the plurality of Peltier devices includes the first Peltier device.
19. The method of claim 18, further comprising:
- selecting different Peltier devices from the plurality of Peltier devices.
20. The method of claim 18, further comprising:
- activating all of the plurality of Peltier devices when the measured temperature is outside a temperature range.
21. The method of claim 20, further comprising:
- activating a proper subset of the plurality of Peltier devices when the measured temperature is within the temperature range.
22. The method of claim 21, further comprising:
- deactivating all of the plurality of Peltier devices when the measured temperature reaches a hysteresis temperature.
23. A non-transitory computer-readable storage medium storing computer-executable instructions that, when executed, cause at least one processor to perform operations comprising:
- measuring a measured temperature of a serving surface; and
- activating selected Peltier devices from a plurality of Peltier devices based on the measured surface temperature.
24. The computer-readable medium of claim 23, wherein the computer-executable instructions, when executed, cause the at least one processor to perform:
- selecting different Peltier devices from the plurality of Peltier devices.
25. The computer-readable medium of claim 24, wherein the computer-executable instructions, when executed, cause the at least one processor to perform:
- activating all of the plurality of Peltier devices when the measured temperature is outside a temperature range.
26. The computer-readable medium of claim 25, wherein the computer-executable instructions, when executed, cause the at least one processor to perform:
- activating a proper subset of the plurality of Peltier devices when the measured temperature is within the temperature range.
27. The computer-readable medium of claim 26, wherein the computer-executable instructions, when executed, cause the at least one processor to perform:
- deactivating all of the plurality of Peltier devices when the measured temperature reaches a hysteresis temperature.
Type: Application
Filed: Jan 10, 2012
Publication Date: Jul 11, 2013
Applicant: Spring (U.S.A.) Corporation (Naperville, IL)
Inventors: Francis Thomas Brija (Palm Beach Gardens, FL), Ping Wu (Ningbo)
Application Number: 13/347,229
International Classification: F25B 21/02 (20060101);