Abstract:
In some embodiments, transpiration cooling and fuel cell for ultra mobile applications is presented. In this regard, an apparatus is introduced having an integrated circuit device, a fuel cell to power the integrated circuit device, wherein the fuel cell produces water as a byproduct, a chassis to house the integrated circuit device and the fuel cell, and a skin to cover the chassis, the skin comprising a waterproof layer configured to prevent water from contacting the integrated circuit device and a water absorbent layer of hydro gel configured to absorb water. Other embodiments are also disclosed and claimed.

Description:
FIELD OF THE INVENTION 
     Embodiments of the present invention generally relate to the field of passive cooled devices and, more particularly, to transpiration cooling and fuel cell for ultra mobile applications. 
     BACKGROUND OF THE INVENTION 
     The demand for more powerful handheld electronic devices presents problems in keeping the devices from getting too hot to handle. Passive cooling solutions are preferred, because no additional power is required and consumers tend to dislike the noise of a fan. Generally, a cooling solution is considered unacceptable if the skin temperature is allowed to exceed 45 degrees Celsius. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements, and in which: 
         FIG. 1  is a graphical illustration of a cross-sectional view of an example ultra mobile personal computer with transpiration cooling and fuel cell, in accordance with one example embodiment of the invention; 
         FIG. 2  is a graphical illustration of a cross-sectional view of the skin of the ultra mobile personal computer depicted in  FIG. 1 , in accordance with one example embodiment of the invention; and 
         FIG. 3  is a block diagram of an example electronic appliance suitable for implementing transpiration cooling and fuel cell, in accordance with one example embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art that embodiments of the invention can be practiced without these specific details. In other instances, structures and devices are shown in block diagram form in order to avoid obscuring the invention. 
     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. 
       FIG. 1  is a graphical illustration of a cross-sectional view of an example passive cooled ultra mobile personal computer with transpiration cooling, in accordance with one example embodiment of the invention. As shown, ultra mobile personal computer  100  includes one or more of skin  102 , chassis  104 , integrated circuit devices  106 , fuel cell  108 , display  110 , fuel tank  112 , water connection  114 , and fuel input port  116 . 
     Skin  102 , as described in greater detail in reference to  FIG. 2 , provides transpiration cooling for ultra mobile personal computer  100 . In one embodiment skin  102  is configured to be held in a person&#39;s hand. Transpiration cooling, as used herein, is a cooling solution that removes heat through water evaporation, producing much better results than natural convection and radiation. While shown as surrounding chassis  104 , skin  102  may directly contact integrated circuit devices  106  and/or power supply  108 . 
     Chassis  104  represents a housing for integrated circuit devices  106 , fuel cell  108  and fuel tank  112 . Chassis  104  may be comprised of metal and may provide attachment points for a printed circuit board (not shown). 
     Integrated circuit devices  106  represent functional components ultra mobile personal computer  100  and may use several watts of electricity when fully functioning that becomes heat. Integrated circuit devices  106  may be coupled with heatsinks, not shown. 
     Fuel cell  108  represents a power source that provides electricity to integrated circuit devices  106  and produces water as a byproduct. In one embodiment, fuel cell  108  is a direct methanol fuel cell. In another embodiment, fuel cell  108  is a hydrogen fuel cell. Fuel tank  112  may hold fuel, such as methanol or hydrogen, for use by fuel cell  108 . 
     Display  110  may be a liquid crystal display (LCD) that provides a graphical user interface for ultra mobile personal computer  100 . 
     Water connection  114  represents a conduit to provide water byproduct from fuel cell  108  to skin  102  as shown in greater detail with reference to  FIG. 2 . Fuel input port  116  allows for the replenishment of fuel from a fuel source, for example a container of methanol, into fuel tank  112 . 
       FIG. 2  is a graphical illustration of a cross-sectional view of the skin of the ultra mobile personal computer depicted in  FIG. 1 , in accordance with one example embodiment of the invention. In accordance with one example embodiment, skin  102  includes one or more of water absorbent layer  202  sandwiched between waterproof layer  204  and outer layer  206 . 
     Water absorbent layer  202  represents a material or combination of materials capable of absorbing and at least temporarily holding water. In one embodiment, water absorbent layer  202  is a temperature sensitive hydro gel, such as the acrylic acid-grafted carboxymethyl cellulose described in  Water - Absorbing Characteristics of Acrylic Acid - Grafted Carboxymethyl Cellulose Synthesized by Photografting , Shin Kuwabara and Hitoshi Kubota, Journal of Applied Polymer Science, Vol. 60, 1965-1970 (1996). In one embodiment, water absorbent layer  202  has a water absorbency that varies with temperature. In one embodiment, the water absorbency of water absorbent layer  202  is higher at lower temperatures and lower at higher temperatures with a significant drop in water absorbency at about 30 degrees Celsius. In one embodiment, water absorbent layer  202  is a sponge. Water absorbent layer  202  may be able to absorb water from ambient air or may need to have liquid water added to it. 
     As ultra mobile personal computer  100  is being used and the temperature of its internal components increases, skin  102  will also get warmer. Water previously absorbed in water absorbent layer  202  may then be released, either due to a decreased absorbency of water absorbent layer  202  or otherwise. This released water may then evaporate and thereby remove some heat from skin  102 . In one embodiment, the thickness of water absorbent layer  202  is determined so as to provide a sufficient amount of water absorbency to ensure that the effects of transpiration cooling will be available based on the amount of water produced by fuel cell  108 . In one embodiment, water absorbent layer  202  is one millimeter thick. 
     Waterproof layer  204  prevents water from contacting integrated circuit device  106 . In one embodiment, waterproof layer  204  is plastic. In another embodiment, waterproof layer  204  is metal. In one embodiment, waterproof layer  204  is integrated with chassis  104 . Waterproof layer  204  may include an opening through which water connection  114  may provide water produced by fuel cell  108  to water absorbent layer  202 . 
     Outer layer  206  substantially covers water absorbent layer  202  and provides openings for water to move into and out from water absorbent layer  202 . In one embodiment outer layer  206  is plastic. In another embodiment outer layer  206  is rubber. As shown, outer layer  206  includes micro-pores  208 . To prevent water from escaping from water absorbent layer  202  when ultra mobile personal computer  100  is not in use, outer layer  206  may include a cover (not shown) that may slide over or snap over the openings in outer layer  206 . 
     Micro-pores  208  may have a diameter sufficiently large enough to allow water to pass through and sufficiently small enough to prevent portions of water absorbent layer  202  from passing through. 
       FIG. 3  is a block diagram of an example electronic appliance suitable for implementing transpiration cooling, in accordance with one example embodiment of the invention. Electronic appliance  300  is intended to represent any of a wide variety of traditional and non-traditional electronic appliances, laptops, cell phones, wireless communication subscriber units, personal digital assistants, or any electric appliance that would benefit from the teachings of the present invention. In accordance with the illustrated example embodiment, electronic appliance  300  may include one or more of processor(s)  302 , memory controller  304 , system memory  306 , input/output controller  308 , network controller  310 , and input/output device(s)  312  coupled as shown in  FIG. 3 . Electronic appliance  300  may include a fuel cell and be enclosed with a skin described previously as an embodiment of the present invention. 
     Processor(s)  302  may represent any of a wide variety of control logic including, but not limited to one or more of a microprocessor, a programmable logic device (PLD), programmable logic array (PLA), application specific integrated circuit (ASIC), a microcontroller, and the like, although the present invention is not limited in this respect. In one embodiment, processors(s)  302  are Intel® compatible processors. Processor(s)  302  may have an instruction set containing a plurality of machine level instructions that may be invoked, for example by an application or operating system. 
     Memory controller  304  may represent any type of chipset or control logic that interfaces system memory  306  with the other components of electronic appliance  300 . In one embodiment, the connection between processor(s)  302  and memory controller  304  may be referred to as a front-side bus. In another embodiment, memory controller  304  may be referred to as a north bridge. 
     System memory  306  may represent any type of memory device(s) used to store data and instructions that may have been or will be used by processor(s)  302 . Typically, though the invention is not limited in this respect, system memory  306  will consist of dynamic random access memory (DRAM). In one embodiment, system memory  306  may consist of Rambus DRAM (RDRAM). In another embodiment, system memory  306  may consist of double data rate synchronous DRAM (DDRSDRAM). 
     Input/output (I/O) controller  308  may represent any type of chipset or control logic that interfaces I/O device(s)  312  with the other components of electronic appliance  300 . In one embodiment, I/O controller  308  may be referred to as a south bridge. In another embodiment, I/O controller  308  may comply with the Peripheral Component Interconnect (PCI) Express™ Base Specification, Revision 1.0a, PCI Special Interest Group, released Apr. 15, 2003. 
     Network controller  310  may represent any type of device that allows electronic appliance  300  to communicate with other electronic appliances or devices. In one embodiment, network controller  310  may comply with a The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 802.11b standard (approved Sep. 16, 1999, supplement to ANSI/IEEE Std 802.11, 1999 Edition). In another embodiment, network controller  310  may be an Ethernet network interface card. 
     Input/output (I/O) device(s)  312  may represent any type of device, peripheral or component that provides input to or processes output from electronic appliance  300 . 
     In the description above, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well-known structures and devices are shown in block diagram form. 
     Many of the methods are described in their most basic form but operations can be added to or deleted from any of the methods and information can be added or subtracted from any of the described messages without departing from the basic scope of the present invention. Any number of variations of the inventive concept is anticipated within the scope and spirit of the present invention. In this regard, the particular illustrated example embodiments are not provided to limit the invention but merely to illustrate it. Thus, the scope of the present invention is not to be determined by the specific examples provided above but only by the plain language of the following claims.