DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present invention relates to a miniature metal hydride thermal storage cartridge for the cooling of laptop computer chips and other mobile electronic consumer devices (e.g., cell phones, mobile cold storage for campers) to subambient temperatures, the cartridge composed of at least two chambers containing different metal hydrides. FIG. 1 shows a design of a miniature metal hydride thermal storage cartridge 10 for cooling of laptop computer chips to subambient temperatures. The cartridge 10 includes two chambers 21 and 22 containing two different metal hydrides, lanthanum nickel metal alloy 23 and magnesium nickel metal alloy 24, as shown in FIG. 2. The two chambers 21 and 22 are connected by an on/off miniature valve 25 that may be activated by the motion of inserting the cartridges 10 or 27 into the main and supplemental heat sinks 28 and 29, as shown in FIG. 1. The chambers and valve form a seamless, cylindrical outer surface, which provides effective contact between the cartridges 10 and 27 and the heat sinks 28 and 29.

[0014] As shown in FIG. 2, prior to utilization of the apparatus of the present invention, all hydrogen should be inside the chamber that has a low-temperature metal hydride, e.g., the magnesium nickel metal alloy chamber 21, and the valve 25 should be closed. Upon inserting the cartridge 10 into the heat sinks 28 and 29, the valve 25 is open, and the hydrogen begins disassociation with the magnesium nickel metal alloy 23 and flows into the lanthanum nickel metal alloy 24 in chamber 22. The two chambers 21 and 22 will reach internal pressure balance when the magnesium nickel metal alloy and lanthanum nickel metal alloy chambers 21 and 22 reach −10° C. and 70° C., respectively. As a result of this process, the cartridge 10 cools the chip 30 to subambient temperatures (e.g., −10° C.), and dissipates the heat (at, e.g., 70° C.) to ambient through the supplemental heat sink 29, as shown in FIG. 1.

[0015] The effective time of use for a particular cartridge depends on both the mass of the metal hydrides inside the cartridge, as well as the cooling requirement. For instance, a chamber of 0.25 inches in diameter and 3 inches long is capable of storing approximately 20 grams of metal hydrides and 0.4 grams of hydrogen. Therefore, the chamber is capable of storing approximately 6,000 joules of thermal energy, assuming the metal hydride has an enthalpy change of hydriding reaction of about 6 kcal/mole-H₂. This is equivalent to 10 watts of subambient cooling for ten minutes. In a preferred embodiment of the present invention, a combination of four cartridges will provide effective cooling for an extended period of time (about 40 minutes) where “super computing performance” is required. In this case, the total amount of hydrogen inside the four cartridges is approximately 1.6 grams.

[0016] The cartridge 10 may be “recharged” by inserting the lanthanum nickel metal alloy end into a hot socket 40, in order to drive all of the hydrogen into the magnesium nickel metal alloy chamber for furture use. This can be done along with recharging the battery 41 in a battery charger 42, as shown in FIG. 3. An added benefit is the cooling of the battery charger 42 by the H₂ disassociation in the lanthanum nickel metal hydride chamber.

[0017] In a further preferred embodiment of the present invention, as shown in FIG. 4, the metal hydride powders are “glued” together and to the chamber inner walls using e.g., silicone. FIG. 4 shows a cross section of chamber 10 containing metal hydrides 43. The H₂ passages 44 may be formed by e.g., mandrels during the “gluing” process. In order to improve the heat conduction of the powder matrix, an effective amount of high conductance metal (e.g., Cu, Si) powders may be mixed with the metal hydride powders before being glued together. Such powders are inert in a hydrogen environment; the powders enhance effective thermal conductivity of the porous structure.

[0018] Thus, a preferred embodiment of the present invention employs the use of two different metal hydrides to achieve subambient cooling of electronic devices, e.g., laptop computers, mobile phones and other consumer electronic equipment. The cartridge-type thermal storage device may be recharged along with batteries. The metal hydrides may be mixed with e.g., copper powder, to improve thermal conductivity. In an alternative hydride bonding design, mandrel-formed H₂ passages in a packed metal hydride powder structure may also achieve the purposes of the present invention.

[0019] While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of this invention will be obvious to those skilled in the art. The appended claims and this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the present invention.