Field of the Invention

The present invention relates to air conditioners and, in particular, metal hydride air conditioners.

Background of the Invention

Metal hydride beat exchangers have been considered for use in providing cool passenger air to vehicles, such as automobiles. Such application is described in U.S. Patent No. 5,571,251. To effect the described heat exchanger operation, adequate heat must be available on-board the vehicle to facilitate compression of gaseous hydrogen. Unfortunately, due to a lack of high quality heat available in hybrid vehicles, other means must be considered to effect the necessary compression of hydrogen during the operation of metal hydride heat exchangers.

Summary of the Invention

According to one aspect of the present invention there is provided a system for flowing gaseous hydrogen comprising; a collection container; compression machinery disposed within the collection container, and including an inlet, a fluid compression space, and an outlet, wherein the inlet is fluidly coupled to the outlet through the fluid compression space, and wherein the inlet is coupled to an inlet fluid conduit and the outlet is coupled to an outlet fluid conduit and each of the inlet and outlet fluid conduits extends through and externally of the container, and a hydrogen storage container containing hydrogen storage material and flindly coupled to the outlet of the compression machinery; wherein the collection container is configured for receiving gaseous hydrogen leakage flow from the compression space, and wherein the collection container is fluidly coupled to the inlet of the compression machinery to facilitate flow of the leaked gaseous fluid to the inlet of the compression machinery. According to another aspect of the present invention, there is provided a system for flowing gaseous fluid comprising: a collection container; compression machinery comprising; an inlet; a fluid compression space fluidly coupled to the inlet; a raoveable member disposed in force application communication relative to the fluid compression space and configured for effecting an application of a force to the fluid compression space upon a movement of the moveable member; and an outlet fluidly coupled to the fluid compression space; and a hydrogen storage container containing hydrogen storage material and fluidly coupled to the outlet of the compression machinery; wherein the collection container is configured for receiving gaseous fluid which leaks across the moveable member from the compression space, and is fluidly coupled to the inlet of the compression machinery to facilitate flow of the leaked gaseous fluid to the inlet of the compression machinery.

According to a further aspect of the present invention, there is provided a vehicle including a passenger compartment and a cooling system, the cooling system comprising: a first hydrogen storage container containing a first hydrogen storage material; a first process fluid conduit disposed in thermal communication disposition with the hydrogen storage container, and fluidly coupled to the passenger compartment for flowing hot ambient air flow received from within the passenger compartment and effecting heat transfer from the hot ambient air flow to the first hydrogen storage container to provide a cooled ambient air flow to the passenger compartment; compression machinery fluidly coupled to the first hydrogen storage container for receiving a low pressure gaseous fluid from the hydrogen storage container, and configured for pressurizing the received low pressure gaseous fluid to provide a high pressure gaseous fluid, and discharging a flow of the high pressure gaseous fluid; a second hydrogen storage container fluidly coupled to the compression machinery for receiving the discharged flow of the high pressure gaseous fluid, the second hydrogen storage container containing a second hydrogen storage material; and a second process fluid conduit disposed in thermal communication disposition with the hydrogen storage container, and fluidly coupled to an environment exterior to the vehicle. According to a further aspect of the present invention, there is provided a method of effecting cooling of a first process fluid and heating of a second process fluid comprising: transferring heat from a hot first process fluid to a first hydrogen storage material to effect desorption of gaseous hydrogen and provide a cooled first process fluid; mechanically compressing the desorbed gaseous hydrogen to provide pressurized gaseous hydrogen; effecting absorption of the pressurized gaseous hydrogen by a second hydrogen storage material to produce heat energy; transferring the produced heat energy to a second process fluid.

Brief Description of the Drawings

The invention will be better understood by reference to the following detailed description of the invention in conjunction with the following drawings, in which:

Figure I is a schematic sectional illustration, illustrating the circulation of ambient air from the interior or a vehicle and across heat exchanges, and also the circulation of ambient air external to the vehicle and across an embodiment of the system of the present invention, where a single fan is used to effect flow of external air across either heat exchanger, and where separate fans are provided to effect flow of interior vehicle air across each heat exchanger;

Figure 2 is a process flow diagram of an embodiment of a system of the present invention;

Figure 3A, 3B, and 3C are, respectively, side elevation (3A), front elevation (3B), and top plan, (3C) detailed views of the collection container of the present invention, with associated piping components, and internal components (eg., compressor and piping) in dotted outline;

Figure 4 is a schematic illustration of the suction and discharge piping of the compressor of the present invention, as well as the return conduit effecting fluid coupling between the collection container and the suction conduit of the compressor; Figure 5 A is a schematic sectional illustration of a compressor used in an embodiment of a system of the present invention;

Figure 5B is a schematic sectional illustration of another compressor used in another embodiment of a system of the present invention;

FIG. 6A illustrates in an exploded view a modular heat exchanger assembly useful in practice of the invention;

FIG. 6B illustrates the assembled modular neat exchanger of FIG. 6A;

FJG. 6C illustrates a detail view of the assembly of FIG. 6A and the connection to tubular elements which contain the hydrogen storage material; and

Figure 7 is a schematic illustration of a vehicle employing an embodiment of a system of the present invention.

Detailed Description

The present invention provides a system 2 for cooling air.

The preferred embodiment of the cooling system includes two heat exchangers 802, 804. Each of these heat exchangers comprises a container containing at least one hydrogen storage material.

References to hydrogen are intended to refer to protium and deuterium (isotopes of hydrogen), alone or in combination.

Each of the hydrogen storage materials within each of the containers consists essentially of a hydrogen storage composition and/or a hydridable form of the hydrogen storage composition.

ϊn the context of the hydrogen storage material, "consisting essentially of means that matter other than the hydrogen storage composition and/or the hydridable form of the hydrogen storage composition may or may not be present in the hydrogen storage material, ϊn other words, the hydrogen storage material can consist entirely of the hydrogen storage composition and/or the hydridable form of the hydrogen storage composition. However, if present, this other matter may be present as impurities introduced into the hydrogen storage material as by-products arising during processing or from the raw materials, or introduced by contamination when assembling the system or during operation of the system. This other matter may also be intentionally present to function as a catalyst for hydrogen transfer (eg., hydrogenation or dehydrogenation) reactions, or may also be intentionally present to function as a dessicant. This other matter is present in amounts which are not significant so as to effect the desired properties of the hydrogen storage material, as discussed herein, or to noticeably interfere with any of the processes occurring during the operation of the system of the present invention.

Various gaseous fluids are described below as "consisting essentially of gaseous hydrogen". In the context of the gaseous fluids, the term "consisting essentially of means that matter (eg., other gases) other than gaseous hydrogen may or may not be present in the gaseous fluid. In other words, the gaseous fluid can consist entirely of the gaseous hydrogen, without any further matter present. However, if present, this other matter may be present as impurities introduced into the gaseous fluid as by-products arising during processing or from the raw materials, or as impurities introduced into the system of the present invention when assembling the system or during operation of the system. This other matter is present in amounts which are not significant so as to effect the desired properties of the gaseous hydrogen, or to noticeably interfere with any of the processes occurring during the operation of the system.

It is understood that the hydrogen storage composition of each of the at least one first hydrogen storage material is different for each of the at least one first hydrogen storage material.

The hydridable form of a hydrogen storage composition can be any of: a metal, a metalloid, an alloy of a metal, an alloy of a metalloid, a compound of a metal, or a compound of a metalloid. The metal or the metalloid of the hydridable form must be available to become associated with hydrogen so as to form the hydrogen storage

composition. Conversely, decomposition of the hydrogen storage composition (dissociation of hydrogen from the first hydrogen storage composition) results in the formation of the hydridable form.

Absorption of hydrogen by hydrogen stprage material refers tα the association of hydrogen with the hydrogen storage material. Possible mechanisms for association in a "simple metal hydride" include: dissolution, covalent bonding, or ionic bonding. Dissolution describes the process where a hydrogen atom is incorporated in the voids of a lattice structure of a metal or intermetallic alloy, Examples of such materials include vanadium hydrides, titanium hydrides, and hydrides of vanadium-titanium alloys. An example of hydrogen association with a hydrogen storage material by way of a covalent bonding mechanism is magnesium hydride. An examples of hydrogen association with a hydrogen storage material by way of an ionic bonding mechanism is sodium hydride and potassium hydride. Complex hydrides are metal hydrides which exhibit partially covalent / partially ionic bonding between any of (i) a trivalent group IIIB metal, or (ii) a metalloid atom (such as aluminium), (iii) or a transition metal (such as iron) of the hydrogen storage material and a hydrogen atom. It is understood that the present understanding of the metal-hydrogen or metalloid-hydrogen bonding coordination in a complex metal hydride is explained in Hauback et al., "Accurate Structure of LiAlD4 studied by combined powder and x-ray diffraction", Journal of Alloys and Compounds 346 (2002) 184-189, Elsevier Science B.C. Examples of complex hydrides are sodium alanate and lithium alanate.

The term "a hydrogen storage composition and/or a hydridable form of the hydrogen storage composition" means any of : (i) the hydrogen storage composition, (ii) the hydridable form of the hydrogen storage composition, and (iii) a homogeneous or an inhomogeneous combination of the hydrogen storage composition and the hydridable form of the hydrogen storage composition.

In one embodiment, each of the hydrogen storage materials is in the form of a powder. Preferably, the powder has an average diameter of less than 0.01 inches before it has been hydrided the first time, and less than 0.000039 inches after it has undergone several hydriding and dehydriding cycles.

Suitable hydrogen storage compositions include simple metal hydrides and complex metal hydrides. In a preferred embodiment, the hydridable form of the hydrogen storage composition is lanthanium pentanickel (LaNis). In another preferred embodiments the hydrogen storage composition (in a hydridable form) is Tix Zrx M% Vx Fe* Crx Nix , where x is 0.001 to I, and y is 0.01 to 2.0. A preferred species of this hydrogen storage material is Tio.ss 2xa.ιi2 Mnj .437 V0.407 Fe0.048 Cro,04s NΪO.QQ6,

The system 2 cools air by using the heat energy of ambient air to effect desoiption of hydrogen from a first hydrogen storage material disposed in a first container 30. The combination of the first container 30 and the first hydrogen storage material functions as a first heat exchanger 802. The first container contains the first hydrogen material and a gaseous liquid consisting essentially of gaseous hydrogen, wherein the gaseous fluid is in contact with the first hydrogen storage material. Hydrogen desorption from the first hydrogen storage material and into the gaseous fluid occurs at a predetermined temperature, and upon input of a predetermined amount of heat energy, when the first hydrogen storage material comprises a hydrogen storage composition having, at the predetermined temperature, a desorption plateau pressure which is greater than the partial pressure of gaseous hydrogen in the gaseous fluid contacting the hydrogen storage composition of the first hydrogen storage material.

Desorption of hydrogen from the first hydrogen storage material is an endothermic reaction, requiring an input of heat energy to the first hydrogen storage material. Such heat energy is supplied by a fluid, preferably air for which cooling is desired. In the preferred embodiment, the first container 30 is contacted with air for which cooling is desired, The air is characterized by a higher temperature than the temperature of the first hydrogen storage material disposed in the first container 30. Preferably, the air is drawn from the interior passenger compartment of a vehicle 4 (see Figure 7), such as an automobile, and forced by a first fan 10a through conduit 302 to flow across and contact the first container 30. The air flows across the container 30, and heat is transferred from the air to the first hydrogen storage material, effecting desorption of hydrogen from the hydrogen storage material, and also a reduction in the temperature of the air. The cooled air is then returned to the interior of the vehicle through conduit 304.

Once the hydrogen of the first hydrogen storage material available for desorption becomes desorbed or substantially desorbed from the first hydrogen storage material, regeneration of the first hydrogen storage material with hydrogen must be effected so that the first hydrogen storage material can continue to function as an effective heat sink to effect desired cooling of the air (this is referred to as "regeneration")- ϊn the present invention, mechanical compression machinery such as a mechanical compressor 20 is provided and fluidly coupled to the fust container 30. The mechanical compressor 20 receives a low pressure gaseous fluid consisting essentially of hydrogen through an inlet or suction 22, imparts mechanical energy to the low pressure gaseous fluid to effect pressurization thereof to form a high pressure gaseous fluid consisting essentially of gaseous hydrogen, and delivers the high pressure gaseous fluid to the first container through an outlet or a discharge 24. Absorption of hydrogen, from the high pressure gaseous fluid consisting of essentially hydrogen, by the first hydrogen storage material occurs at a predetermined temperature when the first hydrogen storage material comprises a hydridable form of a hydrogen storage composition having, at the predetermined temperature, an absorption plateau pressure which is less man the partial pressure of the gaseous hydrogen in the high pressure gaseous fluid contacting the hydridable form of the hydrogen storage composition of the first hydrogen storage material.

Hydrogen absorption by the first hydrogen storage material is an exothermic reaction, resulting in the generation of heat energy. Such heat energy is removed by a cooling system. In one embodiment, the necessary cooling is effected by the first container 30 being contacted with a fluid, wherein the fluid is characterized by a lower temperature than the temperature of the first hydrogen storage material disposed in the first container 30. Preferably, the fluid is ambient air which is drawn from the environment 7 external to the vehicle (see Figure 7) and is forced by a second fan 50 through conduit 402 to flow across and contact the first container 30. The ambient air flows across the first container 30, and beat is transferred from first hydrogen storage material to the ambient air to facilitate hydrogen absorption by the first hydrogen storage material. The ambient air is heated and is returned through conduit 404 to the environment 7 external to the vehicle.

Referring to Figures 1 and 2, in one embodiment, so as to continue to provide the necessary desired cooling of the air from within the vehicle during regeneration of the first hydrogen storage material of the first container 30, the present invention provides a second container 40 containing a second hydrogen storage material. The combination of the second container 40 and the second hydrogen storage material functions as a second heat exchanger 804. While the first hydrogen storage material is being regenerated by the compressor 20, the second container 40 is contacted with a fluid, preferably air, at a higher temperature than the second hydrogen storage material, Heat energy is transferred from the air to the second hydrogen storage material to effect desorption of hydrogen from the second hydrogen storage material. Desorption of hydrogen from the second hydrogen storage material occurs at a predetermined temperature, and upon input of a predetermined amount of heat energy, when the second hydrogen storage material comprises a hydrogen storage composition having, at the predetermined temperature, a desorption plateau pressure which is greater than the partial pressure of gaseous hydrogen in the gaseous fluid contacting the hydrogen storage composition of the second hydrogen storage material.

Preferably, the air is drawn from the interior passenger compartment of a vehicle 4, such as an automobile, and forced by a fan to flow through conduit 602 and across the second container 40. The air contacts and flows across the container 40, and heat is transferred from the air to the second hydrogen storage material, and the cooled air is then returned through conduit 604 to the interior of the automobile.

Referring to Figure 1, in one embodiment, a third fan 10b is used to effect flow of ambient air from an interior of a vehicle and across the second container 40. In another embodiment, the system can be configured such that the first fan lOa could be used to perform the function of third fan 10b if the conduits 304 and 604 are joined together. Upon the first hydrogen storage material being fully or partially regenerated and becoming available to participate in the cooling of the desired air mass, the second hydrogen storage material can then be regenerated in a manner similar to that described as for the first hydrogen storage material, with the use of the compressor 20. The compressor is fraidly coupled to the second container 40. The compressor 20 receives a low pressure gaseous fluid consisting essentially of hydrogen through the suction 22, imparts mechanical energy to the gaseous fluid to effect pressurization of the gaseous fluid (and, therefore, the gaseous hydrogen) to form a high pressure gaseous fluid consisting essentially of hydrogen, and delivers the high pressure gaseous fluid to the second container 40 through the discharge 24. The second hydrogen storage material becomes regenerated when hydrogen is absorbed by the second hydrogen storage material. Such absorption occurs, at a predetermined temperature, when the second hydrogen storage material comprises a hydridable form of a hydrogen storage composition having, at the predetermined temperature, an absorption plateau pressure which is lower than the partial pressure of gaseous hydrogen in the high pressure gaseous fluid contacting the hydridable form of the hydrogen storage composition of the second hydrogen storage material.

During regeneration of the second hydrogen storage material, heat energy is generated. Preferably, the second fan 50 is used to cool the second container 40 during the regeneration cycle by drawing ambient air from the environment external to the vehicle and forcing such drawn ambient air to flow through conduit 502 and across the second container 40. The ambient air becomes heated as it flows across the second container 40. and this heated air is then returned through conduit 504 to the environment external to the vehicle.

Preferably, the second hydrogen storage material is the same as, or substantially the same as the first hydrogen storage material. However, it is understood that it is not necessary that the first and second hydrogen storage materials are me same or substantially the same. Like the first hydrogen storage material, suitable second hydrogen storage materials include simple metal hydrides, complex metal hydrides, and hydridable forms thereof. Like the first hydrogen storage material, in one embodiment, the second hydrogen storage material is in the form of a powder, and, preferably, the powder has an average particle size diameter of less than .

Preferably, each of the first and second containers 30, 40 containing the respective hydrogen storage materials, includes a plurality of modules of the modular heat exchanger configuration described and illustrated in U.S. Patent No. 5,623,987.

Referring now to FIG. 6A, an exploded view of a preferred modular heat exchanger assembly useful in heat exchangers 802 and 804 is illustrated.

For each modular assembly, an inlet conduit 9222 is provided and with expanded flat end 9228. The inner surface adjacent end 922S includes threads 9230, shown in phantom, for connection to other elements of the assembly. An annular, radially extending, flat end surface 9232 of the end 9228 extends through a plane which lies substantially perpendicular to the centerline of 9222.

A cylindrical ring manifold 9238 is provided comprising a tubular element with two threaded ends 9240, 9242 and a number of apertures 9244 which extend through the tube wall and are disposed circuraferentially around the ring manifold 9238. Each of the apertures 9244 provides gas communication to the inside of the manifold 9238. The threaded end 9240 is adapted for connection to the threads 9230 on the inner surface of the end 9228 of conduit 9222 and provides a framework for further connection with additional elements of the assembly, as is discussed below.

The ring manifold 9238 advantageously includes upstanding ribs 9246 which separate groups of apertures 9244. The other threaded end 9242 provides a connection for other elements of the assembly. Plural modular ring elements 9250 are each adapted for sliding onto and over the ring manifold 9238. Each ring element 9250 comprises an annular ring having a central opening which has an inner diameter slightly larger than the outer diameter of the ring manifold 9238. The ring element 9250 has a plurality of apertures 9254 which extend radially through the circumferential wall of the element 9250 from the outer to the inner diameter surfaces. Each ring element 9250 can. be fitted over the ring manifold 9238 until it reaches a position overlying the apertures 9244 of the ring manifold. Optimally, each aperture 9254 of the ring element 9250 is disposed over a portion of ring manifold 9238 which includes an aperture 9244. This arrangement should essentially provide more or less direct communication from the inner diameter of the manifold 9238 through the apertures 9244, 9254 to the outside diameter of the ring element 9250.

Each ring element 9250 further provides two radially extending faces 9256, 9258 which, when assembled, are each disposed substantially perpendicularly to the centerline of the device. Preferably, each of the ring elements 9250 are identical and interchangeable. Placing the plural ring elements 9250 end-to-end, that is, each face 9256 of one ring is placed adjacent face 9258 of the next adjacent ring, provides a cylindrical tube having stacked annular ring elements 9250. When assembled, the cylindrical tube formed by the ring elements 9250 overlies the ring manifold 9238.

The axial widths of the ring elements 9250 between the faces 9256, 9258 are of a predetermined dimension. When the ring manifold 9238 is screwably attached to valve threads 9230 and the ring elements 9250 are assembled over the ring manifold 9238, there is a substantial portion of the threads 9242 which protrude through the central opening of the last ring element 9250 in the stack of plural ring elements. An end piece 9260, having a chamber 9262 with a threaded, circumferential, internal surface, is securably attached to the ring manifold 9238. Threads 9242 of the ring manifold 9238 conform to the internal threads of the surface, thus enabling the end piece to be screwably attached onto the ring manifold 9238. Each piece 9260 has an outer thread in order to accommodate a bracket or fixture that will allow the entire heat exchanger to be mounted from the manifold 9238 and not the component tubes 9270 (see below).

End piece 9260 also has a radially extending, circumferential flanged member 9266 having a face 9268 at the axial terminus which is coextensive with the face 9258 of the last of the plural, stacked ring members 9250. Accordingly, after assembly of the ring elements 9250 over the ring manifold 9238, the face 9256 of the first ring element 9250 is adjacent and opposite the flat end surface 9232 and also, each of the walls 9256, 9258 of the other ring elements 9250 are adjacent and opposite each other. Rotation and engagement of the end piece 9260 onto the threads 9242 of the ring manifold 9238 brings the end face 9268 of the end piece 9260 opposite and adjacent the face 9258 of the last ring element 9250 in the stack.

As the end piece 9260 is screwed onto the ring manifold 9238, the face 9268 exerts an axial pressure on the face 9258 of the ring element 9250 and, in turn, on each face 9256, 9258 of the stack of ring elements. In order to provide an airtight enclosure for the space inside the cylindrical tube comprised of the ring elements 9250, a sealing element 9269, such as a washer or O-ring, is disposed between each pair of faces 9256, 9258, 9232, 9256 and 9258, 9268. The sealing clement 9269 may be inserted into a circumferential groove 9267 in each face 9256 and in face 9268, best shown in FIG. 6C. In one embodiment, the sealing element 9269 comprises a soft crushable metal, such as 321 stainless steel (silver-plated) which will hermetically seal the faces against each other to eliminate passage of all gases, including hydrogen, through the seal. In the preferred embodiment, the sealing element 9269 is a VITQN™ o-ring.

FIG. 6C shows a front view of one of the ring elements 9250, together with certain of the elements which are connected thereto. Referring now to FIGS. 6A, 6B and 6C, tubes 9270 are shown connected into the ring elements 9250. Each of the apertures 9254 are adapted to receive a tube end 9272 therethrough. FIG. 7 shows two tubes 9270, the ends 9272 of which tubes 9270 have been inserted into adjacent apertures 9254 which are disposed on the same modular ring element 9250. FIG. 6C shows the ring element 9250 having a radial face 9256 and central opening 9252, and being connected to only two of the plurality of tubes 9270 for purposes of illustration.

FIG. 6B shows an assembled modular exchanger assembly with the same numbering as FIG.6A.

An end 9272 of each tube 9270 is shown inserted into an aperture 9254 in fluid-tight relationship and extending in a spiral around the ring element 9250. When the outwardly directed spiral of tube 9270 reaches a point spaced farthest from the ring element 9250, the spiral then becomes inwardly directed and returns toward the ring element 9250 ai

another aperture 9254 on Has same ring element 9250. For greater ease in manufacture and assembly, the tube 9270 is not contained in a single plane but the path of the tube is shifted in a lateral direction, i.e. along toe axial direction as defined by the centerline of FIG. 6A, and the other end 9272 of each tube is inserted through an aperture 9254 that is in a different circumferential and axial position on the ring element 9250.

For convenience during assembly, the apertures 9254 can comprise twelve equally spaced apertures disposed along a circumferential path on the ring element 9250 in two rows. One row is connected to all of the outwardly directed spirals of tubes 9270, and the other row of apertures 9254 is connected to all of the inwardly directed tube ends 9272. The second row of apertures 9254 are not visible in FIG. 6C because they are behind the outwardly directed tube ends 9272.

The shift in lateral position of the tube 9270 is necessary because as each tube 9270 reaches its outer periphery as measured from the ring element 9250, the tubes 9270 would intersect if they were in the same plane. Because each tube 9270 has an identical path, but a different circumferential starting and end point (at successive apertures 9254 in different planes) each of the twelve tubes 9270 are of&et by 30 degrees in the circumferential direction. Thus intersection of the tubes at the outer periphery is avoided, and the final configuration appears to comprise a single assembly of plurality of intertwined tubes 9270 with layers of tubes 9270 being disposed one on top of another,

Preferably, the tubes 9270 are copper tubing, having an outer diameter of about 1/8 of an inch and having a radial wall thickness of 0.010 inches. These parameters have been found capable of containing gas underpressures of up to 1000 p.slg. without failure of the tube 9270. The length of tubes 9270 can be any desirable length, depending on the desired final dimensions of the assembled modular heat exchange unit. A length of about two feet is appropriate for a smaller size heat exchange unit, and results in the outer periphery of all of the tubes 9270 having an essentially circular configuration with a diameter of about 68 inches. In the preferred embodiment, the length is 22 inches.

The tubes 9270 are not in the same plane, but are shifted slight distances, as is explained above. The distance which tubes 9270 are shifted, however, is small compared to the

IS

outer diameter of the periphery of the assembly. In fact, all of the tubes 270 are within a space which is bounded by the planes defined by the radial walls 9256, 9258 of modular ring element 9250.

This configuration provides for assembly of the modular ring elements 9250 in stacks after the tubes 9270 have been connected to the apertures 9254 of the ring elements 9250. Other configurations are possible in which the tubes 270 may be out of the plane boundaries, as long as each modular ring element 9250 is consistently identical and the tubes 9270 do not interfere with the tubes 9270 of the adjacent modular ring elements 9250.

It is also possible that the tube 9270 can have a shape other than a spiral, or indeed, that only one end 9272 of each tube 9270 is connected to the ring element 9250. The configuration shown in FIGS. 6A, 6B and 6C, however, is preferable from the consideration of compactness, and also to provide better circulation and transfer of gas through the tubes 9270 and through the system during operation.

In accordance with generally known practices, positioned within tubes 9270 are the metal hydride alloys. Preferably, as described in U.S. Patent No. 4,396,114, flexible tubular means porous to the passage of hydrogen gas therethrough, e.g., a stainless steel garter spring, coaxial with tube 9270, is provided. The annular space between the outer surface of the spring and the inner surface of tube 9270 is packed with the appropriate metal hydride alloy. The center portion within the flexible spring provides a passage for hydrogen during use.

In practice of the invention, for each heat exchanger S02, S04, one or more modular assemblies containing the hydrogen storage material is mounted by conventional means in the housing 806 such that the modular assembly is configured for heat exchange relationship with air flowing through the housing 806 such that the air passes in direct contact with tubes 270 of the modular assembly. Each modular assembly is suitably fluidly coupled to respective conduits 8022, 8042, for facilitating hydrogen supply and return. Ih the preferred embodiment, each heat exchanger 802, S04 includes fifteen (15) modular assemblies (ie. separate ring manifolds 9238) disposed in parallel relative to each other. The ring manifold 9238 for each of the modular assemblies is separately fluidly coupled to respective conduits 8022, 8042. Each modular assembly includes twelve (12) tubes 9270.

In one embodiment, heat exchangers 802 and 804 are mounted to a bracket fastened within a metal duct housing 806. The metal duct housing 806 defines air flow conduits 302, 304, 402, 404, 502, 504, 602 and 604.

Preferably, the gaseous hydrogen of the low pressure gaseous fluid received by the compressor 20 is hydrogen which has been desorbed from the hydrogen storage material of one of the first ana second containers 30, 40. Accordingly, in one embodiment, a low pressure gaseous fluid is provided consisting essentially of hydrogen desorbed from one of the first and second hydrogen storage materials (during the "cooling cycle"). The low pressure gaseous fluid consisting essentially of hydrogen desorbed from one of the first and second hydrogen storage materials is received by the compressor 20. The compressor 20 then compresses the delivered low pressure gaseous fluid to form a high pressure gaseous fluid consisting essentially of gaseous hydrogen desorbed from one of the first and second hydrogen storage materials and effects the delivery of this high pressure gaseous fluid to the hydrogen storage material of the other one of the first and second containers 30, 40. In this respect, while the hydrogen storage material of one of the first and second containers 30, 40 is undergoing a cooling cycle, the hydrogen storage material of the other one of the first and second containers 30, 40 is undergoing a regeneration cycle, and the desorbed hydrogen from one of the containers 30, 40 is used to charge (become absorbed by) the hydrogen storage material of the other one of the containers 30, 40.

Air flow across the heat exchangers 802, 804 is controlled by dampers 3021, 3045, 4022, 4046, 5023, 5047, 6024 and 6048 disposed in the conduits 302, 304, 402, 404, 502, 504, 602, and 604. The damper 3021 is disposed in the conduit 302 for opening and closing fluid communication between ambient air being drawn from the interior of the vehicle and the heat exchanger 802. The damper 3045 is disposed in the conduit 304 for opening and closing fluid communication between fluid flowing across the heat exchanger 802 and the interior of the vehicle. Both dampers 3021 and 3045 must be open to allow fan 10a to effect flow through conduits 302 and 304 and across heat exchanger 802. The damper 4022 is disposed in the conduit 402 for opening and closing fluid communication between outside ambient air being drawn from the external environment and the heat exchanger S02, The damper 4046 is disposed in conduit 404 for opening and closing fluid communication between fluid flowing across heat exchanger 802 and the external environment (outside ambient air). Both dampers 4022 and 4046 must be open to allow fan 50 to effect flow through conduits 402 and 404 and across heat exchanger 802. The damper 5023 is disposed in the conduit 502 for opening and closing fluid communication between the outside ambient air being drawn from the external environment and the heat exchanger 804. The damper 5047 is disposed in the conduit 504 for opening and closing fluid communication between fluid flowing across the heat exchanger 804 and the external environment (outside ambient air). Both dampers 5023 and 5047 must be open to allow fan 50 to effect flow through conduits 502 and 504 and heat exchanger 804. The damper 6024 is disposed in the conduit 602 for opening and closing fluid communication between ambient air being drawn from the interior of the vehicle and the heat exchanger 804. The damper 6048 is disposed in the conduit 604 for opening and closing fluid communication between fluid flowing across the heat exchanger 804 and the interior of the vehicle. Both dampers 6024 and 6048 must be open to allow fan 10b (in the Figure 1 embodiment) or fan 10a (in the embodiment where a single fan 10a is used to also perform the function of fan 10b, where conduits 304 and 604 are joined together) to effect flow through conduits 602 and 604 and across heat exchanger 804.

The dampers can be in the form of any of any mechanical closing device such as a flat piece of metal that slides, or is brought to lay over, the duct opening. Modes of actuation of this damper can vary, with electro-mechanical actuators such as solenoids, servos, or pistons performing the conversion of electrical or compressed gas energy into mechanical motion.

Air flow across the heat exchangers 802, 804 is generated by fans 10a and 50 (and, in the Figure 1 embodiment, also fan 10b). In the preferred embodiment, each of the fans is EBM Model No. W2G130-AA33-01, 14 Watts. Each of the fans is mounted with simple metal brackets and sheet metal screws to the metal duct work housing 806. Figure I shows the presence of separate fans 10a, lOb for each of exchangers 802, and 804. The function of these two fans could also be accomplished with only one fan if the conduits (ducts) 304 and 604 are joined together.

Referring to Figures 3A, 3B, 3C, and 4, the compressor 20 is disposed within a collection container 60 which defines a collection space 62 to effect collection and containment of any gaseous fluid (consisting essentially of gaseous hydrogen) which may escape or leak from the compressor 20 as gaseous fluid leakage flow. Preferably, the collection container 60 is made from 6061 aluminum. The outer diameter of this compressor coniainer 60 or "can" is U inches, with a wall thickness of 0.5 inches, and a length of 17 inches. Flat, circular, aluminum end plates 61, 63, that are 0.75 inches thick, are attached to the ends of a tubular portion 65 to seal the "can". The end plates 61, 63 are attached to the tubular portion 65 via the use of 36 equally spaced high strength machine screws. An O-ring is disposed between each of the ends of the tubular portion 65 and the respective end plates 61, 63 to provide a leak tight seal of the endplates 61, 63 to the tubular portion 65. The container is mounted on a stand 19 which, in turn, is mountable to the frame 6 of the vehicle 4.

Preferably, the interior of the container 60 includes a precious metal based catalytic material that has been treated to operate in a moist environment and is provided to convert free oxygen within the space 62, with hydrogen that is present, into water vapor, thus keeping the presence of oxygen in the system at very low concentrations at all times. Preferably, the catalytic material is a fuel cell type catalytic electrode material that has been applied to an 8 inch porous substrate, and then suitably mounted within the container 60.

The collection space 62 is fluidly coupled to the suction 22 of the compressor through a return conduit 64. The return conduit 64 is coupled, at a tee junction 66, to a suction conduit 26 extending from the suction 22 of the compressor. A one-way valve 68 (eg. a check valve) is disposed in the return conduit 64. The one-way valve 68 is configured to prevent flow from the suction conduit 26, through the return conduit 64, and to the collection container 60. The one-way valve is normally biased closed (ie., preventing fluid flow through conduit 64). Once sufficient gaseous fluid (consisting essentially of hydrogen) becomes collected within the collection container 60 so that the pressure of the collected gaseous fluid exceeds the combination of the mechanical bias of the one-way valve 68 and the fluid pressure on the downstream side (when fluid flow is understood to be from the collection container 60, through the conduit 64, and to the compressor suction 22) of the one-way valve 68, the one-way valve 68 is forced open so as to facilitate flow of the collected gaseous fluid from the collection container 60 and to the compressor suction 22 so as to thereby effect usage of at least a portion, and preferably a significant portion, of the gaseous fluid which leaks from the compressor 20. In this respect, the valve 68 opens in response to the condition where the pressure in the container 60 exceeds the fluid pressure in the suction conduit 26 (or suction 22) by a minimum predetermined amount. The valve 68 is rated to open at 1 psig. In the preferred embodiment, the valve 68 is a Circle Seal Model No. 2232B-2MM.

The collection container 60 is also provided with a relief valve 6002 mounted to the exterior of the container 60. The relief valve 6002 is rated to open at 50 psig and is fluidly coupled to the collection space 62 and is provided to provide overpressure protection for the container 60 in the event that pressure in the container 60 were to rise above 50 psig, thus preventing the possibility of excessive pressure occurring within the container 60. The relief valve 6002 is configured to discharge to the immediate environment. Preferably, the relief valve 6002 is Circle Seal, Model No.HP532B-2M~50.

Upstream of the relief valve 6002, and disposed within the collection space 62, a check valve 6004 is provided. The check valve is rated to open at 1 psig. The check valve 6004 prevents air and/or contamination from entering the compressor container 60 if the relief valve 6002 were to be inadvertently oρeneds or if one desired to replace the relief valve 6002 with a relief valve of a different setting. Preferably, the check valve 6004 is Circle Seal, Model No.2232B-2MM.

The collection container is further provided with an access valve 6006 mounted to the exterior of the container 60. The access valve 6006 is fluidly coupled to the collection space 60 for removing air and/or contamination from the collection space, and for ttie addition of hydrogen and/or other gases into the collection space. In the preferred embodiment, the access valve 6006 is Swagelock Model No. B-4HK4.

Referring to Figure 5, the compressor 20 includes a variable volume space 2002 disposed within a housing 2004 of the compressor 20. The variable volume space 2002 communicates with the suction 22 and discharge 24 of the compressor 20. The compressor 20 receives a low pressure gaseous fluid consisting essentially of gaseous hydrogen (and, in a preferred embodiment, gaseous hydrogen desorbed from a hydrogen storage material) through the suction 22, and the received gaseous fluid is then flowed to the variable volume space 2003, The gaseous fluid in the variable volume space is then compressed by a moveable piston 2006 of the compressor 20, resulting in the pressurization of the gaseous fluid. In this respect, the space 2002 is an example of a fluid compression space. The piston 2006 is connected by a connecting rod 2008 to a crank 2010 on a shaft of an electric motor. The shaft turns the crank 2010, which in turn drives or otherwise actuates the piston 2006 via the connecting rod 200S to effect compression of the gaseous fluid and to form a high pressure gaseous fluid consisting essentially of gaseous hydrogen. The high pressure gaseous fluid then becomes discharged from the compressor through the discharge 24, and is flowed to the container 30 or 40 containing the hydrogen storage material undergoing a regeneration cycle.

The piston 2006 is substantially sealed against the housing 2004 of the compressor 20 with a sealing member 2014 so as to substantially prevent leakage of the gaseous fluid from the variable volume space 2002. Referring to Figure 5a, in one embodiment, the sealing member is a u-cup seal, an o-ring seal, or a piston ring seal. Alternatively, and referring to Figure Sb1 the sealing member 2014 is a rolling diaphragm seal which extends between, and is coupled to each of the piston 2006 and the housing 2004. Preferably, the rolling diaphragm seal is an aluminized Mylar™ sheet, bonded on both sides with a rubber diaphragm material (preferably VITON™) (ie., the aluminized Mylar™ stø.et is sandwiched between two diaphragms of VITQN™), However, when leakage of the gaseous fluid does occur from the variable volume space 2002 and past or across the sealing member 2014 of the piston 2006 by virtue of a bypass conMt 2009, such leaked gaseous fluid flow 2011 is intended to be collected within the collection container 60, and then re-introduced to the suction 22 of the compressor 20 in the manner described above. Leakage from the compressor 20 is understood to include leakage from the variable volume space 2002 and includes flow past or across the sealing member 2014 of the piston 2006 which effects substantial sealing of the piston 2006 against the housing 2004. For the u-cup seal, or o-ring seal, or piston ring seal, the major leakage is between the sealing member and the housing. In the case of the rolling diaphragm seal, the leakage results from diffusion of the gaseous fluid across the diaphragm. The rate of leaked gaseous fluid flow can be expected to be anywhere from less than 5% to less than 50% of the total flow of gaseous fluid through the compressor 20. Preferably, the compressor 20 is a Thomas Model No. 2650CE44. This compressor 20 has a suction pressure of 15 psia and a discharge pressure of 75 psia at a flow of 125 SLPM.

Referring to Figures 3A, 3B, and 3C, the compressor 20 fluidly communicates with the first and second hydrogen storage materials via fluid passages defined by fluid flow conduits extending through (or penetrating) the collection container 60. The fluid flow conduits are sealed or substantially sealed to the collection container 60 (eg., by means of welding, or by means of conventional tapered national standard pipe threads) for preventing, or substantially preventing, any leakage of collected gaseous hydrogen from the collection container 60 and externally of the collection container 60, Additionally, the compressor 20 is electrically coupled to a power supply via suitable wiring which extends through (or penetrates) the collection container 60. The wire connections are sealed or substantially sealed to the collection container 60 via "Pete's Plug" fittings. These effect sealing of the wire against the collection container 60 by compressing rubber seals evenly around the protruding wire.

The suction conduit 26 extends from the compressor suction 22 and is fluidly coupled to a hydrogen return conduit 806 coupling to a tee junction 808. The hydrogen return conduit S06 is fluidly coupled to each of the hydrogen supply/return conduits 8022, 8042 for the respective containers 30, 40, by a respective tee junction, S024, 8044. Each of the hydrogen supply/return conduits 8022, 8042 is fluidly coupled to a respective container 30, 40. This described manner of fluid coupling facilitates fluid communication between each of the containers 30, 40 and the compressor suction 22, and thereby facilitate flow of low pressure gaseous fluid consisting essentially of gaseous hydrogen from containers 30, 40 during the respective cooling cycle.

The tee junction 808 includes a pressure gauge port. This port allows either an analog pressure gauge or pressure transducer to be attached, which enables the pressure of the gaseous fluid at this point to be known during the operation of the system.

Each of pressure relief devices S028, 8048 are mounted to the respective tee junction 8024, 8044. These pressure relief devices are set to release gaseous fluid from the system at arty time if the pressure of this gaseous fluid were to rise to a value greater than 150 psig, thus keeping the system pressure at less than or equal to 150 psig. In the preferred embodiment, each of the relief devices 802S9 8048 is a Circle Seal, Model No. HP532B- 2M-150.

Each of manual isolation valves 8029, 8049 is disposed in a respective hydrogen supply/return conduit 8022, 8042 between a respective tee junction 8024, 8044 and a respective container 30, 40. These isolation valves help to isolate the heat exchangers 802, 804 from the system piping so that air and contamination cannot enter the heat exchangers 802, 804 during system assembly. In the preferred embodiment, each of the isolation valves is a Nupro Model No. B-4P6T4.

Each of particle filters 8030, 8050 is also disposed between a respective isolation valve 8022, 8024 and a respective container 30, 40. These particle filters capture and thus prevent particle contamination from entering the solenoid valves, and thus prevents disruption of successful and leak tight operation. In one embodiment, the particle filters are Parker/Balston's model number 97S6.

Solenoid valve 8026 is disposed in conduit 806 between tee junctions 808 and 8024 to open and close fluid communication between the container 30 and the compressor suction 22. Solenoid valve 8026 is open when the heat exchanger 802 is in the cooling cycling mode, and is closed when the heat exchanger 802 is in the regeneration cycle mode. Solenoid valve 8046 is disposed in conduit 806 between tee junctions 808 and 8044 to open and close fluid communication between the container 40 and the compressor suction 22. Solenoid valve 8046 is open when the heat exchanger 804 is in the cooling cycle mode, and is closed when the heat exchanger 804 is in the regeneration cycle mode.

The isolation valve 261 is used (the valve is closed) only during system assembly, to keep air and contamination from entering the container 60. In the preferred embodiment, the isolation valve 261 is McMaster-Carr Model No, 4912K48.

A discharge conduit 241 extends from the compressor discharge 24, and is fluidly coupled to a hydrogen supply conduit 810 by coupling to a tee junction 812. Isolation valve 245 is disposed in conduit 241, between the discharge 24 and the tee junction 812. Isolation valve 245 is used (ie. the valve is closed) only during system assembly, to keep air and contamination from entering the discharge outlet connection of the compressor 20. The hydrogen supply conduit 810 is fluidly coupled to each of the hydrogen supply/return conduits 8022, 8042 by a respective tee junction 8024, 8044. This described manner of fluid coupling facilitates fluid communication between each of the containers 30, 40 and the compressor discharge 24, and thereby facilitates flow of high pressure gaseous fluid consisting essentially of hydrogen from the compressor discharge 24 to the containers 30, 40 daring the respective regeneration cycle.

A relief valve 247 is fluidly coupled to discharge conduit 241 between the discharge 24 and the isolation valve 245. The relief valve 247 is a 130 psig relief valve, Preferably, the relief valve 247 is Circle Seal, Model No. HP532B-2M-130. The relief valve 247 discharge is fluidly coupled to the suction conduit 26 between the isolation valve 261 and the suction 22. The relief valve 247 is provided for allowing high pressure gas to flow back to the suction of the compressor 20 should valve 245 (or any other solenoid or access valve) be inappropriately closed, thus prolonging the operational life of the compressor 50.

A further relief valve 249 is fluidly coupled to discharge conduit 241 downstream of the relief valve 247 and upstream of the isolation valve 245. The relief valve 249 is a 150 psig relief valve. Preferably, the relief valve 249 is Circle Seal, Model No. HF532B-2M- ISO.The relief valve 249 discharges to the immediate environment, and is provided for allowiug high, pressure gas to escape the discharge of toe compressor should relief valve 247 not function properly and/or the pressure at the discharge exceed 150 psig.

Preferably, the isolation valve 245 is McMaster-Carr Model No.4912KS6.

Solenoid valve 8032 is disposed in the conduit 810 between the tee junctions 812 and 8024 to open and close fluid communication between the container 30 and the compressor discharge 24. Solenoid valve 8032 is open when the heat exchanger S02 is in the regeneration cycle mode, and is closed when the heat exchanger S02 is in the cooling cycle mode. Solenoid valve 8052 is disposed in the conduit SlO between the tee junctions 812 and 8044 to open and close fluid communication between the container 40 and the compressor discharge 24. Solenoid valve S052 is open when heat exchanger 804 is in the regeneration cycle mode, and is closed when the heat exchanger 804 is in the cooling cycle mode.

In the preferred embodiment, each of the solenoid valves 8026, 8046, 8032 and 8052 is a Kip Model No. 241116.

A H2/Fill/Purge Evacuation valve 243 is disposed in the discharge conduit 241, between the compressor discharge 24 and the tee junction 812. This valve 243 is used to provide an access port during system assembly so that air and contamination can be removed from the system, via the use of a vacuum. Once the system has been evacuated, then gaseous hydrogen can be introduced through the valve 243 and the system can then be "charged" with the necessary amount of hydrogen gas. An example of the valve 243 is "Whitey valve, model number B-1KF4.

A programmable logic controller 900 is provided to control the operation of the compressor 20, the fans 10a, 10b and 50, and the solenoid valves 8026, 8046, 8032, 8052, including effecting parallel operation of cooling and regeneration cycles. This controller will open the solenoid valves at the appropriate time so as to provide the most optimal operation of the heat exchangers 802, 804 given the ambient conditions and the desired cooling output temperature. The controller 900 may also be used to operate the above- mentioned dampers. Jn general, components of the system will be connected using sobered, silver soldered, and welded connections. The fluid conduits and other components which contain gaseous hydrogen are copper tubing with an outer diameter of 0.375 inches, and a tube wall thickness of 0.035 inches.

Electrical power can be supplied to the various components by coupling of electrical motors to an electrical system of the vehicle. Alternatively, power can be supplied by an independent electrical generator.

Referring to Figure 7, the system 2 can be mounted to the frame 6 of a vehicle 4. and suitable fluid connections of the conduits of the system can be made to existing air flow ducts of the vehicle for fluid communication with vehicle interior air 5. Also, for those conduits requiring fluid communication with the ambient air 7 external to the vehicle, conduits (ducts) can be configured to extend outside of the engine compartment to receive such ambient air without substantial thermal influences from the engine compartment.

The operation of the preferred embodiment of the system of the present invention will now be described with reference to Figures 1 and 2, where each of the first and second hydrogen storage materials consists essentially of La Nis and also includes about 0.25wt% platinum and 0.25 wt% palladium (each based on total weight of the hydrogen storage material) for catalytic function, and also includes about 0.5wt% (based on total weight of the hydrogen storage material) of Syloid-63 (a dessicam).

1. Start: All components off.

2. Action:Turn on main power switch from either "Off1 to "Manual Control", or "Off to "Automatic Cooling".

3. If switched to "Manual Control", power would now be supplied to several on/off "power" switches. Each solenoid, fan and compressor (and dampers) will have its own switch that can be manually energized as desired, so as to effect operation of the system in a manner similar to that described below for the "Automatic Cooling" mode.

4. If switched to "Automatic Cooling", system would proceed through four separate, consecutive time intervals, namely Time Interval Nos. l through.4.

The system then repeats itself, for so long as desired.

During Time Interval Nos. I and 2, heat exchanger 802 is in the cooling mode, and heat exchanger 804 is in the heat rejection mode (regeneration). Flow of gaseous fluid consisting essentially of gaseous hydrogen during this time will average about 125 SLPM (Standard Litres Per Minute). The temperature of heat exchanger 802 during this time will be about 70C, and the heat exchanger 802 operates at a pressure of about 15 psia (ie. the pressure of the gaseous fluid consisting essentially of gaseous hydrogen within the heat exchanger is about 15 psia). The temperature of the air leaving the heat exchanger S02 should be about 180C. The temperature of heat exchanger S04 daring this time will be about 40°C» and the heat exchanger 804 operates at a pressure of about 75 psia (ie. the pressure of the gaseous fluid consisting essentially of gaseous hydrogen within the heat exchanger is about 75 psia). The temperature of the air leaving heat exchanger 804 should be about 4O0C.

Initially, the system operates in Time Interval No. 1. The duration of Time Interval No. 1 is variable, and lasts from 0 to at least 30 seconds. Three (3) seconds is a preferred duration for Time Interval No. I. At the beginning of Time Interval No. I, compressors are turned on (compressors remain on after this and continuously through Time Interval Nos., 1, 2, 3, and 4). Heat exchanger 802 is in the cooling mode, and the dampers 3021 and 3045 are open. Heat exchanger 804 is in the heat rejection mode (regeneration), and the dampers 5023 and 5047 are open. All other dampers are closed, Fans 10a and 50 are on. Air flow rate generated by fan lOa (during cooling mode) is maintained relatively less than the air flow rate generated by fan 50 (during regeneration). Preferably, the air flow rate during cooling mode is 50% less than the air flow rate during regeneration mode, ϊn this respect, air velocity during the regeneration mode is 5 m/ss and air velocity during the cooling mode is 2.5 m/s. However, the program controller may determine Λat a higher air flow rate for either fan 10a and/or fan 50 is desired in order to provide optimal heat exchanger performance.

Solenoid valves 8026, 8046, 8032, and 8052 are all open during Time Interval No. 1. This is done to allow the hydrogen pressure in the system to equilibrate quickly, thus equalizing the temperature of each heat exchanger and ensuring that the pressure differential (between the compressor inlet and the compressor discharge) are minimal during system bed switchover, thus providing a gentle and gradual pressure gradient for the compressor, as well as improve the efficiency of the heat exchangers.

After Time Interval No. 1 is completedj Time Interval No. 2 begins and lasts from 0 to at least 500 seconds. One hundred and twenty (120) seconds is a preferred duration for Time Interval No. 2. Upon commencement of Time Interval No. 2, solenoid valves 8046 and 8032 close. This leaves solenoid valves 8026 and 8052 open, and heat exchanger 802 is in the cooling mode, and heat exchanger 804 is in the regeneration mode.

After Time Interval No. 2 is completed, Time Interval Nos. 3 and 4 proceed sequentially. During Time Interval Nos. 3 and 4, heat exchanger 802 is in the heat rejection mode (regeneration), and heat exchanger 804 is in the cooling mode. Flow of gaseous fluid consisting essentially of gaseous hydrogen through the compressor during this time will average about 125 SLPM. The temperature of heat exchanger 804 during this time will be about 7°C, and the heat exchanger 802 operates at a pressure of about 15 psia. (ie. the pressure of the gaseous fluid consisting essentially of gaseous hydrogen within the heat exchanger is aboαt ISpsia). The temperature of the air leaving heat exchanger 804 should be about 18°C. The temperature of heat exchanger 802 during this time will be about 40°C, and the heat exchanger 802 operates at a pressure of about 75 psia (ie. the pressure of the gaseous fluid consisting essentially of hydrogen within the heat exchanger is about 75 psia). The temperature of the air leaving heat exchanger 802 should be about 40°C.

The duration of Time Interval No, 3 is variable, and lasts from 0 to at least 30 seconds. Three (3) seconds is a preferred duration for Time Interval No. 3, During Time Interval No. 3, heat exchanger 802 is in the heat rejection mode (regeneration), and dampers 4022 and 4046 axe open. Also, heat exchanger 804 is in the cooling mode and dampers 6024 and 604S are open. All other dampers are closed. Fans lOb (or IQa, in the case of the above-described embodiment where conduits 304 and 604 are joined together) and 50 are on. Air flow generated by fan 50 during cooling is maintained relatively less than the air flow rate generated by fan 10b (or 10a) during regeneration. Preferably, air velocity during the regeneration mode is 5 m/s, and air velocity during the cooling mode is 2.5 ra/s (ie. preferably, the air flow rate during the cooling mode is 50% less than the air flow rate during regeneration mode). However, the program controller may determine that a higher air flow rate for either fan lOb (or 10a) and/or fan 50 is desired in order to provide optimal heat exchanger performance.

Solenoid valves 8026, 8046, 8032 and 8052 are all open during Time Interval No. 3. This is done to allow the gaseous fluid pressure in the system to equilibrate quickly, thus equalizing the temperature of each heat exchanger and ensuring that the pressure differential (between the compressor suction and the compressor discharge) are minimal during system bed switchover, thus providing a gentle and gradual pressure gradient for the compressor, as well as improve the efficiency of the heat exchangers.

After Time Interval No, 3 is completed, Time Interval No. 4 begins and lasts from 0 to at least 500 seconds. One hundred and twenty (120) seconds is a preferred duration for Time Interval No. 4. Upon commencement of Time Interval No. 4, solenoid valves 8026 and 8052 close. This leaves each of solenoid valves 8032 and 8046 in an open condition, arid heat exchanger S02 in the regeneration mode, and heat exchanger 804 in the cooling mode.

After completion of Time Interval No. 4, the system can repeat itself, beginning at Time Interval No. I, and moving through Time Interval Nos.2, 3, and 4.

Although the disclosure describes and illustrates preferred embodiments of the invention, it is to be understood that the invention is not limited to these particular embodiments. Many variations and modifications may occur to those skilled in the art within the scope of the invention.