HEAT TRANSFER DEVICE

Abstract: A heat transfer device (10, 110, 210, 30, 270, 290, 300, 410, 510, 610, 710) for cooling or heating a beverage (12, 112, 244, 255, 295, 303, 314, 374, 422, 520, 622, 714) contains a refrigerant (22, 122, 212, 241, 252, 276, 334, 371, 632) and a refrigerant take up agent (18, 118, 222, 214, 277, 301, 335, 373, 418, 514, 614). The device (10, 110, 210, 30, 270, 290, 300, 410, 510, 610, 710) further includes operative means (26, 28, 126, 215, 242, 253, 271, 293, 294, 302, 370, 432, 528, 638, 726, 732) for allowing evaporation of the refrigerant (22, 122, 212, 241, 252, 276, 334, 371, 632). The take up agent (18, 118, 222, 214, 277, 301, 335, 373, 418, 514, 614) takes up the evaporated refrigerant (22, 122, 212, 241, 252, 276, 334, 371, 632) such that heat absorbed on evaporation of the refrigerant (22, 122, 212, 241, 252, 276, 334, 371, 632) is evolved at the take up agent (18, 118, 222, 214, 277, 301, 335, 373, 418, 514, 614) to enable heat to be transferred to or from a material (12, 112, 244, 255, 295, 303, 314, 374, 422, 520, 622, 714) to be heated or cooled. The take up agent (18, 118, 222, 214, 277, 301, 335, 373, 418, 514, 614) may be an absorbent or adsorbent.

Description: Heat Transfer Device This invention relates to heat transfer devices. In particular, but not exclusively, this invention relates to heat transfer devices for heating or cooling edible or potable materials. The development of efficient and "environmentally-friendly" technologies for cooling drink and food products has been sought after. The trend towards more leisure time being spent in locations away from home is on the increase as the range and availability of outdoor entertainments and pastimes increases. Advances have been made in developing cooling devices, including cold boxes, thermo-electric picnic coolers and portable chilling units. However, these units have the disadvantages of being bulky .and expensive. One device, known as the "chill can" has been subjected to International restrictions owing to environmental concerns over its use. Furthermore, little attention has been paid to the development of heating devices for heating drinks and food products. According to one aspect of the invention there is provided a heat transfer device containing a refrigerant, and said device further including operative means for allowing transfer of the refrigerant from a first region of the device to a second region of the device and means to drive said transfer of the refrigerant, thereby transferring heat from said first region to said second region, such that heat can be transferred to or from a material to be heated or cooled. Preferably, the transfer of said refrigerant occurs by evaporation of the refrigerant. Desirably, the means to drive said transfer of the refrigerant comprises a refrigerant take up agent to take up said refrigerant. Thus, heat can be extracted from the material by transfer of the refrigerant and heat is given out by the take up agent when the refrigerant is taken up thereby. The take up agent may be in the form of an adsorbent or absorbent. According to another aspect of this invention there is provided a heat transfer device containing a refrigerant and a refrigerant take up agent, and said device further including operative means for allowing evaporation of the refrigerant, whereby the take up agent takes up said evaporated refrigerant such that heat absorbed on evaporation of the refrigerant is evolved at the take up agent to enable heat to be transferred to or from a material to be heated or cooled. Advantageously, the device is of a suitable size to be inserted in, or arranged in, or installed, or arranged around, a vessel suitable for holding a beverage. Preferably, the taking up of the refrigerant occurs at a first region of the device and evaporation of the refrigerant by the take up agent occurs at a second region. The take up agent may be an adsorbent or an absorbent. Thus, heat of adsorption or absorption is given out when the evaporated refrigerant is adsorbed onto the adsorbent or absorbed by the absorbent. Desirably, the device comprises a first part for the take up agent and a second part for the refrigerant. The first part is preferably at a lower pressure than the second part before the operative means is operated. In one embodiment, the second part may be at ambient pressure and the first part may be evacuated. In another embodiment, the second portion may be at above ambient pressure and the first part may be at ambient pressure. Alternatively, both the first and second parts are evacuated. The first and second parts are advantageously isolated from each other. The operative means may be adapted to provide communication between the first and second parts on operation thereof. The first and second parts may be permanently attached to each other, for example they may be integral with each other. Alternatively, the first and second parts may be initially separate from each other to be attached together to allow communication therebetween on operation of the operative means. The device may comprise a first element, which may be in the form of a first wall, on which the take up agent can be arranged, and a second element, which may be in the form of a second wall, to provide dispersion of the refrigerant. The first element may be substantially cylindrical in shape, but it may be of any other suitable shape. The second element may be cylindrical in shape and dispersal means may be provided on said second element to disperse the refrigerant around the second element, disperse means may comprise wicking means. The first and second elements are desirably spaced from each other to allow heat transfer from one to the other. In one embodiment, the first part includes the second element and the second part may be in the form of a container adapted to release refrigerant into the second element on operation of the operative means. The operative means may comprise a release member adapted to provide an aperture in the second part to release said refrigerant. The release member may be in the form of a spike or pin to pierce the second part. The second part may be formed of a suitable plastics material, and may be in the form of a bubble. In another embodiment, the second part may comprise the second element. The operative means may comprise an elongate rod having at one end thereof a substantially cylindrical member. A membrane may be provided between the first and second parts to isolate the first part from the second part. The cylindrical member preferably has an open end arranged adjacent the membrane, whereby operation of the operative means pushes the open end of the cylindrical member into engagement with the membrane and pierces the membrane. The membrane is preferably formed of a metallic foil, for example aluminium foil. Where the device is to be used to cool the material, the second element is advantageously adapted to be arranged adjacent, or in contact with, said material, and the first element is arranged such that heat transfer thereto can be dissipated to the atmosphere. Where the device is to be used to heat the material, the first element is advantageously adapted to be arranged adjacent, or in contact with, said material and the second element is arranged such that heat can be extracted from the atmosphere to be transferred to the first element thereby heating said material. Preferably, at least the first part is in the form of a tube or pipe, although both first and second parts may be generally in the form generally of a tube or pipe. The first part or both first and second parts may be in the form of an elongate tube, wherein the first part constitutes a first portion of the tube and the second part constitutes a second portion of the tube. In one embodiment, the first part constitutes a double skin of a vessel holding the material to be heated or cooled, the double skin comprising inner and outer walls. In another embodiment, the tube is in the form of a sleeve having said inner and outer walls, the said sleeve being adapted to receive a vessel, for example a bottle or a can to be heated or cooled. Preferably, where the material is to be heated, the inner wall constitutes said first element and the outer wall constitutes said second element. Preferably, where the material is to be cooled, the outer wall constitutes the first element and the inner wall constitutes the second element. In a further embodiment, the device is configured to be arranged inside a vessel for heating or cooling the material therein. The device may be manufactured separately to be inserted in the vessel when desired, or may be arranged in the vessel during manufacture. In another embodiment, the second part constitutes a double skin of a vessel holding the material to be cooled, the double skin comprising inner and outer walls. Preferably, the inner wall is provided with wicking means which preferably substantially covers the inner wall. Advantageously, the wicking means is wetted prior to use of the device. The wicking means may be formed of a porous fabric, for example cloths sold under the trade mark J-Cloth or similar. The fabric is preferably perforated to define at least one aperture, and desirably a plurality of apertures therethrough to prevent or reduce the formation of ice on the fabric. In a further embodiment, the first part is preferably arranged on the second part. The first part may be in the form of a first tube and the second part may be in the form of a second tube. The second part is receivable in the material and may further include heat exchange members adapted to extend into the material to enhance the transfer of heat. The heat exchange members may comprise a plurality of fins which are preferably in the form of wire loops. Further heat exchange members may extend in the second part, which may comprise a plurality of fins preferably in the form of wire loops. One of said first and second elements may surround the other of said first and second elements. The other of said first and second element can preferably be arranged in a material to be heated or cooled. In one embodiment, the first element is in the form of a first tube surrounding the second element, which is preferably in the form of a second tube. The second element is desirably adapted to be arranged in a material to be cooled. A conduit arrangement may extend between the first and second elements to conduct the evaporated refrigerant, thereby transferring heat from the second element to the first element. When the device is to be used to cool the material, the first element surrounds the second element and, when the device is to be used to heat the material, the second element surrounds the first element. Heat exchange members may extend from the first or second element into the material to be heated or cooled. The first and second elements may comprise first and second tubes initially separate from each other and adapted to be connected in communication for heating or cooling. The second part may comprise a container connected to the second part. The operative means may comprise a valve between the first and second parts. The valve is preferably movable to an open position to allow the first and second parts to communicate with each other. Heat absorption means may be arranged adjacent one of the first or second elements. Where the device is to be used to cool the material, the heat absorption means may be arranged in thermal contact with the first element to absorb heat given out by the take up agent. The heat so absorbed by the heat absorption means may be desorbed to the atmosphere. Where the device is to be used to heat the material, the heat absorption means may be arranged in thermal contact with the second element, whereby heat absorbed by the heat absorption means can be desorbed via the second element to evaporate refrigerant in the first part. In one embodiment, the heat absorption means is provided in a chamber which may be defined at least partially by the first or second element. Preferably, the chamber surrounds, or is surrounded by, said first part. In one embodiment, the chamber is in the form of a substantially cylindrical tube defined substantially wholly by said first or second element internally of the first part. In another embodiment, the chamber is in the form of a sleeve defined partially by the first or second element externally of said first part. The sleeve is conveniently defined between said first or second element and an external wall. In one embodiment, the heat absorption means comprises a refrigerant adapted to evaporate when heat is absorbed thereby. Valve means may also be provided to release to the atmosphere evaporated refrigerant from the heat absorption means. The valve means is particularly suitable where the device is to be used for cooling the material. In another embodiment, the heat absorption means may be a phase change material adapted to change phase from solid to liquid or from solid to vapour on absorption of heat. Where the phase change material changes from solid to vapour, valve means may be provided to release the vapour to the atmosphere. The use of valve means is particularly suitable where the device is to be used in coohng the material. In a further embodiment, the heat absorption means may be a heat pipe preferably having one end region in thermal contact with the first part and the opposite end region outside the first part. The end region of the heat pipe external of said first part may be provided with fin means to assist in heat transfer to or from the heat pipe. In this embodiment, said one end region is preferably surrounded by the first part. In another embodiment, the device may comprise at least one heat pipe, and preferably a plurality of heat pipes extending from the second part into the material. The, or each, heat pipe is preferably in the form of a needle heat pipe. In this embodiment, a valve is provided between the second part and the first part, whereby when the valve is opened, refrigerant in the second part is evaporated to be taken up by the take up agent in the first part, and the evaporation of the refrigerant causes heat to be transferred from the material along the heat pipes to an end region of the or each heat pipe in the first part, thereby cooling the material. In this embodiment, the first part is arranged outside the vessel containing the material, and the second part is arranged inside the vessel. Alternatively, where heating is required, the second part may be arranged outside the vessel, and heat pipes may extend from the first part inside the vessel whereby when the valve is opened, evaporating refrigerant is taken up by the take up agent and heat dissipated by the, or each, heat pipe into the material. The above embodiments are particularly suitable for use with a take up agent in the form of an adsorbent. 8 In a further embodiment, where the take up agent comprises an absorbent, the device may be provided with a third part initially containing the absorbent. The third part may be provided with release means, whereby when the release means is activated, absorbent is released into the second portion. In this embodiment, when the operative means for the second part is operated, the refrigerant is released into the first part to be evaporated therein and absorbed by the absorbent thereby releasing heat. The third part may be a further bubble, and the operative means may be suitable for piercing the bubble, or otherwise forming an aperture in said further bubble. According to another aspect of the present invention there is provided a heat-transfer device comprising an elongate, generally tubular member adapted to contain a refrigerant and an adsorbent or absorbent, together with means to cause the refrigerant to be adsorbed by the adsorbent, whereby heat is evolved from the adsorbent or absorbent and absorbed by the refrigerant material. In one embodiment, the device may comprise a pipe (or a linked plurality of pipes). Preferably, a device according to this embodiment comprises an elongate pipe having a first portion to containing the adsorbent or absorbent, a second portion initially separated from said first portion and adapted to contain the refrigerant, and communication means between said first and second portions, whereby operation of said communication means causes the refrigerant to be adsorbed or absorbed by the adsorbent or absorbent, with evolution of heat from the first portion of the device and corresponding absorption of heat at the second portion of the device. The second portion (to contain the refrigerant) is generally integral with the elongate pipe. The second portion may be adapted to contain the refrigerant either under sub-ambient or under super-ambient pressure, i.e. under vacuum or under pressure respectively, relative to ambient pressure. The second portion may contain the refrigerant under permanent sub- ambient or super-ambient pressure. Alternatively, means, such as a pump, may be provided to produce a sub- ambient or super-ambient pressure in the first portion when required. Means may also be provided to purge air from the first portion, thereby increasing the efficiency of the device. The first portion (to contain the adsorbent or absorbent) may likewise be integral with the elongate pipe. Alternatively, the first portion may be initially discrete relative to the second portion and adapted to be connected thereto. Such connection may preferably include operating means for causing communication between the first and second portions of the elongate pipe. The communication means may, for example, comprise one or more valves (such as one-way or throttle valves). Alternatively, the communication means may comprise a three-way (or ejector) valve. In another embodiment, the heat-transfer device may comprise a pipe (or a linked plurality of pipes). In a further embodiment, the device comprises an elongate pipe in which the refrigerant and the adsorbent or absorbent are combined and under super- ambient pressure within the pipe. In this embodiment, the adsorption or absorption of the refrigerant by the adsorbent or absorbent, with consequent cooling and heating respectively, is achieved by the release of the super- ambient pressure by means of a valve or the like provided in operative association with the elongate pipe. In yet another embodiment, the refrigerant is contained, under sub- ambient pressure, in an outer skin of a vessel containing a hquid such as a soft 10 drink) to be cooled. A valve is provided in the skin for the release of the vacuum and the valve is operable by means including a container for the adsorbent. The heat-transfer device according to any of the foregoing embodiment of the present invention may be provided with an internally-located wick to assist movement of the refrigerant. Such a wick can be made, for example, of metallic mesh (e.g. copper mesh or stainless steel mesh), or of a sintered powder (e.g. sintered copper or P.T.F.E.). The device according to the present invention, may be permanently fixed inside a vessel to contain a hquid to be cooled or heated. Alternatively, such a device may be provided as a "portable" or "pocket" device, to be placed in an opened container (such as a can of beer to be cooled or a can of soup to be heated) when required. Devices according to the present invention may be operated by producing communication between the refrigerant and the adsorbent or absorbent (generally by actuating a valve). The provision of the communication causes the refrigerant to volatilise and to interact with the adsorbent or absorbent. As a result of that interaction, heat is evolved from the adsorbent or absorbent and heat is correspondingly absorbed from the surroundings of the refrigerant. In one instance, where a device according to the present invention is placed in, say, a can of beer, with the portion containing the adsorbent or absorbent being outside the can and the portion containing the refrigerant material being inside the can, interaction between the refrigerant and the adsorbent or absorbent causes the evolution of heat to the atmosphere and absorption of heat from the beer within the can leading to cooling. In a second instance, where the device is placed in, say, a can of soup, with the portion containing the adsorbent or absorbent being inside the can, 11 interaction between the refrigerant and the adsorbent or absorbent again causes evolution of heat from the adsorbent, but the heat evolved is used to heat the soup within the can instead of being vented to the atmosphere. Operation of the valve may be achieved by means external to the device (as, for example, where a pump or the like is operatively associated with the elongate pipe or the adsorbent material is contained in a discrete "plug-in" member). Alternatively, the valve may be actuated by means of the internal pressure of the contents of a vessel (as, for example, a can of potable liquid to be cooled or heated by means of a device according to the present invention). Refrigerants suitable for use with a present invention preferably include the following: - Water, alcohols (e.g. methanol, ethanol), haloalchols (e.g. trifluoro- ethanol), haloalkanes (e.g. trifluoro-ethane), alkanes (e.g. C 3 to C 6 , ammonia, carbon dioxide, aromatic hydrocarbons (e.g. benzene, toluene, aniline), acetophenone, butyl acetate, butyric acid, cellulose acetate, cresol, cumene, cyclohexanol, cyclohexanone, dibutylphtalate, diethanolamine, diethylsulphate, dimethylformamide, dimethylhydrazine, dimethylphtalate, ethylene glycol, hydrazine, methylhydrazine, methylpyrrolidinone, naphthalene, styrene, sulfolane, tetrachloroethylene, trichloroethylene, undecane. Take up agents suitable for use with the present invention preferably include the following: silica gel, activated alumina, zeolites (molecular sieves), activated charcoal, alkanes (e.g. C 3 to C 6 ), alcohols (e.g. methanol, ethanol), amides (e.g. N, N-dimethyl acetamide), ketones/lactams (e.g. N-methyl pyrrolidone), carboxylic acid salts (e.g. potassium formate), esters, alkali metal salts (e.g. lithium bromide, lithium nitrate). Thus, the refrigerant may be a volatile hquid or a gas, and the take up 12 agent may be a solid or a hquid. Suitable combinations of refrigerant/take up agent for use with the present invention preferably include the following: Water/zeolites-activated carbon, ethyl alcohol/silica gel, water/silica gel, water/activated alumina, carbon dioxide/activated alumina, water/zeolites 4A, 5 A, 13X, ammonia/zeolites 4A, 5 A, 13X, carbon dioxide/zeolites 4A, 5 A, 13X, ethene/activated carbon, ammonia/activated carbon, water/activated carbon, methyl alcohol/activated carbon, water/polymers, ammonia or water/metal in organic salts (e.g. water/ Ca Cl 2 , ammonia Ca Cl 2 hydrogen/LaNi 4 , hydrogen/FeTi, water/potassium formate), hydrofluorocarbons (HFC) refrigerant/adsorbent combinations (e.g. R134a/activated carbon), fluid mixtures (e.g. water, methanol/activated carbon, water/ammonia, ammonia (or carbon dioxide/potassium formate, water/ thium bromide, N- methylpyrrohdinone/trifluorethanol, dithioglycol (DTG)/tetrafluorethane, water/ammonia-lithium nitrate, carbon dioxide/N, N-dimethylacetamide, H 2 O/CaO. It is desirable to increase the surface area of the adsorbent as much as possible. This can be achieved by the following means, for example coating the surface with the adsorbent (e.g. by using a binder or growing adsorbent on the surface) using adsorbent membranes (e.g. growing zeolites on a mesh) using an adsorbent cloth (e.g. activated carbon). Examples of wicking means that can be used with the present invention preferably include the following: Tissue paper, plastic foam, or paper fibre, metallic meshes (e.g. copper meshes or stainless steel mesh), sinted powder (e.g. sintered copper or PTFE). Suitable phase change materials that can be used with the present invention preferably include the following: 13 Glycerol, oils, coconut/butter, paraffin wax, glauber salt (Na 2 SO 4 . 10H 2 O, butyl phenol, methanol, pentane, ethane. In most circumstances, the take up agent can be regenerated once adsorption has occurred. Regeneration may be achieved by heating the adsorbent (for example by means of a Peltier or like device) or by means of an integral compressor provided in association with the device. The present invention further provides a method for heating or cooling the contents of an enclosed vessel, in which one or more heat transfer devices of the type hereinabove described are placed in contact with the contents of the vessel and each said device is caused to transfer heat by means of an adsorption-based process between a refrigerant material and an adsorbent material, whereby heat is respectively liberated into or absorbed from the contents of the vessel. Thus, a method according to the present invention can be applied to the heating of soup, tea or the like in an enclosed vessel. Alternatively, the method can be applied to the cooling of beer, soft drinks or the like in an enclosed vessel. According to another aspect of this invention there is provided an assembly comprising a vessel for holding a material to be cooled or heated and a heat transfer device as described above arranged in thermal contact with the material. Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings in which: - Figs. 1 and 2 show a heat transfer device according to a one embodiment for coohng a material in a vessel; 14 Figs. 3 and 4 shows another embodiment of the heat transfer device for heating a material in a vessel; Figs. 5 to 7 show further embodiments of the heat transfer device with heat absorption means, the device being installed in a vessel; Figs. 8 and 9 show further embodiments of heat transfer device with heat absorption means, the devices being insertable into a vessel for heating or cooling; Figs. 10, 11 and 12 shows further embodiments of the heat transfer device with heat absorption means arranged around the device, the device being adapted to receive a vessel; Fig. 13 shows a further embodiments of the heat transfer device including heat pipes; Fig. 14 shows another embodiment of the heat transfer device using an absorbent; Fig. 15 shows examples of alternative means by which surface area of evaporation and adsorption can be increased; and Fig. 16 shows a further embodiment of the heat transfer device. Figs. 17, 18 and 19 show further embodiments of the heat- transfer device; with the portion containing the adsorbent being integral with the device; Fig. 20 and 21 show further embodiments of the heat-transfer device with the portion containing the adsorbent being separable from the device; Fig. 22 shows a heat- transfer device provided with an external adsorption unit; 15 Fig. 23 and 24 show further embodiments of the heat- transfer device in which a three-way (ejector) valve is used; Fig. 25 shows the use of a heat transfer device to heat the contents of the vessel; Figs. 26, 27 and 28 show further embodiments of the heat-transfer device. Figs. 29 to 33 show further embodiments of the heat transfer device with a pump arrangement; Fig. 34 shows a further embodiment of the heat transfer device with a second adsorbent; Fig. 35 shows a further embodiment of the heat transfer device with the refrigerant surrounding the material; Fig. 36 shows a modification of the device shown in Fig. 35; Fig. 37 is a further embodiment of the heat transfer device showing the use of heat exchange means to enhance a transfer; Figs. 8A to C show the sequence of events for using the embodiment shown in Fig. 37; Fig. 39 is a modification of the device shown in Fig. 37; Fig. 40 is a further embodiment of the heat transfer device, in which the adsorbent is arranged around the material, and a conduit arrangement is used to deliver evaporated refrigerant to the adsorbent; Fig. 41 is a further embodiment of the heat transfer device which is a 16 modification of the embodiments shown in Figs. 1 and 2; and Fig. 42 is a further embodiment of the heat transfer device using an enlarged chamber for the adsorbent. Referring to drawings, there is shown several embodiments of a heat transfer device. Referring to Fig. 1, there is shown a heat transfer device 10 for use in cooling a liquid 12 in a drinks can 14. The heat transfer device 10 comprises a first part 16 for an adsorbent 18, and a second part 20 for a refrigerant 22. The second part 20 is in the form of a bubble formed from a suitable plastics material that can be pierced. A spike 26 mounted on a bubble 28 provide an operative means whereby on pressing the button 28, the spike 26 pierces the bubble 20, thereby allowing the refrigerant (for example water) in the bubble to enter the first part 16. The first part 16 comprises a double skin of the drinks can 14 having an inner cylindrical wall 30 and an outer cylindrical wall 34. Wicking means 32 is provided around the outer surface of the inner cylindrical wall 30. The adsorbent 18 is provided on the inner surface of the outer cylindrical wall 34 such that the adsorbent 18 substantially covers the outer cylindrical wall 34. As can be seen, the second part 20 is provided adjacent the wicking means 32 whereby when the button 24 is pressed to pierce the bubble 20, the water therein is dispersed by the wicking means 32 around the inner wall 30. The second portion 16 is at a low pressure and is, preferably, evacuated. Fig. 2 shows what happens when the button 24 is pressed to release the water 22 into the first part 16. The water 22 is dispersed by the wicking means 32 around the inner wall 30 whereupon the water 22 evaporates thereby 17 extracting heat from the liquid 12, thereby cooling the hquid. The evaporation of the water 22 is indicated by the arrows A whereby heat is transferred from the inner wall 30 to the adsorbent 18 on the outer wall 34. The arrows B indicate the transfer of heat between the inner and outer walls 30, 34. The adsorbent 18 adsorbs the water and releases heat of adsorption which is dispersed into the atmosphere as indicated by the arrows C. Referring to Figs. 3 and 4, there is shown a device similar to that shown in Figs. 1 and 2 but is provided to heat the material 12 in the can 14. The construction of the embodiment shown in Figs. 3 and 4 is very similar to that shown in Figs. 1 and 2, with the exception that the wicking means 32 is provided on the outer wall 34, and the adsorbent 18 is provided on the inner wall 30. When the button 28 is depressed to pierce the bubble 20, water is released into the first part 16. This collects at the bottom 17 and is wicked by the wicking means 32 to be spread around the outer wall 34, as shown by the arrows D. Heat is extracted from the atmosphere as shown by the arrows E to evaporate the refrigerant which then passes across to the adsorbent 18, as shown by the arrows A. Heat of adsorption is then passed by the arrows F into the material 12, which may be a soup or other material requiring heating. Referring to Fig. 5, there is shown a second embodiment in which the heat transfer device is in the form of a pipe or tube provided inside the can 14. In this embodiment, which is for cooling the contents of the can 14, the device again comprises an inner wall 30 and an outer wall 34, but this time, the wicking means 32 is provided on the outer wall 34, and the adsorbent 18 is provided on the inner wall 30. The reason for this is that the outer wall 34 is in contact with the hquid 12 to be cooled. The inner wall 30 defines a cylindrical inner space 36 in which is provided heat absorption means 38 which, in the embodiment shown in Fig. 3 is in the form of a refrigerant. Pressure release means in the form of a valve 40 is provided, the purpose of which will be explained below. When the bubble 20 is pierced by the operative means 24 to release the 18 water 22, the water 22 falls to the bottom of the first portion 16, as indicated by the numeral 17. The water is wicked into the wicking means 32 as shown by the arrows D the refrigerant evaporates whereby heat is extracted from the hquid 12 thereby cooling it. The evaporated refrigerant is passed to the adsorbent 18 as indicated by the arrows A, to be adsorbed thereby with a consequent release of heat. Thus, heat is transferred from the outer wall 32 to the inner wall 34. The heat of adsorption is then passed into the heat absorption means 36 as shown by the arrows C, whereby the refrigerant 38 is evaporated. The evaporated refrigerant is released, thereby dissipating the heat into the atmosphere by operation of the valve 40. Referring to Fig. 6, there is shown a device similar to that shown in Fig. 5, the same features have been designated with the same reference numeral. The device shown in Fig. 6 differs from that shown in Fig. 5 in that the heat absorption means 38 is in the form of a phase change material. The device shown in Fig. 6 operates in the same way as that shown in Fig. 5 with the exception that heat of adsorption evolved from the adsorbent 18 is absorbed by the phase change material 38. The change of phase can be from solid to hquid, as shown in Fig. 6, but the phase change material can also be from solid to vapour in which case a pressure release means 40, such as that shown in Fig. 5 would be required. Referring to Fig. 7, there is shown a heating device similar to that shown in Figs. 5 and 6 in which the heat absorption means 38 in the space 36 is in the form of a heat pipe 50. The heat pipe 50 contains a refrigerant therein. On operation of the operative means 24 to release the refrigerant 22 into the second portion 16 heat is extracted from the material 12 by evaporation of the refrigerant 22 from the wicking means 32. Heat is transferred from the wicking means on the outer wall 34 to the adsorbent on the inner wall 30 to be adsorbed thereby. Heat of adsorption therefrom is absorbed by the heat pipe 50 to evaporate the refrigerant therein. The circulation of refrigerant in the heat pipe transfers heat to the top region 52 thereof where fins 54 dissipate heat into the atmosphere as indicated by the arrow C. 19 Referring to Fig. 8, there is shown a "pocket" or "portable" cooling device which can be used to be inserted into drinks or the like for coohng them. The device operates in the same way as that shown in Fig. 3 but differs in that it is separate from any drinks can 14. The heat absorption means in the space 36 is the same as that shown in Fig. 5 and a valve 40 is provided to release the evaporated refrigerant from the space 36. Referring to Fig. 9, there is shown a "pocket" or "portable" device 10 for heating a fluid, for example a cup of tea, or bowl of soup. The device 10 in Fig. 9, is similar to that shown in Fig. 8, with the exception that the adsorbent 18 is provided on the outer wall 34, and the wicking means 32 is provided on the inner wall. The heat absorption means 38 in the space 36 is in the form of a refrigerant or a phase change material which has previous absorbed heat. When the refrigerant 22 is released into the first portion 16, the second portion 20 by operation of the operative means 24, evaporation of the refrigerant 22 from the wicking means 32 occurs by the transfer of heat to the refrigerant 22 from the heat absorption means 38. The evaporated refrigerant 22 passes to the adsorbent 18, shown by the arrows A, thereby transferring heat, to the adsorbent 18. Heat of adsorption produced by the adsorbent 18 is dissipated into the material to be heated as shown by the arrows F. Referring to Fig. 10, there is shown a further embodiment similar to that shown in Figs. 1 and 2 which differs therefrom in that the outer wall is surrounded by a chamber containing a phase change material 42. The device shown in Fig. 7 operates in the same way as that shown in Figs. 1 and 2 with the exception that heat of adsorption is not dissipated directly to the atmosphere but rather is absorbed by the phase change material 42 thereby enhancing the removal of the heat from the first part 16. Referring to Figs. 11 and 12, there is shown a heat transfer device 10 in the form of a sleeve which operates in the same way as that shown in Fig. 10, with the exception that the device 10 in Figs. 11 and 12 defines a cylindrical space 150 to receive therein a can 114 of drink to be cooled. The apparatus 10 20 shown in Fig. 11 then operates in the same way as that shown in Fig. 10. Similarly, the device 10 in the form of a sleeve can be provided around a bottle 152, as shown in Fig. 12, to cool the contents 112 in the same way as the device 10 shown in Fig. 11. Each device 10, in Figs. 11 and 12 comprises a phase change material 42 which is the same or similar to that shown in Fig. 10. Referring to Fig. 13, there is shown a can 14, and a heat transfer device 110 representing schematically. The heat transfer device 110 comprises a first portion 116 holding an adsorbent 118. A second portion 120 is provided in the can 14 and holds a refrigerant 122. A plurality of needle heat pipes 123 extend from the second portion 120 into the material 12 in the can 14. Operative means 124 in the form of a valve 126 is provided to allow communication between the second portion 120 and the first portion 116 via a conduit 128. The heat pipes 123 extend into the second portion 120 whereby end regions 125 of each heat pipe 124 project into the second portion 120. On opening the valve 128, the refrigerant 122 in the second portion 120 extracts heat from the end regions 125 of a heat pipes 123 thereby causing the refrigerant 122 to evaporate and pass along the conduit 128 to be adsorbed by the absorbent 118. This causes evaporation of further refrigerant in the heat pipes 123, thereby cooling material 12 in the can 14. Heat is transferred from the material 12 into the heat pipes and thereafter along the heat pipe to the second portion 120 until all the refrigerant 122 therein is evaporated. Referring to Fig. 14, there is shown a modification to the design shown in Figs. 1 to 13 using absorbent rather than an adsorbent. The physical form of the adsorbent can be cloth, membrane, powder with binder, composite, adsorbent bed, pallets, or beads. The devices are hkely to be manufactured from simple plastic-coated metal foil (e.g. aluminium sheet) and wicking materials made from tissue paper, plastic foam or paper fibre and the like. 21 In the embodiment shown in Fig. 14, the device 10 comprises a first bubble 20 to release refrigerant onto wicking means 32, and a second bubble 220 to release the absorbent 222 onto a suitable substrate 218 arranged over the inside of the inner wall 30. The refrigerant 22 is evaporated from the wicking means 32 and passes from the outer wall 34 to the inner wall 30 as shown by the arrows A to be absorbed by the absorbent 222. Heat of absorption is passed into the inner region 36 to evaporate the refrigerant 38 therein. The evaporated refrigerant can be released by operation of the valve 40. Referring to Fig. 15, there is shown various ways in which a surface area for evaporation and adsorption can be increased. In Fig. 15 A, there is shown a tubular device 10 having a refrigerant 22 wicking means 32 and an absorbent 18. Fins 154 are provided at the lower end of the tube to enhance the transfer of heat indicated by the arrow Ql into the device 10. This evaporates the refrigerant and it passes to the absorbent 18 whereby heat of adsorption can be released as shown by the arrow Q3. Referring to Fig. 15B, there is shown a device 10 in the form of a substantially rectangular plate. The plate has an adsorbent 18 at one side and wicking means 32 for the refrigerant at the opposite side. This provides an increase in surface area whereby enhancing the evaporation of the refrigerant 32. Referring to Fig. 15C, there is shown a further device 10 comprising a tube having a wick 32 at one end and an adsorbent 18 at the other end. Referring to Fig. 15D there is shown a device 10 having a frusto conical configuration having a refrigerant 22 and a wick 32 at one side, with an adsorbent 18 at the opposite side. As can be seen from Fig. 15D, the wick 32 is at the side having the largest area thereby enhancing evaporation of the refrigerant. 22 Referring to Fig. 16, there is shown a device 10 in two parts for cooling the material. The first part constitutes the first portion 16 and contains the adsorbent 18. The second part comprises the second portion 20 and is in the form of an evaporator. Wicking means 32 is provided in the second portion 20. A conduit 60 extends between the first portion 18 and the second portion 20. If it is desired to cool the material, the second portion 20 is inserted in the material and when communication is estabhshed between the first and second portions 16, 20 heat is extracted by the refrigerant 22 by evaporation thereof from the material thereby cooling it, as indicated by the arrows Ql. The evaporated refrigerant passes via the conduit 60 as shown by the arrow X to pass into the first part 16 to be adsorbed onto the adsorbent 18. Heat of adsorption is then given out to the atmosphere. Alternatively, if it is desired to heat the material, the first part is arranged in the material and the second part 16 is arranged outside. When communication is established between the first and second portions 16, 20, these are extracted from the atmosphere to evaporate the refrigerant 22 therein which is passed to the adsorbent 18 whereby heat of adsorption heats the material. It is envisaged that, for cooling, the material or beverage should be cooled from an initial temperature of 25°C to a final temperature of 8°C in the time of not more than 2 minutes. Where heating is required, heating should occur from 25°C to approximately 60°C in not exceeding 2 minutes. The volume of the device 10 should not exceed 20% of the volume of the container. Referring to Figs. 17, 18 and 19, a heat-transfer device 210 comprises a second portion 211 to contain the refrigerant 212 (e.g. water) under reduced (i.e. sub-ambient) pressure and a first portion 213 to contain the adsorbent material 14 (e.g. carbon). The portions 211 and 213 are initially separated from each other by a one-way valve 215 having actuating means 216. 23 The devices of Figs. 17, 18 and 19 are identical, except that the device of Fig. 18 is provided with a wick 217. In Figs. 17 and 18, the device is placed, when required, into a vessel 220 (e.g. a can of soft drink), while in Fig. 3 the device is already installed in the vessel. Operating the actuating mans 16 (as shown in Figs. 17 and 18) or opening the vessel 220 to release the pressure shown schematically by arrows P (see Fig. 19) opens the valve 215, causing the refrigerant to volatilise and become adsorbed by the adsorbent material. Heat is evolved from the second portion 213 of the device. Consequently, heat is absorbed by the first portion 211 of the device and since the absorbed heat is taken from the hquid surrounding the portion 211, the drink in the vessel 220 is cooled. Fig. 18 also shows a "pocket" version 30 of a device according to the invention. Referring now to Fig. 20, the device comprises an elongate pipe 40 containing a refrigerant 241 (e.g. water) under vacuum, the vacuum is maintained by means of a one-way valve 242. The adsorbent (e.g. carbon) is contained in a "plug" device 243 adapted to engage and operate the valve 242. On operation of the valve, the refrigerant volatilises (as shown at 241a) and is adsorbed by the material contained in device 243. Heat is absorbed from the hquid 244, which in consequence becomes cooled, the heat being evolved from the plug device 243 and vented to the atmosphere. In the embodiment of the present invention shown in Fig. 21, a vessel 250 comprises a double outer "skin" 251 adapted to contain a refrigerant 252 (e.g. water) under vacuum, the vacuum being maintained by means of a valve 253. The adsorbent (e.g. carbon) is contained in a "plug" device 254 adapted to engage and operate the valve 253. On operation of the valve, the refrigerant 24 volatilises and is adsorbed by the material contained in device 254. Heat is absorbed from the hquid 255 in the vessel, the liquid being cooled in consequence. The device shown in Fig. 22 functions in a manner similar to that shown in Fig. 4, an externally-arranged, additional adsorption unit 260 being provided. In the device shown in Figs. 23 and 24, the adsorption pipe 270 is provided with a three-way valve 271 including an ejector nozzle 272 to enhance the rate of adsorption and thus to increase the rate of coohng the hquid 273 in the vessel 274. Means including an on/off valve 275 are provided to permit the use of the gas present in the enclosed vessel 274 (generally carbon dioxide) for operating the valve 271. The refrigerant 276 may suitably be water and the adsorbent 277 may be carbon. Referring to Fig. 25, the device 290 comprises a portion 291 to obtain an adsorbent (e.g. carbon) and a portion 292 to contain a refrigerant (e.g. water) under vacuum. The portions 291 and 292 are separated by means of a one-way valve 293 having operating means 294. In the embodiment shown in Fig. 25, the device 290 is to be used to heat the liquid (e.g. soup) 295 contained in can 296, so that the portion 291 of the device will be placed inside the can 296. On operation of the means 294, the refrigerant colatilises and is adsorbed at portion 291 of the device. Heat is evolved by the adsorbent (as shown by arrows H) and therefore heats the liquid 295. In Fig. 26, a pipe 300 contains a combination of refrigerant and absorbent (sown schematically at 302) under pressure. The pressure is maintained by means of a valve 302. On operation of the valve, heat is evolved by the adsorbent and vented to the atmosphere, resulting in the coohng of hquid 303 in vessel 304. In Figs. 27 and 28, heat pipes and adsorption (or absorption) 25 compressors are employed. Heat pipes are devices with high thermal conductance and may consist of a sealed pipe 310 provided with an internal wick 313 (e.g. of stainless steel mesh) as a concentric lining to the pipe, the pipe is charged with a refrigerant 311. In operation, heat (from the hquid 314 in the vessel 315) applied to the lower end of the pipe, causes the hquid refrigerant to evaporate. The resulting vapour travels to the upper "cool" end where it condenses, surrendering energy. The hquid refrigerant returns through the wick by capillary action to the lower "hot" end. Adsorption (or absorption) compressor 313 is used to cool the upper end of the pipe 310. This consists of a vessel containing a second refrigerant/adsorbent (or absorbent) combination under pressure. When valve 312 is opened, the second refrigerant evaporates to the atmosphere causing a temperature drop in the refrigerant/adsorbent vessel 313. This consequently lowers the temperature of the upper end of pipe 310. The heat removed from the pipe 310 is released to the atmosphere. In the embodiment shown in Fig. 28, the adsorption (or absorption) compressor 323 forms part of the heat pipe 310 (or is placed inside the heat pipe 310). Absorption of heat from the liquid 314 is indicated by arrows H. Figs. 29 to 34 show further possible arrangements for the operation of a device according to the present invention. In Figs. 29, 30, 31 and 32 (wherein hke numerals denote hke parts) a simple pump 130, comprising a bellows 331 and a piston 332, is operatively associated with an adsorption device in the form of a pipe 333 to create a vacuum. The pipe 333 is charged with a refrigerant 334 (e.g. water) and an adsorbent 335 (e.g. a zeohte or carbon) and the vacuum is created by means of the pump 330. On operation of the pump, the vapour pressure of the refrigerant 334 is lowered, leading to evolution of heat at the adsorbent 335 and consequent cooling of the hquid 336 within the container 337. The rate of coohng of the hquid 336 can be controlled by appropriate control of the pump 26 330. Air which is removed from the system in creating the vacuum may be vented by way of a flap-valve (or other non-return valve) 338. The device shown in Fig. 32 is intended to be used as a "portable" or "pocket" heat-transfer device. In Fig. 33, there is shown a further arrangement in which a valve (such as a dimple valve) 370 is operable to allow the flow of refrigerant 371, through pipe 372, so as to interact with adsorbent 373, thus cooling the liquid 374 contained in vessel 375. In Fig. 34, the refrigerant and adsorbent are combined and held under pressure as shown at 380. A second adsorbent 381 (which may be the same or different ) is placed in the opposite end of the device. The pressure on the adsorbent/refrigerant combination 380 is maintained by operation of the bellows 382 and piston 383. On releasing the pressure, the combination 380 is adsorbed by the second adsorbent 381, thus coohng the liquid 384 contained in vessel 385. Referring to Fig. 35, there is shown a heat transfer device 410 comprising a first part 416 comprising a cylindrical chamber 419 for an adsorbent for 418, and a second part 420 which cools a beverage 422 to be cooled, and comprises a double skin in the form of a pair of concentrically arranged outer and inner walls 424, 426. Wicking means 428 is provided on and surrounds the inner wall 426. The wicking means 428 is soaked in a suitable refrigerant, for example water can be a porous fabric material capable of dispersing the refrigerant throughout the fabric by capillary action. One example of a suitable fabric is that sold under the Trade Mark J-Cloth. The space between the outer and inner walls 424, 426 is evacuated. Mixing means in the form of a disc 430 provided with a plurality of perforations is provided in the beverage 422, the purpose of which is explained below. Operative means in the form of a plunger 432 is provided in the first 27 part 416 and comprises an elongate rod 434 extending between a button 436 to be pressed to operate the operative means 432, and piercing means 438 at the opposite end region of the rod 434 to pierce a membrane 440 separating and isolating the first and second parts from each other. The operative means extends through an elongate hole 435 through the cylindrical chamber 417. The piercing means 438 is in the form of a substantially cylindrical member, the lower end 439 being open. The edge of the cylinder surrounding the open end is sharp and can readily pierce the membrane 440 which is in the form of a suitable metal foil, for example aluminium foil. In operation, the button 436 is depressed which causes the piercing means 438 to pierce the membrane 440. Upon piercing of the membrane, the water in the space between the outer and inner walls 424, 426 is adsorbed by the adsorbent 418, and evaporates from the wicking means 428 thereby extracting heat from the beverage 422. In order to ensure that heat is extracted from all parts of the beverage 422, the device 410 is inverted to enable the mixing disc 430 to descend thereby creating eddy currents and stirring the beverage. As the water evaporates from the wicking means, it is absorbed by the adsorbent 418 until all the water has been so adsorbed. A ring pull 442 is provided to allow the beverage to be consumed. Referring to Fig. 36, there is shown a modification of the device shown in Fig. 36 in which the first part 416 is surrounded by heat absorption means, or a heat sink 444. The heat sink 444 absorbs heat from the adsorbent 418. The heat sink 444 could, for example, be further wicking means, soaked in a suitable refrigerant e.g. water, whereby as the adsorbent releases heat of adsorption, the refrigerant evaporates thereby removing the heat of adsorption from the device. Again, the further wicking means could be a porous cloth, for 28 example a cloth sold under the Trade mark J-Cloth. Alternatively, in an embodiment not shown, the further wicking means could be provided around the inside walls of the elongate hole 435. Micro capsules containing water may be provided in the further wicking means to enhance the removal of heat of adsorption. The micro capsules may, instead of water, contain phase change material. Both the first part and the second part of both embodiments, shown in Figs. 31 and 36 are placed under vacuum. The adsorbent is placed in a cylinder made from stainless steel or copper mesh. The operative means extends through the hole 435 through the centre of the cyhnder. Referring to Figs. 37 to 39, there is shown a heat transfer device 510 which comprises a first part 512 which holds an adsorbent 514 arranged in a cylinder of stainless steels or copper mesh 516. The second part 518 is provided on the first part 512 and extends into a beverage to be cooled 520. The second part 518 consists of a cylindrical tube 522 having provided on the inner surface thereof wicking means 524 which is saturated with a suitable refrigerant, for example, water. Heat exchange means in the form of wire fins 526 extend outwardly from the tube 522. Both the first and second parts 512, 518 are under vacuum. Operative means 528 is provided in the first part 512 and extends through a bore in the cyhnder holding the adsorbent 514. The operative means 528 comprises a button 530 and piercing 532 adapted to pierce a membrane 534 separating and isolating the first and second parts from each other. A rigid rod 536 extends between the button 530 and the piercing means 532 such that depression of the button 530 causes the piercing means 532 to pierce the membrane 534. 29 Referring to Figs. 38A to 38C, there is shown the sequence of events for using the device shown in Fig. 37. Fig. 38A shows the device as it appears in Fig. 37, i.e. before operation. Referring to 38B, when it is desired to consume the beverage 520, the button 530 is pushed down. This causes the piercing means 532 to be pushed through the membrane 534 by the rod 536. Immediately this is done, the water on the wicking means 524 evaporates and is adsorbed by the absorbent 516. This extracts heat from the beverage 520 and this heat extraction is enhanced by the fins 526. When the heat transfer has been completed, and the beverage 520 is cooled, a ring pull 538 can be pulled to allow the beverage 520 to be poured into a glass 540 for consumption. Referring to Fig. 39, there is shown a modification to the device shown in Fig. 37 in which the inside of the tube 522 forming the second part 518 is provided with an internal arrangement 542 of looped wire. Referring to Fig. 40, there is shown a further embodiment 610 in which a first part 612 comprising a vessel having a double skin inner and outer wall 616, 618, the adsorbent 614 being arranged circumferentially around the outer wall 618. An inner tube 620 extends into the beverage 622 and comprises wicking means 624 arranged internally of the tube 620, and fins 626 extending outwardly from the tubes 620 into the beverage 622. The second part 628 is provided separate from the vessel, and comprises a copper container 630 holding a refrigerant 632, for example water. A conduit 636 extends from the container 628 to a region adjacent the bottom of the tube 620. A valve 638 is provided in the pipe 636 which is initially set to its closed position and, upon opening, allows water in the container 630 to flow into the tube 620. An arrangement of conduits 640 extends from the tube 620 into the first part 612 30 for the purpose of delivering evaporated refrigerant to the first part 612. A water trap 642 is provided at the top of the tube 620 to connect the tube 620 to the conduit arrangement 640, whereby any water condensing prior to entering the conduit arrangement 640 is returned back to the tube 620 to undergo evaporation again. In operation, the valve 638 is opened and water from the container 630 is emptied into the tube 620. The water is then dispersed by the wicking means around the inside of the tube 620 and is evaporated by the transfer of heat from the beverage via the fins 626. The evaporated water thereby extracts heat from the beverage to cool it down. Water vapour passes through the tube via the conduit arrangement 640 into the first part 612 to be adsorbed by the adsorbent 614 arranged on the outer wall 618. A covering of insulating material 644 is provided around the inner wall 616 to ensure that, once cooled, the beverage 622 is kept cool. When the cooling process is completed, the ring pull 646 can be pulled to allow the beverage to be consumed. A lid 648 is provided which can be removed to allow the water in the adsorbent 614 to be discharged thereby allowing the device to be used again. Referring to Fig. 41, there is shown a modification to the device shown in Figs. 1 and 2. The device shown in Fig. 41 is designated 710 and comprises an inner cylinder 712 holding a beverage 714. Wicking means 716 is provided on the wall of the cylinder 712. An outer wall 718 is provided on the inside thereof with an adsorbent 720 which extends substantially wholly around the inside of the wall 718. A container 722 is provided separate from the vessel and contains a suitable refrigerant, for example water. The container 722 is connected to the wicking means 716 via a conduit 724 and a valve 726. The space between the inner and outer walls 712, 718 is under vacuum. On operation, the valve 726 is opened to allow the water in the container 31 722 to empty into the space between the two walls 718, 712 whereupon the water is dispersed around the outside of the cyhnder holding the beverage 714. In evaporation the water therefrom extracts heat from the beverage 714. The evaporated refrigerant is then adsorbed by the adsorbent 720 surrounding the inside of the outer wall 718. In this way, the beverage 714 is cooled. A plastic hd 728 is provided to cover the space between the inner and outer wall 718, 712 and the conduits 724 is drilled into the lid 728. An evacuation point 730 is provided on the lid, to allow the water adsorbed onto the adsorbent 720 to be discharged therefrom to allow the device to be used again. The container 722 can be refilled with water through a suitable fill point 732. The container 722 is suitably formed from copper. Referring to Fig. 42, there is shown a further embodiment 710 and is formed in two separate but connected elements 712. The first element 712 comprises a large cylinder the adsorbent 718 extends substantially wholly around the inside of the wall of the cylinder 716. A lid 720 is provided on the cylinder to allow water adsorbed onto the adsorbent 718 to be reused. The second element 714 comprises a tubular member 722 having provided on the outside thereof a plurality of fins 724. Wicking means 726 extends around the inside of the wall of the tube 722. A container 728, initiahy charged with a refrigerant, for example water is provided separately from the tube 722 and is connected thereto by pipes 730 and a valve 732. A flange 734 is provided to connect the two elements 712, 714 together. On operation, the first element 712 is connected to the second element 714 by the flange 734. The tube 722 is then inserted in a material to be cooled, and a valve 732 is opened to allow the water to enter the tube 722 to be dispersed around the inside wall of the tube. Heat is transferred to the inside of the tube via the fins 724 to evaporate the water thereby coohng the material. The evaporated water is then passed into the first element 712 to be adsorbed by the adsorbent 718. When the process is completed, the cooled material can 32 be consumed, and the first element can be used again by removing the water from the adsorbent 718 by, for example, heating. Where "heat-pipe" is referred to in the foregoing description, it is to be understood as including any one or more of needle heat-pipes, loop heat-pipes or micro heat-pipes. Various modifications can be made without departing from the scope of the invention. For example, each of the embodiments shown above comprises one adsorber or absorber unit. The devices may comprise two or more absorber or adsorber units to enhance the cooling/heating programme. Also, a device may comprise a combination of solid/gas adsorption and liquid/gas absorption. In the pocket/portable coolers/heaters (or, indeed any of the embodiments shown in the drawings) the refrigerant may be desorbed from the adsorbent to allow the adsorbent to be re-used. A fresh bubble 20 could then be presented to provide fresh refrigerant. Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Apphcant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims: 33 CLAIMS 1. A heat transfer device containing a refrigerant, and said device further including operative means for allowing transfer of the refrigerant from a first region of the device to a second region of the device and means to drive said transfer of the refrigerant, thereby transferring heat from said first region to said second region, such that heat can be transferred to or from a material to be heated or cooled. 2. A heat transfer device according to claim 1 wherein the transfer of said refrigerant occurs by evaporation of the refrigerant. 3. A heat transfer device according to claim 1 or 2 wherein the means to drive said transfer of the refrigerant comprises a refrigerant take up agent to take up said refrigerant. 4. A heat transfer device according to claim 3 wherein the take up agent is in the form of an adsorbent or absorbent. 5. A heat transfer device containing a refrigerant and a refrigerant take up agent, and said device further including operative means for allowing evaporation of the refrigerant, whereby the take up agent takes up said evaporated refrigerant such that heat absorbed on evaporation of the refrigerant is evolved at the take up agent to enable heat to be transferred to or from a material to be heated or cooled. 6. A heat transfer device according to any of claims 3 to 5 wherein the taking up of the refrigerant occurs at a first region of the device and evaporation of the refrigerant by the take up agent occurs at a second region. 7. A heat transfer device according to claim 6 wherein the take up agent may be an adsorbent or an absorbent, heat of adsorption of absorption being given out when the evaporated refrigerant is adsorbed onto the adsorbent or 34 absorbed by the absorbent. 8. A heat transfer device according to any of claims 3 to 7 wherein the device comprises a first part for the take up agent and a second part for the refrigerant, the first and second parts being initiaUy isolated from each other, wherein the operative means is operable to allow communication. 9. A heat transfer device according to claim 8 wherein the first and second parts one either substantially permanently attached to each other or initially separate from each other to be attached together to allow communication therebetween on operation of the operative means. 10. A heat transfer device according to claim 8 or 9 wherein the device comprises a first element, on which the take up agent can be arranged, and a second element to provide dispersion of the refrigerant. 11. A heat transfer device according to claim 10 wherein the first and second elements are respectively in the form of first and second walls. 12. A heat transfer device according to claims 10 or 11 wherein dispersal means is provided to disperse the refrigerant over the second element. 13. A heat transfer device according to claim 12 wherein the dispersal means comprises wicking means. 14. A heat transfer device according to any of claims 1 to 13 wherein the first part includes the second element and the second part is in the form of a container whereby on operation of the operative means refrigerant is released into the first part. 15. A heat transfer device according to claim 14 wherein the second part is in the form of a container containing the refrigerant. 35 16. A heat transfer device according to any of claims 10 to 13 wherein the second part comprises the second element. 17. A heat transfer device according to any of claims 10 to 16 wherein the operative means comprises a means to orm an aperture in the second part, for example a spike, rod or pin. 18. A heat transfer device according to claim 17 wherein the operative means comprises an elongate rod having at one end thereof a substantially cyhndrical member, and a membrane is provided to separate the first and second parts. 19. A heat transfer device according to claim 18 wherein the cyhndrical member has an open end arranged adjacent the membrane, whereby operation of the operative means causes the open end of the cylindrical member to engage the membrane and pierces the membrane. 20. A heat transfer device according to claim 18 or 19 wherein the membrane is formed of a metallic foil. 21. A heat transfer device according to any of claims 10 to 16 wherein the operating means is in the form of a valve movable to an open position to allow communication between the first and second parts. 22. A heat transfer device according to any of claims 10 to 21 wherein when the device is to be used to cool the material, the second element is arranged adjacent, or in contact with, said material, and the first element is arranged such that heat transfer thereto can be dissipated to the atmosphere and where the device is to be used to heat the material, the first element is arranged adjacent, or in contact with said material and the second element is arranged such that heat can be extracted from the atmosphere to be transferred to the first element thereby heating said material. 23. A heat transfer device according to any of claims 10 to 22 wherein at 36 least the first part is in the form of a tube or pipe. 24. A heat transfer device according to claim 23 wherein the first part constitutes a first portion of the tube and the second part constitutes a second portion of the tube. 25. A heat transfer device according to any of claims 23 or 24 wherein the first part constitutes a double skin of a vessel holding the material to be heated or cooled, the double skin comprising inner and outer walls. 26. A heat transfer device according to claim 25 wherein the tube or pipe is in the form of a sleeve having said inner and outer walls, the said sleeve being adapted to receive a vessel. 27. A heat transfer device according to claim 25 or 26 wherein when the device is used to cool the material the outer wall constitutes the first element and the inner wall constitutes the second element, and where the device is used to heat the material the inner wall constitutes the first element and the outer wall constitutes the second element. 28. A heat transfer device according to claim 25 wherein the device is configured to be arranged inside a vessel for heating or coohng the material therein, the device being manufactured separately to be inserted in the vessel when desired, or being arranged in the vessel during manufacture. 29. A heat transfer device according to any of claims 22 to 24 wherein the second part constitutes a double skin of vessel holding the material to be heated or cooled, the double skin comprising inner and outer walls. 30. A heat transfer device according to claim 29 wherein the inner wall is covered with wicking means, the wicking means being wetted prior to use of the device. 37 1. A heat transfer device according to claim 30 wherein the wicking means is formed of a porous fabric. 32. A heat transfer device according to claim 31 wherein the material is perforated to define a plurahty of apertures therethrough to prevent or reduce the formation of ice during coohng. 33. A heat transfer device according to any of claims 29 to 32 wherein the first part is arranged on the second part. 34. A heat transfer device according to claim 33 wherein the first part constitutes a first tube and the second part constitutes a second tube, the second part being received in the material, and further including heat exchange members adapted to extend into the material to enhance the transfer of heat. 5. A heat transfer device according to claim 34 wherein the heat exchange members comprise a plurality of fins, preferably in the form of wire loops. 36. A heat transfer device according to claim 34 or 35 including further heat exchange members extending into the second part. 37. A heat transfer device according to claim 36 wherein the further heat exchange members comprises a plurahty of fins, preferably in the form of wire loops. 38. A heat transfer device according to any of claims 10 to 22 wherein the first element is in the form of a first tube surrounding the second element, which is in the form of a second tube, the second element being adapted to be arranged in a material to be cooled. 39. A heat transfer device according to any of claims 10 to 22 wherein one of said first and second elements surrounds the other of said first and second elements, and said other of said first and second element scan be arranged in a 38 material to be heated or cooled. 40. A heat transfer device according to claim 39 wherein a conduit arrangement extends between the first and second elements to conduct the evaporated refrigerant, thereby transferring heat from the second element to the first element. 41. A heat transfer device according to claim 39 or 40 wherein, when the device is to be used to cool the material, the first element surrounds the second element and, when the device is to be used to heat the material, the second element surrounds the first element. 42. A heat transfer device according to any of claims 40 and 41 which includes heat exchange members extending from the first or second element into the material to be heated or cooled. 43. A heat transfer device according to any of claims 34 to 42 wherein the first and second elements comprise first and second tubes initially separate from each other and adapted to be connected in communication for heating or cooling, and the second part comprising a container connected to the second part. 44. A heat transfer device according to any of claims 34 to 43 wherein the operative means comprises a valve between the first and second parts, the valve being movable to an open position to allow the first and second parts to communicate with each other. 45. A heat transfer device according to any of claims 10 to 44 wherein heat absorption means is arranged adjacent one of the first or second elements, whereby where the device is to be used to cool the material, the heat absorption means is arranged in thermal contact with the first element to absorb heat given out by the take up agent, the heat so absorbed by the heat absorption means being desorbed to the atmosphere, and where the device is to be used to 39 heat the material, the heat absorption means is arranged in thermal contact with the second element, whereby heat absorbed by the heat absorption means is desorbed via the second element to evaporate refrigerant in the first part. 46. A heat transfer device according to claim 45 wherein the heat absorption means is provided in a chamber which may be defined at least partially by the first or second element, the chamber surrounding or being surrounded by, said first part, the chamber is in the form of a substantially cyhndrical tube defined substantially wholly by said first or second element internally of the first part. 47. A heat transfer device according to claim 46 wherein the chamber is in the form of a sleeve defined partially by the first or second element externally of said first part. 48. A heat transfer device according to claim 46 wherein the chamber is in the form of a sleeve defined partially by the first or second element externally of said first part. The sleeve being defined between said first or second element and an external wall. 49. A heat transfer device according to any of claims 45 to 48 wherein the heat absorption means comprises a refrigerant adapted to evaporate when heat is absorbed thereby, valve means being provided to release to the atmosphere evaporated refrigerant from the heat absorption means. 50. A heat transfer device according to any of claims 45 to 48 when the heat absorption means may be a phase change material adapted to change phase from solid to liquid or from solid to vapour on absorption of heat, whereby where the phase change material is one which changes from solid to vapour, valve means is provided to release the vapour to the atmosphere. 51. A heat transfer device according to any of claims 45 to 48 wherein the heat absorption means is a heat pipe having one end region in thermal contact with the first part and the opposite end region outside the first part. 40 52. A heat transfer device according to claim 51 wherein the end region of the heat pipe is provided with heat exchange means to assist in heat transfer to or from the heat pipe. 53. A heat transfer device according to any of claims 8 to 13 comprising at least one heat pipe, extending from the second part into the material, a valve being provided between the second part and the first part, whereby when the valve is opened, refrigerant in the second part is evaporated to be taken up by the take up agent in the first part, and the evaporation of the refrigerant causes heat to be transferred from the material along the heat pipes to an end region of the or each heat pipe in the first part, thereby coohng the material. 54. A heat transfer device according to any of claims 8 to 15 wherein the take up agent comprises an absorbent, the device being provided with a third part initiaUy containing the absorbent, the third part may be provided with further operative means, whereby when the further operative means is operated, absorbent is released into the second portion. 55. A heat transfer device according to claim 47 wherein the third part is a further container and the operative means may be suitable for piercing the bubble, or otherwise forming an aperture in said further bubble, or may be in the form of a valve. 56. A heat transfer device substantiaUy as herein described with reference to the accompanying drawing. 57. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.

Inventors: RIFFAT SAFFA BASHIR, RIFFAT, SAFFA, BASHIR
Applicants: RIFFAT SAFFA BASHIR, UNIV NOTTINGHAM, RIFFAT, SAFFA, BASHIR, THE UNIVERSITY OF NOTTINGHAM
Application year: 1999
Main classification: F25B17
IPC codes: F25B17, F25D5, F25D7, F25D31