Improved latent heat storage device

Abstract

A rapid absorption and extraction latent heat storage device according to the invention comprises a means ( 1 ) for containing at least one phase change material ( 2 ) within a containment vessel ( 3 ), the containment vessel forming a supporting structural exoskeleton. The containment means ( 1 ) is in the form of rods or tubes, which are made out of elastomeric material ( 4 ) containing the PCM ( 2 ). A heat exchange fluid ( 6 ) flows between and along the length of the rods ( 1 ).

1 . A latent heat storage device comprising:
 at least one containment vessel forming a supporting structural exoskeleton;   at least one phase change material (PCM); and   at least one PCM containment means comprising an elastomeric material wall, the elastomeric material being selected to have as thin a wall thickness as possible to structurally retain the PCM and at the same time to provide the minimum effect on the transfer of heat to and from the PCM by way of improved thermal conductivity, the PCM containment means containing the PCM and wherein the PCM can expand and contract as it absorbs or gives up heat in use; wherein the at least one PCM containment means is arranged within the containment vessel such that there are channels between at least parts of the PCM containment means to allow heat exchange fluid to pass between said containment means to facilitate the absorption and extraction of thermal energy from the PCM within the containment means and wherein the containment vessel provides a supporting structural exoskeleton to the elastomeric walls of the containment means, when the PCM is in a melted state in use.   
     
     
         2 . A latent heat storage device according to  claim 1  wherein the containment vessel comprises inlet means and outlet means to allow flow of heat exchange fluid through the containment vessel. 
     
     
         3 . A latent heat storage device according to  claim 1 , wherein the expansion and contraction of the PCM causes the elastomeric material of the containment means to expand and contract firstly in and out of the top of the vessel and subsequently in the heat exchange channels within which the heat exchange fluid flows. 
     
     
         4 . A latent heat storage device according to  claim 3  wherein the expansion acts to progressively restrict the flow of heat exchange fluid to providing a safety mechanism to prevent overheating of the PCM, elastomeric and or other materials used. 
     
     
         5 . A latent heat storage device according to  claim 1  wherein the thin elastomeric material is formed into chambers of thin section having a circular, multi-sided or other shaped cross-section, filled with PCM. 
     
     
         6 . A latent heat storage device according to  claim 1  wherein the containment means comprises at least one continuous tube of elastomeric material, filled with PCM and sealed at both ends, the containment means being folded along its length to form a series of connected portions and being positioned within the containment vessel. 
     
     
         7 . A latent heat storage device according to  claim 1  wherein the containment means comprises thin elastomeric material formed as an array of tubes connected by web sections, the tubes being filled with PCM and sealed at both ends. 
     
     
         8 . A latent heat storage device according to  claim 7  wherein the tubes are of circular, multi-sided or other shaped cross-section. 
     
     
         9 . A latent heat storage device according to  claim 7  wherein the array of tubes is an extruded array. 
     
     
         10 . A latent heat storage device according to  claim 1  wherein the containment means comprises thin elastomeric material formed as an array of concentric rings linked by web sections to enable heat exchange fluid to flow between them, the rings being filled with PCM and sealed at both ends and the flow channels for the heat exchange fluid being between each concentric ring. 
     
     
         11 . A latent heat storage device according to  claim 10  wherein the outermost ring adjacent the wall of the containment vessel comprises a corrugated arrangement of channels of PCM linked by web sections to enable heat exchange fluid to flow between the outer surface of the outermost ring and the wall of the containment vessel. 
     
     
         12 . A latent heat storage device according to  claim 1  wherein very small quantities of very fine powders of suitable conductive material are added to the PCM to improve the thermal conductivity. 
     
     
         13 . A latent heat storage device according to  claim 12  wherein the powder comprises fine nano-particles of conductive powder. 
     
     
         14 . A latent heat storage device according to  claim 13  wherein the powder comprises fine nano-particles of carbon or aluminum. 
     
     
         15 . A latent heat storage device according to  claim 1  wherein the device has a multiplicity of different PCM, with different properties, within different containment means within at least one containment vessel. 
     
     
         16 . A latent heat storage device according to  claim 1  wherein the device has a multiplicity of different compartments within at least one vessel. 
     
     
         17 . A latent heat storage device according to  claim 16  comprising means to direct a flow of heat exchange fluid to the different compartments. 
     
     
         18 . A latent heat storage device according to  claim 16  comprising means to control the flow of heat exchange fluid such that the flow of fluid can be directed to different parts of the store to accommodate different requirements at different times. 
     
     
         19 . A latent heat storage device according to  claim 16  wherein the compartments provide structural integrity for the elastomeric material of the containment means, once the PCM has melted in use. 
     
     
         20 . A latent heat storage device according to  claim 1  wherein the device has a multiplicity of vessels within the one device. 
     
     
         21 . A latent heat storage device according to  claim 1  wherein the vessel has a sealed lid. 
     
     
         22 . A latent heat storage device according to  claim 21  wherein the device has a gas or fluid within the sealed vessel to effect a different atmosphere or environment. 
     
     
         23 . A latent heat storage device according to  claim 21  wherein the gas is nitrogen or carbon dioxide. 
     
     
         24 . A latent heat storage device according to  claim 1  wherein the device has a means whereby heat exchange fluid is supplied to the vessel and removed from the vessel, so as to be a closed circuit such that whatever fluid is supplied is also removed at the same time to avoid overfilling or emptying of the vessel. 
     
     
         25 . A latent heat storage device according to  claim 1  wherein the vessel is surrounded by a secondary additional layer such as PCM, water or other suitable material, such that any thermal energy that escapes from the inner vessel or vessels will be absorbed and there will be minimal loss to the surrounding atmosphere. 
     
     
         26 . A latent heat storage device according to  claim 25  wherein the secondary additional layer comprises a PCM having a lower phase change temperature than the PCM of the vessel.