Abstract: A heat storage unit (100) in the form of a rectangular parallelepiped is provided with a removable closure element (104), and contains a plurality of removable closed plastic tubes (126) holding a heat storage substance, the tubes being laterally supported by adjacent tubes and longitudinally supported to be spaced from ends of the unit by grids (124a and b). A transfer fluid flows from one end of the unit to the other through spaces between the tubes. A heat storage system (FIGS. 4 or 5 for example) is conveniently custom built by attaching a plurality of the rectangular parallelepiped units to form a cluster of units. Each unit includes a special structural frame (106) to allow such attaching. The units contain heat storage substances of various adjustable melting temperatures, thereby providing for the storing of heat as the latent heat of fusion at several temperature levels.

Abstract: A selective extraction heat storage assembly (32) for use in a system including a plurality of such assemblies (32a-c) and for use by itself, includes a heat unit (10) connected in parallel with a fluid circulating passage (54) and has a separate unit heat extractor (exchanger) (34) mounted in the unit (10). The unit (10) can be charged and discharged by fluid flow through the unit caused by an outside fluid circuit and can be similarly discharged thereby. However, in addition, the unit can be charged and discharged by means of the separate unit heat extractor (exchanger) (34) within the unit by closing off the heat storage assembly from the outside fluid circuit and circulating fluid through the unit via the parallel fluid circulating passage (54). A pump (42), several sensors (46 and 52), and valves (44 and 60) form a part of the heat storage assembly to provide for this operation.

Abstract: A heat storage unit in the form of a cylinder is provided with a removable end closure, and contains a plurality of closed tubes holding a heat storage substance, the tubes being supported at either end thereof by screens. A transfer fluid flows from one end of the cylinder to the other between tubes for transfer of heat. A heat storage system is provided by the combination of a plurality of units, the units containing heat storage substances of various melting temperatures, thereby providing for the storing of heat as the latent heat of fusion at several temperature levels.