GB1017665A - Improvements in or relating to heating systems utilizing a heat storage medium - Google Patents

Abstract

1,017,665. Heat storing apparatus. J. H. ELLINGER. July 15, 1963 [April 19, 1962; April 16, 1963], Nos. 15186/62 and 14766/63. Headings F4A and F4U. In a heat storage method, an electrical heating element heats a mass of heat storage medium during off-peak periods, the medium including a eutectic whose temperature is raised to a temperature above its melting point by the heater. The mass of heat storage medium is preferably of the type in which the eutectic changes from solid to liquid around 270‹ C. In Fig. 7 (not shown), a double-walled metal container 2 contains a heat storage medium 1 in which is embedded a heat-sensitive element 4 and electrical heating elements 3. Spaced away from the container 2 is a heat-insulated outer casing, defining an inverted U-shape passing with the container. Air to be heated passes through this passage from an inlet in wall la to the outlet 11 in wall 1b with the aid of fan 10. Alternately air may pass through channel 8 according to the position of valve 9. Baffles in the U-channel reduce convector heat loss. The heat storage medium is heated during off-peak periods and consists of a mixture containing a eutectic of sodium hydroxide and sodium nitrate, which is preferably heated from its solid phase to its liquid phase to best utilize the latent heat of fusion. The room temperature is thermostatically controlled by the rate of air delivery caused by the speed of the fan. In the modification of Fig. 8 (not shown), a shroud 15 surrounds a container 13 containing the mass of heat storage medium, whilst cool air is forced either between the shroud and the container to be heated or externally of this shroud thus remaining cool, by a fan 18. Adjustable shutters 19 control the ratio of hot to cold air entering the room by the action of a thermostatic temperature control 21. In the modification of Fig. 9A, the heat storage medium 30 in an annular tank 31 is used to heat water stored within a surrounding insulated tank 35. The tank 31 is surrounded by a hood 41 open at its base, the inside of which is connected to a pump 42. Cold water enters the tank by pipe 37 and through orifices 37b in the bellows 37a. Water is maintained at a common level CL by the air pressure within the hood 41, and this water is heated by contact with the surface 51 of the tank 31 before passing around the outside of the hood 41 to its outlet pipe 38. A bellows 39 is connected by pipe 44 to the inside of the hood 41. If the required supply of heated water is increased, the trapped air in the hood 41 and bellows 39 is cooled and contracts resulting in a higher surface level of the water within the hood 41. This creates a greater contact with the heating surface 51 and an increase in the rate of heat exchange.