HEAT ACCUMULATING TYPE HEAT TRANSFER TUBE

PURPOSE:To improve the utilizing rate of heat accumulating material during the operation of a heat exchanger and permit the distribution of voids, generated in accordance with the change of the phase of the heat accumulating material, into respective parts of a vessel by constituting an area, in which a heat transfer tube makes contact with the heat accumulat ing material in the vessel, is constituted so as to be spiral. CONSTITUTION:Heat accumulating material 12 is sealed into a vessel 11 while a first spiral heat transfer tube 13a, penetrating the vessel 11 lengthwisely, and a second spiral heat transfer tube 13b, pairing with the first spiral heat transfer tube 13a, are provided in the vessel 11 respectively. In this case, the first and second spiral heat transfer tubes 13a, 13b are formed so that a distance between the first and second spiral heat transfer tubes 13a, 13b and another distance L between the heat transfer tubes and the internal surface of the vessel 11 become given values. In above-described constitution, medium to be heated flows through the spiral heat transfer tubes 13a, 13b from the side of sunshine to the side of shade and the heat accumulating material at the side of shade is heated by the medium to be heated, whose temperature is increased, and, therefore, the utilizing rate of the heat accumulating material 12 may be increased. On the other hand, the distance L is kept in the vessel 11 and, therefore, initial solidified parts A appear between the spiral heat transfer tubes 13a, 13b and the like whereby voids are distributed in respective parts of the vessel 11.