Hitachi, Ltd.

Hitachi Chemical Company, Ltd.

Naohisa Watahiki

Moriaki Tsukamoto

Hiromi Tokoi

Isao Sumida

Kazutake Imani

Hisashi Souma

Takanobu Yamamoto

In a sodium-sulphur cell, liquid sodium is anodic reactant, sulphur and sodium polysulphide are cathodic reactants and sodium ions are conducted by a solid electrolyte. To increase cell capacity and improve safety, a storage region for cathodic reactants is provided away from said solid electrolyte and containing said cathodic reactants in the form of two contacting layers of immiscible liquids formed by gravitational separation. Liquid sulphur being stored does not contact the solid electrolyte. The sodium may also be stored out of contact with the electrolyte. Capillary-action means for feeding the sodium polysulphide from the two liquid layers to the cathode reaction, and for feeding sodium to the anode reaction are included.

Sodium-sulphur cell, method of operating same and method of load

A solar heat collector comprises an evacuated transparent pipe; a solar heat collection plate disposed in the transparent pipe; a heat pipe, disposed in the transparent pipe so as to contact with the solar heat collection plate, and containing an evaporable working liquid therein; a heat medium pipe containing a heat medium to be heated; a heat releasing member extending along the axis of the heat medium pipe and having thin fin portions extending from the axis to the inner surface of the heat medium pipe; and a cylindrical casing surrounding coaxially the heat medium pipe to provide an annular space which communicates with the heat pipe. The evaporable working liquid evaporates, receiving solar heat collected by the heat collection plate. The resultant vapor heats the heat medium through the heat medium pipe and the heat releasing member.

Solar heat collector

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Mito, Japan

Naohisa Watahiki