Thin-Film Steam Generators of Binary Geothermal Power Plants

Abstract

BACKGROUND: The cost of electricity generated by a geothermal power plant is twice as low as that of energy sources. However, at present, geothermal power plants mainly use submersible-type apparatus, and the most promising thin-film steam generators have not been sufficiently investigated. AIM: The purpose of this work is to show the advantages of a thinfilm steam generator in comparison with an immersion type heat exchanger. MATERIALS AND METHODS: The basis for this publication is the experimental research of the author and the analysis of data cited in the literature on heat exchange during the boiling of a film irrigating a bundle of finned pipes. CONCLUSIONS: The use of thin-film steam generators will significantly reduce the amount of expensive refrigerant in a geothermal power plant circuit. With a cocurrent flow of steam and liquid, the ingress of large drops onto the surface of a superheater tubes is excluded. The use of finned tubes in a bundle with optimal finning parameters ensures a uniform irrigation. The artificial centers of vaporization of the finned tube repeatedly intensify the heat transfer during film boiling, which ultimately leads to a reduction in the weight and dimensions of the superheater.