Abstract
In order to improve a thermal efficiency of power plant two ways of thinking i.e. combined plant system and co-generation system might be applied. The former utilizes an exhaust gas energy of primary engine as the reheat source of secondary power plant, the latter as the latent heat source for hot water or hot air. A race for the high level total thermal efficiency is being seriously unfolded especially for land use plant. Thus an effective utilization of medium of low level energy of exhaust gas will become inevitable from the both view points of preservation of the earth environment and an energy saving. Authors focused the attentions of the exhaust gas of diesel engine for ship's generators, which was exhausted without any uses to an atmosphere and made conceptual designs and calculations of combined plant of Rankine cycle of steam or Freon as a working fluid. A sulfuric corrosion which might occur at temperature lowered up to a dew point was avoided by applying a special coating on the surface of heat recovery equipment.
