by Takenobu Kajikawa, SHONAN Institute of Technology Japan
This study examines an open cycle OTEC system with direct contract condenser containing desalination. The proposed system does not employ the conventional surface condenser to produce fresh water. Desalinated water is produced inside many guidetubes of which outside surface is cooled with falling cold seawater. Residual steam flows through guide-tube into a parallel flow type direct contact condenser employing used cold seawater. This first stage direct contact condenser can be said the condenser with combined surface and direct-contact condensation. In this system the trouble of the sealing between seawater at atmospheric pressure and vapor space at low pressure is substantially reduced on its principle. The relationship between desalination flow rate and system design parameter including heat transfer performance, configuration and seawater flow rate at each section is obtained based on the local analysis. A conceptual design of 1000kWe class open cycle system producing 580 tons per day in fresh water is presented.