Shell-and-Plate-Type Heat Exchangers for OTEC Plants

New titanium, shell-and-plate type heat exchangers for ocean-thermal-energy-conversion (OTEC) plants have been developed which include three different plate types (fluted, impinging, and porous-surface) for the evaporator and two kinds of plates (No. 1 and No. 2) for the condenser. Performance tests with fresh water show that the overall heat transfer coefficient U of the evaporator using the porous plate is the highest among the three plates; it can reach 4000–4500 W/m2K using ammonia as the working fluid and 3500–4000 W/m2K for a Freon, R-22. The U of the condenser using the No. 2 plate is higher than that using the No. 1 plate; it can reach 3800–4500 W/m2K for ammonia and 2000–3500 W/m2K for R-22.