Assessment of the Influence of Hot Seawater Temperature on OTEC Performance

Abstract

The study of the influence of hot seawater temperature on the performance of a 40KW OTEC that will be situated in Bonny Island has been conducted. Daytime surface temperatures in these waters range from a warm 24°C to 30°C, while at a depth of 1000 meters, temperatures are a chilly 4°C to 6°C - an impressive thermal gradient approaching 26°C. This substantial ocean temperature difference has rendered the Niger Delta coastal region an ideal site for the study of the proposed Closed cycle conventional OTEC. The results from both Hysys and MATLAB simulations are compared to evaluate the impact of varying sea water temperatures on system performance and it shows that as the temperature increases from 20°C to 40°C: the turbine power output rises dramatically from 14.41 KW to 99.49 KW in the Hysys simulation and from 14.45 KW to 99.53 KW in the MATLAB simulation ; The pump power increases from 0.2037 KW to 0.8148 KW in the Hysys simulation and from 0.2041 KW to 0.8152 KW in the MATLAB simulation and the turbine net power output increases from 14.21 KW to 98.68 KW in the Hysys simulation and from 14.25 kW to 98.72 kW in the MATLAB simulation. It is recommended that the seawater temperature should be controlled within 280C – 300C for optimum power generation and thermal efficiency.