Steady-State and Dynamic Performance of an Otec Plant

Objectives of the computer simulations of TRW's designs for the OTEC PSD-1 and PSD-ll plants were: 1) determine steady-state performance of plants at nominal and off-nominal conditions; 2) design steady-state control system; and 3) determine dynamic power response caused by ship's heave. The simulations were constructed of modules that modelled the heat exchangers, turbine, ammonia pumps, water pumps, pipes, valves, and fittings in the steady-state, using a relaxation method. A simpler dynamic program, considering only the oscillatory heave motion of the ship and plant variables affected by ship motion using numerical integration, led to a quantitative understanding of the off-nominal system performance. Control mechanizations were developed for each plant that permit optimum full-power operation and economical part-power throttling of the plant. After being validated by small-scale test data and being updated to reflect new design information, the simulation models will be used to predict the performance of larger plants.