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.