Thanks for continuing reading Geothermal Power Plants Modeling 201: fast rating and optimization. In 101, a very rigorous approach is introduced to give users great confidence to guarantee output with real geometries of heat exchangers and so on. However, the disadvantage is the slow calculation speed. With slow calculation speed, it is almost impossible to optimize the whole plants. In this blog 201, a simplified yet accurate approach is used to optimize the whole power plants by finding the optimum process parameters.
As usual, we have the vaporizer, expander, air cooled condenser and the feed pump. What's special about this simulation is the two user unit operations written by me. One is the expander nozzle and the other one is the ACC fans. For a standard product, the expander nozzle area is a variable to optimize, subject to the maximum area constraint. For air cooled condensers, eight bays are selected and the condensing temperature is to be optimized. In addition, the feed pump discharge pressure is another key process parameter to optimize.
Since we've fixed vaporizer UA and selected 8 bays for air cooled condenser, so the capital cost remains fairly constant in this optimization process.
In summary, the optimize variables are expander nozzle area, condensing temperature and the feed pump discharge pressure, subject to the constraint as you can see on the screen. The goal is to maximum the net output. Currently the plant is producing net 6200 kW.
Let us run the optimization.
Now we are making 6408 kW without spending additional capital cost, by simply finding the optimum process variables.
From a common sense point of view, people in general believe to make the most power, the ACC fans should be running at 100% speed. As you see, the optimum speed for this situation is actually 88%.
Series 201 shows how a fast rating and optimization of geothermal power plants can be done. Thanks for watching this Geothermal Power Plants modeling series. This video is brought to you by Guofu Chen.
