Application of Optimal Preview Control to Power Plant Cooling Systems

This paper deals with the application of dynamic control to cooling systems of power plants. The operation of heat dispersal systems with control can result in a saving of power and cooling water. The performance of all cooling systems depends, mainly, upon the ambient conditions and the heat load to be dissipated. Hence, a control scheme that makes use of information obtained by previewing the weather and load conditions, i.e., preview control, is ideally suited for this problem. An iterative procedure is presented for determining the optimal preview control policy for a dynamical system whose dynamics vary depending upon the mode of operation that the controller selects. The algorithm is applied to two types of cooling systems: one consisting of a spray pond and a natural draft wet cooling tower, and the other consisting of a spray pond and a dry cooling tower. The preview control scheme is shown to be a substantial improvement over the uncontrolled case.