TEMPERATURE CONTROL OF A HEAT-EXCHANGER F OR THE PHOTOSENSITIVE MATERIALS COATING AND DRYING PROCESS

A feedforward/feedback control system was developed to maintain the te mperature profile of air in an air conditioning system for photosensit ive material coating and drying. The feedforward control was attained based on a heat exchanger dynamic model using the flow rate of hot wat er as the manipulated variable and the air temperature as the controll ed variable, while feedback control was performed by means of optimum control theory based on a linearized heat exchanger dynamic model. To evaluate the performance of the control system developed in this study , simulation and experimental studies were carried out where a stepwis e change of set values is performed in order to maintain uniform produ ction quality for each product grade. It is shown that the control sys tem under consideration successfully controls air temperature in an ai r conditioning system for photosensitive material coating and drying.