IMPROVEMENT OF TEMPERATURE CONTROL PERFORMANCE FOR ELECTRIC HEATING WATER TANK

Temperature control is an important factor which influences the accuracy of refrigerant heat transfer experimental results. In this paper, the three temperature control methods for the electric heating water tank (EHWT) in the single tube heat transfer experimental rig are investigated. The error of proportional-integral-derivative (PID) controller is +/- 1 degrees C and the stability time is 390 seconds. The control performance is not satisfactory. A fuzzy controller and a fuzzy PID controller are designed to improve temperature control performance. The designed controllers are simulated by MATLAB/SIMULINK and the results prove that the designed controllers is suitable for EHWT. The experimental results show that the performance of the designed controllers are improved concerning. The error of two controllers is +/- 0.1 degree celsius. Compared to the PID controller, the stability time of the fuzzy controller and the fuzzy PID controller are decreased by 14.9% and 43.1% and the overshoot of the two controllers are reduced by 100% and 62.5%, respectively. The results and the control method have great significance for the refrigerant heat transfer experiment.