Experimental construction of a cascade control structure for liquid temperature stabilization in a stirred tank

Abstract

In food and beverage production, precise liquid temperature control is crucial for product quality. Similarly, in the nuclear industry, liquid temperature strongly affects efficiency, safety, and lifespan. This paper presents a cascade control method for liquid temperature regulation in a mixing tank, with an inner loop regulating flow rate via pump motor speed and an outer loop controlling temperature. The two-loop structure is compared with a conventional single-loop PI controller on the TecQuipment CE117 experimental module. Experimental results show that the cascade PI improves control quality, reducing settling time by approximately 17–36% under different operating conditions and halving recovery time under pump-stoppage disturbances, compared with the single-loop PI. These results indicate that the proposed cascade architecture is suitable for thermal process applications requiring accurate and robust temperature control.