Design of a fuzzy controller for the active chilled beam system

This paper presents a fuzzy controller for the Active Chilled Beam (ACB) system, which is capable of maintaining the predetermined indoor relative humidity and temperature under time-varying thermal loads. Following the divide-and-conquer strategy, the complex nonlinearities are mitigated by a set of linear Takagi-Sugeno's (T-S) fuzzy approximations. Accordingly, the Linear Quadratic Regulator (LQR) is utilized. The thermal loads upon the system and the unknown state are estimated via an observer and then a disturbance rejection component is appended to the LQR. The relative humidity and the temperature are respectively controlled by varying the primary air volume flow rate and the chilled water inlet temperature. Simulations are performed based on a simulated single zone thermal system and an experimentally verified ACB terminal unit. The utility of the proposed control strategy is demonstrated.