A novel control logic for fan coil unit considering both room temperature and humidity control

Abstract

This paper proposes a novel fan coil unit (FCU) control logic, which controls fan speed level and water valve duty ratio to make both temperature and humidity match the set-points. The performance of the proposed control logic is compared with two other control logics using simulation. One of them is to open/close water valve to make room air temperature match the set-point, which is the usually used control logic. Another control logic is to open/close water valve according to a duty ratio decided by a fuzzy logic. The simulation results show that the proposed control logic can achieve control performance: the temperature is tset ± 0.5°C and humidity is dset ± 3% when duty ratio period is 300 s, and the temperature is tset ± 1°C and humidity is dset ± 7% when duty ratio period is 600 s. The control performance of proposed control logic is better than the valve on/off control logic and the fuzzy control logic.