Efficient Variable Air Volume Air Conditioning System Based on Fuzzy Logic Control for Buildings

Abstract

A variable air volume (VAV) system is highly preferred to be an energy efficient airconditioning scheme in modern heating, ventilation and air conditioning (HVAC)applications. Based on the energy consumption characteristics, VAV systems are fastreplacing constant air volume (CAV) systems and are capable of maintaining the thermalcomfort for varying load conditions. Fuzzy logic controllers (FLC) are highly preferred ratherthan conventional controllers since FLC exhibits reduced peak overshoot that is observedunder transient conditions of the system. FLC has the capability of controlling the systemprecisely with the set points defined. This paper describes the thermal comfort and energyconservation potential of the VAV system utilizing a fuzzy logic controller (FLC) thatenhances the system performance substantially. A simple VAV building model wasdeveloped and the energy utilization of the VAV system has been experimentallyinvestigated. Input data for fuzzy logic are zone temperature and duct static pressure and theoutput is supply air fan speed. Experimental results show that the energy saving potential ofthe VAV system was 27% at part load conditions, compared with the CAV system.Experimental results express that the required thermal comfort was achieved using FLC.