Optimization and operation control for the combined impinging jet ventilation and chilled ceiling system with different cooling loads

Abstract

The matching relationship of operating parameters between the air supply and radiant systems has significant impact on the indoor thermal comfort and energy efficiency for combined air-conditioning system. The impinging jet ventilation (IJV) and chilled ceiling (CC) combined system (IJV/CC) overcomes the drawback of IJV which cannot be used in spaces with high cooling load. However, the matching relationship between the operating parameters of the IJV and CC are not clear due to limited research on IJV/CC at present. To ensure good thermal comfort and indoor air quality of the IJV/CC in an energy efficient way, this study mainly focuses on exploring the optimal combination of the operating parameters between the IJV and CC (including the supply temperature and supply velocity of IJV and internal surface temperature of CC (Tc)). First, the indoor thermal environment for IJV/CC operating with different combinations of design parameters is simulated by CFD. Second, response surface methodology (RSM) is utilized to establish predictive models for various ventilation performance indicators by collecting the simulation results. Then, the optimal combinations of operating parameters between the IJV and CC are determined by using the technique of order preference by similarity to ideal solution (TOPSIS) coupled with the developed RSM models. Finally, control strategies for the IJV and CC are discussed and it suggests setting the value of Tc in the range of 20–21 °C and a variable air volume system is preferred for the control of the air supply system to achieve efficient operation of IJV/CC.