A hybrid predictive sequencing control for multi-chiller plant with considerations of indoor environment control, energy conservation and economical operation cost

Abstract

Reliable automatic control of heating, ventilating and air-conditioning (HVAC) systems is essential to address buildings energy efficiency and response to the worldwide challenges of human health, energy conversation and carbon emissions. Among the various controls of HVAC systems, chiller sequencing control is of great importance for multi-chiller plant to keep cooling reliability, system stability and energy efficiency. However, conventional chiller sequencing control usually lacks consideration of system stability and the accessional cost caused by the sequencing actions. Especially, those short-time or unnecessary sequencing actions become the main reason for operators to shut down automatic control. To enhance the reliability of chiller sequencing control, a hybrid predictive control is developed. This control is developed based on a typical sequencing control strategy and use an autoregressive with exogenous (ARX) prediction model to double check the necessity of sequencing commands so as to reduce the unexpected sequencing actions. Case studies were carried out on a secondary school in subtropical city. Results showed that the switch number and economical operation cost can be reduced more than 20% and 6.72%, respectively. Additionally, energy consumption was also reduced while keeping acceptable indoor environment, which is of great importance for carbon emissions’ reduction and sustainable city development.