Conventionally, excessive indoor CO2 condition is related to abnormal occupancy condition and can be solved by increasing overall outdoor air rate through air handling unit (AHU). More energy is consumed to condition and deliver the outdoor air by AHU and deliver outdoor air and fans. To be energy-efficient, this study proposes a multi-room outdoor air coordination strategy in response to abnormal occupancy condition by utilizing wireless sensor network (WSN) technology without increasing overall outdoor air rate through AHU. For critical rooms, a simplified occupancy estimation method is applied, and one-step model-based predictive control for dampers is developed. For non-critical rooms, an optimization problem is formed to reallocate the rest part of overall outdoor air rate. The proposed strategy is applied in a real case in Hong Kong. The reduced highest CO2 and exposure time to undesirable CO2 in critical and non-critical rooms prove the ability of proposed strategy in response to abnormal occupancy condition. And compared with extra energy consumption for AHU and fans in conventional strategy, smaller energy for adjusting dampers proves the energy efficiency of proposed strategy.
Keywords Energy efficiency, excessive CO2, multi-zone ventilation, WSN technology, model-based prediction, genetic algorithm (GA)