Simulation-based Hybrid Ventilation System Design and Evaluation

Design and operation of an extended hybrid ventilation system are fully investigated in this study through an example building. Tools of genetic algorithm optimization, computer fluid dynamics and energy simulation are employed to assist the process. The objective is to maximize natural ventilation while maintain good indoor thermal and air quality. The dynamic operation of vents is based on wind directions, wind speed and outside dry bulb temperature. The overall results show that the hybrid ventilation strategy saves significant amount of energy comparing with traditional HVAC systems. Furthermore, the average natural ventilation time during occupied period from June to August is 69% of the total occupied hours. It was found, beside the good energy performance of the hybrid system, the thermal comfort can be ensured for more than 90% of the occupied time.