Numerical Study of Optimal Building Scales With Low Cooling Load in Both Hot and Mild Climatic Regions

Abstract

Natural ventilation is one of the primary strategies for buildings in hot and mild climatic regions to reduce building cooling energy requirement. This paper uses a building energy simulation program and a computational fluid dynamics program to investigate the influence of building scales on building cooling energy consumption with and without natural ventilation. The study examines the energy performance of buildings with different L/W and H/W ratios in both Miami, FL and Los Angeles, CA. The simulation results show the varying trends of natural ventilation potential with increased building scale ratio of L/W and H/W. The comparison of the predicted energy consumptions for twenty buildings discloses the most energy-efficient building scales for rectangular-shape buildings in both hot and mild climates with and without natural ventilation. The study indicates that natural ventilation is more effective in mild climates than in hot climates, which may save cooling energy by 50% and vent fan energy by 70%. The paper analyzes the most suitable seasons for natural ventilation in Miami and Los Angeles. Further simulations indicate that extra cooling benefits associated with more natural ventilation cannot compensate additional heat gains through larger windows.