Natural Ventilation of a Solar House in Hot and Humid Climate: A Study Using Building Energy Simulation Method

The solar powered house at the Engineering Center of Florida International University is out of the U.S. Solar Decathlon 2005 competition. A computational simulation using EnergyPlus is conducted to study different ventilation strategies in this solar house model, with consideration of the hot and humid climate in Miami, Florida. Several modes of ventilation including mechanical cooling systems, natural ventilation utilization, and hybrid systems were considered to seek the best possible option for ventilation in such extreme climate. While the need for a mechanical ventilation system is always present, a resort to natural ventilation could significantly reduce energy consumption. As for natural ventilation utilization, a few methods including earth tubes (ET), thermal chimneys (TC), cooling towers (CT), and openings have been simulated and compared with the mechanical cooling system of the original house. However, as the simulation results suggested, relying on only natural ventilation could cause a dramatic impact to the human thermal comfort. Therefore, a coupling strategy between mechanical systems and natural ventilation was extensively investigated in hope for a better solution in terms of both energy consumption and thermal comfort. In fact, the hybrid system has proved to tremendously reduce energy consumption while complying with the minimum requirements for thermal comfort recommended by ASHRAE standards.