Annual thermal evaluation of a ventilated roof under warm weather conditions of Mexico

An annual thermal evaluation of a ventilated roof (VR) for energy-saving purposes in two Mexican cities with warm weather is presented. It was developed a numerical code based on the global energy balance method to predict the thermal behavior of the VR. The code was verified, and it showed a good agreement with data reported in the literature. Weather data of the coldest and warmest days of each month for the two cities were provided to the numerical code as boundary conditions to perform the simulations. Thus, to quantify the benefits of using the VR, it was compared with a conventional roof (CR). The results showed that the implementation of VR significantly reduces the annual total heat gain by up to 50 and 60% for the climates BWh and Aw, respectively. In addition, it was found that for both climates the payback period of VR is smaller than a year and a half. In this way, VR is a passive technology with high potential to reduce the energy consumption for thermal comfort in buildings at a relatively low cost.