Abstract
In the developed countries the air-conditioning of buildings involves a great electric energy demand: for example in the United States around one-sixth of all the electricity generated is used by HVAC units. The study of innovative building envelopes can greatly reduce the heating and cooling loads, also increasing the quality of life inside the buildings. The horizontal roof gives a strong contribution to the summer loads of buildings due to the solar radiation. The utilisation of a green roof was considered to reduce the corresponding cooling load, taking into account both the effect of the thermal capacity of a mass of soil and evaporative cooling due to vegetative greenery. This analysis was applied to a factory for the production of solar cells, to be built up in the next months, with a novel design to reduce the HVAC loads. The analysis aims to study the effects of different thicknesses of soil, separating the influence of thermal capacity and evaporation.