Effects of solar shading devices on energy requirements of standalone office buildings for Italian climates

In Europe, the building energy demand is about 40% of the total energy requirement. In order to obtain significant energy saving in this sector, the European Energy Performance Building Directive (EPBD) 2002/91/CE and the EPBD Recast (Directive 2010/31/UE) promote the use of passive strategies for buildings, which improve indoor thermal conditions above all in summer and so allow the reduction of size and energy requirements of air conditioning systems. This paper analyzes the influence of external solar shading devices on the energy requirements of a typical air-conditioned office building for Italian climates. A type of office building widespread in Europe has been considered. The energy saving related to the solar shading refers only to summer air conditioning, but the evaluation has been carried out for the entire year, by using a building energy simulation code. The energy demand of the main technical systems (heating, cooling and lighting) and the energy saving related to the use of solar shading devices have been evaluated, as a function of the most significant parameters, such as the climate, the geometrical characteristics of the shadings and the building, the thermal transmittance of the building envelope and the building orientation. The solar shading devices have shown the highest energy efficiency for warm summer climates: for example, the global annual energy saving related to the use of suitable shading devices has been evaluated between 8% for Milan (the coldest climate) and 20% (for Palermo, the warmest one).