Development of a new vertical angle selective façade for solar control

Many recent researches attests that the 40% of the European energy consumption it’s due to the building. In particular the 80% of building energy consumption currently occurs during service-life. The energy demand for cooling is raising day by day (especially in Mediterranean climates. But it’s also attested that all the buildings, residential and commercial, have an enormous potential for improvement the energy efficiency (think about the standard passive-house in Germany and Austria) and of energy systems integration, like pv-systems or solar cooling systems, to produce energy from sun. This is particularly true for non-residential sector and high-rise buildings. The penetration in residential buildings (solar domestic hot water and pv-systems), in particular in single family house, it’s much better in Germany and Central Europe, where the incentives from the States cover a good percentage of the installation costs. Other matter is the integration into high or tall buildings where the only place to integrate the systems is the façade. In facade construction, in particular for high-rise buildings, the portion of the glazed area of the façade rises continuously. The architects like very much transparency, the sun and the contact with the city and the context. This causes the positive effect of higher daylighting for the internal space and reduction of energy consumption for artificial lighting. But, on the other hand, it produces the risk of overheating, in particular during summer period and/or high cooling loads For that reason sun protection (with solar control systems) is necessary. It’s also very common in Central or North Europe to control the solar gains with external shading systems (for example venetian blinds). This solution has some advantages for residential house (family houses), because of the low cost for installation, but on the other hand venetian blinds doesn’t produce energy (no electricity production) and are not good for high-rise buildings and other windy locations. The new angle selective façade combines in one element, three important tasks: solar protection, glare protection and integrated pv-system for electricity generation. These three elements as are completely integrated in the function of the façade doesn’t reduce the architectural goal of the glazed façade and the view from the interior to the exterior is guaranteed. The new angle-selective-façade system is a static seasonal sun protection, which can be produced using the usual production technologies of windows and glazing units. The system is currently optimised in the Fraunhofer ISE in collaboration with the corresponding author who is a PHD student at Politechnico di Milano. In the publication we will describe the goals and the concept of the new façade element.