Integration of Solar Energy Technologies in Switzerland : From Building to Nanoscale

The Solar Energy and Building Physics Laboratory of the Ecole Polytechnique Fédérale de Lausanne (EPFL) has been involved in research and technological development of solar energy for building applications since the middle of the seventies. Focusing first on the investigation of passive and hybrid solar technologies by the way of a dedicated experimental building [1], the laboratory contributed to generate knowledge in favour of low energy houses, characterised by thermal energy intensities lower than 110 MJ/m2.year (equivalent to 3 litres of fossil fuel/m2.year). These pioneering activities were translated later on for practitioners through novel building codes [2] and energy standards - such as Minergie and Minergie-P [3], which contributed in a very significant way to the stabilisation of the national demand for heating fuel, while mitigating simultaneously the related GHG emissions. Important research and tech transfer efforts were dedicated in the nineties to the integration of other solar technologies to buildings, as illustrated by the exhibition center for photovoltaic building integration on the EPFL campus [4]. Joined to daylighting and passive cooling research and practice, they altogether led to the recent construction in Switzerland of a first EnergyPlus building, showing a positive net energy balance over a yearly period (i.e. generating more heat and electricity than required for its operation) [5].The research emphasis is placed over the last years on the investigation of technologies issued from nano sciences, which can contribute to improve further the integration of solar technologies into buildings. Among the later the elaboration of coloured energy efficient solar collectors is aimed : it could contribute to disseminate decentralised energy production through the country by the way of such efficient solar buildings.