Integration of Photovoltaics for Next Generations of Offices Building - Challenges for Efficient, Economical, Sustainable and Architectural Solutions
Creators: name: Cassagne, V.
name: Durand, G.
name: Mas, V.
name: Lebourgeois, J.
name: Karsenty, J.-P.
name: Le Bars, M.-A.
Publisher: name: WIP
Year: 2011
Subjects: PV Systems
PV and Architecture

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 4073-4078
description: Buildings are one of the main sources of energy consumptions and the design of offices buildings is
particularly targeting a strong reduction of this energy consumptions. The new generation of zero net energy building
are supposed to lower the energy need and then to generate locally energy from renewable sources in order to reach a
positive balance. This is the aim of the consortium “Positive Energy Stake” animated by several international
companies around building promotion, energy management and offices operation. The usage of photovoltaics as the
main source of energy is a natural trend as it allows compensating directly electrical needs and using the available
surfaces of the building.
In this study, we worked on two typical cases of offices building: an urban, large building and a set of smaller
buildings “technopark” like. First, we evaluate the consumption levels and the possible PV systems integration
according the sizing and the location the building (Western Europe) using a pre-sizing model which calculates
surfaces, roughly gives PV energy production and systems end electricity costs. From this, we determine that the
energy balance for small building is easily achievable by the roof usage and solutions can be chosen from economical
or architectural point of view, while for buildings higher than 4 floors, the PV on roof is not enough in standard
conditions.
For these large urban building, a deep economic-technical analysis is done to achieve energy equilibrium. The first
item is the optimization of “on roof” PV system evaluating surface usage optimization and modules technologies.
Then the facades surfaces are taken into account for energy generation, electrical yield are calculated for the different
applications (cladding, spandrels and sun shades). The major productivity enemy after vertical orientation is shading.
The self-shading and surrounding building shadows were studied for specific and generic cases which allowed
providing dimensions rules of the faced orientations and the geometrical usage rate of these facades.
A specific focus has been done on sun shades, identified as commonly efficient solution until engineering integration
is deeply studied. Above electricity generation, sun shade has other energetic impacts on the building as it positively
and negatively influences the heating, the cooling and the office lighting by filtering the sun rays source. A
geometrical optimization has been conducted to find the best compromise between energy consumption and the PV
electricity production, and finally improving the net energy balance of the whole building over the full year. In
conclusion, the integration of PV system in positive energy building must be included at early beginning of the
building project in order to optimize energy efficiency, aesthetics and costs.