Building-integrated photovoltaics

Building-integrated photovoltaics ( BIPV ), often called BiPV (of English Building -integrated Photovoltaic ), stands for the integration of photovoltaic modules into the building envelope, where not only the classical energy ( conversion of sunlight into electrical energy) but also additional functions are desired. The section "Photovoltaics in Buildings" under the umbrella of the Federation of Building Systems eV BiPV describes as an architectural, building physics and constructive involvement of PV elements in the building envelope, taking into account the multifunctional properties of the PV module. Multifunctionality can thereby be weather protection, insulation, shading, aesthetics and design as well as privacy protection, sound insulation, electromagnetic shielding effectiveness, burglary protection, light control and management.

Area of ​​application

BiPV is used in the roof, on the façade, window and shading solutions. This project-oriented variants are ( appropriate to the building) in size, shape, material, color, variance in transparency and design desired, in order to achieve the most homogeneous overall appearance.

Modules used

In order to take into account the architectural requirements and the desired multi-functionality, adaptability of the PV modules is desired size, shape or type of materials. Also, the various mechanical and electrical integration requirements must be taken into account.

There are basically two types of technologies that can be used for modules for BIPV:

Crystalline Modules

Crystalline modules are based on a plurality of silicon wafers, usually constituted in serial interconnection. The grid size of the variation in size is determined by the size of the wafer and the flexibility required for the interconnection and isolation. This amounts to 15-25 cm. When cell material, a distinction between monocrystalline and polycrystalline silicon, which differ in their efficiency. This indicates what percentage of the incoming solar energy is converted into electrical energy. (Mono- ) crystalline modules now offer the highest efficiency (15-20% ) with optimum alignment. In BiPV However, such an optimal alignment is usually not given (eg facade with vertical orientation ). Furthermore, crystalline solutions very sensitive to shading and a reduction of power at high temperatures, which are common in building applications. Therefore, it is advisable to use a simulation software for true energy efficiency. Crystalline solutions have a high variability in the selection of the packaging material, which is very positive for BIPV. Various glass thicknesses, plastics can be used, but crystalline cells are very susceptible to breakage and can not be bent. Semi-transparency in simple patterns can also be generated.

Thin-film modules

Thin film modules (usually glass ) is applied to a substrate. In the glass substrate variant size variance is very restricted. The choice of material in this variant of the substrate is very limited, since very high temperatures are used during the process of the PV cell structure that make certain variations in the glass (eg, glass ) is not possible.

Other thin-film solutions are applied eg on plastic or sheet metal ( steel, copper). These solutions currently offer the highest degree of variation in size and packaging, and allow also flexible and very lightweight solutions (plastic / plastic) offer. Thin-film solutions currently have efficiencies of 6-14 % depending on the technology used to have a better yield at suboptimal alignment (scattered light, low light ) and are less temperature dependent in their performance.

Special Promotions

Various policy measures to promote the use of BIPV: Powered by the 20 -20-20 - goals and the desire to promote energy self-sufficient building, are in some countries (eg Italy, France) in addition to the feed-in tariffs (see Germany EEG ) increased tariffs for BIPV offered.

Building regulations

A strong driver for the use of BIPV are the successive tightening of policies regarding the energy performance of buildings (zero -energy house, CO2 footprint ). In Germany, the Energy Saving Ordinance applies here as reference, based on the EU Directive on the energy performance of buildings. Furthermore, there are country-specific sustainability-related building reviews with different levels of quality, also promote the high -energy building quality and low environmental effects. Examples of this are the leadership developed in the U.S. in Energy and Environmental Design (LEED ), BREEAM from the UK or the German Sustainable Building Certificate.