B.P. Jelle, S. Ng, S.A. Mofid, T. Gao
SINTEF Building and Infrastructure / Norwegian University of Science and Technology (NTNU),
Keywords: building integrated photovoltaics, BIPV, review, research pathway, materials science
Summary:The demand for energy-efficient and energy-harvesting buildings is increasing, hence initiating the exploration of miscellaneous solutions. Building integrated photovoltaics (BIPV) may in this respect represent a powerful and versatile tool for achieving the ever increasing demand for zero energy and zero emission buildings of the near future. The BIPV systems offer an aesthetical, economical and technical solution to integrate solar cells harvesting solar radiation to produce electricity being an integral part of the climate envelopes of buildings. Building integration of photovoltaic (PV) cells are carried out on sloped roofs, flat roofs, facades and solar shading systems. PV cells may be mounted above or onto the existing or traditional roofing or wall systems. However, BIPV systems replace the outer building envelope skin, thus serving simultanously as both a climate screen and a power source generating electricity. Thus, BIPV may provide savings in materials and labour, in addition to reducing the electricity costs. Nevertheless, in addition to specific requirements put on the solar cell technology, as the BIPV systems act as the climate protection screen it is of major importance to have satisfactory requirements on rain tightness and durability, where various building physical issues like e.g. heat and moisture transport in the building envelope also have to be considered and accounted for. Research within materials science in general and within PV technology in particular may enable and accelerate the development of highly innovative and efficient BIPV materials and systems. Sandwich, wavelength-tuned, dye sensitized, material-embedded concentrator, flexible (e.g. copper indium gallium selenide CIGS and cadmium telluride CdTe), crystalline silicon on glass (CSG), thin amorphous silicon, quantum dot, nanowire, brush-paint and spray-paint solar cells and various combinations of these are examples of possible research pathways for PV and BIPV. Furthermore, in addition to the ones already mentioned, miscellaneous other surface technologies may also be very interesting and promising for utilization on solar cells, e.g. light-trapping geometries, anti-reflection, self-cleaning, superhydrophobic and icephobic surfaces. The robustness, long-time durability and life cycle assessment (LCA) of these will also be crucial tasks to address. From a materials science perspective, this work presents a review and bridges the path from the current state-of-the-art BIPV to possible research pathways and opportunities for the future BIPV.