Background: The development of high performance photovoltaic parts has been heavily stimulated by space research programs. Using available solar light as source for electricity production is a challenge and a necessity for the future. The trends of development for solar cells follow the need of being efficient, small and light-weighted, however with a high price. Such technologies are today highly developed and in practical use. However, since in solar farms big collector surfaces are needed, which are as such very expensive and need mechanical rigid structures to cope with wind and sand storms, especially in desert areas, the costs become very high. Here however the requirement for small, light and high efficiency cells is no more valid. Often the space for large installations is available. The limiting factor is the price if solar light energy is considered as energy source in agricultural applications. In hot areas, mainly cooling and water pumping become an important economical factor. Recently it has been reported that soft and bendable photovoltaic surfaces can be built. This is an important step to wider applications of photocells mounted to any kind of flat surface. Considering nature, that’s what evolution reached by the development of chlorophyll containing soft photocells, called leaves and needles. Still, usually heavy and rigid, structures like wooden trunks and branches are needed to carry the mobile, soft, and exchangeable solar collectors: the leaves of a tree. The light absorbing organelles in the cells, called chloroplasts, capture the light, create a photocurrent by extracting electrons from water and use the solar light to lift the water electrons on a higher energy level, to be stored in organic compounds built mainly by the elements C and O originating from CO2 and H from H2O. The need for bendable and flexible photovoltaic strings and fibers becomes evident: The priorities for photocells on earth however are different than for the highly efficient small photocells in space missions. A huge amount of agricultural products are produced in warm and hot countries under nets with drip irrigations. Huge greenhouses built by wind permeable nets are used worldwide for the cultivation of legumes and fruits. Often windmills supply the energy for water pumping. The function of the nets is multiple: 1)The nets bring mechanical protection from wind and sand, keeping the above ground products clean. 2)The nets create a shading effect and reduce the water loss by evaporation in a big extent. 3)The nets reduce the excessive solar light intensity, which would reduce the crop yield by photoinhibitory events. The absorbed light energy however is warming up the nets and has to be displaced by ventilation. Conclusions: Introducing bendable photovoltaic strings and fibers into the existing netting material would create solar panel systems of huge surfaces without the need of independent structures. The locally available solar energy will b
Tematska oblast:
SIMPOZIJUM B: Biomaterijali i nanomedicina
Datum:
15.06.2012.
Br. otvaranja:
342
Contemporary Materials - 2012 - Savremeni materijali
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