Influence of geometry on shading effect inside photovoltaic greenhouses
During the last years, European government remuneration polices promoted the realization of photovoltaic (PV) systems integrated with the structures instead of on ground PV plants. In this context, in rural areas, greenhouses covered with PV modules have been developed. In order to interdict the building of greenhouses with an amount of opaque panels on covering not coherent with the plant production, local laws assigned a threshold value usually between 25 and 50% of the projection on the soil of the roof. These ranges seem not to be based on scientific evaluation about the agricultural performances required to the building but only on empirical assessments. The purpose of this paper is to contribute to better understand the effect the shape of the greenhouse having the same configurations of PV panels on the covering. For this aim, daylighting analysis were performed by means of the software Autodesk® Ecotect® Analysis on greenhouse models with different geometry and the same covering ratio (CR) of polycrystalline photovoltaic panels on the roof. Analysis were performed on a multispan duo-pitched roof and a Venlo, N-S oriented, both with an area of 30.0×32.0 m2 having the same height at the ridge, 5.0 m. For the calculations, different sites were simulated: Hannover in Germany and Rome in Italy. The daily total sunlight duration inside both photovoltaic greenhouses on a horizontal plane 1.50 m from the ground, in Hannover and in Rome, was calculated. Results allowed to better understand the performance in terms of radiation passing through the covering system.
Castellano, S. 2017. Influence of geometry on shading effect inside photovoltaic greenhouses. Acta Hort. (ISHS) 1170:813-820
renewable sources, sun-light hours