A Photovoltaic Greenhouse with Passive Variation in Shading by Fixed Horizontal PV Panels

Simona Moretti and Alvaro Marucci
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Simona Moretti: Department of Agricultural and Forest Sciences, University of Tuscia, Via San Camillo de Lellis, s.n.c., 01100 Viterbo, Italy
Alvaro Marucci: Department of Agricultural and Forest Sciences, University of Tuscia, Via San Camillo de Lellis, s.n.c., 01100 Viterbo, Italy

Energies, 2019, vol. 12, issue 17, 1-18

Abstract: The traditional shading systems that greenhouses use cause some of the solar radiation that is reflected or absorbed to be lost and, therefore, not used by the plants under cultivation. An interesting solution to these problems is to position photovoltaic (PV) panels on the roofs of greenhouses. All of the photovoltaic greenhouses that have been realized in Mediterranean areas are characterized by a fixed position of the PV panels and excessive shading, especially in autumn and winter. The purpose of this study is to describe a prototype of a photovoltaic greenhouse with both fixed and horizontal PV panels that exploit the natural variation in the elevation angle of the sun’s rays during the year to allow for “passive” variation in shading. The considerable variation in the elevation angle of the sun’s rays (from 24.4° to 71.1°) results in a high variation in shading (from 39.4% to 72.6%), with the highest values in the summer months and the lowest values in the winter months. This trend is favorable for meeting the photosynthetically active radiation (PAR) needs of greenhouse plants. If the plants under cultivation require more solar energy, it is necessary to increase the distance between the panels. We implement a specific mathematical relationship to define the precise distance to be assigned to the photovoltaic panels on the roof pitch.

Keywords: passive variation of shading; fixed horizontal PV panels; PAR; renewable source; passive cooling system (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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