ISHS Acta Horticulturae 614: VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation
CHARACTERIZATION OF THE SOLAR DIFFUSE COMPONENT UNDER "PARRAL" PLASTIC GREENHOUSES |
| Authors: | A. Baille, M.M. González-Real, J.C. López, J. Cabrera, J. Pérez-Parra |
| Keywords: | Greenhouse, cover material, solar radiation, diffuse radiation, transmission |
| Abstract:
The diffuse and direct components of solar global radiation were measured during autumn months under a “parral” type greenhouse, commonly used in South East of Spain. For the covering material tested during this period (co-extruded three-layers film), the ratio of diffuse to global radiation (D/G) was significantly enhanced under the greenhouse. On sunny days, the inside diffuse radiation (Di) can reach values as high as three o four times the outside diffuse radiation (D0). The transmission of direct radiation (direct to direct) reached 0.21 on a daily average basis while the direct to diffuse transmission (  ) was about double.
It was found a significant correlation between the ratio Di/D0 and the outside diffuse to global ratio, allowing to predict the greenhouse diffuse radiation from the knowledge of the outside solar radiation components.
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