A greenhouse’s light transmission can be increased by 10% through a combination of measures, as shown by a pilot study by Wageningen UR Horticulture.
The effect has been calculated by optimizing several measures such as the roof pitch, ridge orientation, greenhouse roof symmetry, reflection of the structural components and the effect of condensation on the light transmission of the greenhouse. With these measures, the effects of standard glass on the transmission are higher than with diffuse glass. The measurements of the effect of condensation show a wide variation, but it appears that on average condensation can cost 2% of light (standard glass), but can also yield 6% of light. Economic feasibility and possible restrictions in constructions were not included in the calculations.
Under Dutch conditions light is the limiting factor for the growth of the crop in winter. The design of the Venlo glasshouse has not changed significantly for many years. However, the development of diffuse glass and the use of anti-reflective coatings are of recent date. The results of the pilot study are such that a consortium is revising the design of the Venlo greenhouse roof because a considerable optimization is possible. The consortium consists of Bom kassenbouw and Glascom Tuinbouw, in collaboration with DA glass, Ludvig Svensson and Bayer CropScience with Wageningen UR Horticulture. The final design, implementation and demonstration of the so-called WinterlichtKas [Winter light greenhouse] will come into being in 2016.
Source: Kas als Energiebron [Greenhouse as Energy source]