Technokas has developed The Daylight Greenhouse, a canopy that collects the direct sunlight and converts it to energy to make greenhouses more efficient.
The technology also eliminates the need for an additional shading system.
A unique roof construction consisting of well-insulated, double-glazed panels with embedded Fresnel lenses is the centre of the new generation of greenhouses.
The lenses focus the sunlight onto a collector mounted on a 2-axis sun tracker, which in turn converts the light energy to thermal energy.
Gerard-Jan Vlekke
Van Tilborgh, one of the three Managing Directors of Technokas, said: “The concept wouldn’t work without the interaction between the various components. The harvested energy in terms of hot water is then stored and used for heating during night hours or winter months.”
In addition to the development of a movable solar collector that tracks the movement of the sun, another technical challenge was the design of the lenses.
“The lens material had to be able to collect and focus the direct sunlight, without absorbing diffuse sunlight which is required by the plants," added Van Tilborgh.
“We decided on PLEXIGLAS because it transmits light extremely well and offers long-term stability—especially compared to other plastics."
Peter Battenhausen, Senior Business Manager at Evonik, explained: “That means it will retain its high light transmittance for decades. Plus, PLEXIGLAS is capable of reproducing surfaces with tremendous precision, and without that we wouldn’t even have been able to produce the highly precise, 1,25 mm prism structures.”