A study by Wageningen University in the Netherlands showed that glass with an anti-reflective coating can save about 22% of the energy used in greenhouses. The AR coating lets more light through, and a low-emissivity (low-e) coating reduces heat loss. The glass is made by AGCulture, the horticultural glass business of AGC.
Conventional low-e coatings reduce how much light glass transmits and need extra protection to keep from breaking down. That is why, until now, they could only be used on the inner side of double glazing. Combining anti-reflection and low-e in a single coating led to significant energy savings. How ordinary glass, polycarbonate, and film compare on light transmission, heat retention, and condensation is laid out in the wiki on the greenhouse as a system.
The new AR/low-e glass, named Geysir, is the first energy-saving single-pane glass with high light transmission. The university’s calculations show that energy use for growing tomatoes can be cut by about 22% when the glass is combined with other energy-saving measures such as one or two energy screens. Because the glass insulates, the greenhouse warms up a bit faster, and the tomatoes flower earlier. The low-e coating also means less condensation, which keeps light transmission high. The flip side of high transmission shows up in July, when there is too much light, and the wiki explains how to pick a shade percentage without cutting yield in its article on shading and reflective surfaces.
Experiments with coatings for glass and solar panels sometimes produce unexpected results. A group of scientists from universities in the US, China and Turkey found that L-glutathione, an antioxidant food supplement, raises the efficiency and light transmission of solar cells. Green crops grown under panels with this organic coating gave higher yields.
