How a New Coating Could Lead to Greenhouse Energy Savings

By Wageningen University and Research|September 29, 2023

A newly developed coating for greenhouse glass can potentially save energy up to 20%. The coating (low ε) is “baked” on the outside of the glass and prevents heat from leaving the greenhouse, which saves energy, especially in winter. This technology is being tested by the Greenhouse Horticulture and Flower Bulbs Business Unit of Wageningen University & Research (WUR) into the cultivation of tomatoes. This year, WUR is investigating the effect of the coating on eggplant cultivation.

Model calculations showed that the Low_ε coating could save 20% energy. WUR conducted a practical test to determine whether that percentage is feasible. To this end, tomatoes were grown at the research location in Bleiswijk in 2022 in two compartments: one with low-ε coated glass, and one with traditional glass.

The research showed that considerable energy savings are indeed feasible in the cultivation of tomatoes, while production is comparable to cultivation under traditional glass. The energy savings are mainly realized in winter. The greenhouse heats up faster and cools down slower. This results in more ventilation and a greater loss of CO₂ in summer. In the long warm period last year, no difference was demonstrated compared to traditional glass: due to outside weather, researchers ventilated almost the same amount in both departments.

The exact savings depend, among other things, on the cultivation strategy of the company in question, gas prices, and other available technical installations. The coating can provide additional added value if it is combined with, for example, active dehumidification and green energy sources.

In 2023, WUR is investigating the effect of the low_ε coated glass on crops with a higher heat demand. Eggplant is currently being grown in two compartments for this purpose. The provisional conclusion is that the energy savings are greater than 20%.