"SUSTAINABLE ENERGY GREENHOUSE" RESULTS OF THE PROJECT: REDUCTION OF ENERGY CONSUMPTION AND ENERGY STORAGE IN AQUIFER

In the current context of predicted shortage of fossil energies, fuel prices are rising drastically. Energy costs, after labour, are the second largest item in the budget (from 25 to 40% of total costs) for French heated greenhouse growers. Their economic viability is threatened. Moreover, the increasing awareness of environmental concerns (e.g., greenhouse gas emissions) has to be taken into account.
The greenhouse is a solar energy captor which is however not fully exploited as part of the captured energy is expelled outside by ventilation. Besides, the greenhouse has a very low thermal inertia, which gives rise to important thermal losses.
The “Sustainable Energy Greenhouse” project which lasted for 5 years aimed to:

• reduce thermal losses: a double plastic cover F-Clean® was tested, double thermal screens on the roof and thermal screens on the walls were installed,
• improve the humidity control with industrial dehumidifiers,
• develop a greenhouse equipped to store and use the excess energy through reversible air conditioning devices (Aquifer Thermal Energy Storage – ATES), the semi-closed greenhouse.

According to the tested solutions, energy savings of 12 to 43% were achieved. In the semi-closed greenhouse an extra yield of 20% and a reduction of greenhouse gas emissions of 70% were observed.