Reversible Climatisation of Greenhouses in France Using Aquifer Thermal Energy Storage: Pre-Feasibility Study

In the actual context of predicted shortage of fossil energies and of awareness of environmental preoccupations (greenhouse gases for example), saving energy and converting to renewable ones have become priorities. As energy-intensive consumers, greenhouses are directly implicated. That's why it's important to develop the concept of "sustainable greenhouses" in France, using renewable energy. In this case, the method which retains the attention is the concept of reversible climatisation through Aquifer Thermal Energy Storage (ATES). This technique is already in application in other European countries, especially in the Netherlands, but has never been tested in France. The objective of the research project led by the Ctifl and the BRGM (French Geological Survey) is to determine which parameters are necessary to evaluate the pre-feasibility of this technique on an agricultural site. First, a thermal dimensioning of a typical greenhouse was carried out for two climatic contexts in France (North-West, and South-East). It allows the power which is necessary to maintain temperature setpoints in summer and in winter to be determined. These elements also allow the determination of the temperatures and of the volumes of water that have to be alternatively pumped and injected into the aquifer (in the cold and the hot wells). The second part of the project consists in studying the aquifer thermal energy storage through sets of numerical simulations. The model used is a finite differences model developed by BRGM, which can treat both water flow and heat transfers. A sensibility analysis is carried out on several sets of parameters, which depend either on exploitation conditions (pumping and injection discharge, distance between wells, etc.), or on aquifer conditions (geometry, thermal and hydraulic characteristics, etc.).