S06 - Session P1 - Numerical study of a Venlo greenhouse: one-year results analysis based on energy and crop yield indicators

Authors: Samuel Sourisseau *, Cyril Toublanc, Etienne Chantoiseau, Michel Havet

During the last decades, intensive research has been led to improve greenhouses performances from crop production to energy consumption points of view. In particular, soil-less cultivation in heated glass greenhouses has been commonly adopted in Northern Europe since it allows high crop yields with limited water and chemicals inputs. However, heating during the cold season involves an important fossil energy consumption that can hardly be reconciled with current climate challenges. The SERRES+ project has thus been initiated with the objective of developing a new and fossil-energy-free greenhouse system adapted to Northwestern France conditions. Greenhouses being characterized by highly coupled phenomena, equipment and cultivation practices shall be evaluated as a whole, in conjunction with the crop itself: for this reason, a system approach will be applied to analyse combinations of solutions based on energy and water saving as well as on crop growth performance criteria. As a first step, this work presents the modelling of an entire tomato production in an experimental 1000 m2 greenhouse located near Nantes (France) using the Greenhouses Modelica library from the Liege University (Belgium). Besides re-using existing components, it has been possible to take advantage of its open-source philosophy to modify and implement new models corresponding to this case study (outdoor climate, greenhouse characteristics, equipment as well as farming and harvesting practices) that will be described, in conjunction with parameters estimates. Comparisons between simulations and on-site measurements (indoor climate, crop growth indicators) will be presented and analysed over the simulated year. In addition to being a prerequisite for the next steps of the SERRES+ project involving an increasing model complexity through the inclusion of various energy and indoor conditions control systems, this approach can also be extended to other climates and greenhouse types thanks to its inherent modularity.