Preliminary experimental and CFD results on airflow and microclimate patterns in a closed greenhouse.

摘要

This study presents the preliminary results about the analyse of airflow circulation and microclimate distribution in an experimental energy saving greenhouses with a tomato crop in South France. The studied energy saving greenhouse is based on the closed greenhouse concept, with inter seasonal storage. The distributed micro-climate investigations inside the greenhouse relies on experimental measurements and numerical simulations to solve the mass, momentum and energy conservation equations of the heat and mass transfers. In this study we present the preliminary results of this investigation. Its novelty rests on the newness of the studied energy saving greenhouse together with the realism of the 3D modelling with (i) a coupling of convective and radiative exchanges using Discrete Ordinate (DO) modelling, and (ii) the simulation, in each mesh of the crop canopy, of the sensible and latent heat exchanges between greenhouse air and a tomato crop. The distributed climate within the greenhouse revealed by the experimental and numerical approaches are presented. It is characterized by an important vertical stratification with very high air temperature above crop cover and high air humidity within crop cover. The dynamics of the sources and sinks of heat and water vapour shows that 2/3 of the captured radiative energy is transferred to latent heat and increases air humidity whereas only the remaining part contributes to greenhouse air warm up and heat accumulation just below the roof.