A THEORETICAL APPROACH FOR A SENSITIVE ANALYSIS OF THE INFLUENCES OF EXTERNAL FACTORS ON GREENHOUSE MICROCLIMATE
The control and management of microclimate inside greenhouses is currently possible thanks to the growing availability of affordable electronic sensors and control units. Moreover, manufacturers need to carefully evaluate not only the different aspects involved in the design of greenhouses, such as materials, but also the geo¬graphical area where the greenhouse will be placed. In particular, greenhouse manufacturers need to fully consider all environmental control components in order to fit their design into different climatic areas. This effort is nowadays important in order to avoid unnecessary active microclimate adjustments for heating or cooling with the relevant costs for energy supply. In order to take these aspects into account, several tools were developed and used by the designers, one of these being the Compu¬tational Fluid Dynamics (CFD). We carried out a CFD simulation to asses inner temperature and air velocity values of a greenhouse with different boundary conditions. Two window-opening configurations were considered (0-30° and 10-20° expressed as window degree of opening) taking into account the combined effect of the leeward and windward openings. The longitudinal axis of the greenhouses was normal to the imposed wind direction, thus exposing the roof opening combination set-ups differently. The external situation used for the simulation was representative of winter conditions in northern Italy. Two wind speeds (2 and 4 m s-1) and two outdoor temperatures (-2 and 7°C) were used considering an indoor set point temperature of 16°C. The aim of this work was to provide a statistical analysis for each cell in order to evaluate which external factor, among temperature, humidity, wind speed and window opening, had the greatest impact on greenhouse internal climate conditions.
Romano, E., Nucci , F. and Bisaglia, C. (2011). A THEORETICAL APPROACH FOR A SENSITIVE ANALYSIS OF THE INFLUENCES OF EXTERNAL FACTORS ON GREENHOUSE MICROCLIMATE. Acta Hortic. 919, 81-88
greenhouses, vent openings, natural ventilation, computational fluid dynamics