Naturally ventilated greenhouse designs for optimum cooling

A naturally ventilated commercial greenhouse was evaluated with a computational fluid dynamic model and tested in full-scale. Structural variables were greenhouse width, roof and side vent locations, vent opening widths, windward side aerodynamic profiles, internal and external shading systems, and benching for various wind speeds and directions. The predicted influence of windward side vent openings in concert with top vents were shown graphically. When the side vent was closed, the predicted air exchange rate was 0.38 A.C./min compared to 0.90 A.C./min when the side vent was open. Internal temperature extremes were 10 degrees and 3 degrees C above outside when the roof vents were open and the side vent was closed and open, respectively. In most cases, the measured inside temperature was within I degrees C of outside when all vents were open.