The effect of ventilator configurations in naturally ventilated greenhouse applications

In this paper the climate inside a greenhouse subject to various vent configurations is investigated. The greenhouse considered is a four span glass greenhouse, containing a plastic partition separating the greenhouse into two compartments. The temperature and velocity distribution at plant level is numerically analyzed with computational fluid dynamics. Six cases were considered. The first three cases have the roof vents open to the leeward side, while the side ventilators are opened at 30° and 45° respectively, after which a second row of side ventilators opened at 45° were added to the geometry. The last three cases have the roof vents open towards the windward side, with the same side ventilator configuration as mentioned for the first three simulations. Contour plots for both temperature and velocity are discussed and analyzed. Results seem to indicate that the temperature and velocity at plant level are significantly influenced by the arrangement and number of vents. The presence of a plastic partition also has an effect on the climate. The temperature in the east span of the greenhouse is slightly higher for the leeward ventilators compared to the windward roof ventilators, and the temperature distribution is also less homogeneous if the roof ventilators are opened leeward. The velocity distribution in the west span for leeward roof ventilators are higher compared to windward ventilators, and also less homogeneous. Comparing the velocity distribution in the east span for both leeward and windward roof ventilators, the results show an increase in air movement for the east span of the greenhouse. It is also shown that CFD can be a useful tool in development and design of greenhouses