Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.
Greenhouses are used worldwide to effectively produce crops
and flowers out of season by protecting them from adverse
environmental factors [2]. High inputs (water, nutrients, plant
protection chemicals, handling material and fossil energy) are
required for this method of production, which may
unfortunately lead to environmental problems [3]. Due to an
increased interest in reducing energy consumption, natural
ventilation has become a popular alternative method to control
the indoor climate of greenhouses. Effective control of the
indoor climate of greenhouses is of vital importance, as this
directly influences the quality and quantity of the crop
production. The purpose of this paper is to investigate the effect
of bench arrangements on the internal environment in naturally
ventilated Venlo-type greenhouses. The study will be
conducted numerically, using computational fluid dynamics
(CFD). Two-dimensional models will be created and a mesh
sensitivity study will be conducted to determine a suitable mesh
size. The effect of various bench arrangements used commonly
in industry on the temperature and velocity distributions inside
the greenhouses will be assessed. The case of a heated floor
will be examined, with single, double and triple solid bench
arrangements. A three-dimensional double span greenhouse
will also be created containing four longitudinally arranged
benches, and compared to a corresponding two-dimensional
model. It was found that overall the wind direction and bench
arrangements do have a significant effect on the microclimate
at plant level, creating large velocity and temperature
differences between the various bench arrangements.
