PREDICTING GREENHOUSE VENTILATION RATES

An energy balance model was used to predict ventilation rates in a Venlo glasshouse.
In order to validate the model, measurements of the ventilation rate were made at the same time with the dynamic tracer-gas method.
Experiments were carried out for the closed glasshouse and with four different openings of the leeward ventilators (10, 20, 30 and 40% of the maximum opening). The influence of wind speed, wind direction and inside-outside temperature difference was analysed.

The predictions of the model show good agreement with the measured values for ventilator openings larger than 20% of the maximum.
When the ventilators were closed or opened at small angles, the agreement between predicted and measured values was poor, due to the fact that the energy involved in leakage and ventilation in these cases was very small.

International Workshop on Greenhouse Crop Models

J.E. Fernandez, B.J. Bailey

https://doi.org/10.17660/ActaHortic.1993.328.7