Model-based control of natural ventilation in dairy buildings
Without automatic control, the ventilation rate in naturally ventilated dairy buildings is often significantly higher than the required to provide good conditions for the animal in windy conditions, and this over ventilation will result in increased ammonia emission. Therefore, automatic control of the ventilation via adjustment of the ventilation openings in relation to the weather conditions can be used to reduce the ammonia emission. In this context, the model-based control method can be used and a predictive model can estimate the wind driven ventilation rate of a naturally ventilated dairy building as a function of the outdoor wind conditions and sizes of sidewall openings. In the present study, the Response Surface Methodology (RSM) was applied to develop the predictive model. Three dimensional numerical simulations for a real dairy building were conducted to estimate the ventilation rate under different wind and opening conditions. The model was formulated by the results of thirty cases of CFD simulation, which were planned by the experimental design method: optimal design. Results showed that sizes of two sidewall openings significantly influenced the ventilation rate of the building. Based on the developed RSM model, the most desirable level of opening sizes can be determined for control of the ventilation air exchange rate in prevailing wind conditions.
model-based control natural ventilation response surface methodology (rsm) air exchange rate computational fluid dynamics (cfds)