DETERMINATION OF MINIMUM VENTILATION RATE IN PIG HOUSES WITH NATURAL VENTILATION BASED ON CARBON-DIOXIDE BALANCE

The measurement of ventilation rate is necessary for good climatic con trol in pig houses with natural ventilation and heating. A model based on a carbon dioxide balance is developed for pig houses. Included are diurnal variation patterns in carbon dioxide production. The model ca n estimate the ventilation rate in a pig house when carbon dioxide con centration in the pig house is measured. Measurements were made of the rates of decay in concentrations of a tracer gas in an occupied pig h ouse with natural ventilation. The results of the tracer gas experimen ts and carbon dioxide model calculations showed a mean discrepancy of 13% for a natural ventilated pig building over ventilation rates betwe en 0.1 and 0.3 kg/s. This indicates that estimation of ventilation rat es by using carbon dioxide measurements and applying the carbon dioxid e model can be a convenient technique in climatic control of pig house s with natural ventilation.