Control of the ventilation rate in agricultural buildings by using a newlydesigned ventilation rate sensor in the controller feed-back loop.

A new ventilation control system for livestock buildings, based on the cont inuous measurement of the ventilation rate with an improved ventilation rat e sensor, has been developed. Control parameters have been optimised in suc h a way that pressure changes over the ventilation system, caused by wind e ffects, do have a minor effect on the produced ventilation rate. The new control system has been compared to a traditional ventilation contr oller for livestock buildings by means of simulation technique. In this sim ulation analysis, where real measured pressure data were used as a disturba nce input for the fan, it was found that the average deviation between the desired and the simulated ventilation rate could be reduced from about 700 m(3)/h with a traditional fan control system to about 30 m(3)/h with the ai r flow rate based controller.