Measurements and Calculations of Ventilation Rate for Naturally Ventilated Animal Buildings: A Review

Ventilation rate is a very important factor for estimating the gases emissions from animal buildings. As wind speed and direction always changes, ventilation rate of naturally ventilated animal building is difficult to measure accurately. According to the previous studies, the available methods of measuring and calculating ventilation rate for naturally ventilated animal buildings could be generalized as analytical model, empirical model, experimental study and computer simulation. Due to the absence of standard method, all the efforts are made to evaluate and improve the current methods to reduce the errors in recent decades. In this paper, the CO2 balance and tracer gas methods are recommended for field test, however, the data of CO2 generation of different animals should be updated and methods of measuring CO2 generation from different litters should be improved. For simulation analysis research purpose, it is suggested to combine tracer gas and CFD simulation together, and more studies on accuracy of tracer gas method are needed.