Numerical simulation of a novel double-duct ventilation system in poultry buildings under the winter condition.

The tunnel ventilation system is usually adopted to create the indoor environment in poultry buildings in China. However, it is difficult to maintain an appropriate indoor temperature to cause the cold stress and reduce the production performance of chickens in winter. To address it, a novel double-duct ventilation system was proposed by combing the advantages of the exhaust air heat recovery system and the perforated duct ventilation system in this study. The indoor airflow pattern, air temperature distribution, NH 3 concentration distribution, and air age distribution in a laying hen building with the novel double-duct ventilation system were compared with the traditional tunnel ventilation system by using computational fluid dynamics (CFD) method. The results show that (1) the novel double-duct ventilation system can increase the average indoor temperature by 4.4 °C to maintain a warmer indoor environment, owing to the heat recovery from the exhaust air; (2) the in-homogeneity coefficients of indoor air velocity, temperature, NH 3 concentration, and air age are decreased by 38.5%, 66.7%, 35.3%, and 30.8%, respectively, to create a more uniform indoor environment; (3) although the heat recovery efficiency is 33.2% owing to the small heat exchange area, the coefficient of performance (COP) is as high as 6.4 and the payback period is only about 5 months. Therefore, the novel double-duct ventilation system can improve the ventilation performance and create a better indoor environment with low cost. It will provide a new method and theoretical guidance for the ventilation design in poultry buildings. • Novel double-duct ventilation system with exhaust air heat recovery was proposed. • Indoor temperature is increased by 4.4 °C to maintain a warmer indoor environment. • Distribution of air velocity, temperature, NH 3 concentration, and air age is uniform. • Heat recovery efficiency is 33.2%, but coefficient of performance is as high as 6.4. [ABSTRACT FROM AUTHOR]