Influence of tunnel ventilation on the indoor thermal environment of a poultry building in winter

Abstract

Tunnel ventilation systems are widely used to create thermal environments for poultry buildings in China. However, existing research mainly focuses on the indoor thermal environment in summer and rarely considers the winter season. A field test was conducted in a layer breeder building in Handan City, China to systematically investigate the characteristics and problems of the thermal environment in winter. Forty-two measuring points were set to analyze the indoor air velocity and temperature distributions, and the nonuniformity coefficient and temperature humidity velocity index (THVI) were adopted as the evaluation indices. Furthermore, the exhaust fan layout of tunnel ventilation was explored to improve the indoor thermal environment using a validated computational fluid dynamics (CFD) method. The results show that (1) the indoor air velocity distribution is quite nonuniform with a nonuniformity coefficient of 0.74, the maximum difference of which is as large as 0.62 m/s; (2) the nonuniformity coefficient of indoor air temperature distribution is 0.16, and the maximum temperature difference is as large as 12.9°C; (3) the indoor THVI is below the appropriate range of 18–25, making the thermal comfort zone only 61.4%; (4) separately installing exhaust fans at the front and end walls with the symmetrical locations and sizes can improve the distribution uniformities of indoor air velocity and temperature by 22.0% and 88.3%, respectively. The experimental results and parametric optimization of tunnel ventilation in this study will be beneficial for designing an appropriate thermal environment for poultry buildings during winter. • The non-uniformity coefficient of air velocity in experimental poultry house is 0.74. • The maximum difference of air temperature in experimental poultry house is 12.9 °C. • The thermal comfort zone in experimental poultry house is only 61.4% of entire space. • Separately installing exhaust fans on front and end walls improves the environment.