Simple Summary

Swine barns often experience extreme temperature fluctuations, making it challenging to

maintain optimal conditions for both animal welfare and reducing environmental impact.

In hot weather, increased ventilation, while necessary for cooling, can inadvertently lead to

higher ammonia emissions. Conversely, reducing ventilation in cold weather to conserve

heat can worsen indoor air quality. This study investigated the effects of a ground channel

ventilation system on ammonia emissions from swine barns. This system utilizes an

underground air passage to moderate incoming air temperature. By pre-tempering the

air, the system enables higher ventilation rates even in cold weather, improving air quality

without compromising barn temperature. Furthermore, it reduces the need to maximize

ventilation for cooling during hot weather, thereby helping to lower ammonia emissions.

The results demonstrated that this system helped stabilize ammonia emissions across

seasons. In conclusion, controlling inlet air temperature offers a promising strategy for

managing ammonia emissions and promoting a more sustainable swine production system.

Abstract

This study evaluated the impact of a ground channel ventilation system on seasonal ammonia

emissions in a swine-finishing barn over three distinct seasons: summer, late autumn,

and winter. The ground channel system tempered inlet air, cooling it during summer

and warming it during colder seasons, maintaining stable room temperatures despite

external fluctuations. During summer, the ground channel reduced the incoming air temperature

from 26.9 ◦C to 22.5 ◦C, contributing to steady barn temperatures (28.0 ◦C) and

mitigating ammonia emissions, which reached 111.0 ± 23.6 g day−1 AU−1

. In late autumn and winter, it warmed the inlet air from 4.7 ◦C and −0.7 ◦C to 8.1 ◦C and 6.8 ◦C, respectively,

maintaining stable room temperatures (25.1 ◦C and 24.3 ◦C). Ammonia emissions

remained consistent across seasons, with 125.0 ± 37.3 g day−1 AU−1

in late autumn and 107.1 ± 20.5 g day−1 AU−1 in winter. 

Thus, ammonia emissions showed no seasonal differences,

highlighting the system’s effectiveness in balancing ventilation rates with emissions.

During late autumn and winter, it improved air quality without compromising thermal

comfort for the swine. In summer, the reduced ventilation demand lowered ammonia

emissions, supporting the effective management of ammonia emissions year-round. Future

research should investigate the system’s effects on other gases and slurry pit temperatures.