• Energy Research

Precise ventilation control of broiler houses is essential to effectively exhaust pollutants and attain the required breeding environment. However, the ventilation rate used in practise is always lower than the desired or designed value because of difficulties in measuring the pressure difference between the indoor and outdoor pressure of the facility. In this study, a new formula was developed to estimate the total ventilation rate for mechanically ventilated broiler houses using the number of operating fans and the slot opening rate, both of which are relatively easy to measure in practice. The proposed formula was derived from the in-situ fan performance curve and the discharge coefficient, which represent the ventilation characteristics of the exhaust fans and slot openings respectively. This was evaluated through a field experiment and a computational fluid dynamics (CFD) simulation. The measured ventilation rate was 24.1–26.6% lower than the desired ventilation rate showing that the in-situ fan performance curve was 33.7 Pa lower on average than the designed fan performance curve provided by the manufacturer. The distribution of static pressure in the broiler house was analysed using CFD models and it was found that the new formula could be applied to broiler houses having difference lengths.

The pig industry needs strategies to solve problems such as poor rearing environment, diseases, odours, and high energy loads. In this study, an air recirculated ventilation system (ARVS) was developed with optimally designed modules and an operating algorithm. Validation experiments conducted in winter and reported here but experiments carried out during the summer and during changes in season and reported in Kim et al. (2023). Environmental data (air temperature, relative humidity, carbon dioxide, ammonia, and ventilation rate) were automatically collected during winter and livestock disease and stress of piglets were evaluated by sampling. In winter the ARVS reused internal heat energy to satisfy the pig thermal demand. Each module of ARVS modules was designed and integrated based on the previous researches. Environmental factors were monitored in real time, and then ARVS was automatically controlled using developed algorithm. The ventilation rate of the ARVS was about 3 times more than that of the conventional ventilation system (CVS). Air temperature, relative humidity, and ammonia gas inside the ARVS piglet room were optimally maintained. Also, by reusing about 73% of internal energy, it was possible to reduce heating costs. The average concentrations of ammonia and odour measured at the outlet were 2.1 ppm and 251 OU. Piglets of the ARVS weighed 1.6 kg more than those of the CVS. The disease detection rate was <1% with beneficial bacteria increased and harmful bacteria decreased.