Thermal environment assessment and controller performance comparison for a wean-finish barn

Abstract.

The thermal environment (TE) inside swine facilities has a substantial impact on animal growth performance and facility energy usage; therefore, proper control and measurement are required to maintain the optimal TE that maximizes feed efficiency and consumes minimal resources. An inexpensive and novel network of 44 thermal environment sensor arrays (TESAs) capable of capturing the spatial and temporal distribution of the TE were deployed in August 2016 inside a two-room (designated as North; N and South; S), wean-finish barn (~1200 hd and 22 TESAs per room) and placed about 1.8 m above the slatted floor. All TESAs simultaneously measured and averaged 20 samples of dry-bulb temperature, back globe temperature, airspeed, and relative humidity at 1 min intervals. The objectives of this research were to: (1) summarize the TE observations from this monitoring period and (2) develop some preliminary analysis methods to quantitatively compare the TE in each room. Each room of the fully mechanically, power-tunnel ventilated facility featured independent TE control (i.e., fan, heater, inlet, and tunnel curtain operation) by a unique ventilation controller. A set point uniformity coefficient (γ_SP; binned by ambient temperature; t_a) was used to assess ventilation controller performance and a two-sample (from random subsampling of t_a bins) t-test was used to test if γ_SP in each room was statistically different. Results showed a statistically significant difference between N and S room γ_SP for t_a bins <8°C (p < 0.01; p < 0.01; p < 0.01). No statistically significant difference was found between N and S room γ_SP for t_a bins >8°C (p = 0.26; p = 0.07; p = 0.73; p = 0.31). This is a preliminary and novel approach to assessing ventilation controller performance and future approaches will need incorporate all parameters of the TE.