Effects of Ventilation Systems on Ammonia Concentration Distributions in Manure-Belt Egg Layer Houses Using Computational Fluid Dynamics Xinjie Tong1 Se-woon Hong1, Lingying Zhao1, Albert Heber2 1Dept. of Food, Ag., and Biological Engineering, The Ohio State University 2Dept. of Ag. and Biological Engineering, Purdue University

Introduction Poultry industry contributes large amounts of ammonia (NH3) emission. NH3 has direct adverse effects on human health, animal health and welfare in poultry house. NH3 concentration has large spatial variations which causes different levels of health threat to hens. Visit farm, smelly, the level could affect birds and farmers’ health in long run.

Significance Computational Fluid Dynamics (CFD) is a powerful tool to simulate fluid dynamics phenomena based on conservation of mass, momentum, and energy. CFD models has been accurately used to simulate NH3 concentration distribution in livestock building. Gap: no previous study on simulation of NH3 concentration distribution in manure-belt layer house.

Objectives Develop and validate CFD models for evaluation of NH3 concentration distributions in manure-belt layer houses. Use the validated CFD model to assess the NH3 exposure of farmers and hens in different seasons and ventilation systems. Visit layer house, different aisle, center/end of building length, comfortable/uncomfortable, some spot are very stuffy, humid, and hot, some spots are cool, “windy”. Heat stress is significant in concentrated animal feeding operations. Tunnel ventilation: cooler at inlet, hotter at outlet. Once model is validated, we can change parameters and seek for improved ventilation system / production management which leads to improved thermal environment for layer house. CFD modeling: 3D spatial distribution of temperature & velocity Efficiency of ventilation system Improvement on ventilation system & production management

Study Site Parameter Value House Dimension 110 m x 19 m x 6 m No. of Hens 162,000 Cages 8 rows x 8 tiers Age of Hens 28 weeks No. of Fans 48 (D = 137 cm) 6 m

CFD Simulation Input (summer) Boundary conditions Hens: heat sources Software ANSYS Fluent 15 ICEM CFD Models Reynolds Averaged Navier-Stokes SST k-⍵ turbulence model Domain and mesh 110 m x 19 m x 6 m 8.5M hexahedron cells Boundary conditions Hens: heat sources Manure belt: NH3 sources Inlet: ΔP Fan: velocity Cage: porous volume Input (summer) Ambient T = 27.5 ºC Ventilation = 188 m3/s = 400,000 cfm NH3 emission = 14.9 kg/d

Data for Validation USDA long-term air emission data End Wall Data for Validation USDA long-term air emission data One year continuous T/RH Ventilation rate NH3 concentration and emission rate CO2 concentration and emission rate PM concentration and emission rate Weather condition Side Wall Ammonia analyzers: TEI Model 17C chemiluminescence MSA Chillgard photoacoustic IR USDA long-term air emission study year round ammonia emission data . T/RH data

CFD Simulation – Air Velocity > 2.0 m/s

CFD Simulation – NH3 Concentration > 5 ppm

CFD Simulation – Temperature > 34.0

CFD Simulation – NH3 Concentration ppm Side wall > 5.00 Upper End wall Lower

Model Validation Model is adequate 𝑁𝑀𝑆𝐸= ( 𝐶 𝑂 − 𝐶 𝑃 ) 2 𝐶 𝑜 × 𝐶 𝑃 𝑁𝑀𝑆𝐸= ( 𝐶 𝑂 − 𝐶 𝑃 ) 2 𝐶 𝑜 × 𝐶 𝑃 Parameter Temperature NH3 Concentration Criteria NMSE 6.2E-4 0.61 < 1.5 Model is adequate

CFD Simulation – NH3 Concentration ppm Side wall > 5.00 Upper End wall Lower

Conclusion The normalized mean square error of temperature (6.2E-4) and NH3 concentration (0.61) both meet criteria (<1.5), indicating that the model is adequate. The validated model can be used to assess NH3 exposure of farmers and birds in different cases.

Future Research Simulate other seasons Evaluate ventilation effectiveness Suggest practical strategies or new ventilation system to improve indoor air quality

Acknowledgement National Research Initiative Competitive Grant No. 2005-35112-15422 from the USDA Cooperative State Research, Education, and Extensive Service Air Quality Program. Collaborating egg producer Air quality and Bioenvironmental Engineering Lab Purdue University Air Quality Lab

Thank you! Xinjie Tong, Ph.D. student Advisor: Dr. Lingying Zhao tong.129@osu.edu 614-270-9007 249 Agricultural Engineering, 590 Woody Hayes Dr. Columbus, OH 43210