1. 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

2. 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.

3. 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.

4. 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

5. 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

6. 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

7. 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

8. CFD Simulation – Air Velocity
> 2.0 m/s

9. CFD Simulation – NH3 Concentration
> 5 ppm

10. CFD Simulation – Temperature
> 34.0

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

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

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

14. 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.

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

16. Acknowledgement
National Research Initiative Competitive Grant No 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

17. Thank you! Xinjie Tong, Ph.D. student Advisor: Dr. Lingying Zhao
249 Agricultural Engineering,
590 Woody Hayes Dr.
Columbus, OH 43210