This document summarizes a study that used thermal modeling of livestock housing for broilers to optimize equipment and control parameters. The modeling examined how carbon dioxide (CO2) concentrations are affected by factors like weather, farmer-controlled settings on ventilation minimums and temperature setpoints, and structural elements of housing insulation and heating type. Increasing the ventilation minimum flow rate was found to lower CO2 levels, but with economic and environmental impacts. Indirect combustion heating and improved insulation had greater effects on CO2 than settings alone. The conclusions suggest optimizing short-term settings and making medium-term investments to housing and equipment to better manage CO2 levels, especially in cold weather.

1. Thermal modelling of livestock housing for
broilers to optimize the choice of equipment
and control parameters.
P. Robin1, G. Amand2, C. Nicolas3, D. Chevalier4, S. Gallot2,
E. Pigache4 , A. Keïta5
1INRA, 2ITAVI , 3CRAB , 4CRAPL , 5ANSES - France

2. Lille - 22 to 24 February 2017
Livestock housing: let's build the future 2
Summary
• Why model? example of CO2
• Problem of managing CO2
– Variability of concentrations on farm (uncertainty)
– Effect of control parameters: minimum flow, temperature setpoint
(farmer settings)
– Effect of structural choices: thermal insulation, type of heating
(housing - equipment)
– Weather impact (weather)
• Conclusion: implications for management or investment
decisions

3. Why model? example of
CO2

4. Why model?
example of CO2
introduction uncertainty farmer settings housing - equipment weather conclusion
uncertainty
of observation?
causes of
excesses?
 remedies?
ppm
CO2
Frequencyof
excess• Requirement: 3000 ppm CO2 in broilers

5. Why model?
example of CO2
introduction uncertainty farmer settings housing - equipment weather conclusion
• Requirement: 3000 ppm CO2 in broilers
• Processes affecting concentration
CO2animals
= f(weight,
growth,
activity)
heating
= f(weather, insulation,
ventilation)
bedding
=
f(thickness,
humidity)
Ventilation
= f(animals, weather)
causes of
excess
• housing
design
• farmer
settings
• weather

6. Problem of managing
CO2

7. Variability of concentrations on farm
• Variability increases
in cold weather
• Increased variability
is due to the
difficulty in mixing
air between:
 incoming cold air
(low in CO2)
 hot air blown by
the gas heater (high
in CO2)
 ambiant air
introduction uncertainty farmer settings housing - equipment weather conclusion
• ANSES observation, 2015, standard chicken

8. Effect of the control parameters:
simulation of scenarios
• Baseline scenario =
– mild weather at start of batch, cold at end of
batch
– “traditional” housing insulation
– gas heating by direct combustion in the
housing
– minimum flow rate as per AFSSA, 1980
– setpoint temperature 19°C at end of batch
introduction uncertainty farmer settings housing - equipment weather conclusion
• Test scenarios =
 weather effect = 5°C decrease in temperature (symbol )
 effect of settings = increased minimum flow (0.5 to 2 m3/h/kg bodyweight)
 housing effect = insulation; indirect combustion (no CO2 produced in the housing;
line - - - -)

9. Effect of the control parameters:
minimum flow
introduction uncertainty farmer settings housing - equipment weather conclusion
increase in minimum flow
• effect of settings = increased minimum flow (0.5 to 2 m3/h/kg bodyweight)
 lower concentration of CO2 when min. flow increases

10. Effect of the control parameters:
minimum flow
introduction uncertainty farmer settings housing - equipment weather conclusion
increase in minimum flow
• effect of settings = increased minimum flow (0.5 to 2 m3/h/kg bodyweight)
 increase in gas consumption; limited impact at start of batch
 considerable economic and environmental impact at end of batch

11. Effect of structural choices:
thermal insulation; indirect combustion
introduction uncertainty farmer settings housing - equipment weather conclusion
• housing effect = thermal insulation; heating mode
 low effect of insulation
 greater effect of indirect combustion
normal insulation reinforced insulation (LEB)

12. weather effect
introduction uncertainty farmer settings housing - equipment weather conclusion
• weather effect = increase in CO2 content and gas consumption
 increase in gas consumption; limited impact at start of batch
 considerable economic and environmental impact at end of batch
When the weather is cold the heat produced by the animals is insufficient to heat the
incoming air => heat exchangers needed at end of batch

13. Conclusion: implications
for management or
investment decisions

14. Conclusion
 Possible decisions = short term
 housing settings: minimum flow at start of batch; setpoint temperature at end
of batch
introduction uncertainty farmer settings housing - equipment weather conclusion
 Possible decisions = medium term (depending margin/m² housing,
availability)
 investments in housing/equipment: indirect combustion; biomass (economic
and environmental impact at end of batch); reinforced thermal insulation; heat
recovery exchangers
 Controls  to check settings; planning of farm modernization;
development of adapted equipment

15. Any questions?