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

Lille - 22 to 24 February 2017Livestock 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

Why model? example of CO2

Why model? example of CO2

introduction uncertainty farmer settings housing - equipment weather conclusion

uncertainty of observation?

causes of excesses?

remedies?

ppm CO2

Freq

uenc

yof

ex

cess

• Requirement: 3000 ppm CO2 in broilers

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

• housingdesign

• farmer settings

• weather

Problem of managing CO2

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

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 - - - -)

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

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

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)

weather effectintroduction 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

Conclusion: implications for management or

investment decisions

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

Any questions?