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Environmental Control Housing :Myths and Reality

Benefit of Closed Environment Housing Stocking Density Bird Requirements The House Ventilating Closed Environment House “Limits”

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Benefit of Closed Environment Housing• Bird performance/production revolves around bird

comfort and air quality.• Bird comfort and air quality depend on how well you

can control air flow into and through the house.• How much control you have depends on the house

and the ventilation system.• You will ALWAYS have more CONTROL in Closed

Environment (CE) houses• CE houses give you CONTROL of how you ventilate

the birdsSponsors

With Closed Environment housing we can control:• Where the air will enter.• How it will enter (fast, slow).• In what direction it will travel.• How much will enter (and be removed).• At what speed it will travel over the birds.

This is crucial for achieving bird comfort.

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OH vs CE – Questions To Ask Yourself

• Am I getting maximum performance/production?• Does my performance/production drop at certain

times of the year?• Am I utilising my house floor area to its extent?• Am I getting the maximum kg/m² from my house?• How much does late heat stress mortality cost me?• Is my FCR where I want it to be?• Is my heating cost too high?Above answers will be influenced by ventilation

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Recommended Stocking Density

The following is an example of recommended stocking density in hot climates:

• CE – 30kg/m²• Open house – 20-25kg/m² (poor ventilation)

These densities can vary depending on relative humidity.

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Bird Requirements

• Warm floor during brooding• Good temperature control (actual and effective)• Good air quality (oxygen)• No temperature fluctuations• No drafts (in cold weather)• No environmental stresses

• It doesn’t matter what type of housing you have!• These are the bird requirements and somehow you

must provide them• Closed environment houses are better equipped to

provide this Sponsors

The House

• Good ventilation system starts with a “good” HOUSE.Closed Environment (CE) houses should be :• Well sealed

– Air tight– Minimal air leakage

• This allows control over where and how air will enter• New houses should be “pressure tested” before final

payment is made• This does NOT mean that older houses can’t be

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Well Sealed vs Poorly Sealed

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Poorly Sealed

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The Roof

Properties of a good chicken house roof (open or closed environment)

1. Insulation (polyurethane, polystyrene, glass wool)– Keeps heat in during winter– Minimises radiant heat during the summer

2. Radiant barrier– Reflective layer to deflect radiant heat away from the

house

3. Protection against thermal bridging– “Steel-on-steel” contact in the structure

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The Roof

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Outer roof sheetStructural steel

Sun

Heat radiates into the house

You cannot ventilate radiant heat away

The Roof

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Outer roof sheet

Inner roof sheet

Structural steel

Insulation Insulation

Sun

Heat radiates into the house

Thermal Bridging

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Thermal Bridging

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Minimum Ventilation

• Minimum ventilation is when the house temperature is at, or below, the required house set temperature.

• It is a time when we are heating the house.• At the same time we must introduce a bare minimum

amount of air to maintain air quality.• We need to control moisture levels in the house.• We must keep the birds warm, comfortable, and with

good air quality.

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Minimum Ventilation – Open Houses

• Curtain management is crucial.• Air entering through the curtain drops to the floor.• Problems :

– Stress on the birds– Increased heat consumption– Wet litter

• If you open too much, the temperature goes down.• If you open too little, air quality deteriorates.

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House Leakage

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Cold floors, stressed chicks, wet litter, heater activated

Wasted Heat

Air Leakage

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Minimum Ventilation – CE House

• Operates with “negative pressure”.• Pressure differential is used to control how the air

enters the house.• The air travels away from the birds into the heat

accumulated in the roof.• No air movement at bird level – bird comfort.• Re-uses the heat from heaters and birds.• Reduces heating costs.• WE determine how much air enters the house, not

the outside wind.• Can increase stocking density.

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Minimum Ventilation

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High air speed in roof area

Air speed at bird level < 0,25m/s

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Transitional Ventilation – Open Houses

• Outside temperature is higher than required set point.

• Curtains are opened more than minimum ventilation.• If there is a prevailing wind, then need to be careful.• If there is no wind, then birds may soon start to get

too hot.• Amount of air flow and cooling on the birds depends

on outside wind.

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Transitional Ventilation – CE Houses

• Using fans and side inlets, WE control how much air enters the house.

• Large volume enters away from the birds.• Bird comfort is regulated by the number of fans

being used (controlled).• As temperature increases, more fans can be used to

keep the birds comfortable.

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Hot Weather Ventilation

• When ambient temperature is higher than the required set point.

• Along with high temperature may be high RH.– This is probably the most dangerous weather condition.

• The birds are hot and panting (stress).• Activity/growth/production may decrease.• There may be mortality.• THE BEST CHANCE OF SURVIVING HOT, HUMID

CONDITIONS IS AIR MOVEMENT, AIR EXCHANGE.

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Hot, Humid Weather – Open Houses

• Stocking density is often decreased in hot season.• Curtains may be fully opened.• Circulation fans may be used.

– These fans only cover certain area of the house– House conditions are very uneven– Usually they just recirculate the hot, humid air

• Spray cooling used along with circulation fans.• Not all the birds experience the same cooling/relief.• System has a limited house air exchange rate.

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Hot, Humid Weather – CE Houses

• Liveability depends on air speed and air exchange.• Can create high air speed (3+ m/s).• Can exchange all the air in the house in 30-40sec.• This will be uniform across all the birds.• Birds can tolerate higher RH if air speed is high.• Evaporative cooling pads can reduce temperature.• During tunnel ventilation we need to control bird

effective temperature.– dry bulb temperature, RH, air speed, bird age, density.

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Wind Chill Example

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0.5 1.0 1.5 2.0 2.5 3.0

Air Velocity (m/s)

8.0

5.5

1.0

9.0

6.5

4.5

2.0

Win

d Ch

ill (°

C)

3.5

Cooling Potential

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ΔT = Maximum cooling possible

Dry Bulb Wet Bulb

CE House Reality

• Closed environment houses can/should be used in all climates around the world.

• The more extreme the climate (hot, cold, high RH) the greater the need for Closed Environment.

• India :– 0°C; 45°C; high rainfall; high humidity

• CE housing does NOT guarantee good results/performance/production.

• It is just another MANAGEMENT TOOL to help you manage your flock.

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CE House “Limits”

• House must be :– Well sealed (air tight)– Well insulated

• Ventilation system must be designed correctly– Heating capacity and distribution– Side wall inlets for transitional ventilation– Side wall fans for minimum ventilation– Fans for tunnel ventilation– Pad area

• This depends on pad thickness• Depends on flute angle of the pad Sponsors

Transition Ventilation Inlets

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Pad Flute Angles

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CE House “Limits”

• Bad house design– Owners who design their own house from “internet info”– Equipment companies that don’t know their business

• Over complicated ventilation control systems– There is NO need for the controller to be complicated.– There is NO such thing as a controller that does not have

to be adjusted during the flock.– Beware of equipment companies that tell you they will

program the controller and you won’t need to change it!!– Keep the control system simple to understand and use,

making sure it can still do what you need it to do.Sponsors

CE House “Limits”

• Lack of education and training.– There are new concepts in CE houses.– Farmers must be educated about the principles.– They must understand how the control system “thinks”.– They must know how to manage this to achieve bird

comfort.

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Bernard GreenGreen Environmental ServicesConsultantEmail: bernard@greenenviro.co.zaPhone: +27 82 412 5821Skype / LinkedIn / Twitter / Etc.:

Contact

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