ventilation

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Ventilation Management in ECH
Dr. Rashid Sohail
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Ventilation

• Ventilation is
• Moving FRESH AIR INTO a house and moving STALE
  AIR OUT of the house
• Sending UNWANTED heat, EXCESS moisture, ammonia,
  OUT of the house and
• AIR MIXING to get heat, moisture, ammonia INTO
  THE AIR that leaves the house.

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Objectives

• Provide a suitable environment to facilitates
• Maximum livability
• To take maximum growth rate
• To take better feed conversion

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WHAT IS STATIC PRESSURE

• Definition
• Static pressure is the difference between the
  inside and outside atmospheric pressure
• Units expressed in units of inches of water
  colum (WC) and pascals
• 1 w c 250 pascals
• When ext. fan runs, it creates negative pressure
  in the house.Inside and outside pressure
  difference (static pressure) rises and allows to
  move the air into the house

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EXH.FAN VS STATIC PRESSURE
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MANOMETER
MEASURING INSTRUMENT OF STATIC PRESSURE
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WHY IT IS NECESSARY

• To maintain the maximum level of freshness in a
  house.
• To remove stale air containing excess amount of
  waste gases(ammonia,co2,co)
• To maintain optimum level of Temperature and RH
  according to the need of bird.

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COMPARISON (AIR PATTERN)
Insufficient static pressure.
Proper static pressure
Static pressure too high.
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STATIC PRESSURE VS TEMP. DIFFERENCE
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Air Quality
Oxygen(O2) more than 19.6
Carbon Dioxide(CO2)less than 0.3
Carbon Monoxide(CO) less than 10 PPM
Ammonia(NH3)less than 10 PPM
Dust less than 3.4 mg/m3
Relative humidity (RH) 45-65
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The bird!
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Where is the most heat coming from?
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BODY HEAT PRODUCTIONOF POULTRY

• A 2-kilogram (4.4 lbs.) bird with a daily weight
  gain of 65 grams (14.3 lbs/100) takes in about
  500 kcal daily.

• Of this, 130 kcal are used for growth, the
  remaining 370 kcal must be excreted in one form
  or another.

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Methods of heat loss
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Ventilation goals

• Proper temperature
• Optimum humidity
• Adequate fresh air
• No noxious gases

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Types of ventilations

• Natural Ventilation
• Forced Ventilation

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Types of Forced Ventilation

• Minimum ventilation
• Transitional ventilation
• Tunnel ventilation

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Conti.

• Natural Ventilation
• Only Minimum ventilation is available but
  no mechanical vent.
• Minimum Ventilation
• Low air velocity but long air exchange
  during brooding and cold weather.
• Transition Ventilation
• Low air velocity, better air exchange
  rate.
• Summer Ventilation
• Temperature control, high air speed to
  reduce effective temperature.

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VENTILATION PARAMETERS

• Tunnel fans capacity.
• Cooling pads.
• Minimum ventilation fans.
• Air inlets.
• Climate controller.
• Insulation.

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Volume of air in a house

• Length x Width x Average height
• Example
• Length 328 feet
• Width 46 feet
• Average height
• 10 feet
• Volume 328 x 46 x 10 150,880 feet3

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Tunnel fan capacity

• Depends upon
• House area
• Bird target wt.

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On the basis of cross sectional area of house and
desired velocity

• Cross Section W x H 46 X 9
• Desired Velocity 600 ft./min.
• CONE FANS
• 600 x 46 x 9/26000CFM 10
• BOX FANS
• 600 x 46 x 9/20000CFM 12

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On the basis of body wt.

• Cone fans
• 25000 birds x1.9kg. x 4cfm/kg. body wt./
  26000(cfm) 8
• Box fans
• 25000 birds x1.9kg. x 4cfm/kg. body wt./
  20000(cfm) 10

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CONE FANgtgt26000 CFM

• ltltBOX FAN
• 22000 CFM

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Cooling pads area
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• Normal pad dimensions
• 6.5 x 2.0 x 6.0
• One pad area will be 13 sq. ft.

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Minimum ventilation fans

• capacity for minimum ventilation should be
  25-30 of total ventilation.

Air inlets/Vents
82600 x / 700 cfm
118 sq. ft. 118/2.1875(7 x45)
54 Vents
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Air speed/air exchange

• During brooding there is no need of air speed
  across the birds but proper air exchange is a
  must
• After brooding the air speed across the birds to
  be 1.5 m/s to 2.5 m/s

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Air inlet area

• Total CFM of the fans standard CFM per square
  feet / Minute of 6 inch Pads
• Note
• For 6 inch cool pads (45 x 45 or 30 x 30)
• 400 CFM per 1 ft2

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Air baffels

• Air baffles can be installed to reduce cross
  section of the house and to increase air velocity
  along the house.

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Relative Humidity (RH)

• RH is the amount of moisture in the air
  compared to the maximum amount of moisture the
  air can hold relative to the dry bulb
  temperature.

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Insulation
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Insulating Walls
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Time calculation for minimum ventilation

• Suppose as we have 25000 birds, then
• 0.5 cfm/kg. is required for winter season.
• 1.00 cfm/kg. is required for summer season.

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In case of winter season

• 25000 x0.04kg. x0.5/10000 cfm0.05 min
• 0.05 x30015 sec.
• It means that fan will be on for 15 sec. and off
  for 285 sec.
• If 1sq.in. air inlet is opened then 4 cfm will
  pass through.

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In the case of summer season

• 25000 x0.04kg. x1/10000 0.1min
• 0.1 x300 30 sec.
• It means that fan will run for 30 sec. and off
  for 270 sec.

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What air speed we need in house to cool our birds
?

• Depends upon a number of factors
• Temperature
• Bird size/age
• Density
• Humidity

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Estimated effective temperature reduction when
air temp is 85-90F
Air velocity Bird age
Ft/min 1 week 4 weeks 7 weeks
100 -4 -2
200 -12 -5 -2
300 -22 -10 -4
400 -15 -7
500 -18 -10
Air Velocity Bird Age
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HEAT STRESS INDEX TABLE

C F 60 65 70 75 80 85 90 95 99
35 95 155 160 165
32.2 90 150 155 160 165
29.4 85 145 150 155 160 165
26.7 80 140 145 150 155 160 165
23.9 75 135 140 145 150 155 160 165
21.1 70 130 135 140 145 150 155 160 165 164
TEMPEATURE. RELATIVE HUMIDITY

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Air speed and air temperature

• The higher the temperature, greater amount of
  wind speed required.
• The higher temperature, the more younger birds
  benefited from wind speed.
• Excessive air movement can be problematic when
  air temperature are relatively low.

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Bird cooling and Relative humidity

• As humidity increases, effectiveness of panting
  decreases.
• As humidity increases, the cooling produced by
  pads decreases.
• 20 increases in relative humidity evaporative
  pad cooling decreases by 25.

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Air speed and Relative humidity

• The more humid climate the more speed you need.
• The longer tunnel opening the larger dead spot
  and more humid.

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Potential problems

• Not uniform temperature in the house
• Proper insulation of the house.
• First go on tunnel ventilation, then cooling.
• Increased heating cost
• Center house brooding.
• Proper insulation.

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Potential problems

• Uneven ventilation
• Excessive leakage near the pads area, doors,
  windows, and air inlets.
• Litter caking
• During Winter
• Improper minimum ventilation.
• Requires proper air inlets opening along with
  proper no. of 36 fans.
• During Summer
• Low air movement.
• Proper ventilation. (First go on tunnel
  ventilation, then cooling).

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Fan setting during summer season
Age (weeks) Temperature(C) Tunnel fans Evap. Cooling(C) PUMP CLOSE(C)
1 32.5 F1 36 4
2 30.5,31.5 F1,F2 34 4
3 28.5,29,29.5,30 F1,F2,F3,F4 32 4
4 26.5,27,27.5,28,28.5,29 F1,F2,F3,F4,F5,F6 30 4
5 24.5,25,25.5,26,26.5,27,27.5,28 F1,F2,F3,F4,F5,F6,F7,F8 28 4
6 23.5,24,24.5,25,25.5,26,26.5,27,27.5,28 F1,F2,F3,F4,F5F6,F7,F8,F9,F10 28 4