Exhaust Fan Selection
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Exhaust fan selection
Selecting the right fan...
1)
By far the most important aspect of designing a tunnel ventilated house: Determines the grower’s ability to cool his birds:
2)
Wind-chill Temperature uniformity Trapped heat removal Reduces the effects of high humidity
Determines the grower’s electricity costs
Electricity is quickly becoming a grower’s largest expense.
Six factors to consider: 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
1) Air moving capacity
Air moving capacity of a 48 - 50” fan
15,000 to 30,000 cfm+
Bird cooling
Large differences in air moving capacity can result in large differences in cooling if a poultry company only specifies the number of fans a house should have.
12m X 150m House with nine fans 15,000 cfm Cfm = 135,000 cfm Temp diff. = 7.9 F Air vel. = 1.63 m/s Wind-chill = 2.7 C
23,000 cfm Cfm = 207,000 cfm Temp diff. = 2.8 C Air vel. = 2.5 m/s Wind-chill = 6.1 C
Most poultry companies do not do this anymore... But, you must be careful not to specify tunnel fans just by type or manufacturer either. Because there can be large differences between fans of the same type, even within the same manufacturer.
Example:
Choretime cone fans (0.05”) 38450-4822 38441-4822 43575-4822 38264-4821
17,900 20,400 22,800 24,000
cfm cfm cfm cfm
Tunnel fan selection:
The first step in selection a fan for a tunnel house is to understand the different styles of fans available.
Three basic fans configurations 1) 2) 3)
Traditional exterior shutter Slant wall Slant wall – Cone Most fan models are offered in all three configurations
Exterior shutter
Fan is often installed in it wooden shipping box. 48” shutter mounted on the outside of the house.
Exterior shutter
The relatively small shutter, 48” shutter on 48” diameter fan, reduces air flow. The exterior mounted shutter makes it difficult to push air out of the house.
Air flow into a fan
Spinning fan blades
Spinning fan blades
Air exiting a fan
Shutters restrict this flow pattern
Slant wall fan
Larger shutter Air is pulled though shutter instead of being pushed.
Interior shutter
Slant wall
Larger shutter Air is pulled though shutter Fan is tilted slightly
Match shutter angle Protects fan from weather
Tilted fan
Slant wall
The combination of the slant and the interior shutter increases air flow 5 to 10%
Fan configuration example
Belt drive (Coolair NBF/CBL 48) exterior shutter (17,100 cfm) slant wall (19,200 cfm)
Slant wall Larger shutter Air is pulled though shutter Fan is tilted slightly Easier to clean! Collects less dust
Three basic fans configurations 1) 2)
Traditional exterior shutter Slant wall
3)
5 to 10 percent more air
Slant wall – Cone
Discharge cone fans
Interior shutter advantages Reduces “back” pressure on fans
Tilted fan
Discharge cone
Discharge cone fans
The discharge cone can increase air flow an additional 5 to 10%
Fan configuration example
Belt drive (Coolair NBF/CBL 48) exterior shutter (17,100 cfm) slant wall (19,200 cfm) slant wall with cone ( 21,000 cfm)
Though… Slant wall tend to move more air than fans with exterior shutters… Cone fans tend to move more air than slant wall fans… There can still be significant difference between fans of the same configuration
Example
Choretime slant wall (0.05”) 38785-4822 42331-4822 45576-4822
16,500 cfm 18,000 cfm 20,500 cfm
Though… Slant wall tend to move more air than fans with exterior shutters… Cone fans tend to move more air than slant wall fans… There can still be significant difference between fans of the same configuration This is why you must specify either fan cfm or total cfm
Fan specifications:
Total cfm
Or number of fans of that move a specific amount of air
I.e. nine fans that move between 22,000 and 24,000 cfm
Interior shutter
Cone optional
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Exhaust Fan Selection (energy efficiency)
Not specifying specific energy efficiency ratings for fans can result in... excessive energy bills for the producer poor bird management loss of income for the grower/company
How much power will a particular fan use?
The label “Energy Efficient” on a motor means very little...
How much power will a particular fan use?
Motor size does not tell the whole story.
1 h.p motor can use more power than a 1.5 h.p. motor
Fan power
(Two different 48” fans with discharge cones)
Bess #92093 1.5 h.p motor 24,600 cfm 1300 watts
Bess #98229 1.0 hp motor 21,500 cfm 1310 watts
How much power does a fan use?
Motor size does not tell the whole story.
1 h.p motor can use more power than a 1.5 h.p. motor
Plate amperage can be misleading.
indicates full load amperage…not necessarily working amperage.
Energy efficiency
How much power will the fan use?
motor size does not tell the whole story.
plate amperage can be misleading.
1 h.p motor can use more power than a 1.5 h.p. motor indicates full load amperage…not necessarily working amperage.
Just because a fan uses less power does not mean it will save you money.
Fan power usage: (two different 48” fans)
Bess # 96321
918 watts
16,800 cfm
Fan power usage: (two different 48” fans)
Bess # 96321
918 watts
16,800 cfm
Bess #96132
1116 watts (18 % +)
24,000 cfm (30 % +)
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used:
Cfm/watt
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used:
1 Cfm/watt For every 1 cfm moved…the fan will use 1 watt of power
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used: The higher the number the better
Energy efficiency ratings Energy efficiency ratings typically range between 15 and 25 cfm/watt Can be obtained from independent fan test lab booklets.
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt
Fan B = 22 cfm/watt
Power usage
Watts
=
cfm / cfm per watt
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt Watts = 20,000 / 17 = 1,176
Fan B = 22 cfm/watt Watts = 20,000 / 22 = 909
Power usage
1 Kw
=
1,000 watts
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt
Watts = 20,000 / 17 = 1,176
Kw
= 1.18
Fan B = 22 cfm/watt
Watts = 20,000 / 22 = 909
Kw
= 0.91
Power usage
Cost
=
Power rate X Kw
Power rate is the charge of using 1 kw of power for an hour
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt 1.18 Kw 10.6 cents per hour
Fan B = 22 cfm/watt 0.91 Kw 8.2 cents per hour
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt 1.18 Kw 10.6 cents per hour Eight fans
$ 142 per week $ 2,544 per year
Fan B = 22 cfm/watt 0.91 Kw 8.2 cents per hour Eight fans
$110 per week $1,968 per year
Energy efficiency ratings
A 2 cfm/watt difference will result in approximately a 10 percent difference in electricity usage… Minimum acceptable rating is 19.1 Ideal rating is 20.1 or better
Fan specifications:
Total cfm
Interior shutter
Or number of fans of that move a specific amount of air Cone optional
Minimum Cfm/watt = 19.1
Ideal 20.1 or better
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Fan Output vs Static Pressure
Cfm
22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
Static Pressure
0.2
0.25
Fans react differently to increases in static pressure...
Fan Output vs Static Pressure
Cfm
22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
Static Pressure
0.2
0.25
You want a fan that holds up well under pressure… Most houses day one will operate at a pressure around 0.10” Over time it will increase
Dirty shutters Evaporative cooling pads
Clogged evaporative cooling pads
One way to quantify this is comparing fans air flow ratio’s
Air Flow Ratio = air flow (0.20)/air flow (0.05)
Cfm
Fan Output vs Static Pressure 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
0.2
Static Pressure AR = 1
AR=0.82
AR=.68
AR=0.55
0.25
Fan specifications:
Total cfm
Interior shutter
Cone optional
Minimum Cfm/watt = 19.1
Or number of fans of that move a specific amount of air
Ideal rating = 20.1+
Minimum air flow ratio = 0.67
Ideal rating = 0.72 +
Independent fan performance information Output at different static pressure Energy efficiency Air flow ratio
Independent fan performance information
BESS Labs (Univ. of Ill) or AMCA
Independent fan performance information Tests conducted with shutters and guards in place. Manufacturers can challenge one another Poultry companies can send fans in for testing
Obtaining information Test booklets Web site
www.bess.uiuc.edu
Fan manufacturers
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Direct drive vs. Belt drive
Direct drive advantages: No belts to tighten No belts to replace
Direct drive vs. Belt drive
Direct drive disadvantages Tend to move less air Tend to be less energy efficient
Direct drive vs. Belt drive
ACME AGD direct drive with cone
19,700 cfm (19 cfm/watt)
ACME BDR 48” slant wall with cone
21,400 cfm (21.4 cfm/watt)
Direct drive vs. Belt drive
ACME AGD direct drive with cone
19,700 cfm (19 cfm/watt)
ACME BDR 48” slant wall with cone
21,400 cfm (21.4 cfm/watt)
10 percent less air 10 percent less energy efficient
Direct drive vs. Belt drive
Direct Drive Tend to move less air Tend to be less energy efficient Often do not hold up as well under higher static pressures
Direct drive vs. Belt drive
Direct Drive Tend to move less air Tend to be less energy efficient Often do not hold up as well under higher static pressures expensive motors
But, if they meet the previously listed specs, they can be used.
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Quality of construction Difficult to determine Thickness of metal/fiberglass on housing and fan blades Length of warrantee Reputation
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Price
Better fans tend to cost more...
Aerotech, Inc. American Coolair Canarm Chore-Time Cumberland Ellison & Ellison Co., Inc. General Shelters of Texas, S.B., Ltd. Glacier Cor Hired Hand, Inc. Munters TekSupply
Selecting the right fan...
1)
By far the most important aspect of designing a tunnel ventilated house: Determines the grower’s ability to cool his birds:
2)
Wind-chill Temperature uniformity Trapped heat removal Reduces the effects of high humidity
Determines the grower’s electricity costs
Electricity is quickly becoming a grower’s largest expense.
Six factors to consider: 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
1) Air moving capacity
Air moving capacity of a 48 - 50” fan
15,000 to 30,000 cfm+
Bird cooling
Large differences in air moving capacity can result in large differences in cooling if a poultry company only specifies the number of fans a house should have.
12m X 150m House with nine fans 15,000 cfm Cfm = 135,000 cfm Temp diff. = 7.9 F Air vel. = 1.63 m/s Wind-chill = 2.7 C
23,000 cfm Cfm = 207,000 cfm Temp diff. = 2.8 C Air vel. = 2.5 m/s Wind-chill = 6.1 C
Most poultry companies do not do this anymore... But, you must be careful not to specify tunnel fans just by type or manufacturer either. Because there can be large differences between fans of the same type, even within the same manufacturer.
Example:
Choretime cone fans (0.05”) 38450-4822 38441-4822 43575-4822 38264-4821
17,900 20,400 22,800 24,000
cfm cfm cfm cfm
Tunnel fan selection:
The first step in selection a fan for a tunnel house is to understand the different styles of fans available.
Three basic fans configurations 1) 2) 3)
Traditional exterior shutter Slant wall Slant wall – Cone Most fan models are offered in all three configurations
Exterior shutter
Fan is often installed in it wooden shipping box. 48” shutter mounted on the outside of the house.
Exterior shutter
The relatively small shutter, 48” shutter on 48” diameter fan, reduces air flow. The exterior mounted shutter makes it difficult to push air out of the house.
Air flow into a fan
Spinning fan blades
Spinning fan blades
Air exiting a fan
Shutters restrict this flow pattern
Slant wall fan
Larger shutter Air is pulled though shutter instead of being pushed.
Interior shutter
Slant wall
Larger shutter Air is pulled though shutter Fan is tilted slightly
Match shutter angle Protects fan from weather
Tilted fan
Slant wall
The combination of the slant and the interior shutter increases air flow 5 to 10%
Fan configuration example
Belt drive (Coolair NBF/CBL 48) exterior shutter (17,100 cfm) slant wall (19,200 cfm)
Slant wall Larger shutter Air is pulled though shutter Fan is tilted slightly Easier to clean! Collects less dust
Three basic fans configurations 1) 2)
Traditional exterior shutter Slant wall
3)
5 to 10 percent more air
Slant wall – Cone
Discharge cone fans
Interior shutter advantages Reduces “back” pressure on fans
Tilted fan
Discharge cone
Discharge cone fans
The discharge cone can increase air flow an additional 5 to 10%
Fan configuration example
Belt drive (Coolair NBF/CBL 48) exterior shutter (17,100 cfm) slant wall (19,200 cfm) slant wall with cone ( 21,000 cfm)
Though… Slant wall tend to move more air than fans with exterior shutters… Cone fans tend to move more air than slant wall fans… There can still be significant difference between fans of the same configuration
Example
Choretime slant wall (0.05”) 38785-4822 42331-4822 45576-4822
16,500 cfm 18,000 cfm 20,500 cfm
Though… Slant wall tend to move more air than fans with exterior shutters… Cone fans tend to move more air than slant wall fans… There can still be significant difference between fans of the same configuration This is why you must specify either fan cfm or total cfm
Fan specifications:
Total cfm
Or number of fans of that move a specific amount of air
I.e. nine fans that move between 22,000 and 24,000 cfm
Interior shutter
Cone optional
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Exhaust Fan Selection (energy efficiency)
Not specifying specific energy efficiency ratings for fans can result in... excessive energy bills for the producer poor bird management loss of income for the grower/company
How much power will a particular fan use?
The label “Energy Efficient” on a motor means very little...
How much power will a particular fan use?
Motor size does not tell the whole story.
1 h.p motor can use more power than a 1.5 h.p. motor
Fan power
(Two different 48” fans with discharge cones)
Bess #92093 1.5 h.p motor 24,600 cfm 1300 watts
Bess #98229 1.0 hp motor 21,500 cfm 1310 watts
How much power does a fan use?
Motor size does not tell the whole story.
1 h.p motor can use more power than a 1.5 h.p. motor
Plate amperage can be misleading.
indicates full load amperage…not necessarily working amperage.
Energy efficiency
How much power will the fan use?
motor size does not tell the whole story.
plate amperage can be misleading.
1 h.p motor can use more power than a 1.5 h.p. motor indicates full load amperage…not necessarily working amperage.
Just because a fan uses less power does not mean it will save you money.
Fan power usage: (two different 48” fans)
Bess # 96321
918 watts
16,800 cfm
Fan power usage: (two different 48” fans)
Bess # 96321
918 watts
16,800 cfm
Bess #96132
1116 watts (18 % +)
24,000 cfm (30 % +)
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used:
Cfm/watt
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used:
1 Cfm/watt For every 1 cfm moved…the fan will use 1 watt of power
Energy efficiency
A fan’s energy efficiency must be expressed in terms of how much air it will move per watt of power used: The higher the number the better
Energy efficiency ratings Energy efficiency ratings typically range between 15 and 25 cfm/watt Can be obtained from independent fan test lab booklets.
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt
Fan B = 22 cfm/watt
Power usage
Watts
=
cfm / cfm per watt
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt Watts = 20,000 / 17 = 1,176
Fan B = 22 cfm/watt Watts = 20,000 / 22 = 909
Power usage
1 Kw
=
1,000 watts
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt
Watts = 20,000 / 17 = 1,176
Kw
= 1.18
Fan B = 22 cfm/watt
Watts = 20,000 / 22 = 909
Kw
= 0.91
Power usage
Cost
=
Power rate X Kw
Power rate is the charge of using 1 kw of power for an hour
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt 1.18 Kw 10.6 cents per hour
Fan B = 22 cfm/watt 0.91 Kw 8.2 cents per hour
Fan comparison
(20,000 cfm, power cost $0.09 per kw*hr)
Fan A = 17 cfm/watt 1.18 Kw 10.6 cents per hour Eight fans
$ 142 per week $ 2,544 per year
Fan B = 22 cfm/watt 0.91 Kw 8.2 cents per hour Eight fans
$110 per week $1,968 per year
Energy efficiency ratings
A 2 cfm/watt difference will result in approximately a 10 percent difference in electricity usage… Minimum acceptable rating is 19.1 Ideal rating is 20.1 or better
Fan specifications:
Total cfm
Interior shutter
Or number of fans of that move a specific amount of air Cone optional
Minimum Cfm/watt = 19.1
Ideal 20.1 or better
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Fan Output vs Static Pressure
Cfm
22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
Static Pressure
0.2
0.25
Fans react differently to increases in static pressure...
Fan Output vs Static Pressure
Cfm
22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
Static Pressure
0.2
0.25
You want a fan that holds up well under pressure… Most houses day one will operate at a pressure around 0.10” Over time it will increase
Dirty shutters Evaporative cooling pads
Clogged evaporative cooling pads
One way to quantify this is comparing fans air flow ratio’s
Air Flow Ratio = air flow (0.20)/air flow (0.05)
Cfm
Fan Output vs Static Pressure 22000 20000 18000 16000 14000 12000 10000 8000 6000 4000 2000 0 0
0.05
0.1
0.15
0.2
Static Pressure AR = 1
AR=0.82
AR=.68
AR=0.55
0.25
Fan specifications:
Total cfm
Interior shutter
Cone optional
Minimum Cfm/watt = 19.1
Or number of fans of that move a specific amount of air
Ideal rating = 20.1+
Minimum air flow ratio = 0.67
Ideal rating = 0.72 +
Independent fan performance information Output at different static pressure Energy efficiency Air flow ratio
Independent fan performance information
BESS Labs (Univ. of Ill) or AMCA
Independent fan performance information Tests conducted with shutters and guards in place. Manufacturers can challenge one another Poultry companies can send fans in for testing
Obtaining information Test booklets Web site
www.bess.uiuc.edu
Fan manufacturers
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Direct drive vs. Belt drive
Direct drive advantages: No belts to tighten No belts to replace
Direct drive vs. Belt drive
Direct drive disadvantages Tend to move less air Tend to be less energy efficient
Direct drive vs. Belt drive
ACME AGD direct drive with cone
19,700 cfm (19 cfm/watt)
ACME BDR 48” slant wall with cone
21,400 cfm (21.4 cfm/watt)
Direct drive vs. Belt drive
ACME AGD direct drive with cone
19,700 cfm (19 cfm/watt)
ACME BDR 48” slant wall with cone
21,400 cfm (21.4 cfm/watt)
10 percent less air 10 percent less energy efficient
Direct drive vs. Belt drive
Direct Drive Tend to move less air Tend to be less energy efficient Often do not hold up as well under higher static pressures
Direct drive vs. Belt drive
Direct Drive Tend to move less air Tend to be less energy efficient Often do not hold up as well under higher static pressures expensive motors
But, if they meet the previously listed specs, they can be used.
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Quality of construction Difficult to determine Thickness of metal/fiberglass on housing and fan blades Length of warrantee Reputation
Six factors to consider 1) Air moving capacity 2) Energy efficiency energy efficiency ratio
3) Air moving capacity vs. static pressure air flow ratio
4) Drive type 5) Quality of construction 6) Price
Price
Better fans tend to cost more...
Aerotech, Inc. American Coolair Canarm Chore-Time Cumberland Ellison & Ellison Co., Inc. General Shelters of Texas, S.B., Ltd. Glacier Cor Hired Hand, Inc. Munters TekSupply
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