UGA Poultry Housing

University of Arkansas / University of Georgia Bord Cooling Workshop, Yi Liang from University of Arkansas, speaking on bird sprinkler systems.

University of Arkansas / University of Georgia Bird Cooling Workshop. Mike speaking on evaporative cooling principles .

University of Arkansas / University of Georgia Bird Cooling Workshop. Brian speaking on how bird density affects bird body temperatures during hot weather.

Getting ready for cold weather…. On a 90 F day in NW Arkansas😃. Spent our afternoon discussing out testing protocol for our heat exchanger study we will be starting in the fall.

Operating variable speed fans vs. Fixed speed fans. In a house with variable-speed fans, you will be operating more fans to move the same amount of air but since most of the time they will be operating at a lower speed, you will be saving a significant amount of power.

Let's see if can do this without confusing everyone ....myself included :)

1) If I have a tunnel fan with a 240 volt-single phase, 1 h.p. motor rotating at let's say 630 rpm, moving 32000 cfm and it's using 1,600 watts of power and I change out the single phase motor for a three-phase motor and add a VFD, or change the motor to EC motor (DC motor) and add an inverter/VFD, or even install at 2 hp 240 volt-single phase motor AND I don't change the speed of the fan, power usage will remain about the same.

2) Power cannot be measured with an amp meter. The power company charges you for watts, not amps. Fan Power = voltage X current X power factor and with variable speed fans the power factor can change. Power must be measured at the panel using a watt meter...not an amp meter.

3) The purpose of using a variable speed motor on a tunnel fan is to take advantage of the fact that as you slow a fan down it becomes much more energy efficient.

For instance:
Choretime 57" Endura fan (at 0.10") static pressure.

Full speed 631 RPM - 32,000 cfm, 1,618 watts 19.7 cfm/watt

10% reduction in speed 576 RPM - 28,900 cfm (-10%) 1,181 watts (-27%) - 22.5 cfm/watt

20% reduction in speed 500 RPM - 24,400 cfm (-25%) 885 watts (-45%) - 27.5 cfm/watt

30% reduction in speed 425 RPM - 18,200 cfm (-40%) 612 watts (-76%) - 29.8 cfm/watt

4) Tunnel fan staging for power savings... Turn on tunnel fans one at a time at let's say 70% of full speed. Once they are all operating at 70%...speed them up to 80%....then 90%...then 100%. You don't lose your power savings until all the fans are operating at 100%

I hope this helps.

Exhaust fan "starting" current can be over five times "operating" current. Does this significantly increase the cost of operating a fan?

No.

This is because starting currently only lasts for about a second. So, though a fan's power usage may increase five-fold or more during start-up, when you average it over the 5, 10, 60, 120 minutes, etc. a fan will operate, the increase in overall power usage is insignificant.

Here is a newsletter from 1995 that you might find of interest.
https://www.poultryventilation.com/wp-content/uploads/vol7n3.pdf

Below you will find BESS Labs three performance tests for a popular 56" fan....one with a single-phase motor, one with a three-phase motor, and one with a VFD. Notice that at 0.10" pressure and a speed of approximately 540 rpm that all three fans move about the same amount of air (26,000 cfm) and have a similar power usage (1240 watts). The key to increasing a fan's energy efficiency is manipulating its speed. Slowing it down a little, results in moving a little less air, but using a lot less power. Bottom line it is better to run more fans at a lower speed than running fewer fans at full speed.

You might find this newsletter of interesthttps://www.poultryventilation.com/wp-content/uploads/vol29n6.pdf

Quiz time :)
I have a tunnel-ventilated poultry house with 12 tunnel fans equipped with standard single-phase, 240 volt motors. I have an identical house next to it with the identical type and number of tunnel fans (same rpm and air moving capacity), but equipped with three-phase 240 motors. Approximately how much power will I save by using three-phase motors?

a) less than 5%
b) 10 - 20%
c) 20 - 30%
d) 30 - 40%

Something to keep in mind when managing a tunnel ventilation system during hot weather is that the target air speed depends as much on density as it does bird age. As a result, there is no single "wind chill" curve that is correct for any given age bird.

The same age birds are in both pictures. Obviously, you wouldn't have to operate all the tunnel fans to keep them cool on hot, summer day. But, if you only had a wind speed of 150 ft/min and the house temperature was 94 F which 10 day-old-birds would more likely be comfortable?

Spent the last couple of days with Munters exploring the relationship between pad length and house air speed. Reducing pad length 20% on this particular house increased the static pressure by approximately 0.02", which dropped the air speed with all fans operating from 675 ft/min to 650 ft/min.

The moral to the story is that air speed is determined more by the quality of the tunnel fans installed than pad system length.

Over the last 10 years, what do you believe is the highest recorded RH in Fayetteville, Arkansas when the outside temperature was 95 F? 100 F?

It could be worse….😃

Which pad did the pressure increase 0.05” when water was flowing over it? Which one did the pressure increase 0.005” when water was flowing over it? The moral of this story if your pressure increases over 0.01” when you add water to your pads they need to be cleaned.

Question….???
You have two houses…40x500 and 60x600 with 10 and 20 fans respectively. Both have the same maximum air speed of 600 ft/min. If there are four stages of tunnel fans when operating in tunnel mode for the 500’ house how many stages of tunnel fans should there be in the 600’ house?

Comments?

Something you may want to try this summer....

1) Check your static pressure with all tunnel fans operating.
2) Reduce the tunnel door opening until the static pressure increases 0.01" (video).

The slightly reduced tunnel door opening will tend to increase the amount of air movement in the tunnel inlet area/end wall and can help wall-to-wall air speed distribution throughout the house. A slightly reduced tunnel door opening can also help improve the amount of air movement under the tunnel door. The 0.01" increase in static pressure will have a negligible effect on overall tunnel fan performance.

Before/After

The graph below illustrates the body temperatures of 15 seven-week-old broilers along with the room temperature over a six hour period of time. Even though they are all in the same 5'X5' pen there is a 1.5 - 2 F range in body temperatures amongst the 15 birds. Birds are individuals and as a result, there isn't a single optimal set temperature. Furthermore, all birds have a thermal comfort zone...not a specific thermal comfort temperature. This means that birds can be comfortable within a range of temperatures. The older the bird the wider this range tends to be...especially when it comes to cooler temperatures.

It's a simple fact of growing broilers the tighter you try to maintain house temperature the higher your heating costs will tend to be. It is important to keep in mind that older birds are fairly forgiving of relatively low temperatures. After all, they are well-feathered and are in close proximity to other birds. If the house temperature is a little low the birds can simply fluff their feathers, sit closer to other birds. or bed down a little in the litter. They are not fragile like day-old-chicks. There is simply no need to have the heat come on within a degree or two of the set temperature. In fact, with older birds, it is perfectly acceptable for the heat to come on 4 - 6 F below the set temperature. When the heat is set close to the set temperature it is highly likely that the exhaust fans and heaters will constantly fight each other for control resulting in excessive gas usage.

An example of a very poorly insulated ceiling. Thin board insulation with minimal R-value and with gaps between boards which allow hot air to be pulled into the house from between the insulation board and the very hot metal roof.

Be careful about using screens in front of evaporative cooling pads. If not properly sized and kept clean they can easily cause more of a restriction to air flow than the pads. In this case the screens increased the static pressure the fans were working against by 0.10”. To minimize fan restriction as a general rule screens should have about three times the surface area of the pads they are covering.

The University of Arkansas and the University of Georgia are conducting a two-day workshop on maximizing bird cooling during hot weather (July 1 - 2). Topics to be covered include:

Bird cooling methods
Tunnel ventilation and static pressure
Evaporative cooling principles
Commonly asked questions about evaporative cooling
Evaluating tunnel ventilation system performance
Bird density and its effect on bird cooling
Latest on bird sprinkling
Evaporative cooling App demo/exercise
Tunnel fan/pad maintenance

The workshop will be held in Fayetteville Arkansas July 1st and 2nd.

Presenters:
Brian Fairchild - University of Georgia
Michael Czarick - University of Georgia
Yi Lang - University of Arkansas

I hope you can join us.

Details can be found at:
bit.ly/bird_cooling_workshop