By The National Poultry Technology Center
Practical Application #1: Reduce Temperature Stratifications
AUBURN, Ala. — Hot air rises, cold air falls. Smoke emitters are used in this picture to illustrate what happens to residual heat from brooders during preheating and brooding. While the goal is to heat the floor, many growers don’t realize how much valuable heat rises to the ceiling in the process. All of the heat from brooders rises to the top of the house eventually. Recirculation fans can repurpose this residual heat that comes from the heaters in the house and puts it to use near the floor where it is needed. One of the single most effective tools that can be used to improve in-house conditions and save gas in an older house, aside from house tightness and insulation, is the use of recirculation fans. Most recirculation fans designed for poultry cost about $100 each. They are a great way to improve the efficiency of your heating and ventilation systems in winter. The payback for the typical system is less than 1 year in an older house and less than 4 years in a modern house. If you are experiencing high fuel bills and wet floors and seem to have trouble keeping up during winter growouts, a new recirculation fan system should be considered. Contact your company representative for approved fan designs, suggested layouts and methods of operation that might work best for your specific operation.
Practical Application #2: Good Incoming Air
Here is an example of good air flow through sidewall inlets on a cold day using thermal imagery. Notice all the cool air is entering the house and being kept along the ceiling. No cold air is hitting the walls or floor. The air is moving with sufficient velocity that it reaches the peak where only then does it lose momentum, mixing with the heat gathered there and falling slowly as tempered, warm air. This is accomplished by combining needed fan power with proper opening to create sufficient static pressure to throw the air into the center of the house. Any insufficiency in these three points and cold air can impact the floor and the birds causing many difficulties. See NPTC Newsletter #86 on poultryhouse.com for more details on improving winter ventilation air flow.
Practical Application #3: Recirculation Fans and Layouts
Basket Fan (low ceiling) vs. Paddle Fan (high ceiling)
Here are two examples of the most common and cost effective recirculation fan types used in poultry houses today. Basket fans with a more open wire cage design are common in dropped ceiling houses. These are low powered fans blowing air parallel to the ceiling. Paddle fans are used in high ceiling houses in the up-blowing mode to help reduce temperature stratification and repurposing valuable hot air. Pictures are for educational purposes only and not brand specific.
Example layouts for recirculation fans. Dimensions are for educational purposes only. Actual dimensions and layouts should be coordinated with your live production service representative or housing coordinator. Alternate layouts, fan directions, and operation may be necessary.
Growers with 66-foot wide houses have some unique problems to deal with when it comes to winter ventilation. The width of these houses often makes conventional ideas of ventilation and airflow used in older style houses less effective. This fact makes innovation a necessity and trial and error is often where that starts. As you can see in this photo, this grower has made a very simple adjustment to his stir fans in his 66-foot wide house. He has turned them at 45 degree angles to the length of the house. This causes his stir fans to “wipe” the peak of his ceilings, more effectively mixing the hot air found there than the straight line “race-track” manner they were originally installed at. He has two lines of stir fans in his houses, located approximately between the outside and inside feel lines. He kept the general “race-track” direction but turned every fan toward the center 45 degrees, so each adjacent fan’s stream is passing each other along the center of the house. This method may not be for every grower or every house, but it has proven effective for this farm keeping his sidewalls noticeably drier.
Good luck saving energy this winter from the National Poultry Technology Center team.
This is the first in an ongoing series from the National Poultry Technology Center at Auburn University to appear regularly in Poultry Times. More information from the NPTC can be obtained at www.poultryhouse.com.