In November, over 50 attendees participated in the Flock Talk, “Ventilation: Exchanging Expertise”. We are including a series of articles in EggNotes as part of an ongoing effort to share learnings from those sessions. This article focuses on heating systems.
•Recirculating/stir fans are good for moving heat, but once the heat is off, they should be off. Typically, they should only be used to move the air off thin pipes. Recirculating fans need good maintenance as cleaning out the tubes can be difficult, and they can harbor disease.
•When the heat shuts off, this stir fans should be off. You don’t ever need them for summer ventilation if the system is properly designed.
•Fans may help in the winter if you are trying to keep baffles open. These need to be tied
continues on next page to the heating and the pump, circulation pump, and fan should be turned on at same time.
•Box heaters have been used historically because they are inexpensive to install and easy to fix. Consider the following:
– They may not be efficient if you need to increase ventilation to remove the gas.
– It is possible to achieve a million BTU in four boxes with circulating fans and they barely turn on however, box heaters are on/off. You have a million BTU and then you have nothing. You may be getting too much heat at once.
•Infrared is good option because you are directly heating the bird instead of the air around them. Keep the following in mind if considering infrared heating:
– It may be difficult to achieve uniformity from one end to the other. Using a lot of
smaller heaters as opposed to less long ones may be better.
– Because you need a direct line of sight to the target infrared heating doesn’t work as well in caged facilities. The birds on the bottom row don’t see the infrared tubes hitting them. The system works better for free range or organic where birds can get direct exposure to it and there is the added benefit that the infrared will also dry the litter a bit.
BOILERS AND PIPE
•Starting and firing up a boiler takes a lot of energy versus idling at 20%. A 3 way mixer valve lets the controller keep the boilers steady instead of trying to heat the water up with on/off cycling. This may also be easier on the boilers and increase their longevity.
•With respect to thin pipe, there is a lot to consider about material:
– Material may impact maintenance. Aluminum never loses efficiency. Other materials can build up dust on the pipe and then lose their efficiency.
– If using aluminum, you need to treat the water properly or it may wear through.
– Continuous and serrated thin pipe will have the same BTUs although continuous thin pipe might be easier to keep clean and therefore not lose efficiency.
– Delta tube is cheaper than aluminum, but you may have to run more tube.
– The recommended flow depends on how far you are running the tube. Ideally you would have a maximum 4 degrees difference from the source to return. If the water is leaving at 160 degrees and coming back at 140 degrees you won’t have uniformity in your barn, you will have a big temperature difference from the front to the back. 1 gallon per 10,000 BTUs is a rough calculation.
– Some flow rates are difficult to achieve with aluminum because the opening is too small
•Consider the placement of thin pipe: It should ideally be underneath or behind the inlet and not in front, The cost of heating can go up 40% if it is in front as you may be blowing cold air onto the top of the pipe.
•Keep in mind if you are covering the floor with straw, manure, or bedding you aren’t getting much heat out of it
•If there is poor outside foundation insulation it might be helpful to put a couple of loops just around the outside edge if frost is coming through the foundation
•You won’t use much of it in a caged system, it might not be the most efficient
The above represents information presented and discussed at three Flock Talk meetings in November 2018 by experts with a broad base of perspective. Information is from the
perspective of those experts present. Farmers designing or changing ventilation systems are advised to consult their own experts who have knowledge of their specific barn and system.