Mike Czarick (University of Georgia) explained the advantages of doing this and the costs implications of using improved circulation fans, during IPPE 2019 in Atlanta, USA.
Hi Dr, I got a question for you, if you don't mind, could you tell me why the minimum ventilation cycles are always based on a 5 minutes time, I mean every time I use the calculator the time on and off is always based in 5 minutes. and how can it affect the system if we have cycles of less and more than five minutes. The president of the poultry company always change the cycles to less than 5 minutes and I have noticed that with shorter cycles we save more propane but we have most of the time and increase on the humidity with the consequential effect of wet litter and in some cases high ammonia levels in quails in the first two weeks.
Gerardo Rosales In general the shorter the timer cycle the more consistent the house temperature and air quality will be. For instance, operating minimum ventilation fans 1 minute out of 5 will produce less temperature variation and air quality variation than operating them 2 minutes of of 10. Since the house temperature varies less sometimes you will save fuel. We typically do not use a timer less than 5 minutes because it can be very tough on the fans and the inlet machines resulting in reduced equipment life. If you are getting wet litter and high ammonia it simply means you are not ventilating enough. It doesn't matter if we are talking about a 5 minute timer or 3 minute timer. How short of a timer cycle are you using?
Our business is Quail production and the pens we are talking about are ours smallest pens with a capacity of 25.000 birds each one. We run periods of time of about 3 or 4 minutes (adjusting proportionally with the results of the 5 minutes program on the minimum ventilation calculator on your website) and our air inlets are in the ceiling and they are counterweight, we have circulation fans (we took the idea from your seminary) and our litter have been a problem due to summer time and an over population. We tried to keep 10.000 birds more for 3 weeks with the intention to drop them down to the pen downstairs. We use shavings as a bed and we are controlling it as much as we can. We decided to reduce the numbers of birds to the original capacity.
Gerardo Rosales In the summer time I would think that you would not be operating the fans on timer and more on temperature. How do you determine how much to operate your fans on timers?
This pens are old and the only ones not controlled by a computer, so we have data loggers on them , every morning we read the humidity and temperature inside the pen and we check out how they were during the 24 hours before. So with this information and the one provided by the weather channel app, we introduce it in the calculator providing at the same time the water consumption of the day before and the fan RPM used for the minimum ventilation.
Gerardo RosalesDo you measure the humidity? Ideally it would be around 60% if it is much higher the minimum ventilation rate should be increased regardless of the calculated value.
Hi Mike,
I am following the UGA app to calculate min vent, it seems to be quite aggressive at times, over ventilating, as in dropping cold air on the birds before the heaters kick in is causing problems, not saying it’s just vent levels, other factors to consider, feed quality etc . But to maintain low humidity seems really difficult when outside humidity is averaging 85% on a good day. Is it a case of more air is better or is there a point where you say back it off. Humidity in house is not excessive but litter capped and not improving.
Lee Baxter Hi Lee: Of course the calculator has its weakness. For instance, if it is relatively warm outside and humid the required ventilation can seem excessive but that is the nature of the situation. When you are having problems utilizing the "recommended" minimum ventilation rate the question is, is the ventilation wrong or is there problem with how you are brining in the air? For instance, if a house is very loose and most of the air is coming through cracks then you are more likely to cause the heat to come on every time the min vent fans operated. You can also run into problems if you are operating too many fans on a timer for a relatively short period of time instead of running fewer fans for a longer period of time.
Of course if you have feed issues, drinker problems, or bird health issues they can be difficult to solve through ventilation alone.
If you can provide more details I might be able to give you more specific advise.
Take care