Variable speed fans for poultry - Michael Czarick

Have one building using all variable speed fans. Cycling between 30% and 100% depending on summer and winter conditions. Ventilation at extremely low temps much more stable and comfortable by elimination of minimum cycling of fans at these temps. Fans are also controllable by automated environmental systems meaning that ventilation can be lowered even during evaporative cooling season increasing cooling efficiency. Another positive is that variable speed fans can be adjusted throughout the building to overcome problems or ventilation deficiencies. I have had no problems with ammonia increases in winter due to the fact that air is always moving and being replaced. There is some negative as far as shutters not fully opening at reduced speeds but not a major issue.

Electricity costs can be reduced by installing energy efficient fans
or
using fans less...which will not help bird performance
or
keeping fans properly maintained
or
using variable speed technology

There are several ways, in my opinion, where variable drives can be very helpful. What I don't hear a lot of discussion about is multiple fans on individual drives, which can greatly reduce cost and the ability to correct deficiencies or stratification of air by using drive adjustments.

Application of this technology in broiler evap. cooling system can be a bonus to the industry. I am sure Dr. Michael Czarick must have considered all the important parameters such as concentrations of carbon dioxide, ammonia, oxygen and RH in addition to the temperature. If not, these parameters could also be integrated into the system.

Thank you very much, Dr. Czarick for your articles. Can you explain a little bit about the importance of speed controller in this case? I know two kinds of speed controllers - one with voltage reduction and the other will reduce the frequency. I suppose the tension reduction is totally not useful. All the best.

Do we need a different type of controller to operate variable speed fans?
Or can we go for a combination of fixed RPM and variable speed fan when the difference of day and night temperature is we.