Sensorless flow rate estimation in frequency-converter-driven fans

Fan systems account for approximately 11 % of the industrial electricity consumption. Previous studies indicate that there is a significant energy savings potential in fan systems. Increase in the price of electricity has brought forth a need for easily implementable methods to measure the efficiency of fan systems. In this paper, a sensorless fan operating point estimation method is introduced and the limitations of the method are discussed. Operation of the sensorless estimation method is validated through laboratory measurements. It is found that the estimation method is accurate enough to be used for energy efficiency analyses and the detection of inefficient fan operation.