How Does Tunnel Fans Placement Affect Fan Performance and Air Distribution? - Part 1

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Date: 
2011
Volume: 
23
Number: 
9
Tip Category: 
Air speed
Exhaust fans
Tunnel ventilation

A common question for people building tunnel-ventilated houses is how tunnel fan location affects the air-moving capacity of tunnel fans.  Many believe that placing the tunnel fans in the end wall maximizes the air moving capacity of tunnel fans because the air doesn’t have to turn before exiting the house, while others believe that placing fans in the side walls near the end wall doesn’t adversely affect fan performance.

Recently a study was conducted in 60' wide tunnel-ventilated broiler house with 23, 52" tunnel fans to examine how tunnel fan location affects the air-moving capacity of the fans as well as air distribution.  The house was selected due to the large number of tunnel fans in both the end walls (8) and side walls (17).  Five poles, with three anemometer on each, were placed across the width of the house approximately 100' from the tunnel fan end wall (Figure 2).  The anemometers were mounted on each pole two feet above the floor, two feet below the ceiling and 4.5' above the floor.  Each of the 15 anemometers were connected to a data logging system that recorded air speed every minute for 15 minutes.  The 15 anemometers allowed a very accurate determination of both the average house air velocity and air velocity distribution across the width of a house.