Air Velocity Produced by Different Types of Mixing and Ceiling Fans to Reduce Heat Stress in Poultry Houses

Poultry sector is still facing many problems due to heat stress during the periods of high temperatures. These include high mortality due to heat stroke, low chicken's growth rate, body gain, feed consumption and feed efficiency. However, air velocity is a main factor involved in thermoregulation. To overcome high temperature, it is necessary to increase the rate of air movement over the chicken. Fans can play an important role in the ventilation of poultry houses. Therefore, the present study aimed at investigating fan performance and air distribution and velocity by two different types of mixing fans (M4E/40 and M2E/40) and ceiling fans (PV60 and PV36). The effect of fan's height and tilt angle on air velocity in the bird's area was presented. The study was conducted in an experimental building at the Institute of Agricultural Engineering, University of Bonn, Germany. The results indicated that air velocity produced by M2E/40 was significantly greater than M4E/40 with a mean of 3.94 m/s vs. 2.18 m/s, respectively (F=1.32; P<0.05). Overall, in all measuring locations the air velocity produced by fans was significantly low, and then increased until the 4 th and 8 th m of distance, and hereafter decreased until the 10 th m for both M2E/40 (F=9.57; P<0.05) and M4E/40 at both tilt angles of 60° and 55° (F=11.77; P<0.05). The air velocity produced by M4E/40 was significantly greater at 60° than 55° with means of 1.11 m/s vs. 0.58 m/s, respectively (F=5.386; P<0.05). The air velocity produced by PV60 was 1.5-fold greater than PV36, but it was not significantly different with means of 1.56 m/s vs. 1.036 m/s for both fans, respectively (F=0.246; P=0.184). It is to be mentioned that an air velocity of 1.5-3.0 m/s is the optimal to achieve an optimal birds' performance under very hot conditions. In the current study, this optimal air velocity was obtained at different distances and measuring locations for all fans tested. In conclusion, agricultural fans used in this study could provide adequate air velocity, which can decrease the effective temperature inside poultry houses. Selection of fan location and modifying of fan's tilt angle are very important points to be taken into account to obtain the best air distribution and velocity to prevent heat stress effect on birds.