TY - CONF

T1 - The effect of air velocity on heat stress at increased air temperature

AU - Bjerg, Bjarne Schmidt

AU - Wang, Xiaoshuai

AU - Zhang, Guoqiang

PY - 2016

Y1 - 2016

N2 - Increased air velocity is a frequently used method to reduce heat stress of farm animals housed in warm conditions.The main reason why the method works is that higher air velocity increases the convective heat release from the animals.Convective heat release from the animals is strongly related to the temperature difference between the surfaces ofanimals and the surrounding air, and this temperature difference declines when the air temperature approaches the animalbody temperature. Consequently it can it by expected that the effect of air velocity decreases at increased air temperature.The literature on farm animals in warm conditions includes several thermal indices which incorporate the effect of airvelocities. But, surprisingly none of them predicts a decreased influence of air velocity when the air temperatureapproaches the animal body temperature.This study reviewed published investigations on different categories of farm animals to determine how the effect ofair velocity depends on the air temperature. A new expression to calculate the chilling effect of increased air velocitywas suggested. In addition to the parameters air velocity and air temperature this new expression included three constant.Generally usable values for two of these constants were suggested but more work is required to determine how the thirdconstant depends on different conditions including realistic farm conditions.

AB - Increased air velocity is a frequently used method to reduce heat stress of farm animals housed in warm conditions.The main reason why the method works is that higher air velocity increases the convective heat release from the animals.Convective heat release from the animals is strongly related to the temperature difference between the surfaces ofanimals and the surrounding air, and this temperature difference declines when the air temperature approaches the animalbody temperature. Consequently it can it by expected that the effect of air velocity decreases at increased air temperature.The literature on farm animals in warm conditions includes several thermal indices which incorporate the effect of airvelocities. But, surprisingly none of them predicts a decreased influence of air velocity when the air temperatureapproaches the animal body temperature.This study reviewed published investigations on different categories of farm animals to determine how the effect ofair velocity depends on the air temperature. A new expression to calculate the chilling effect of increased air velocitywas suggested. In addition to the parameters air velocity and air temperature this new expression included three constant.Generally usable values for two of these constants were suggested but more work is required to determine how the thirdconstant depends on different conditions including realistic farm conditions.

M3 - Paper

Y2 - 26 June 2016 through 29 June 2016

ER -