Evaporative air cooling in animal rooms
1985
Eikeland, P. (Norges Landbrukshoegskole, Aas (Norway). Inst. for Bygningsteknikk)
Laboratory experiments have been made with evaporative air cooling. Warm, dry air was blown through a wide pipe (diam. 500 mm) filled with hollow plastic balls. The balls were irrigated with water from a nozzle installed at the top of the pipe. As the warm air evaporated the water from the balls' surfaces, it became cooled. Pressure measurements were made to find the air resistance through the ball storage. Six methods were tested to find the best one for moistening the dry air. In all the cooling experiments the temperature of the warm, dry air was 30 degr.C, and the relative humidity was 30 p.c. The experiments showed that one can expect moistening the air up to 80-90 p.c. RH. In these experiments this gave 9.7-10.9 degr.C cooling. Generally evaporative air cooling is most useful in warm, arid areas. In humide climate the method will demand great volumes of ventilation. In Norway the RH in summer is about 45 p.c. in inland areas, at the coast about 65 p.c. On extremely warm days RH can become a bit lower. Based on the experimental results some calculations has been made of the need of ventilation for 1.3 kg's chicken. These calculations show that by using evaporative air cooling in Norwegian climate, the volume of ventilation can be reduced with 50 p.c. of the volume that is generally used today for dimensioning. A ventilation system equipped with a cooler will, however, be some more expensive than a traditional system. The gain is reduced room temperature on warm summer days
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