ミストの蒸発冷却特性測定と制御方式の提案

抄録

Fine water mist sprays with average droplet diameters around 20 microns are being increasingly used as an energy-efficient means of cooling outdoor and semi-enclosed spaces such as rail platforms and shopping arcades. At high relative humidity there is a higher risk of wetting people and the ground beneath mist nozzles. Automated control systems are often set to run above a set dry bulb temperature and below a set relative humidity. Experiments show that mist evaporation rates before reaching the ground are closely related to the difference between the dry bulb and wet bulb temperatures, here labeled ΔT_WB. Changing the operating parameters to include a minimum ΔT_WB can allow use at higher relative humidity levels. If a common 28°C, 70% condition is sufficient to prevent floor-wetting, then a condition of 28°C with a ΔT_WB > 4.3K should still prevent floor-wetting. This would allow operation at 75% relative humidity near 39°C.