HSD - 18D Bottom Outlet Evaporative Air Cooler (18000 AirVolume)The evaporative air cooler is an efficient cooling system that achieves air cooling through the principle of evaporative cooling. By utilizing the heat absorbing property of water evaporation, it transforms heat energy into a cooling effect, effectively lowering indoor temperatures. The HSD 18D , HSD 18D BP features a bottom air outlet. For locations where equipment can be placed on the ground or roof, it can be mounted on windows using an iron frame.