1. Hot air enters the cooler
2. Hot air passes through the core
3. Warm, moist air exhausted outside
4. Fresh, cool outside air passes into the building
Seeley International’s indirect evaporative coolers can feature counter flow (Climate Wizard) or M-Cycle (Coolerado) air to air heat exchangers.
The coloured lines on the psychrometric chart compare indirect evaporative cooler’s performance, such as the Climate Wizard in direct evaporative cooler in this instance to that of a direct evaporative cooler on a hot day.
Consider fresh air entering the cooler at 38°C dry-bulb and 15% relative humidity. If the cooler is a direct evaporative air cooler, the fresh air passes directly through the wet cooling pad where it becomes cool and also moist, and emerges at about 22°C dry-bulb and 75% relative humidity. The process has travelled along the wet-bulb line and the air has gained about 6.5 grams/kg (dry air) of moisture.
If the cooler is a Climate Wizard indirect evaporative air cooler, the fresh air passes through the dry channel where it is super-cooled and emerges at about 16°C. But, no moisture has been added as the cooling process has occurred along the constant moisture line. The ‘wet-bulb effectiveness’ of indirect evaporative coolers is about 125%, whereas regular direct air coolers have a wet-bulb effectiveness of about 85%.
Climate Wizard’s Indirect evaporative coolers can feature a further direct evaporative cooling process (Supercool stage) directly after the indirect evaporative process. This allows the machine to provide an additional reduction in the supply temperature while adding minimal water content.