Frequently Asked Questions - Air Handling Unit Mist System
What maintenance is needed for AHU mist cooling systems?
Typical maintenance includes filter element changes, nozzle inspection/cleaning, leak checks, pump/solenoid checks, and sensor calibration (if automated).
How does high-pressure mist cooling reduce AHU load?
When mist fully evaporates, it lowers the air temperature (adiabatic pre-cooling). Cooler air reduces the cooling duty on the coil, which can help reduce chiller/compressor load depending on climate and operating conditions.
Where is mist cooling installed in an AHU?
It is usually installed in the return air duct, mixed air section, or fresh air intake based on available evaporation distance, access for service, and humidity limits.
Will mist cooling increase humidity inside the building?
It can, but proper systems use RH sensors + staged control (solenoid/PLC) to keep humidity within the set range and avoid over-humidification.
How much temperature drop can I expect from AHU mist cooling?
The temperature drop depends mainly on ambient wet-bulb temperature, airflow (CFM), and existing humidity. Dry conditions generally provide better cooling potential than humid conditions.
Can mist cooling be used for data center HVAC systems?
Yes, when engineered inside the HVAC equipment (AHU/MAU/CRAH) to ensure complete evaporation and no droplet carryover. It should not be designed as direct misting into the server room.
Does mist cooling cause wetting on coils or ducts?
It can if design is wrong. Correct nozzle placement, evaporation distance, droplet size control, and proper staging help prevent carryover and avoid wetting/condensation risks.
What water quality is required for high-pressure mist cooling?
Clean, low-scaling water is recommended. Many sites use softeners/RO depending on TDS/hardness, along with multi-stage filtration to reduce scaling and nozzle blockage.
Is high-pressure mist cooling better than low-pressure misting for AHUs?
Yes for HVAC, because high-pressure systems produce finer droplets that evaporate faster and reduce wetting risk. Low-pressure systems tend to produce larger droplets, increasing carryover chance.
Do high-pressure mist nozzles clog easily?
Clogging risk depends on water quality and filtration. SS-316 nozzles + 3-stage filtration + timely filter replacement greatly reduce clogging and maintain consistent mist quality.
