What is adiabatic humidification?

Evaporation

In evaporation, water is passed over evaporator pads, whilst the air to be humidified flows over these pads at the same time, thereby becoming enriched with moisture. The advantage of air humidification by evaporation is that not only the operating costs but also the capital costs for a humidification system of this type are low. Furthermore, evaporators can be used not only for humidification but also for cooling buildings. Indirect evaporative cooling makes the cooling process particularly energy-efficient. Conventional chillers can be designed to be considerably smaller, and operating costs can be significantly reduced.

Atomisation

In atomisation, water is released into the air to be humidified as tiny water droplets via mechanical atomisers or with the aid of nozzles. As the physical state of the water is altered here too, and energy from the ambient air is required for this, adiabatic air humidification systems can contribute to cooling as well as humidification in environments with high heat generation.

Applications

Adiabatic air humidification is used in many different areas. It has thus become an important component in the field of outdoor air cooling in hot countries. In Medina, 250 ‘air-conditioned parasols’ were installed in the square in front of one of the world’s largest mosques to provide shade and cooling. Through adiabatic air humidification, they ensure a noticeable temperature reduction of 10°C on average. Adiabatic air humidification is also used in the electrical industry, for example at Facebook’s data centre in Luleå, Sweden. Here, three server halls, each covering an area of 28,000 m², are cooled using 13,000 litres of water per hour, equivalent to a capacity of 8,840 kW.

Calculation example for adiabatic humidification

Given:

Calculation of ∆h/∆x:

∆h in kJ/kg

∆x in g/kg dry air