Definition
An adiabatic humidification method in which water is broken into very fine droplets by a high-pressure pump and special nozzles and evaporated in the air. Because the heat of evaporation is drawn from the air, the air cools. Neptronic SKH systems produce droplets below 20 µm at an operating pressure of 70 bar; RO water is recommended as feed water.
Detailed Explanation
In high-pressure atomisation a pump station delivers water to stainless nozzle lines; the water leaving the nozzle breaks into very fine droplets that evaporate in the air. The heat required for evaporation is drawn from the air; on the psychrometric chart the process follows the constant wet-bulb line, and the air can cool at most to its wet-bulb temperature. In practice every 1 g/kg of added moisture means roughly 2.5 K of cooling.
A droplet's evaporation time grows roughly with the square of its diameter, so fine droplets evaporate within a short distance, while large droplets can reach surfaces and cause wetting and hygiene problems.
System components: • Pump station and controls • Water preparation: RO is recommended (Neptronic SKH: hardness ≤ 50 mg/L CaCO₃; RO is mandatory on the 100 kg/h model) • Nozzle lines: in-duct, inside the air handling unit or free space
Neptronic SKH family: three models of 20, 50 and 100 kg/h, control of up to 3 zones, silver-ion hygiene support.
Energy Balance
An electric steam humidifier uses about 0.75 kWh/kg of electricity. In atomisation electricity is used only for the pump; however, the heat of evaporation (≈ 2,450 kJ/kg ≈ 0.68 kWh/kg at around 20 °C) is drawn from the air.
Example: 100 kg/h of atomisation draws ≈ 68 kW of heat from the air. In summer this is a gain that comes off the cooling load; in winter, if indoor temperature is held constant, the same heat is made up by the heating system. The energy advantage of atomisation is that the evaporation energy comes from a cheaper heat source than electricity, or in summer from the air itself. Payback is calculated per site from energy unit prices, operating hours and the summer-winter split.
Engineering Note
• Hygiene: Legionella risk arises when stagnant water, biofilm and respirable aerosol come together. A design that leaves no stagnant water, automatic draining, periodic cleaning and disinfection are the basic measures; silver ions support hygiene but do not replace maintenance. Germany's ventilation-hygiene guideline VDI 6022 is the common reference; for the SKH the manufacturer declares VDI 6022 compliance. • Evaporation distance: nozzle layout and air movement are checked against manufacturer data so that droplets evaporate before reaching surfaces. • Winter operation: preheat → adiabatic humidification → reheat if needed. • Control band: typically ±3–5% RH for adiabatic systems. • For pharmaceutical cleanrooms, operating theatres and laboratories that need a tight RH band and high hygiene, steam humidification is generally preferred.
NKT – Nem Kontrol Teknolojileri provides equipment supply, unit-selection support, technical service and spare parts; design, installation and commissioning remain with the facility's designer and contractor.
