Definition

The conversion of water to steam at 100°C using electrical or gas energy, then injecting that steam into HVAC ductwork or directly into the space to add moisture. Provides mineral-free, microbiologically clean moisture; the standard technology for pharmaceutical, hospital, semiconductor, and museum HVAC. High energy consumption (water vaporization heat), but superior in hygiene and control precision.

Detailed Explanation

In steam humidification water is boiled into steam and the steam is distributed into the duct or the space. Because steam enters with its latent heat, it adds only a small amount of sensible heat to the air (typically below 1 K); on the psychrometric chart the process is almost vertical.

Steam generation methods: 1. Electrode type — current flows through the water; water conductivity is a precondition for operation and the unit will not run on RO/DI water; minerals accumulate in the cylinder and the cylinder is replaced. NKT – Nem Kontrol Teknolojileri does not supply electrode humidifiers. 2. Resistive type (Neptronic SKE4, 5–120 kg/h) — heater elements in a stainless steam tank boil the water; power is modulated 0–100% continuously via SSR. There is no conductivity requirement; it runs on any water including RO/DI. The steam tank is cleaned periodically. 3. Gas-fired type (Neptronic SKG4, 50–400 kg/h) — produces steam with natural gas/LPG; preferred for high-capacity applications where electrical capacity is limited. 4. Steam-to-steam type (Neptronic SKS4, 15–200 kg/h) — produces clean steam from the plant's boiler steam via a heat exchanger. 5. Direct steam injection (Neptronic SKD) — boiler steam is distributed directly; because it may contain boiler-treatment chemicals it is not used in hygiene-critical areas.

Distribution: S.A.M. (absorption distance < 1.5 m) and Multi-Steam™ (< 1 m) distributors, or the SDU space distribution unit for ductless spaces (manufacturer data).

Practical Example

Energy: electric steam generation (90 K × 4.186 kJ/kg·K + 2,257 kJ/kg) ≈ 0.73 ≈ 0.75 kWh/kg; the same for electrode and resistive units.

Example: in an application whose humidification load calculates to 25 kg/h, a 30 kg/h SKE4 model is selected with a 20% safety margin. At full load this unit draws ≈ 22.5 kW. Actual consumption follows the winter load profile through modulation.

Engineering Note

• Safety margin: 15–25% (20% in practice); above 50% is oversizing. • Duct velocity: a common design velocity at the distributor is 2.5–4 m/s. For the same humidification, a higher velocity lengthens the absorption distance; the distance is checked against manufacturer data. • Obstructions: no elbow, damper, filter, coil or sensor within the absorption distance; the high-limit sensor sits outside this distance, at least 4.6 m after the distributor. • Steam hose: total ≤ 5 m; at least 2% slope on descending sections and at least 15% on rising sections; no sagging or kinks. • Control: per Neptronic data, ±1% RH with modulating control, ±5% RH with on/off control. • In hygiene-critical areas (pharma, hospitals) SKS4 or an SKE4 running on RO/DI water is preferred over boiler steam.

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.