How Electrode Steam Humidifiers Work
Electrode steam humidifiers bring water to a boiling point by passing an alternative current between electrodes within a disposable plastic cylinder (the defining feature) utilizing the ions dissolved in the 
water as the means of conduction. Potable water (which contains dissolved ions) will conduct electricity between the electrodes with substantial resistance, it will heat the water until the boiling point is reached and steam is produced. The capacity of the unit will depend on the size of the cylinder (volume of water), the surface area of the electrodes in contact with the water and the rated voltage and kW of the humidifier. A current transformer is used to monitor the current draw of the electrodes. It is the means of controlling the steam output which is accomplished by raising or lowering the water level inside the cylinder. As the cylinder fills with water, more of the electrode surfaces will be immersed allowing more current to pass between them thereby increasing the power consumed and total steam output. Reduction of steam output will occur by lowering the water level.
Mitigation of lime/scale:
The steam generated in an electrode cylinder is pure water (H2O). This means that all the ions from the supply water remain in the tank in the form of scale. The resulting build-up can be mitigated by flushing the cylinder periodically, however, over time the scale will accumulate to a point when the electrodes are coated and unable to generate the capacity required. The plastic tank will then have to be removed and discarded and, a new tank acquired and installed.
How Resistive Electric Humidifiers Work
Resistive electric humidifiers use electric, self-cleaning, immersion heating elements to raise the temperature of the water to the boiling point within a permanent stainless steel evaporation chamber.
Each of these immersion heaters has a specific power rating (KW) at a specific voltage. This radiant heating will raise the temperature of the water within the evaporation chamber to the boiling point, independent of the ion content of the water, thus permitting equal performance in purified (de-ionized or reverse osmosis) water or potable water. The capacity of steam generated is controlled by switching power over time to the resistive elements. This is accomplished in most cases with SSRs (solid state relays) with integrated zero voltage crossing (SCR control).
Mitigation of lime/scale:
In potable water installations, the build-up of ions (scale) within the tank is mitigated with frequent flush cycles. Although the output of the humidifier will not be affected by the build-up of scale, the evaporation chamber will have to be removed and cleaned periodically. In pure water applications, these drain cycles may be greatly reduced or eliminated depending on the purity of the water, effectively increasing the efficiency of the humidifier and reducing the service required.
Comparing Costs
Installation cost:
The initial cost of the Neptronic SKE4 electric resistive humidifiers is competitive with electrode boiler humidifiers of comparable capacity. Similarly, the installation cost is roughly the same. A key benefit of the Neptronic SKE4 is a built-in disconnect switch, included on all models, which eliminates the need to install a separate, wall mounted, disconnect switch. This feature can reduce the installation cost and saves space.
Maintenance cost:
Electrode humidifiers use a disposable, one-time use, plastic tank that must be discarded and replaced at a substantial cost to the owner. Cylinder costs range from $250-450 each, not including the labour! Single-use plastics have become a global environmental hazard. Many municipalities and governments are considering or adopting regulations limiting their use.
For electrode humidifiers, cylinder replacement varies according to water quality and usage. This results in an average of 1-3 plastic cylinder changes per season. Below is an example of the relative cost of an electrode vs resistive humidifier, with an averaged number of cylinder changes
per season.
NEPTRONIC Resistive humidifiers have a permanent stainless-steel tank that requires periodic cleaning. This consists of removing the evaporation chamber, cleaning out the accumulated scale and then reinstalling the chamber. With the Neptronic SKE4, this task is accomplished quickly, easily and completely tool-free.
When using RO/DI water, maintenance of the chamber is almost always eliminated.
Fast & Easy Maintenance
No Tools Required!
No Heavy Lifting Required!
The Neptronic SKE4 electric resistive humidifiers includes a permanent, lightweight and reusable stainless-steel chamber instead of a disposable plastic bottle that must be replaced at least once a year. This results in thousands of dollars of savings.
How to maintain:
Summary
Resistive Humidifiers |
Electrode Humidifiers |
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