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Rosahl Micro-Dehumidifiers

  Rosahl is a unique electric micro-dehumidifier for very small spaces and enclosure where maintenance-free drying is an important factor. It uses a solid polymer membrane (SPE) installed in a flat panel, making it suitable for use in a wide range of enclosures from under two litres up to 4m³ (280 cu ft) in volume. The name Rosahl comes from a Japanese phrase meaning “removing dew”, and it was developed by Mitsubishi Electric Corporation member company Ryosai Technica in Japan in response to a demand for compact maintenance free, air drying solutions to protect sensitive equipment from moisture damage. It has since found its way into uses for protecting museum display cabinets, telecommunications equipment, manufacturing processes and electrical cabinets. Rosahl dehumidifiers work using electrolysis when connected to a 3V DC low power source. As the membrane has no moving parts, it is silent, vibration free, and has a very low average energy footprint. The process does not produce liquid water, making it maintenance free and giving the membrane a long operating life.  

How Rosahl works

Sometime called an ionic membrane dehumidifier, Rosahl works by electrolysis.The SPE consists of a proton-conductive solid polymer electrolyte and porous electrodes with a catalytic layer composed of noble metal particles.When a 3 Volt D.C. voltage is applied to the porous electrode attached to the SPE the moisture on the anode (dehumidifying) side dissociates into hydrogen ions (H+) and oxygen: the hydrogen ions migrate through the membrane to be discharged on the cathode (moisture discharging) side where they react with oxygen in the air, resulting in water vapour being discharged.  Similarly, if the membrane is reversed a humidifying effect is achieved. Rosahl has no moving parts, making it economical to run, silent, and vibration free.  As no liquid water is involved in the process, it is maintenance-free making it suitable for use in remote locations or where servicing is expensive or otherwise difficult. The membrane has a long operating life and has been tested to work from -10 to +50C