Page updated Nov 2022
Rosahl is a special purpose dehumidifier used by original equipment manufacturers (OEMs) to protect electronics, optics, artefacts and other sensitive items from moisture damage.
It uses an ultra-compact solid state ionic membrane to expel moisture from the cabinet or enclosure. Rosahl can reduce relative humidity to below 10% if required and can also work as a humidifier.
Developed by the Mitsubishi Electric Corporation Group member Ryosai Technica Company in Japan, Rosahl addresses the need for compact maintenance free, air-drying solutions to protect sensitive equipment from moisture damage. Rosahl has many benefits over conventional dehumidifiers like silica gel, Peltier devices and heaters.
Maintenance free operation
It is maintenance free, so needs no drainage or cleaning and this minimises the lifetime operating costs. Moreover, it has no moving parts to wear out, so makes no noise or vibration and has a long operating life. Rosahl membranes are ultra-compact to fit into the smallest of spaces such as external CCTV cameras. Finally, their power consumption (about 3W) makes them cheap to operate.
Rosahl is available in a range of sizes for enclosures from 0.2 litres up to 2m³. They are cost effective for enclosures volumes up to 8m³. They need a low voltage 3V dc supply to power the solid polymer electrolyte (SPE) at the heart of the device.
Special purpose dehumidifier
The dehumidifying membrane comes in a thin plastic mounting or integrated into a stainless-steel mounting plate. Installation of the membrane needs a cut-out in the side of the enclosure. Control of the humidity inside the enclosure may be made using a hygrostat or similar device.
Close humidity control is also possible but may need two membranes: one to dehumidify and one to humidify. Rosahl membranes can also run 24/7 without a controller for low humidity applications.
The membranes operate at temperatures from -10º to +50º C with humidity up to 95%. Storage is from -40 to +80º C
Application and selection of Rosahl