In my lab we use a number of materials which are hygroscopic and must therefore be stored in a dry environment. For that purpose we have numerous dry cabinets very similar to the one shown below (Amazon link here).
These cabinets run on electricity, do not require desiccant, and do not have a water outlet such as one finds with home dehumidifiers, yet they are able to maintain low relative humidity (RH) values of < 40%. The temperature inside the cabinet is also the same as (or very close to) the temperature outside of the cabinet, and there are no other connections aside from the electrical plug.
- How do these cabinets maintain such low humidity values?
- Assuming they are removing water from the air, where does the water go?