Datacenters require humidity control, less than years ago due to new materials and better electronics. But aircooling still dominates the server cooling, and with heat loads over 5 kW/m² the air changes temperature between 20 and 30 C every few seconds. Controlling the humidity with traditional RH-sensors normally wast energy by humidifying in some AC-units and de-humidifying in others.
The ideal solution would be the control of absolute umidity. The umidity control (as well as the water piping, condensate drains etc.) could be eliminated from the AC-units and reduced to a separate, dedicated system that keeps the water content at, for instance, 20 g/kg air.
But where can I find this sensor ?