The Hippokrates-System has the enormous advantage that in the course of cooling below dew point any occurring condensate is being absorbed by the calcium-silicate panel which will then be slowly returned into the room when the outside temperature sinks, in particular at night, and as a consequence thereof the Hippokrates-System may be switched off. Returning condensate humidity into the room leads to passive cooling in form of evaporation, i. e. a room may be passively cooled from late afternoon to the following morning. This process is reversible without limit.