Process water from green roof

Green roof: irrigation - evaporation - rainwater retention 

The run-off water from the green roof above the office wing, which was supplied by OPTIGRÜN, is collected in a separate 10m³ cistern, used for research into different cleaning methods and then used for irrigation. The green roof serves the natural climate regulation by cooling by evaporation and the increase of biodiversity. It also minimises rainwater run-off (retention) and extends the service life of the roofing film.


  • Size approx. 300 m²
  • Drain and water storage element FKD 40: approx. 40 mm
  • Extensive multilayer substrate type E: approx. 80 mm
  • Sedum vegetation, type OPTIGRÜN Natural roof

117,600 kWh cooling capacity!

300 m² x 0.8 m precipitation x 0.7 (run-off coefficient 0.3 ) = 168 m³

At x 700 kWh/m³ evaporative cooling --> 117.600 kWh cooling capacity