Evaporative cooling of a building envelope
Type: Industrial, Detailed studies
Client: University of Stuttgart
Summary: Evaporative cooling study of a factory envelope. A tailor-made extension for IDA ICE was developed and used. Comparison between measurement and simulation showed very good agreement.
Its aim is the construction of a model factory with greatly enhanced efficiency through a combined planning of the subsystems ‘building’, ‘technical infrastructure’ and ‘machinery’. The project team included 36 partners from industry and research. In the factory, exhaust heat from the machines is transferred via a water flow to capillary pipes that are located in the building envelope. The envelope is then adiabatically cooled during the day by spraying it with rainwater. Overnight the envelope is cooled through longwave radiation.
The principle behind the envelope of the ETA Fabrik
IDA ICE, the building simulation tool chosen to support the project, could however not model the adiabatic cooling process out-of-the-box.
The comparison between measurement and simulation showed a very good agreement. This validation was important since the implementation contained certain simplifications. For instance is in reality the humidification modulated in intervals of several minutes whereas the evaporation in the model was assumed to be continuously.
Measured and simulated performance with and without humidification
With the good agreement it was concluded that the implementation was sufficiently accurate to interrogate different design scenarios, for instance the simulation of the entire ETA-Fabrik building or the evaluation of the impact of different supply temperatures for the envelope humidification.