Innovative façade refurbishment with integrated air ducting for the existing building stock

For the successful transition of the energy system being sustainable, the energetic retrofitting of the building stock is a crucial factor. By reducing the heat demand of the existing buildings, both natural resources and the associated C02 emissions can be conserved. Extensive refurbishments of buildings often fail due to high costs, leading to only individual measures on the façade being carried out. The increased sealing of the building envelope of renovated buildings often causes moisture related problems due to improper ventilation. A residential ventilation system with heat recovery can ensure the necessary hygienic air change by reducing the ventilation loss considerably. Retrofitting barriers, such as the high cost of the internal ductwork and the impairments caused by dirt and noise for the tenants often prevent the installation of a central ventilation system. A promising solution, developed by the Fraunhofer Institute for Building Physics, provides the implementation of the air duct system in the building envelope. In this case, the air ducts are integrated directly in the mounted insulation panels. Such a system is implemented in a demonstration building in Kassel (GER) and investigated with regard to the achievable heat recovery and the energy efficiency of the system. Parallel to this, the air ducts will be investigated in the flow laboratory to optimize the roughness of the ducts and the associated pressure losses. Furthermore the building and the ventilation system will be implemented in a dynamic computational model, so that design recommendations for optimizing the air duct system on the façade with a high heat recovery potential, low pressure losses and highest energy efficiency can be made.