Monitoring results and optimization of a facade integrated ventilation concept for building retrofit

To simplify the installation of necessary ventilation systems in building energy retrofits, facade integrated ventilation combined with semi-prefabrication of envelope components is a promising solution. By speeding up the mounting time, a significant cost reduction is possible compared to a standard retrofit process. An office building in Freiburg was retrofitted in 2012 applying a demonstrator of this innovative concept. Prefabricated window modules integrating air inlets and outlets, facade integrated air ducts and a heat and moisture recovery ventilation device were implemented. A long term monitoring exercise was set up including energy, temperature, CO2 and humidity measurements. The results of this measurement campaign and an analysis of the system performance are presented, focussing on the influence of facade integrated air ducts on the energy performance of the whole system and on thermal comfort. A new specific definition of the global energy efficiency of facade integrated ventilation systems is proposed and used to evaluate the performance of the system. On the basis of the monitoring results, a simulation model was defined and used to optimize the integration concept for facade ventilation by testing different geometries and materials. The latest developments of the integration system are presented such as the next step of this work which is the implementation of the system on the facades of a multifamily building in Frankfurt.