Rapid retrofit solutions integrating HVAC into prefabricated EWIS systems
Paper presented at CLIMA 2013, Prague, Czech Republic, 16.06.2013-19.06.2013
Within the context of energy renovation of buildings cost reduction is a key requirement to increase the retrofit rate as part of a long term strategy for reduction of CO2 emissions. A new concept consists in the prefabrication of façade components with integration of both, external wall insulation system (EWIS) and heating, ventilation and air conditioning components (HVAC). The semi-prefabrication, consisting in prefabricating only the most sensible parts of the façade, has the advantage of being more flexible and could allow a real reduction of the renovation costs, maintaining a high quality standard. The integration of the ventilation system avoids problems like humidity condensation in renovated buildings with high level of air tightness. The life cycle cost of the ventilation device depends strongly on the centralization level of the device (one per building, per dwelling or per room). The actual market shows that the decentralized devices are very promising on this point of view. The renovation of an office building belonging to the Fraunhofer ISE permitted to test an innovating concept of semi-prefabrication of the façade components, integrating a central balanced ventilation system. This concept simplifies the installation work, particularly for the treatment of the technical details which are concentrated around the windows. The thermal bridges are reduced and the installation of the air inlets and outlets is very easy thanks to their integration in the window frame. The heat losses of the integrated channels in the façade are the weak point of the system and modifications to this concept could be developed in order to improve its performances.