Assessment of the impact of sound emissions of central and decentral air-to-water heat pumps in a renovation project

To reach the European-wide goal of a sustainable, efficient and decarbonized building stock by 2050, the actual renovation rate must be at least triplicated. Heat pumps (HPs) will play in this context a crucial role in replacing the existing fossil-based technologies. On the other hand, multi-family buildings subjected to renovation present non-negligible challenges when HP systems for space heating and/or domestic hot water must be installed, among others source accessibility, destructive installation procedures and noise. To further increase their acceptance, HPs must be therefore efficient, silent and compact. However, incorrect sizing procedures lead frequently to oversizing, which has not only implications in terms of performance but also in terms of sound emissions in the surroundings. Within the research project “PhaseOut”, seven multi-family buildings in Vienna will be renovated. For all of them, the space heating demand will be covered by a centralized monobloc air-to-water speed-controlled HP. For the domestic hot water demand instead, centralized, semi-centralized and fully decentralized options will be adopted. The sound pressure level in the environment surrounding the renovated buildings was evaluated by means of the software CadnaA. Preliminary results highlight that the operation of the centralized air-to-water HPs has the biggest influence on the sound pressure level in the surroundings and that silent mode operation is not sufficient alone in the night to contain the sound emissions below the limit suggested by regulations.