Investigation and comparison of heat pump noise in the lab and field

The presentation covers a contribution from the publicly funded HP-QUEEN MENESA project on the characterisation of a heat pump in the laboratory with comparisons in the field at comparable operation conditions. The data in the lab are obtained from a hemi-anechoic chamber that is equipped with temperature control to allow standardized measurements at -7 °C and 7 °C, for example. In this environment spherical sound radiation pattern are determined on a movable hemi-circle microphone arrangement allowing the assessment of source location and radiation contribution as well as sound power determination at the different operation points of the heat pump. These data are compared and analysed to measurements with the same heat pump in the field at model houses at the Fraunhofer-IBP location in Holzkirchen. Furthermore, we are also investigating the transmission path from the noise of the heat pump outdoors into the building taking sound reduction index of i.e., windows into account. It is planned to connect a sychoacoustic analysis together with a questionnaire to these investigations that allows assessment of the final sound characteristics inside the building.