Noise and vibration characteristics of outdoor heat pumps

Heat pumps are one of the key solutions for climate-neutral building heating and air conditioning. Heat pumps that use air as a heat source dominate with a share of over 70 %. Due to the growing number of these heat pumps, their noise emissions must be minimised. In the QUEEN-HP MENESA publicly funded project network, preliminary investigations, acoustic evaluation, and the development of recommended measures for noise and vibration reduction on components and devices are treated. The focus is on the noise and vibration emissions of externally installed heat pumps. Two laboratories at Fraunhofer IBP have been set up for this purpose. A hemi-anechoic chamber 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. A second laboratory that is designed as a reverberation chamber is equipped with a reception plate to determine impact sound, forces, and impedances together with sound power. With these quantities as input data simulations can be conducted for vibration distribution in buildings and sound radiation into rooms of the building. The paper introduces the described laboratories together with the results of acoustic measurements and analysis regarding the parameters sound power, frequency spectrum, spatial radiation characteristics and structural parameters such as structural power levels. An outlook is given to the application in simulations and validation in the field.