Black hole growth models related to the classical Bondi accretion scenario. Although the rates differ widely and predict extreme upper values, they lie within the parameter range of the observation-based models, which are plotted in Fig. 1. In case of very massive seed black holes around M_• = 10¹⁰ M_⊙ at z = 1, Bondi accretion alone is sufficient to explain the deposited feedback energies even in the most extreme cool core clusters.