The physics reach and feasibility of the Future Circular Collider (FCC) with centre of mass energies up to 100 TeV and unprecedented luminosity has delivered a Conceptual Design Report early 2019. The new energy regime opens the opportunity for the discovery of physics beyond the standard model. Proton-proton collisions at 100 TeV will produce very high energetic particle showers in the calorimeters from both light jets and boosted bosons/top quarks. The reconstruction of such objects sets the calorimeter performance requirements in terms of shower containment, energy resolution and granularity. Furthermore, high-precision measurements of photons and electrons over a wide energy range are crucial to fully exploit the physics potential of the hadron collider, especially given the large amount of collisions per bunch crossing the detectors will have to face (pile-up of <μ> = 1000). The reference technologies for the high-granularity calorimeter system of the FCC-hh detector are presented: liquid argon (LAr) as the active material in the
electromagnetic calorimeters, and the hadronic calorimeters for |η| > 1.3 (endcap and forward region), and a scintillator-steel (tile) calorimeter as hadronic calorimeter in the barrel region. The simulation framework and the reconstruction chain, that includes the calibration and clustering of calorimeter cells and the estimation of pile-up induced, and electronics noise are introduced. The performance studies for single particles and jets in the combined calorimeter system are presented. In conclusion, the achieved performances will be compared to the physics benchmarks of the FCC-hh experiment.