An aircraft comprising a heat exchanging pack comprising an energy recovering module with a hot and a cold side, the hot side thermally contacting the cold side, providing a heat exchange. The heat exchanging pack also comprises a secondary heat exchanger and a compressor coupled with a turbine. The hot side module inlet fluidly communicates with the bleed air duct, the cold side module inlet fluidly communicates with the ram air duct, the hot side module outlet fluidly communicates with the compressor inlet, the compressor outlet fluidly communicates with the hot side secondary inlet, the hot side secondary outlet fluidly communicates with the turbine inlet, and the cold side secondary inlet fluidly communicates with the ram air duct. The energy recovering module comprises a conversion apparatus, configured to generate energy out from the heat exchange taking place in the energy recovering module between the hot and cold sides.