A turbo-compressor (TC) system for extracting energy from an aircraft engine. The TC system has a TC assembly with a turbine mechanically coupled to at least one compressor. The TC system has a TC inlet in fluid communication with a bleed air system in the aircraft engine and a TC outlet in fluid communication with an air conditioning (AC) pack of an aircraft air conditioning system and configured to extract reduced temperature pack inlet air from the TC assembly into the air conditioning pack. The TC system has a ram air inlet coupled to the at least one compressor. The TC system has a TC control valve, and a TC check valve or a TC shutoff valve, both coupled to the TC assembly via a plurality of connective ducts. The TC system extracts energy from the bleed air to reduce bleed air flow and AC pack ram air usage.