Nacelle and aircraft engine with a cooling system for its hot elements

The cooling system (30) includes at least one channel (32) that draws off cold air (300) in a secondary air flow (200). At least one heat exchanger (34) is located in the channel for circulation of hot air (420) from a primary air flow (100) before reaching the hot parts (22) of an aircraft engine (10). The channel is provided with a supply pipe (322), an evacuation pipe (326) and an intermediate box (324). An independent claim is also included for an aircraft engine.