cooling system and / or heating a fluid comprising a heat exchanger deoiled air / fluid

The main object of the invention is a cooling circuit and / or heating (1) of a fluid (A) in a turbomachine (10) comprising a deoiled air duct (2), inside which flows from the oil-free air (HD), characterized in that it further comprises: a tubular heat exchanger (3) comprising an inner lumen formed at least partially by the deoiled air duct (2), wherein air circulates deoiled (HD) and an outer pipe, formed around the inner pipe defining with the inner pipe an inter-duct space in which circulates the fluid (a) to be cooled and / or heated, the transfer of heat between the fluid (A) and the oil-free air (HD) for cooling and / or heating the fluid (A).