Set of heat exchangers (1; 101; 301; 401; 501) intended to form a contactless heat transfer unit between a primary fluid and a secondary fluid, the set of heat exchangers comprising two exchangers (10, 50; 410; 550; 510, 550), namely a first exchanger (10; 410; 510) and a second exchanger (50; 450; 550) suitable for exchanging the heat between at least one primary fluid, for example high-pressure compressed air, and at least one secondary fluid, for example low-pressure - each exchanger (10, 50) comprising a pile of several plates (12, 52) positioned parallel on top of each other, according to a direction known as a pile, in a way to define at least i) primary passages (12P, 52P), conform for the flow of primary fluid and ii) secondary passages (12S, 52S), conform for the flow of secondary fluid, the primary passages (12P, 52P) and the secondary passages (12S, 52S) succeeding each other according to a predetermined pile pattern, - the pile of plates of the first exchanger (10; 410; 510) defining a first connection face (12F; 412F; 512F) connected operatively to the primary passages of the first exchanger (10; 410; 510), the pile of plates of the second exchanger (50; 450; 550) defining a second connection face (52F; 452F; 552F) connected operatively to the primary passages of the second exchanger (50; 450; 550); - the set of heat exchangers (1; 101; 301; 401; 501) being characterised in that the first exchanger and the second exchanger are positioned so that the first connection face is adjacent to the second connection face; and in that it comprises additionally: - a chamber (30; 430; 530) defined by the first connection face, by the second connection face and by a chamber volume extending between the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one primary compartment disposed in the chamber volume to channel all or part of the primary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one secondary compartment which is separate from said at least one primary compartment and which is disposed in the chamber volume to channel all or part of the secondary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F). - each exchanger (10, 50) comprising a pile of several plates (12, 52) positioned parallel on top of each other, according to a direction known as a pile, in a way to define at least i) primary passages (12P, 52P), conform for the flow of primary fluid and ii) secondary passages (12S, 52S), conform for the flow of secondary fluid, the primary passages (12P, 52P) and the secondary passages (12S, 52S) succeeding each other according to a predetermined pile pattern, - the pile of plates of the first exchanger (10; 410; 510) defining a first connection face (12F; 412F; 512F) connected operatively to the primary passages of the first exchanger (10; 410; 510), the pile of plates of the second exchanger (50; 450; 550) defining a second connection face (52F; 452F; 552F) connected operatively to the primary passages of the second exchanger (50; 450; 550); - the set of heat exchangers (1; 101; 301; 401; 501) being characterised in that the first exchanger and the second exchanger are positioned so that the first connection face is adjacent to the second connection face; and in that it comprises additionally: - a chamber (30; 430; 530) defined by the first connection face, by the second connection face and by a chamber volume extending between the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one primary compartment disposed in the chamber volume to channel all or part of the primary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one secondary compartment which is separate from said at least one primary compartment and which is disposed in the chamber volume to channel all or part of the secondary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F). - a chamber (30; 430; 530) defined by the first connection face, by the second connection face and by a chamber volume extending between the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one primary compartment disposed in the chamber volume to channel all or part of the primary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F), - at least one secondary compartment which is separate from said at least one primary compartment and which is disposed in the chamber volume to channel all or part of the secondary fluid between the first exchanger and the second exchanger through the first connection face (12F; 412F; 512F) and the second connection face (52F; 452F; 552F).