Cartridge (1, 1') for moving a thermodynamic fluid between a cold part connected to a first heat source and a hot part connected to a second heat source for a thermodynamic cycle thermal machine, characterised in that it comprises at least: - a first exchanger, forming a so-called cold part, comprising a first hollow section comprising first means for circulating at least one heat transfer fluid, which means are suitable for and intended to be connected to a first heat transfer fluid supply circuit (A, B) connected to a first heat source, said first section comprising an internal wall and an external wall, - a second exchanger, forming a so-called hot part, comprising a second hollow section comprising second means for circulating at least one heat transfer fluid, suitable and intended for connection to a second heat transfer fluid supply circuit (C, D) connected to a second heat source, the said second section comprising an inner wall and an outer wall, - a third hollow section adapted and intended to be connected to at least one circuit for supplying at least one working fluid (J, H), said third section being disposed inside the first section and the second section, said third section comprising an inner wall and an outer wall, at least part of the inner wall of the first profile and a first part of the outer wall of the third profile being spaced apart and facing each other so as to form a first filling space, at least part of the inner wall of the second profile and a second part of the outer wall of the third profile being spaced apart and facing each other so as to form a second filling space, - at least one chamber adapted and designed to contain at least one thermodynamic fluid preferably at high pressure and in the supercritical state, said chamber comprising at least the first filling space and the second filling space which are in communication, - at least one displacer disposed inside said chamber and slidably mounted relative to the outer wall of said third profile and movable between a first position and a second position, and configured to displace said at least one thermodynamic fluid alternately between the first filling space and the second filling space, - a piston disposed inside said third profile and slidably mounted relative to the inner wall of said third profile and movable between the first position and the second position, the piston being adapted and intended to be displaced by said at least one working fluid (J, H) between the first position and the second position, the displacer and the piston being coupled to each other. - a first exchanger, forming a so-called cold part, comprising a first hollow section comprising first means for circulating at least one heat transfer fluid, which means are suitable for and intended to be connected to a first heat transfer fluid supply circuit (A, B) connected to a first heat source, said first section comprising an internal wall and an external wall, - a second exchanger, forming a so-called hot part, comprising a second hollow section comprising second means for circulating at least one heat transfer fluid, suitable and intended for connection to a second heat transfer fluid supply circuit (C, D) connected to a second heat source, the said second section comprising an inner wall and an outer wall, - a third hollow section adapted and intended to be connected to at least one circuit for supplying at least one working fluid (J, H), said third section being disposed inside the first section and the second section, said third section comprising an inner wall and an outer wall, at least part of the inner wall of the first profile and a first part of the outer wall of the third profile being spaced apart and facing each other so as to form a first filling space, at least part of the inner wall of the second profile and a second part of the outer wall of the third profile being spaced apart and facing each other so as to form a second filling space, - at least one chamber adapted and designed to contain at least one thermodynamic fluid preferably at high pressure and in the supercritical state, said chamber comprising at least the first filling space and the second filling space which are in communication, - at least one displacer disposed inside said chamber and slidably mounted relative to the outer wall of said third profile and movable between a first position and a second position, and configured to displace said at least one thermodynamic fluid alternately between the first filling space and the second filling space, - a piston disposed inside said third profile and slidably mounted relative to the inner wall of said third profile and movable between the first position and the second position, the piston being adapted and intended to be displaced by said at least one working fluid (J, H) between the first position and the second position, the displacer and the piston being coupled to each other.