Heat exchange assembly comprising at least one first and one second heat exchange body (5, 7), each body being of the plate heat exchanger type, comprising a plurality of metal plates of substantiallysimilar contour extending along a first dimension or length and a second dimension or width, spaced from and arranged in parallel rows to one another along a third dimension or thickness and sealingmeans bounding flattened passages with the said plates, forming at least one passage of a first type and at least one passage of a second type, the sealing means allocated to each passage releasing one fluid inlet and one fluid outlet, characterized in that one side bounded by a width and a thickness of at least one first heat exchange body is located at least partially opposite a side bounded bya width and a thickness of at least one second heat exchange body, the two sides being separated by insulating material (I).