AbstractA detailed analyaia of the dynamio behaviour of a 4-input counter flow heat exohanger has been per formed by aolving the ayatem partial differential equations with finite differenoe techniques. The model appears in good accordance with praatioe. Model identification with original techniques le ada to reduced order linear models. Results with reepeat to identification goodneaa and to various system working conditions are evaluated. Experi_ menta performed with a proposed identification al gorithm from step response are alao presented.