A dynamic model of plate - fin heat exchangers was studied. The dynamic mathematical model of heat exchangers was established by using the lumped parameter method
especially the theory of the equilibrium surface "continuous method" of analysing the static and dynamic characteristics of heat exchangers was introduced. The accuracy of the lumped parameter method was verified by comparing the results of the lumped parameter method and the numerical method and the test. The characteristics of the equilibrium surface "continuous method" of analysing heat exchangers were thus demonstrated.