The dynamic simulation of an integrated, double pipe heat exchanger network was validated through experimentation. A steam-water, concentric tube, heat exchanger was coupled to a water-water preheater. When the preheater was configured for cocurrent flow with equal fluid velocities in its annulus and core, Lagrangian-based derivations yielded analytical solutions that accurately predicted observed temperature dynamics. When the preheater was configured for countercurrent flow with distinct fluid velocities in its annulus and core, analytical solutions for the heater and connecting tubing were coupled with Eulerian based numerical solutions for the preheater. Programming used Mathcad. Nonlinear regression analysis of steady state data was used to determine system parameters. The significance of time delays through the integration of unit operations is illustrated. (C) 2011 Elsevier Ltd. All rights reserved.