ESDU 98006 provides a series of case studies covering the selection, thermal design and thermal performance of heat exchangers. The case studies follow the calculation procedures laid out in ESDU 98003 and illustrate many of the powerful features of the effectiveness - NTU method, covering both the new design of single exchangers and trains of shells to an exchanger retrofit situation. ESDU 98003 also introduces the method and the graphical, analytical and empirical data used here and presented in ESDU 98004 and 98005. Analytical techniques used to derive the data are described in ESDU 98007.