AbstractIDERS - Interactive Design of Energy Recovery Systems, is based on interactive computation and was created to design power plant hardware for stearn production. The method is based on heat transfer and thermody namic theory [31.[4]. The models and algorithms of IDERS [16]describe the heat transfer, flow, and mechanical properties of this type of waste heat exchanger.The heat transfer models used consider finned tubes in cross-flow, with hot gas heating a fluid flowing within the tubes. Tube and fin material constrail1ts are considered. Standard thermodynamic data and commonly available heat transfer and material models are used. In view of the importance of gas-side pressure drop in such heat exchangers. a basic concept of IDERS is the ability to optimize the usc of available pressure drop.The software consists of five interconnected and cooperating programs: MODE - to design the general thermodynamic process; HOT which determines p,uameters. materials and dimensions of superheater equipment; MED and COLD - which detennine the same things for the boiler and economizer respectively; and PRESS which is used to optimize overall heat exchanger design based upon av,lilable pressure drop. The software is writtell in FORTRAN IV [7] and has been implemented on a PDP 11/55 with graphics facilitie. The programs work in sequence. The user can interact in every stage. correcting the design parameters and optimizing, and return to earlier programs as necessary. Input from the terminal at each stage is illustrated on the TEKTRONIX screen. The user can obtain printer hard copy of the results and a multicolor plotter copy of the graphical output. An example of the design of a specific 'team producing system is included. The Waste Heat Exchanger considered. receives hot gases from a source such as a stationary gas turbine. and uses this energy. sometimes with supplementary heat addition, to generate steam. The system works rapidly and performs the hardware design of this kind uf steall1 plal1t effectivel.