A Computer Program for Design Optimization and Performance Analysis of Supercritical Organic Rankine Cycle System for Low Grade Exhaust Waste Heat Recovery of I.C Engine

摘要

The power generated inside the cylinder of an IC Engine is not completely transferred to the driving wheels of an automobile. Most of the combustion energy of fuel gets wasted via friction, cooling system and majority through exhaust gas of an I.C Engine. Various bottoming and thermodynamic cycle have been proposed to recover the low grade exhaust waste heat into useful work. Organic rankine cycle system proved to be the best among all the proposed cycle for efficient conversion of low grade waste heat energy. However, the compact design and performance optimization of the ORC system is still a challenge. In present work the Supercritical ORC system is devised as internal heat exchanger (IHE) type. The two supercritical organic dry working fluids are selected namely R245fa and R11 after comparative study carried for the ORC system operation. The system performance through each working fluid is analyzed subsequently. A computer program is developed and the simulation is done in engineering equation solver (EES) for the calculation and analysis of different thermodynamic parameters. The developed computer program also investigates the IHE efficiency, and its overall effectiveness on thermal efficiency of the ORC system. The program also helps in design optimization of ORC system by performance analysis for the selected working fluids and given low temperature heat source.