Performance Analysis of a Combined Thermoelectric Generator, Organic Rankine, and Absorption Refrigeration Cycle

This study evaluates the exergetic performance of a novel combined thermoelectric generator (TEG), an organic Rankine cycle (ORC), and an absorption refrigeration cycle (ARC) run by engine exhaust heat. Further, this study investigates the effect of TEG columns on system performance and provides complete information lacking in previous studies related to engine exhaust-driven TEG-ORC systems. It was found that the net TEG and ORC power increases with the number of TEG columns while the ARC’s cold energy decreases. The organic fluid flow rate requires adjustment with the number of TEG columns to heat it up to the saturation temperature at the TEG outlet. Considering R123, R245ca, and R245fa as working fluids in the ORC, R123 and R245ca are found superior to R245fa. From parametric variation, it was found that the TEG and net ORC power decrease as ORC evaporation pressure increases for both R123 and R245ca, though R245ca performs better at lower pressures, while R123 excels at higher pressures. Meanwhile, ARC’s cooling output increases with evaporation pressure, with R123 consistently providing more cooling energy than R245ca. The cooling output surpasses the combined TEG and net ORC power, especially for R123. Consequently, the total energy output increases with evaporation pressure, with R123 outperforming R245ca in all conditions. The overall system energy and exergy efficiencies for R123 were 49.97% and 40.83% with 5 columns and 10 rows of TEG modules at the recommended ORC evaporation pressure of 32 bar.