2E's (energy and exergy) analysis of a multi-stage variable leg-shaped TEG with CNT and graphene-based MXene ternary hybrid nanofluids as new coolant

The current theoretical study analyzes a performance comparison of a two-stage variable leg-shaped thermoelectric generator (TEG) with the combination of dissimilar p-type and n-type materials. For the cold side of the TEG configuration, water, MXene/Water, MXene/CNT, MXene/Graphene, and MXene/CNT/Graphene ternary hybrid nanofluid as new coolants have been considered. The objective of the present study is to ascertain the effect of flow parameters on hot and cold side fluids and to investigate the performance parameters of the TEG. The first stage of TEG is of a regular shape, while the later stage tapers to give a high-temperature gradient. Effect on voltage, power, conversion efficiency, second law efficiency, irreversibility, and normalized voltage with the coolant and exhaust flow rates have been investigated. The results revealed an optimum result of higher power output, second law efficiency, conversion efficiency, current, and voltage with a coolant flow rate of 0.007 kg s-1. Compared to water, MXene/Water nanofluid has 3.5% and 3.27% higher power output and second law efficiency, respectively, followed by MXene/CNT, MXene/Graphene, and MXene/CNT/Graphene ternary hybrid nanofluids. MXene/water nanofluid has 6.42% higher power output than water; MXene/CNT, MXene/Graphene, and MXene/CNT/Graphene ternary hybrid nanofluids have 4.28%, 4.23%, and 15.68% lower power output, respectively. The power output and second law efficiency of MXene/Water nanofluid are 3.5% and 6.84% greater than water. MXene/CNT, MXene/Graphene, and MXene/CNT/Graphene ternary hybrid nanofluids had 8.21%, 9.58%, and 10.95% poorer second law efficiency: with CNT and graphene-based MXene hybrid nanofluids, the improved TEG outperforms traditional units.

Automated summary

The current theoretical study compares the performance of a two-stage variable leg-shaped thermoelectric generator using different coolant materials. The study investigates the effects of flow parameters on the fluids and performance parameters of the generator. The results show that MXene/Water nanofluid outperforms water in terms of power output and second law efficiency.