Thermal efficiency analysis of a nanofluid-based micro combined heat and power system using CNG and biogas

In the present study, a micro combined heat and power (micro-CHP) system using compressed natural gas (CNG) and biogas fuels, was developed. The objective of this research study was to investigate the utilization of nanofluids as a working fluid to improve thermal performance of the micro-CHP system. Three different nanofluids based on the CNT, Al2O3, and SiO2 have been investigated. The nanofluids was used as the circulating fluid to recover the heating power from the micro-CHP system. Three different concentration of nanoparticles (25, 50 and 100 ppm) have been used. The efficiency of separated heat and power (SHP) system was 27.6% while using combined heat and power, the total efficiency increased up to 65.3%. The results showed that by using CNG gas thermal efficiency of micro-CHP improve compared to the biogas. The result of the present study showed that nanofluids enhances the thermal efficiency of the micro-CHP system. By using the Al2O3 nanofluid the efficiency of micro-CHP efficiency is 73%. While by using the SiO2 and CNTs nanofluids the efficiency of micro-CHP efficiency is 70% and 66.3% respectively. So, we can coclude that by using the Al2O3 nanofluid thermal performance of micro-CHP systems improves.