CO 2 mitigation,energy matrices,and the performance analysis of N-evacuated tube collector (ETC)-integrated modified solar distiller for water/electricity co-generation using CQD nanoparticles

Abstract

With advances in science and technology, nanofluids are the ultrafast heat transfer fluids which effectively empowers the distillation process. In this research article, N-evacuated tube collector (N-ETC)-coupled single slope solar still-equipped built-in-passive condenser and roof-top semitransparent photovoltaic (PV) module have been analyzed incorporating carbon quantum dot nanoparticles (CQD-NPs). The effect of volume concentration of nanoparticles (NPs) and packing factor (β_c) is tested to study the system performance (thermal and electrical). The use of CQD-NPs showed impressive enhancement in thermal conductivity (56.06%), Reynold's number ( $7.93\times {10}^3$ ), evaporative (37.9%) and convective (76.94%) heat transfer coefficient even at moderate value of β_c (0.67). Thermal energy efficiency and overall daily productivity is improved by 37.67% and 44.15%, respectively, using CQD-NPs. Moreover, thermal energy/exergy-based energy metrics and life cycle assessment has been performed for different lifespans (n = 1 to 50 years) of the proposed system. Significant improvement in life cycle conversion efficiency [31.90% (β_c= 0), 28.91% (β_c= 0.67), 24.56% (β_c= 0.75), 32.02% (β_c= 0.85), 53.38% (β_c= 0.95)] is observed; also, enviro-economic analysis showed effective rise in annual CO₂ mitigation (tons) [41.39 (β_c= 0), 104.85 (β_c= 0.67), 96.23 (β_c= 0.75), 85.14 (β_c= 0.85), 65.51 (β_c= 0.95)] and carbon credits earned using CQD-NPs. This renewable stand-alone two-in-one output system effectively meet the drinking water and electrical energy requirements of societies, and families living in arid/semiarid regions.