Long-Term Performances and Technoeconomic and Environmental Assessment of Al2O3/Water and MWCNT/Oil Nanofluids in Three Solar Collector Technologies

Abstract

Bringing together nanofluids and solar collectors has been widely discussed without any major advance or long-term study being carried out. In this context, this paper provides a useful feasibility study to help future decisions in using nanofluids in Solar Water Heating Systems (SWHSs) in different locations. The performances of SWHSs using the nanofluid-based flat plate solar collector (FPSC), evacuated tube collector (ETC), and compound parabolic collector (CPC) under the Mediterranean, arctic, and desert climate conditions are presented and discussed. The analysis is carried out using a transient-based numerical approach, solving energy balance equations for different systems. Various performance factors such as energy saving, solar fractions, and environmental impacts of auxiliary energy supplies are evaluated to feasibly assess the use of nanofluids in such devices. Simulation results demonstrate that the use of nanofluids increases the solar heater performance which reduces considerably the payback period ( $P_{\text{P}}$ ) of the investment in solar heating systems up to 3.34 years in Tunisian climate. Under Quebec’s climate region, the annualized solar return of the ETC system increases from 4874.65 US$ to 9785.93 US$ by adding 0.06 v% Al2O3 in water. Also, the use of nanofluids in solar collectors with electric auxiliary heaters reduces harmful CO2 emissions up to 0.49 tons/year.