A Novel Similarity Solution Approach Based Thermal Performance Prediction and Environmental Analysis of Evacuated U-Tube Solar Collector Employing Different Mono/Hybrid Nanofluids

Abstract

In this article, a novel similarity function-based two-dimensional steady-state model is developed to analyze the thermal performance of an individual evacuated U-tube solar collector (EUTC). Using the developed model, the energy and environment assessments of a EUTC have been carried out employing different water-based mono/hybrid nanofluids as energy exchange fluids (EEF). The influence of nanoparticle volume concentration on energy gain, mass flow rate reduction, and efficacy has been analyzed. The influence of Reynolds number on energy gain is also investigated. The results show that Al2O3+MWCNT (multiwalled carbon nanotube) has high energy gain, whereas MgO has high mass flow reduction compared to water as a base fluid at 2% volume concentration. The efficacy of EUTC has been enhanced using nanoparticles as an additive. Employing Al2O3+MWCNT as EEF, the impact of EEF flow rate, EEF inlet temperature, ambient temperature, and solar intensity on the energy gain and efficacy of EUTC have been analyzed. It is observed that solar intensity and ambient temperature have major and minimum influence on EUTC performance.