Performance evaluation of small scale solar organic Rankine cycle using MWCNT + R141b nanorefrigerant

The principal purpose of the current investigation is to analyze the thermal performance of a small scale solar organic Rankine cycle (ORC). Herein, a flat plate solar collector (FPSC) was utilized to feed heat to ORC. A mathematical model formulated in Engineering Equation solver (EES), uses FPSC's experimental output to assess the thermal performance of ORC. To choose the most appropriate organic fluid for ORC, a preliminary study is conducted for the comparison of the performance of R141b with other organic fluids of previous research studies. In the preliminary analysis of this study, the MWCNT + WO₃/water nanofluid is used in the solar collector for its performance enhancement and obtained a maximum thermal efficiency of 73.21% at 3 lpm and 1.5 vol%. Moreover, MWCNT/R141b nanorefrigerant is used as an organic fluid in ORC due to its enhanced thermophysical properties. The parametric analysis is also executed to compute the energetic and exergetic performance of ORC at different nanoparticle concentrations and volume flow rates. The parametric study demonstrated a significant increment from 16.30 to 24.82% and 9.03 to 15.33% in energy and exergy efficiency, respectively, for 0.5 vol% of nanorefrigerant and 3 lpm volume flow rate in collector when nanofluid volumetric concentration changes from 0.5 to 1.5 vol%.