Evacuated tube solar collector performance using copper nanofluid: Energy and environmental analysis

The effect of metallic copper nanoparticles on the thermal efficiency of an evacuated tube solar collector was studied. Different volume concentrations of copper nanoparticles e.i. 0.01%, 0.02% and 0.03% were examined to explore the effect of nanoparticles on evacuated solar collector performance. The tests were performed at three volume flow rates of 0.6 L/min, 0.7 L/min and 0.8 L/min. The results demonstrate a 50% increase in the output temperature. Also, the heat energy incremented from 417 W to 667 W, which is equivalent to 34% area reduction for the same energy production. The remarkable enhancement in the heat removal factor to reach a value of 0.97. Copper nanoparticles played a significant role to increase both the absorbed energy and the removal energy parameters. Their maximum values were found for a volume concentration of 0.03% and at the volume flow rate of 0.8 L/min to be 0.83 and 21.66, respectively. Finally, environmental analysis is carried out to find the role of copper nanoparticles in CO₂ reduction. The comparison between current results with reported results in the literature for other types of nanoparticles, show the high potential of copper nanoparticles for solar collector applications.