Exergy and thermoeconomic analyses of serpentine tube flat-plate solar water heaters coated with CuO nanostructures

Abstract

This study aims to evaluate the effect of cuprous absorber plate coated with copper oxide nanoparticles (CuO NSs) on exergy and economic changes and performance of flat plate collector solar water heater and compare the absorber performance with simple and black painted absorber. For this purpose, three solar water heaters were fabricated with the simple flat copper absorber plate, black painted copper absorber plate, and copper absorber plate coated with CuO NSs. All the three water heaters were tested together under the same conditions. The results revealed the performance of water heaters coated with CuO NSs improved compared to that of water heaters with black and simple copper absorber plates. The efficiency of water heaters coated with nanoparticles improved by 18.8% and 35.8% compared to that of water heaters with black and flat absorber plates, respectively. Analyzing exergy efficiency indicated nanostructures coating on the absorber surface increased absorption of incoming solar radiation and outlet fluid temperature and, consequently, improved exergy efficiency of solar collector by 11.2% compared to matte black absorber. Using solar water heaters coated with nanostructures saved more cost and electricity and shortened the payback period by 0.6 years compared to solar water heaters with simple cuprous absorber.