Design and experimental analysis of nanoparticle-enhanced latent heat storage unit-integrated solar thermal systems

In this thesis, the effect of utilizing nanoparticle-enhanced latent heat thermal energy storage unit on the performance of various solar-thermal systems has been analyzed experimentally. In the study, hybrid photovoltaic-thermal (PVT) air collectors, greenhouse dryers and solar desalination systems have been investigated. Conventional, paraffin-based thermal energy storage unit modified and copper oxide (CuO) nanoparticle-enhanced paraffin-based thermal energy storage unit modified versions of each system have been manufactured and simultaneously tested. In addition, CuO nanoparticle-enhanced matt black paint has been applied to the solar still as absorber coating material. In this context, the effect of combined utilization of nanoparticles has been investigated. PVT collector and greenhouse dryer tests have been performed at between 0.007-0.014 kg/s and 0.009-0.014 kg/s mass flow rates, respectively. According to experimentally obtained results, utilizing nanoparticle-enhanced modification increased thermal and exergy efficiencies of PVT collector between 9.22-14.19% and 13.61-19.01%, respectively in comparison to the conventional system. Moreover, electrical efficiency values of PVT collectors were found between the range of 10.00-13.00%. Agricultural products have been dried in greenhouse dryer tests. Utilizing nanoparticle-enhanced modifications in greenhouse dryer reduced drying time between 120-140 minutes. In addition, employing nanoparticle-enhanced modification decreased specific energy consumption as 23.79%. Specific moisture extraction rate values of greenhouse dryers were calculated between the range of 0.67-1.29 kg/kWh. Four different systems in total have been analyzed in solar desalination system experiments. Integrating nanoparticles in both thermal energy storage unit and absorber surface coating material improved accumulated productivity value as 26.77%. Also, thermal and exergy efficiency values of solar stills were attained between the ranges of 15.96- 19.30% and 1.25-2.01%, respectively. The obtained findings of this study showed that using nanoparticle-enhanced thermal energy storage unit significantly improved the performances of various types of solar-thermal systems.