Single and multi-objective optimization of PVT performance using response surface methodology with CuO nanofluid application

The nanofluid application in photovoltaic thermal (PVT) systems is widely known as an effective solution for improving output performance. However, studies exploring the optimum operation point of PVT systems with nanofluid application are scant in the current literature. The novelty of the study lies in exploring the optimum operating conditions of each PVT output using single-objective optimization and the overall performance optimization using multi-objective study. The conditions were explored with the application of copper oxide nanofluid as a coolant in PVT systems. The investigation was conducted using a numerical equation-based model developed in TRNSYS simulation environment. An experimental test was conducted to validate the outputs of numerical model. After validating the numerical model, TRNSYS model was investigated for 0.10%-0.50% volume concentration and 60–120 kg/h mass flow. The output data was then imported into Design-Expert software for performance optimization. Central composite design was selected as it is the most suitable fractional factorial design option in response surface methodology. In single-objective investigation, the optimization conditions for PVT outputs are identified as follows, the optimum electrical efficiency output was 14.64% at 90 kg/h fluid flow and 0.10% concentration, the thermal efficiency output was 34.94% at 120 kg/h fluid flow and 0.50% concentration, the overall energy efficiency output was 49.28% at 88 kg/h fluid flow and 0.10% concentration, the overall exergy efficiency output was 16.45% at 60 kg/h fluid flow and 0.50% concentration. The multi-objective study indicated that the collective performance of PVT outputs is optimum at 91 kg/h fluid flow and 0.10% concentration.