Investigation and optimization of the performance of a spectrum splitting photovoltaic/thermal system using multiple kinds of core-shell nanofluids

Core-shell nanofluids have better tunability than nanofluids containing nanoparticles made of a single material. Analysis and optimization of nanofluid parameters can help improve the performance of the nanofluid spectrum splitting photovoltaic/thermal system. This study develops and experimentally validates a numerical model of a double-pass nanofluid spectrum splitting photovoltaic/thermal system. The influences of core diameter, shell thickness, and concentration on the optical properties of 11 kinds of nanofluids are investigated, as well as the electrical and thermal performance of the system using the nanofluids as working fluids. Using the genetic algorithm, with electrical and thermal constraints, parameters are determined to achieve the best performance. Results indicate that, when using water as the base fluid, among these kinds of nanofluids, the optimized performance is very similar. The biggest difference in the outlet temperatures is 0.15 K with electrical constraint, while that in the electrical efficiencies is 0.18 % with thermal constraint. After changing constraint, the outlet temperatures in the optimization results decrease by about 1 K, while the electrical efficiencies increase by more than 1.5 %. Using Therminol VP-1 as the base fluid, the optimized performance is also similar. For the system studied, water is a more suitable base fluid than Therminol VP-1.