Analysis of the exergy performances of a glazed and unglazed PV/T collector under different conditions

Abstract

The exergy performances of the hybrid PV/T solar collector using different heat transfer fluids was numerically investigated. The mathematical model is based on the energy balance equations applied to each collector element as well as exergy balance founded on the second law of thermodynamics. The governing equations are discretized and solved using Finite difference method based on alternating directions implicit scheme. A comparative study of the exergy performances of the hybrid collector with and without glass cover using nanofluid Cu−water, distilled water and water-EG mixture as transfer fluids is conducted. The results showed that Cu−water nanofluid enhances the total exergy of the collector by 1.6% and 2.7% highest than water and water-EG respectively. However, regarding the thermal exergy, water-EG mixture is the best fluid which allows to improve the collector production by 17% and 28.5% than water and Cu−water respectively. The maximum energy and exergy efficiencies reached over the day are around 70% and 15% respectively. In addition, it is found that the overall exergy produced by the unglazed system is 6.45% higher than the collector with glass cover. While, the total energy yield of this latter is 26% higher than the system without cover. The effect of operating parameters on the collector exergy effectiveness is analyzed and discussed in this work.