Comparative investigation of concentrated photovoltaic thermal-thermoelectric with nanofluid cooling

Highlights: • A comparison between the CPVT only system and CPVT-TE collectors is conducted. • A transient study using finite volume method is performed for the solar systems. • The impact of adding a 0.5% graphene/water nanofluid in CPVT-TE is analyzed. • Energy and exergy assessment under London climatic condition is performed. Thermoelectric modules are capable of converting heat into electric energy via the Seebeck effect. Therefore the addition of the thermoelectric generator modules (TEG) between the PV module and the absorber plate inside a concentrated photovoltaic thermal (CPVT) solar collector can be a feasible way for to enhance their electrical generation. A comparison between the CPVT only system and CPVT system integrated with TEG (CPVT-TE) is conducted using numerical simulation. Therefore CPVT-TE with water and CPVT-TE with 0.5% graphene/water nanofluid is investigated. A transient study using the finite volume method is presented, and computation is performed for all the considered solar systems for a typical sunny day and cloudy day under London climatic conditions. The CPV and the outlet fluid temperatures, as well as, the energy and exergy calculations are carried out to assess the performance of all the considered solar systems. The results reveal that the improvements in the total electrical power generated by the CPVT-TE with 0.5% graphene/water nanofluid and CPVT-TE compared to CPVT collector are 11.15% and 9.77%, respectively for the summer day, while, that for the winter day is 5.14% and 4.58%, respectively. The reductions in the thermal power provided by the CPVT-TE with 0.5% graphene/water nanofluid and CPVT-TE compared to CPVT collector are 6% and 11.76%, for the summer day, while, that for the winter day are 4.86% and 10.53%, respectively. Moreover, the total exergies generated by 0.5% graphene/water nanofluid CPVT-TE and water CPVT-TE collectors increased by 4.88% and 0.68% respectively, for the summer day, while that for the winter day are 2.99% and 0.95% respectively, in comparison with the conventional CPVT system.