Tetralin + fullerene C60 solutions for thermal management of flat-plate photovoltaic/thermal collector

A new composite heat transfer fluid consisting of tetralin and fullerene has been proposed for photovoltaic thermal hybrid solar harvesting. It features a unique absorption spectrum that is capable of sharply cutting off solar energy irradiated in the range of wavelength from 300 to 650 nm, making it a perfect candidate for simultaneous harvesting of both photovoltaic and thermal components of solar energy. The proposed composite revealed outstanding stability and facile synthesize root, which are the two main obstacles for applicability of nanofluids. It was shown experimentally that the additives of fullerene to tetralin do not alter significantly it's thermophysical properties apart from viscosity that increases moderately. Besides, tetralin/fullerene solutions show similar thermohydraulics performance to that of pure tetralin in laminar flow regime or insignificantly lower in transient and turbulent flow regimes. A new figure of merit was proposed to analyze the thermohydraulics performance that consider not only exergy losses due to the kinetic energy dissipation, but also exergy losses associated with a finite temperature difference in the heat exchanger. As a result, the proposed figure of merit indicates the decrease of the heat transfer performance of tetralin/fullerene solutions that directly proportional to fullerene concentration. The performed simulation suggests that the total energy efficiency of flat-plate photovoltaic/thermal solar collector goes up to 60.4 % estimated according regulation (EU) No. 811/2013. Finally, life cycle analysis revealed further improvement root in view of environmental impact.