Urban concentrated photovoltaics: Advanced thermal management system using nanofluid and microporous surface

Abstract

Distributed clean energy generation through solar radiation has always been considered as the best available potential, however its successful and effective implementation in within the built urban environment is restricted with technological limitations in materials, heat transfer, high cost and limited installation space. Among various solar energy options, Concentrated Photovoltaic (CPV) technology required low installation area due to its high efficiency. Efficient thermal management for CPV system could furthur enhance its cell efficiency and maximum concentration ratio, which results in lowering its cost and installation area. A unique combination of nanofluid over microporous surface has been tested in Nucleate Boiling Heat Transfer (NBHT) system, as a thermal management technique for CPV. The performances of the NBHT system is tested and comparatively analyzed for microporous surfaces, nanofluid, and hybrid-micro nano surfaces. During testing of nanofluid over a microporous surface, the deposition of nanoparticles resulted in blocking of micropores and disturbed the original enhancing phenomena. The decrease in performance is observed with an increase in the concentration of nanofluid: 0.0001%, 0.001%, and 0.01%. Microporous surfaces with deionized water as working fluid resulted in maximum performance enhancement, in critical heat flux (CHF) and heat transfer coefficient (HTC). Compared to the standard plain surface (P), the CHF of the microporous surface increased by 62%, from 690 kW/m2 to 1120 kW/m2, while the average increase in HTC is 101%. The experimental results from NBHT experiments are then coupled with an analytical model for the corresponding CPV performance of electrical efficiency, maximum concentration ratio, and required installation area.