ADVANCED THERMAL MANAGEMENT OF CONCENTRATED PHOTOVOLTAIC SYSTEMS AND INTEGRATION IN MULTIGENERATION APPROACHES

Abstract

Today, highly efficient multijunction solar cells are powering the space satellites. The economic use of such solar cells in terrestrial applications requires concentration of the solar light at an order of more than 300 sun. However, the solar concentration raises the concerns for heat accumulation on the solar cells since it deteriorates the photovoltaic conversion efficiency. The temperature sensitivity of the efficiency of multijunction cells under concentrated solar illumination is propitiously smaller than the crystalline silicon cells, allowing the utilization of the cell heat in several useful applications. An effective thermal management system is still required to transfer the high heat flux from the solar cells at a desired temperature. An advanced boiling heat transfer method for thermal management of concentrated photovoltaic systems is proposed. The cell heat is recovered from the backside surface of the photovoltaic modules via an enhanced nucleate pool boiling method using aqueous suspensions of different colloidal carbon materials. Dispersion of carbon colloids significantly enhances the boiling performance. A series of characterization on the heating surface and fluids is carried out to identify the enhancement mechanism. The electricity and heat generated by the concentrated photovoltaic/thermal (CPVT) system are utilized in multigeneration approaches. The performance of the multigeneration systems is assessed by energy and exergy analysis, based on thermodynamic principals. Further, a comprehensive parametric study is conducted to investigate the effect of varying conditions on the efficiencies and production rate of the proposed systems. Improved boiling heat transfer is identified as a useful method for heat recovery from solar cells, which brings about safer operation at a broader range of solar concentration ratio, reduced exergy destruction, and enhanced efficiency. Splitting the solar light spectrum is also studied as another useful approach for efficient utilization of solar energy.

Date of Award	2019
Original language	American English
Awarding Institution	HBKU College of Science and Engineering