Coupled optical-electrical-thermal loss modelling and energy distributions of a photovoltaic module

Abstract

This paper develops a coupled optical-electrical-thermal loss model of a photovoltaic (PV) module under various conditions. Validation shows that the coupled optical-electrical-thermal loss model is accurate and effective, ranging from 0.17% to −1.88%, which are smaller than limit error in the IEC standard. The developed model is then applied to investigate energy distributions of a PV module under standard test conditions (STC) and dynamic conditions by qualitative and quantitative evaluations. Results show that the energy distributions under dynamic conditions are similar to those under STC. The power output, optical and thermal losses are 16%, 16% and 68%, respectively. The optical losses mainly result from transmission loss (43.4%), reflection loss at air-glass interface (25.5%) and reflection loss at PV layer (25%). As for complicated thermal losses, they are caused by thermalization loss (38.4%), sub-bandgap loss (21.6%), angle mismatch loss (12.9%) and voltage drop loss due to non-radiative recombination (11.6%). Furthermore, some optical suggestions (anti-reflection film, velvet surface and light trapping structure) and thermal suggestions (up conversion, down conversion, stacked structure, surface recombination optimization and the photovoltaic/thermal technology) are proposed to optimize the PV power output.