Experimental investigation of the bifacial photovoltaic module under real conditions

In this study, the bifacial photovoltaic (bPV) and mono-facial photovoltaic (mPV) modules, with similar structure, are employed to validate the previously developed coupled model, and also to estimate the onsite bPV performance. Besides, the daily bPV and mPV electrical and thermal performances are measured and compared under the same conditions. Results show that the bPV module outperforms the mPV module obviously and the average daily bifacial gain is 13.08% and 16.54% for the sunny and cloudy days, respectively, demonstrating that the bPV technology has an obvious advantage in adapting to various weather conditions, especially under low irradiance. For the thermal performance, the temperature of the bPV cells is higher than the mPV under high irradiance but lower under low irradiance. In addition, weekly performance evaluations for the bPV module are also conducted. Results show that the daily bifacial gain for the bPV module ranges from 12.94% to 16.94% and thus the weekly bifacial gain of 14.54% can be achieved. Furthermore, some suggestions are provided for achieving higher bPV power output by investigating the effects of albedo, tilt angle and orientation on the bPV performance. It is recommended to install a bPV module on the high albedo ground, with a tracking technology at an optimum tilt angle to obtain high power output. Finally, long-term predictions of the bPV performance are performed, illustrating that the yearly bifacial gain, array yield, production factor and energy efficiency is up to 14.77%, 3.76 h/d, 87.23% and 17.20%, respectively.