Experimental study on performance assessment of photovoltaic/thermal-thermoelectric generator systems: Bifacial and tandem types

The utilization of photovoltaic/thermal-thermoelectric generator (PV/T-TEG) systems holds great promise for achieving efficient utilization of the full solar spectrum. However, the conventional tandem structure design fails to effectively address the issue of temperature mismatch between the PV and TEG components during operation, highlighting the need for an innovative solution. To address this limitation, an innovative bifacial PV/T-TEG system was developed in this study. A practical test setup was employed to compare the performance of the conventional tandem system with the novel bifacial system under controlled laboratory conditions. The influences of solar radiation and water flow rate on the temperature, electrical, and thermal characteristics of both system configurations were thoroughly investigated and analyzed. The experimental findings unequivocally demonstrate that the recommended bifacial system exhibits lower average PV module temperature and a larger temperature difference in the TEG component when compared to the conventional tandem configuration. Specifically, the temperature reduction in the PV component could be higher than 18 K, while the improvement in temperature difference in the TEG component was larger than 5 K. Moreover, both the PV and TEG components show significantly enhanced power output. The PV power output experiences an improvement ranging from 4.7% to 12.7%, while the maximum power enhancement ratio for TEG reaches 27.8%. Additionally, a notable enhancement of 17% in thermal efficiency is observed when comparing the two systems. The thermal efficiency of the bifacial system improves by 8.37%, and for the tandem system, the improvement is 10.73%, achieved by adjusting the water flow rates.