Optimization of annealing cycles for electric output in outdoor conditions for amorphous silicon photovoltaic–thermal systems

Abstract

Previous studies with fixed operating temperatures have shown that hydrogenated amorphous silicon (a-Si:H) was a promising absorber layer for solar photovoltaic -thermal (PVT) systems because of a) a low temperature coefficient and b) the opportunity to reverse light induced degradation with thermal annealing. This study further refined the simulation of the optimal dispatch strategy for a-Si:H based PVT by studying annealing cycles and analysis of the degradation at other operating temperatures controlled by the varying ambient temperatures.Four representative case studies were evaluated for the combinations of high and low solar flux and high and low average ambient temperature. Electrically-optimized dispatch strategies are found for a range of PVT thermal insulating effectivenesses. The results showed significantly more electricity generation in all the case study representative regions except for areas dominated by low temperatures and low solar fluxes. These results indicate that a-Si:H PV performance can be improved in most populated regions in the world by integrating it into a PVT device and using spike annealing to reverse light-induced degradation effects. The model presented in this paper uses publicly-available data to implement suitable dispatch strategies and execute virtual performance analysis of PVT for any geographic location in the world.

Temperature-dependent performance of amorphous silicon photovoltaic/thermal systems in the long term operation

“…The variation of the normalized electrical performance is displayed in Fig. 10, and the result is consistent with that found by Rozario et al [13]. The electrical efficiencies of a-Si cells degrade by 11.5% and 6.5% at 30 °C and 60 °C, respectively.…”

“…The controlled light-soaking tests on a-Si cells at different temperatures indicated that cycling and changing the exposure temperature modified the efficiency of a-Si cells between 10% and 17% in a recurrent pattern [11]. The a-Si cells could reach higher stabilized efficiencies at higher operating temperatures and the stabilized performance levels depended largely on light exposure and a characteristic temperature [12,13]. Moreover, higher temperatures resulted in faster degradation in the early stages of the degenerated process [14].…”

Effect of Temperature on Long-Term Experimental Performance of an Amorphous Silicon Photovoltaic Thermal System

“…However, the effect of temperature on a-Si PV/T systems is rarely reported so far. Although Rozario et al [14] and Pathak et al [15] proposed the PV/T system using a-Si cells, the study on the electrical performance is based solely on a-Si cells rather than PV/T system. Especially the PV/T systems always operate in recurrent alternating heating and cooling conditions [16].…”

Theoretical and experimental analysis of the solar collectors performances

“…A PVT collector coupled to a new heat input process of use for the desalination process has been proposed by Fine et al [25]. A complete study of a PVT collector using hydrogenated amorphous silicon (a‐Si: H) as an absorbent layer was modelled [26] and its performance was analysed using available data. Many systems capable of satisfying both the heating and the cooling of the building are studied by Entchev et al [27].…”