## 2 A Prototype Design of the Smart Photovoltaic System Blind
### Properties 1: PV panel
#### 2.1.1 PV Techniques Applicable to the SPSB  
The PV techniques applicable to the SPSB are largely divided into two generations: (i) the first-generation PV techniques (i.e., mono-crystalline silicon (mono-Si) and poly-crystalline silicon (poly-Si)); and (ii) the second-generation PV techniques (a-Si, CIGS, and cadmium telluride (CdTe) thin-film). The third-generation PV techniques (i.e., dye-sensitized PV panel (DSSP), organic PV (OPV) panel, and nano PV panel) were excluded from this study since the technology is still in an experimental stage [13; 31; 32; 33; 34; 35; 36]. To determine the PV techniques applicable to the SPSB, this study considered two main issues: (i) usability issues (i.e., efficiency, shading effect, and certification) and (ii) constructability issues (i.e., width, length, thickness, and weight) (refer to Table 2) [37; 38; 39; 40; 41]. 1. Usability issues of the PV panel: The usability issues of the SPSB took into account three factors (i.e., shading effect, efficiency, and certification). First, the efficiency of the PV panel is a factor determined by the photoelectric effect--the conversion of solar radiation into electricity. Additionally, as the photoelectric effect of PV cell is greater, the efficiency of the PV panel increases. As shown in Table 2, the efficiency of the PV panel was determined to be the average efficiency of PV panel in module level (i.e., mono-Si: 14.5%, poly-Si: 14.0%, a-Si: 5.8%, CIGS: 10.5%, and CdTe: 9.9%) [42]. The efficiency of the second-generation PV panel (a-Si: 5.8%, CIGS: 10.5%, and CdTe: 9.9%) was determined to be 1.33-2.50 times inferior to that of the first-generation PV panel (i.e., mono-si: 14.5% and poly-si: 14.0%). However, unlike the first-generation PV panel, the second-generation PV panel exhibits excellent applicability due to the application of the thin film PV technique [35; 42]. Second, the shading effect of the PV panel is a factor that has a significant influence on the electricity generation performance of the PV panel, and there is a noticeable difference in the sensitivity depending on the type of PV panel. As shown in Table 2, the second-generation PV panels (a-Si, CIGS, and CdTe: low) are superior to the first-generation PV panels (mono-Si and poly-Si: high) in terms of the shading effect [17; 43; 44]. Thus, with regard the shading effect of the PV panel, the second-generation PV panels were determined as a PV technique applicable to the SPSB. Third, the possible harmful effects of the PV panel were a \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Classification**} & \multirow{2}{*}{**Classification**} & \multicolumn{2}{c}{**First-Generation PV Panels**} & \multicolumn{2}{c}{**Second-Generation PV Panels**} \\ \cline{3-6}  & & **Mono-Si** & **Poly-Si** & **a-Si** & **CIGS** & **CdTe** \\ \hline \multirow{3}{*}{Usability issue} & Efficiency (module level) & 14.5\% & 14.0\% & 5.8\% & 10.5\% & 9.9\% \\  & Shading effect & High & High & Low & Low & Low \\  & Harmful effect & No & No & No & No & Yes \\ \hline \multirow{3}{*}{Constructability issue} & Width & Customized & Customized & Customized & Customized & Customized \\  & Length & Customized & Customized & Customized & Customized & Customized \\ \cline{1-1}  & Thickness & 35 mm & 48 mm & 2.6 mm & 2.5 mm & 27.9 mm \\ \cline{1-1}  & Weight & 11.7 kg/m\({}^{2}\) & 11.6 kg/m\({}^{2}\) & 2.5 kg/m\({}^{2}\) & 2.4 kg/m\({}^{2}\) & 16.7 kg/m\({}^{2}\) \\ \hline \hline \end{tabular} Note: Mono-Si stands for the mono-crystalline silicon PV panel; Poly-Si stands for the poly-crystalline silicon PV panel; a-Si stands for the amorphous silicon PV panel; CIGS stands for the copper-indium-gallium-selenide PV panel; and CdTe stands for the cadmium telluride PV panel.  
\end{table} 
Table 2: Usability and constructability issues of the first- and second-generation PV panels. factor determined depending on whether or not the toxic material may be used.