## 3 Development of Prototype Models of the Smart Photovoltaic System Blind
### Properties 1: PV panel  
#### 3.1.1 PV Techniques Installed in Prototype Models of the SPSB  
In consideration of the PV techniques applicable to the SPSB (i.e., usability and constructability issues), the a-Si and CIGS PV panels which are the second-generation PV panels were used to develop the prototype models of the SPSB (refer to Table 3). As shown in Table 2, the efficiency of the CIGS PV panel is superior to that of the a-Si PV panel. The CIGS PV panel was used in the first prototype model, whereas the a-Si PV panel was used in the second and third prototype models. The reason for changing from the CIGS PV panel to a-Si PV panel is as follows. The a-Si mini PV panel which can be applied to the SPSB prototype model can be produced as a product, while the CIGS mini PV panel cannot. This is because, unlike the a-Si PV panel, the CIGS PV panel, which applies a roll-to-roll manufacturing process, cannot be produced in the form of mini CIGS PV panel which can be applied to the SPSB prototype model. Thus, a-Si PV panel was used in the second and third prototype models to guarantee the stability and reliability of electricity generation measurement results and the supply of components for developing the prototype model of the SPSB. Specific details for each prototype model are as follows.  
Figure 3: The prototype models of the SPSB and the associated properties.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Properties** & **Classification** & **First Prototype Model** & **Second Prototype Model** & **Third Prototype Model** \\ \hline PV panel & a-Si & - & - & \(\bullet\) & \(\bullet\) \\  & CIGS & \(\bullet\) & - & - \\ \hline \multirow{3}{*}{\begin{tabular}{c} Tracking \\ system \\ \end{tabular} } & Tracker type & \begin{tabular}{c} Single \\ Dual \\ \end{tabular} & \begin{tabular}{c} VSAT \\ - \\ - \\ \end{tabular} & \
\begin{tabular}{c} HSAT, VSAT \\ AADAT \\ \end{tabular} \\ \cline{2-5}  & Tracking & Direct & \(\bullet\) & \(\bullet\) & \(\bullet\) \\  & method & Indirect & - & - & - \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Monitoring \\ system \\ \end{tabular} } & Electricity & Current & \(\bullet\) & \(\bullet\) & \(\bullet\) \\  & generation & Voltage & - & \(\bullet\) & \(\bullet\) \\  & Power & - & \(\bullet\) & \(\bullet\) \\ \cline{1-1} \cline{2-5}  & Environmental & Temperature & - & - & \(\bullet\) \\  & condition & Humidity & - & - & \(\bullet\) \\ \hline \hline \end{tabular} Note. a-Si stands for the for the amorphous silicon PV panel; CIGS stands for the copper-indium-gallium-selenide PV panel; VSAT stands for the vertical single-axis tracker; HSAT stands for the horizontal single-axis tracker; and AADAT stands for the azimuth-altitude dual-axis tracker.  
\end{table}
Table 3: Characteristic by the prototype model of the SPSB.  
The first prototype model consisted of a total of four blind slats, and the 'SP1-75' CIGS PV panels manufactured (maximum power: 75 W) by Solopower were attached to each blind slat (refer to Table 4) [53; 54]. The 'SP1-75' CIGS PV panels were selected as products that can be purchased in South Korea. Since the 'SP1-75' CIGS PV panel is too large to be applied to the first prototype model, 'SP1-75' CIGS PV panels were cut to be applicable size for the blind slat of the first prototype model. In addition, CIGS PV panel attached to all blind slats were linked in parallel. The second and third prototype models of the SPSB used the '502500-16V' a-Si PV panel manufactured by Solar Center (refer to Table 4). Furthermore, a-Si PV panels attached to all of the blind slats were linked in parallel. The second prototype model of the SPSB was composed of nine blind slats per column and had a total of two columns and 18 blind slats. The third prototype model of the SPSB was composed of ten blind slats per column and had a total of two columns and 40 blind slats.