## 3 Results
### CST Field Results  
Results for the CST field outputs as presented in Figure 4 for a week in the winter (a) and summer (b). Figure 4 shows the variation of HTF inlet and exit temperatures entering the PTC field. Also, Figure 4 shows the variation in the mass flow rate of the HTF. As explained above, the variation in the mass flow rate of the HTF with variation in the available solar resources is clearly shown. As solar resources are more limited in winter, the mass flow rates are lower. Still, the aim of raising the HTF temperature to 393 \({}^{\circ}\)C is possible even in the winter by reducing the HTF mass flow rate, which is important to maintain the system's stability, especially because in the topping cycle, the steam generated by the CST will also be adjusted based on the mass flow rate of the PTC's HTF. Figure 4 also demonstrates how, during the summer, the solar resources can compensate for the reduced OR resources and lower power block efficiencies as the PTC field increases the HTF enthalpy to adequate levels at the design temperature and mass flow rates.  
\begin{table}
\begin{tabular}{l l l l} \hline \hline
**Item** & **Value** & **Unit** & **Description** \\ \hline P\({}_{\text{CST}}\) & 10 & MW\({}_{\text{e}}\) & Additional power produced by CST alone. \\  & & & Additional power produced by Biomass alone. \\ P\({}_{\text{Bio}}\) & 6-8-10 & MW\({}_{\text{e}}\) & Operating points. \\  & & & Additional power produced by the topping cycle. \\ P\({}_{\text{Top}}\) & 16-18-20 & MW\({}_{\text{e}}\) & Operating points. \\  & & & Additional power produced by the topping cycle. \\ P\({}_{\text{IPT,LPT}}\) & 4.37 & MW\({}_{\text{e}}\) & Additional power produced by using the excess turbine capacities of IPT and LPT. \\  & & & Total additional power produced. \\ P\({}_{\text{Tot}}\) & 20.37-22.37-24.37 & MW\({}_{\text{e}}\) & Minimum—design—maximum operating points. \\ \hline \hline \end{tabular}
\end{table}
Table 4: The design point properties of the fluid streams.  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**State** & \begin{tabular}{l} **Temperature** \\ [\({}^{\circ}\)C] \\ \end{tabular} & \begin{tabular}{l} **Pressure** \\ **[kPa]** \\ \end{tabular} & \begin{tabular}{l} **Quality** \\ **[\%]** \\ \end{tabular} & \
\begin{tabular}{l} **Mass Flow** \\ **Rate [kg/s]** \\ \end{tabular} &
\begin{tabular}{l} **Description** \\ \end{tabular} \\ \hline
8 & 370 & 1000 & N/A & 9.59 & Topping cycle biomass combuster outlet \\
9 & 293 & 1000 & N/A & 202.75 & PTC Field inlet \\
10 & 393 & 1000 & N/A & 202.75 & PTC Field outlet (Topping cycle superheater inlet—HTF side) \\
11 & 378.78 & 1000 & N/A & 202.75 & Topping cycle evaporator inlet—HTF side \\
12 & 311.15 & 1000 & N/A & 202.75 & Topping cycle superheater inlet—HTF side \\
13 & 19 & 100 & N/A & 682.24 & Bottoming cycle condenser inlet \\
14 & 40.51 & 100 & N/A & 682.24 & Bottoming cycle pump inlet \\
15 & 40.51 & 348 & N/A & 11.05 & Bottoming cycle biomass combuster inlet \\
16 & 139 & 348 & N/A & 11.05 & Bottoming cycle IPT inlet \\
17 & 102 & 110 & 99.95 & 11.05 & Bottoming cycle LPT inlet \\
18 & 46.8 & 10.5 & 0 & 11.05 & Bottoming cycle LPT outlet \\ \hline \hline \end{tabular}
\end{table}
Table 3: _Cont._