## 4 Discussion
### Economic Analysis  
To evaluate the P.B period for the examined system and of an industrial-scale system, the data in Table 7 will be used. The data described in Table 7 are referred to a 2-day period, so for a total year, the same case is repeated 182 times. So, the P.B period for the prototype as it operated occurs for the banana case is 7.5 years. For the case of the potato, the necessary data are described in Table 8.  
The data described in Table 8 are referred to a 2-day period, so for a total year, the same case is repeated 182 times. So, the P.B period for the prototype as it operated occurs for the potato case is 7.5 years. It seems that for the case of the potato, the prices of fresh and dried products lead to a more reasonable P.B period even for the prototype. It should be noted that the scope of the examined system was to evaluate the parameters that affect the drying process and not to evaluate if this prototype is economically viable. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Cost/Income Parameter** & **Value** & **Details** \\ \hline \multirow{3}{*}{C.i} & 3.00 \(\upxi\)/m main tube & The total length of the tube is 5 m, so the total cost is 15.00 \(\upxi\). Three 1.60 \(\upxi\)/90\({}^{\circ}\) tees (These prices are chosen from suppliers in the Greek market) & 90\({}^{\circ}\) tees of 1.60 \(\upxi\) each cost 4.80 \(\upxi\). So, the total cost of the tube is 19.80 \(\upxi\). Black coating and labor cost leads to almost a final cost of 21.80 \(\upxi\) per tube \\ \hline \multirow{3}{*}{C.f} & 1.40 \(\upxi\)/kg (These prices are chosen from suppliers in the Greek market) & The tube includes 5 pieces of banana of almost 7.5 g. So, the total weight is 37.5 g. The cost is 0.0525 \(\upxi\) \\ \hline \multirow{3}{*}{C.e} & 0.15 \(\upxi\)/kWh -price for agricultural electricity supply [38] & The only energy consumption is for opening the side window during the early morning hours. This process lasts seconds, so the energy consumption is almost zero \\ \hline \multirow{3}{*}{I.d} & 14.0 \(\upxi\)/kg (These prices are chosen from suppliers in the Greek market) & The tube includes 5 pieces of banana of almost 7.5 g- so the weight of the drying product is 0.975 g per piece. The final weight is 5 \(\times\) 0.975 = 4.875 g. So, the income is 0.06825 \(\upxi\) \\ \hline \end{tabular}
\end{table} 
Table 7: Parameters for the P.B period of banana drying for the prototype examined case study. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Cost/Income Parameter** & **Value** & **Details** \\ \hline \multirow{3}{*}{C.i} & 3.50 \(\upxi\)/m main tube & The total length of the tube is 5 m, so the total cost is 15.00 \(\upxi\). Three 1.60 \(\upxi\)/90\({}^{\circ}\) tees (These prices are chosen from suppliers in the Greek market) & The total length of the tube is 90\({}^{\circ}\) tees of 1.60 \(\upxi\) each cost 4.80 \(\upxi\). So, the total cost of the tube is 19.80 \(\upxi\). Black coating and labor cost leads to almost a final cost of 21.80 \(\upxi\) per tube \\ \hline \multirow{3}{*}{C.f} & 1.09 \(\upxi\)/kg (These prices are chosen from suppliers in the Greek market) & The tube includes 5 pieces of potato of almost 8.0 g. So, the total weight is 40 g. The cost is 0.0436 \(\upxi\) \\ \hline \multirow{3}{*}{C.e} & 0.15 \(\upxi\)/kWh -price for agricultural electricity supply [38] & The only energy consumption is for opening the side window during the early morning hours. This process lasts seconds, so the energy consumption is almost zero \\ \hline \multirow{3}{*}{I.d} & 17.0 \(\upxi\)/kg (These prices are chosen from suppliers in the Greek market) & The tube includes 5 pieces of potato of almost 8.0 g- so the weight of the drying product is 1.36 g per piece. The final weight is 5 \(\times\) 1.36 = 6.8 g. So, the income is 0.1156 \(\upxi\) \\ \hline \end{tabular}
\end{table} 
Table 8: Caption. Parameters for the P.B period of potato drying for the prototype examined case study.