## 3 Results and Discussions
### Exergy Analysis of Corn Drying with the IRCC Corn Dryer  
#### 3.3.1 General View of Exergy Structure  
The same amount of energy may have different effects in different systems [58]. In this section, Table 4 lists the exergetic performance of each component in the entire drying system during the corn drying process. Results showed that the SI of RA (1.11) and DC (1.86) have low values, while those of CC (2.40) and HE (5.64) are higher than 2 [4]. Lower SI means that the RA and DC are supposed to be ameliorated by adopting some measures. For CC and HE, HE shows good exergetic performance in exergy efficiency (82.28%), and due to the largest r\({}_{\rm d}\), CC has substantial improvement potential. The r  
Figure 11: Variations of the heat-loss rate of the DC.  
of RA was lowest (1.23%) among the all components. In the current work, since the main component of recovering the waste energy in fuel gas is RA, moreover, r\({}_{\text{d}}\) analysis indicated that the contribution rates to the overall exergy destruction are as below (in ascending sequence of significance): RA, HE, DC and CC. Hence, the further optimization of CC as the focus of effort is of practical significance.  
Figure 12 presents a Sankey diagram for the exergy analyses among the four main components of the dryer. In this study, based on the relevant theory of energy-exergy methodology, the exergy brought by the reference state (2) fresh air flow) was supposed as zero, which claims a starting point for the later analysis. According to this diagram, exergy rate about 2077.65 kW carried by the coal (3) was input into the CC. However, the high exergy destruction rate (864.27 kW) indicates that the CC should be vastly ameliorated by taking some measures like changing the fuel type, adding a heat-insulating layer to the CC wall and optimizing the physical architecture of the DC. For the HE, only 178.66 kW exergy is destroyed, accounting for 14.72% of the total. Moreover, the energy recovery by the far-infrared section further improves the exergy efficiency. The above discussions indicate that the HE has excellent performance in aspect of exergy. [PERSON] (2018) conducted a more detailed description of the self-developed heat exchanger used in the present project. For the RA, a 3.54-kW exergy rate was recovered by the radiators (8), accounting for 0.17% of the overall exergy input rate. Although this amount is quite small compared to the overall input exergy, the influence of infrared radiation has a significant performance on improving the quality of the maize kernels, as discussed in Section 3.2.2. For the DC, the average exergy rate for evaporating water was ascertained to be 462 kW (8), which accounts for 46.27% of the overall exergy rate inputting into the drying chamber (2). Furthermore, a high exergy destruction rate (478.36 kW) was found clearly in the DC, indicating the exergy performance of drying chamber can be vastly optimized.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Components** & \begin{tabular}{c} **E\({}_{xin}\)** \\ **(kW)** \\ \end{tabular} & \begin{tabular}{c} **E\({}_{xout}\)** \\ **(kW)** \\ \end{tabular} & \begin{tabular}{c} **E\({}_{xdes}\)** \\ **(kW)** \\ \end{tabular} & \begin{tabular}{c} **n\({}_{ex}\) (\%)** \\ \end{tabular} & **SI** & \
\begin{tabular}{c} **r\({}_{\text{d}}\) (\%)** \\ \end{tabular} &
\begin{tabular}{c} **Improvement** \\ **Priority** \\ \end{tabular} \\ \hline CC & 2077.65 & 1213.38 & 864.27 & 58.40 & 2.40 & 56.11 & 1 \\ HE & 1213.38 & 1034.72 & 178.66 & 82.28 & 5.64 & 11.60 & 3 \\ RA & 36.34 & 17.39 & 18.95 & 9.74 & 1.11 & 1.23 & 4 \\ DC & 1001.92 & 523.56 & 478.36 & 46.11 & 1.86 & 31.06 & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Exergetic performance of the components for the whole dryer.  
Figure 12: Sankey diagram of the overall drying system assisted by the exergy analysis.