# Energy-Saving Network Ventilation Technology of Extra-Long Tunnel in Climate Separation Zone
## 4 Conclusions  
In this paper, an efficient ventilation method was proposed for the extra-long road tunnels in climate separation zones and a case is the ventilation issue of the Nibashan Tunnel. Due to the different climates existing at both ends of the tunnel, the natural wind has obvious effect in the tunnel ventilation. The main natural wind direction is from Lugu to Ya'an. The velocities with a guarantee rate of 95% in the sections of the main tunnel range from 2.01 m/s to 3.14 m/s. Taking daily control strategy, the energy saving effect in July and August is the most obvious, totally 410.5 kW is saved, while the  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Time Intervals** & **Total Power (KW)** & **Energy Saving (\%)** \\ \hline Daytime in January & 1542 & 3.63 \\ Nighttime in January & 1764 & 0.00 \\ Daytime in February & 1542 & 3.63 \\ Nighttime in February & 1431 & 10.56 \\ Daytime in March & 1542 & 3.63 \\ Nighttime in March & 1431 & 10.56 \\ Daytime in April & 1283 & 19.81 \\ Nighttime in April & 1653 & 0.00 \\ Daytime in May & 1431 & 10.56 \\ Nighttime in May & 1542 & 3.63 \\ Daytime in June & 1431 & 10.56 \\ Nighttime in June & 1542 & 3.63 \\ Daytime in July & 1320 & 17.50 \\ Nighttime in July & 1394 & 12.88 \\ Daytime in August & 1320 & 17.50 \\ Nighttime in August & 1394 & 12.88 \\ Daytime in September & 1431 & 10.56 \\ Nighttime in September & 1542 & 3.63 \\ Daytime in October & 1283 & 19.81 \\ Nighttime in October & 1653 & 0.00 \\ Daytime in November & 1542 & 3.63 \\ Nighttime in November & 1431 & 10.56 \\ Daytime in December & 1542 & 3.63 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Energy-saving with the daily control strategy.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Working Condition** & \multicolumn{2}{c}{**Power of Jet Fans (kW)**} & \multirow{2}{*}{**Energy Saving (\%)**} \\ \cline{2-3}  & **Left Line** & **Right Line** & \\ \hline
2.5 m/s & 444 & 740 & 0 \\
1 h & 128.7 & 543.5 & 43.2\% \\
2 h & 166.8 & 633.2 & 32.4\% \\
3 h & 190.2 & 675.3 & 26.9\% \\
4 h & 223.6 & 683.2 & 23.4\% \\
5 h & 223.0 & 698.5 & 22.2\% \\
6 h & 231.7 & 710.1 & 20.5\% \\ \hline \hline \end{tabular}
\end{table}
Table 9: The energy saving benefit in different working conditions.  
energy saving in January and December is quite little. Hourly control efficiently reduces the power of jet fans. The best energy saving percentage is 43.2%. Such ventilation mode in tunnels can greatly reduce the energy consumption of the tunnel operation and provide references for the other road tunnels located in climate separation zones.  
This research was supported by the Sichuan Province Science and Technology project (2015 GZ0244 and 2016 GFW0176), National Natural Science Foundation of China (51478393), Sichuan Provincial Education Department (SCWY16-10, 14 SA0251, and 15 SB0457), Chengdu Science and Technology Project (2015-HM01-00312-SF), and Sichuan Applied Psychology Research Center of Chengdu Medical College (CSXL-162213).  
[PERSON] conceived and wrote the paper; [PERSON] and [PERSON] organized the field tests; [PERSON] analyzed the data and prepared the tables and figures; [PERSON] and [PERSON] collected the data and improved the paper in grammar; and [PERSON] offered useful suggestions for the preparation and writing the paper.  
The authors declare no conflict interest.