## 3 Results and Analysis of the Filed Measurements
### Indoor Environment of Canteen Kitchen
#### 3.2.3 Effect of Stoves Status on Temperature and Relative Humidity  
Figure 7 shows the variety of temperature and relative humidity at different measuring points in the canteen kitchen with the stoves' status. Before the stoves opened, the temperature in the cooking zone decreased, and the relative humidity reached its peak. It was because the exhaust fan opened at 6:46, and the cooking zone was in a negative pressure status. The indoor air flowed into the cooking zone leading to the temperature decreasing and the relative humidity increasing. After the stoves opened, three stoves were used simultaneously between 6:50 and 8:17. The temperature at location 7\({}^{3}\) reached the highest of 35.70 \({}^{\circ}\)C. Three stoves  
humidity at location 71 reached the maximum value of 66.40% RH at 9:07. It was due to the cooking methods having a significant effect on cooking zone temperature and relative humidity [35]. We listed the dishes corresponding to the temperature and relative humidity peaks in Table 4.  
From Table 4, we can see that when three stoves were used simultaneously at 8:00, 9:07, and 12:04. At 12:04, the cooking methods of the three stoves were stir-frying or frying. At this time, the temperature of the cooking zone was 0.60 or 3.50 higher than that two or zero stoves were used to stir-fry or fry, respectively. Similarly, four stoves were used simultaneously at 8:32, 9:47, and 11:03. At 11:03, the cooking methods of the four stoves were stir-frying or frying. At this time, the temperature of the cooking zone was 4.30 or 4.70 higher than that of three or two stoves used to stir-fry or fry, respectively. It may be because when cooked dishes such as stir-fried noodles, stir-fried potato chips, or fried fish, a large amount of heat is released, and the temperature increases. Therefore, chefs can alleviate the overheating of the cooking zone during the cooking process by avoiding cooking stir-fried or fried dishes simultaneously. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Stove**} & \multirow{2}{*}{**8:00**} & \multicolumn{4}{c}{**Dishes Name**} & \multirow{2}{*}{**11:03**} \\  & & **9:07** & & **12:04** & & **8:32** & **9:47** & **11:03** \\  & & & **3** & & & **4** & \\ \hline No.1 & Stir-fry noodles & Mapo tofu & Stir-fry & \multirow{2}{*}{Stir-fry cabbage} & \multirow{2}{*}{Stir-fry cobbage} & \multirow{2}{*}{Stir-fry peak with mushroom} & \multirow{2}{*}{Stir-fry chicken} \\ No.2 & Stir-fry rice & & & & & & \\ \multirow{2}{*}{No.3} & with egg & & & & & & \\ No.3 & Thaw meat & Cooking soup & Stir-fry cabbage & Cooking soup & \multirow{2}{*}{Crow fish} & \multirow{2}{*}{Fry fish} \\ No.4 & Off & Off & Off & & & & \\ No.5 & Off & Off & Off & Off & Off & Off \\ \hline \end{tabular}
\end{table} 
Table 4: Dishes at different times. Figure 7: The variety of temperature and relative humidity at different measurement points with the stoves’ status. 3.2.4. Evaluation of Indoor Thermal Comfort in Canteen Kitchen  
Thermal comfort is a comprehensive perception of temperature, relative humidity and air velocity. In this section, we used the two evaluation index: Predicted mean vote (_PMV_) and predicted percentage of dissatisfaction (_PPD_), proposed by Professor [PERSON], to predict the thermal comfort of the canteen kitchen. Since the calculation formula for _PMV_ value is complicated, and many parameters cannot be obtained directly, this paper calculates it according to Formula (4) [36]. \[PMV=at+bp_{v}+c \tag{4}\]  
where, \(a,b,c\) is the coefficient, \(a=0.212\), \(b=0.293\), \(c=-5.949\). \(t\) is the air temperature, \({}^{\circ}\)C. is the partial vapor pressure, kPa.