## 3 Analyses of Environmental Parameters of Different Modular Wall Greenhouses
### Temperature Analysis inside the Greenhouses during the Test Period  
The detailed information of the inside and outside temperature environments of the two heliogreenhouses over 28 days is not clearly shown in the above figure. Therefore, we determined the detailed parameters of temperature environment by analyzing the changes of indoor temperature for the growth of tomato plants in the daytime and nighttime conditions, which is shown in Table 3. Concrete analysis was as follows:  
The optimum temperature range for tomato growth was 18-25 \({}^{\circ}\)C during the day and 8-13 \({}^{\circ}\)C at night [33]. Thus, 8, 13, 18 and 25 \({}^{\circ}\)C were selected to compare the differences between the two greenhouses. It revealed that the average temperature at night (17:00-09:00) was 0.44 \({}^{\circ}\)C higher in SG than that in PG. Moreover, there was no temperature below 8 \({}^{\circ}\)C in both kinds of greenhouses, which suggested that both greenhouses were suited for the overwintering production of tomato. According to the perspective of nighttime insulation and average temperature in daytime, the indoor environment of SG was better for the growth of tomato than PG. Figure 5: The inside and outside temperature of an active heat storage type solar greenhouse (31 January 2021 9:00–28 February 2021 9:00). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **SG** & **PG** \\ \hline Average minimum air temperature/\({}^{\circ}\)C & 12.12 & 12.52 \\ Average maximum air temperature/\({}^{\circ}\)C & 32.38 & 32.32 \\ Average daily air temperature/\({}^{\circ}\)C & 18.47 & 18.47 \\ Average daytime temperature (09:00–17:00)/\({}^{\circ}\)C & 24.40 & 25.26 \\ Average night air temperature (17:00–next 09:00)/\({}^{\circ}\)C & 15.51 & 15.07 \\ Number of days with minimum temperature \(\leq\) 8 \({}^{\circ}\)C/d & 21 & 18 \\ Number of days with minimum temperature \(\leq\) 5 \({}^{\circ}\)C/d & 0 & 0 \\ Number of days with maximum temperature \(\geq\) 25 \({}^{\circ}\)C/d & 21 & 22 \\ Number of days with average daytime temperature & 22 & 22 \\ (09:00–17:00) \(\geq\) 18 \({}^{\circ}\)C/d & & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Analysis of indoor monthly temperature in two greenhouses (31 January 2021 9:00–28 February 2021 9:00). Comparative Analyses of the Inlet and Outlet Air Temperature and Humidity in the Greenhouse on Typical Sunny Days  
For typical sunny days (19 February 2021 9:00 to 22 February 2021 9:00), the changes of the temperature and humidity in the inlet and outlet air vents of SG and PG are shown in Figure 6. The maximum and minimum temperature in the inlet of SG was 37.02 and 15.68 \({}^{\circ}\)C, respectively. In the outlet of SG, the maximum and minimum temperature was 27.81 and 17.25 \({}^{\circ}\)C, respectively. When it comes to the inlet of PG, 40.76 and 16.16 \({}^{\circ}\)C were the maximum and minimum temperature, respectively. Meanwhile, 31.44 and 17.25 \({}^{\circ}\)C were the maximum and minimum outlet temperature of PG, respectively. The average temperature difference between the inlet and outlet of SG and PG during the heat storage process was 5.03 and 5.98 \({}^{\circ}\)C, and the average relative humidity differences between the inlet and outlet of SG and PG was 17.15% and 11.40%, respectively. The average daily heat storage duration of SG and PG was 6.8 and 6.6 h, respectively. This suggested that during the heat storage process in daytime, SG warmed up faster and the average relative humidity difference changed more than it in PG. However, PG warmed up slowly. The exothermic process carried out at night to ensure that the temperature in the greenhouse would not drop too fast and be lower than 14 \({}^{\circ}\)C. The average temperature difference between the inlet and outlet of SG and PG during the exothermic process was 1.04 and 2.37 \({}^{\circ}\)C. In addition, the average relative humidity difference between the inlet and outlet of SG and PG was 15.99% and 11.50%. The average daily exothermic duration of SG and PG was 10 and 10.5 h, respectively.