*2.2. Outdoor Environmental Parameters*

According to the data statistics of a weather station in Beijing (https://www.xiheenergy.com/, accessed on 1 January 2023), the outdoor temperature and humidity change curve of the ancient building is shown in Figure 1. Through the investigation and analysis of the environmental monitoring of ancient buildings, the relative humidity of the indoor environment of the ancient building is high in summer. The original appearance of the building is damaged by the humid indoor environment. Therefore, the outdoor ambient temperature and humidity for the July period from 2020 to 2022 were selected and averaged as the outdoor meteorological parameter of choice. The outdoor temperature is 26.3 ◦C, the outdoor relative humidity is 67.17%, and the atmospheric pressure is 101.35 kPa. The moisture content is 14.49 g/kg dry air, and the water vapor partial pressure is 2.3073 kPa.

**Figure 1.** Outdoor temperature and humidity change curve.

#### *2.3. Indoor Environmental Parameters*

Based on the relevant research [21], the indoor air temperature is 24.7 ◦C, the indoor relative humidity is 75%, the moisture content is 14.67 g/kg dry air, and the water vapor partial pressure is 2.3347 kPa. The indoor relative humidity of the interior walls is 92%, the moisture content is 18.09 g/kg dry air, and the water vapor partial pressure is 2.8639 kPa.

#### *2.4. Indoor Flooring Parameters*

Soil temperature and humidity can have an impact on the coupled heat and moisture transfer [22]. The ground temperature is set at 23.3 ◦C, and the water absorption rate of ancient grey bricks generally ranges from 14% to 25% [23], so the water absorption rate of grey bricks is set at 14% in this work. Beijing, located in the North China Plain, is sandy soil. According to relevant studies [21,24], the soil volumetric moisture content of ancient buildings in the area is 0.09 m3/m3. The field capacity of sandy soils in the North China Plain is 10–14%. The soil bulk density value of this study is selected from the Second National Soil Survey of China (SNSSC), and the reference value is 0.95 g/cm3. The conversion relationship between the soil's relative humidity and the soil's volumetric water content is expressed as follows [25]:

$$
\boldsymbol{\Theta}\_{\text{V}} = \mathbb{R} \times \mathbf{f}\_{\text{C}} \times \mathbf{S}\_{\text{C}} \tag{1}
$$

where θ<sup>V</sup> is the soil's volumetric water content, m3/m3; R is the soil's relative humidity, %; fC is the soil's field capacity (taken as 10%); and SC is the soil's bulk density, kg/m3.

Consequently, it is calculated that the soil's relative humidity of the indoor building ground is 81.5%, the moisture content is 15.97 g/kg dry air, and the water vapor partial pressure is 2.5371 kPa.

### **3. Numerical Simulation**
