New Insights into Traditional Construction Behind Sibe Dwellings with Swastika Kang for Space Heating in North China
Abstract
1. Introduction
- Validating and analyzing traditional construction wisdom using modern technologies.
- Conducting an in-depth analysis of the “Swastika kang”, a traditional heating system (For a detailed explanation, please refer to Nomenclature).
- Exploring optimization strategies by integrating passive insulation with active heating systems.
2. Literature Review
2.1. Indoor Thermal Comfort
2.2. Kang
2.3. Research Status
3. Methods
3.1. Geographic and Climatic Information
3.2. Building Thermal Model
3.3. Folk Houses and Kang
Number | Equation | Define | |
---|---|---|---|
(1) | Material Layer Thermal Resistance | R: Material Layer Thermal Resistance (m2·K/W). δ: Material layer thickness (m). λ: Material thermal conductivity [W/(m·k)]. | |
(2) | Heat transfer resistance of the envelope | R0: Enclosure heat transfer resistance (m2·K/W). Ri: Internal surface heat transfer resistance (m2·K/W). R: Enclosure flat wall thermal resistance (m2·K/W). Re: External surface heat transfer resistance (m2·K/W). | |
(3) | Heat transfer coefficient | K: Heat transfer coefficient of the enclosure [W/(m2·K)]. | |
(4) | Heat storage capacity | S: Heat storage capacity [W/(m2·K)]. c: Specific heat capacity [KJ/(kg·K)]. ρ: Densities (kg/m3). T: Temperature fluctuation period (h), generally T = 24 h. π: The circular ratio, π = 3.14. | |
(5) | Thermal inertness index | D: Thermal inertness index. |
Material | Thic Thickness (mm) | Thermal Conductivity (λ) W/(m·K) | Heat Storage Coefficient (S) W/(m2·K) | Correction Factor α | Resistance (R) (m2·K/W) | Thermal Inertia D = R × S | Heat Transfer Coefficient K = 1/(0.15 + ∑R) W/(m2·K) |
---|---|---|---|---|---|---|---|
Concrete Tile | 20 | 0.93 | 10.583 | 1 | 0.022 | 0.228 | 1.58 |
lime mortar | 40 | 0.81 | 10.07 | 1 | 0.049 | 0.497 | |
Sagebrush clay | 40 | 0.58 | 7.723 | 1 | 0.069 | 0.533 | |
Planks | 20 | 0.058 | 1.627 | 1 | 0.345 | 0.561 | |
Brickyard | 450 | 0.265 | 10 | 1 | 1.698 | 16.981 | 0.54 |
Wood-plastic windows | 2.5 |
3.4. Indoor Thermal Comfort Evaluation
- APMV: Expected adaptive mean thermal sensory index
- λ: Adaptive coefficient
- PMV: Projected average thermal sensory indicators
3.5. Building Simulation
- External Walls: Two sets of experiments were performed:
- 2.
- Roof: Three sets of experiments were conducted:
- 3.
- Windows: three sets of experiments were carried out using different modern window constructions to study their effects on the indoor thermal environment.
4. Results
4.1. External Wall Impact
- The wall thickness was increased and decreased by 50 mm to 500 mm and 400 mm, respectively. The overall heat transfer coefficients were 0.49 and 0.60, while the thermal inertia index was 18.868 and 15.094, respectively. Simulation results indicated that whether increasing or decreasing wall thickness, the proportion of time meeting the criteria for thermal comfort remained at 24.03%, similar to the baseline case.
- Maintaining a constant wall thickness, adding 20 mm extruded polystyrene foam insulation for both interior and exterior walls resulted in overall heat transfer coefficients of 0.41 and 0.42, with thermal inertia indices of 16.453 and 15.944, respectively. At this point, the proportion of time meeting the criteria for thermal comfort remained at 24.03%.
- Maintaining a constant wall thickness, adding 20 mm extruded polystyrene foam and 20 mm lime mortar for external wall insulation led to a heat transfer coefficient of 0.42 and a thermal inertia index of 15.944. The results showed that the proportion of time meeting the criteria for thermal comfort remained at 24.03%.
- By maintaining consistent insulation materials and thickness while increasing the total wall thickness, constructing interior and exterior walls with 450 mm bricks and 20 mm extruded polystyrene foam for the simulation, the overall heat transfer coefficients and thermal inertia indices reached 17.208. Under these conditions, the proportion of time meeting the criteria for thermal comfort remained at 24.03%.
- Adjusting wall thickness and increasing the insulation material thickness, with walls composed of 450 mm bricks and 50 mm extruded polystyrene foam, yielded a heat transfer coefficient of 0.29 and a thermal inertia index of 17.548. The results showed that the proportion of time meeting the criteria for thermal comfort remained at 24.03%.
4.2. Roof Impact
- With the total roof thickness unchanged and other roof materials held constant, the 20 mm lime mortar was replaced with the same thickness of aerated concrete and foam concrete (ρ = 700), resulting in a heat transfer coefficient of 1.51 and a thermal inertia index of 1.399. In this scenario, the proportion of time within the thermal comfort zone increased to 24.14%, an increment of 0.11% compared to the baseline roof structure.
- Maintaining the total roof structure thickness and other roof materials unchanged, the 20 mm mixed clay was replaced with 20 mm rigid polyurethane foam board PUR (ρ ≥ 35), resulting in a heat transfer coefficient of 0.93 and a thermal inertia index of 4.612. Under these conditions, the proportion of time within the thermal comfort zone remained at 24.03%, consistent with the baseline roof structure.
4.3. External Window Impact
- Replacing the window structure with 6 mm + LE35AMARL film glass, with a heat transfer coefficient of 4.60, resulted in a thermal comfort time ratio of 22.83%, representing a decrease of 1.2% compared to the baseline structure.
- Substituting the window structure with plastic + 6Low-E + 12A + 6 mm transparent hollow glass, with a heat transfer coefficient of 1.90, yielded a thermal comfort time ratio of 23.31%, exhibiting a decrease of 0.72% compared to the baseline structure.
- Changing the window structure to [5 mm + 9A (air) + 5 mm] nanometer-coated glass (HJ-N-series) + 9A (air) + 5 mm white glass (warm edge seal), with a heat transfer coefficient of 1.56, resulted in a thermal comfort time ratio of 24.09%, indicating an increase of 0.06% compared to the baseline structure.
5. Discussion: Swastika Kang Heating Effect
5.1. Surface Temperature Impact
5.2. Heating Area Impact
6. Conclusions
- Simulations of residential structural enclosures revealed that enhancing roof insulation had the most pronounced effect on indoor thermal comfort compared to improving wall or window insulation. However, simulations also indicated that despite continuous enhancements, the effectiveness of passive strategy methods on indoor thermal comfort within structural enclosures is limited and less applicable to Sibe dwellings.
- The configuration of the traditional “kang” combined with the architectural layout of the Sibe residence is better suited for space heating
- Regarding the simulation research on the active heating device—”kang”—it was found that raising “kang” temperature significantly improves indoor thermal comfort, while increasing the “kang” area has a comparatively small effect. Therefore, future improvement measures could emphasize temperature-related factors.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
Nomenclature
Nomenclature | Definition |
Heat storage coefficient (S) W/(m2·K) | The ability of a material to store heat is defined as its thermal capacity. The greater this value, the better the thermal stability of the material. |
Heat transfer coefficient W/(m2·K) | Under steady-state heat transfer conditions, it refers to the amount of heat transferred per unit time through a unit area of a building envelope when there is a temperature difference of 1 degree (K or °C) between the air on either side. |
Kang | In northern China, a kang is a sleeping platform constructed from bricks or adobe, featuring hollow spaces underneath that are connected to a chimney. It can be heated by burning fuel, providing warmth for sleeping and living areas. |
Resistance (R) (m2·K/W) | When heat is transferred through an object, the ratio between the temperature difference across the object and the power of the heat source is defined as the thermal resistance. |
“Swastika kang” | In the bedroom, a continuous kang is built along the north and south walls, with a narrower kang constructed on the west side. In some cases, the west kang is of the same width as the south and north kangs, connecting with them to form a “π”-shaped structure. The chimney extends through the wall to the outside. |
Thermal conductivity (λ) W/(m·K) | The measure of a material’s ability to conduct heat. |
Thermal inertia | The thermal inertia index is a measure of how quickly temperature fluctuations on one side of an object’s surface attenuate within the object when subjected to periodic thermal effects. |
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Number | Indoor Thermal Comfort | Passive | Active | |
---|---|---|---|---|
Modern Technologies | Traditional Wisdom | |||
[4] | ✓ | ✓ | ✓ | |
[11] | ✓ | ✓ | ✓ | |
[16] | ✓ | ✓ | ||
[17] | ✓ | ✓ | ||
[18] | ✓ | ✓ | ||
[19] | ✓ | ✓ | ||
[20] | ✓ | ✓ | ||
[21] | ✓ | ✓ | ||
[22] | ✓ | ✓ |
Number | Types | Structure | Indoor Thermal Environment | Cultural | ||
---|---|---|---|---|---|---|
“Swastika Kang” | Other | Review | ||||
[14] | ✓ | ✓ | ||||
[15] | ✓ | ✓ | ||||
[23] | ✓ | ✓ | ||||
[24] | ✓ | ✓ | ||||
[25] | ✓ | ✓ |
Months | Average Monthly Outdoor Temperature (°C) | Indoor Thermal Comfort Temperature Range (°C) |
---|---|---|
1 | −11.5 | 17.4–24.4 |
2 | −6.5 | 17.4–24.4 |
3 | 1.7 | 17.4–24.4 |
4 | 10 | 17.4–24.4 |
5 | 16.7 | 19.5–26.5 |
6 | 21.5 | 21.0–28.0 |
7 | 25.7 | 22.3–29.3 |
8 | 23.2 | 21.5–28.5 |
9 | 17.2 | 19.6–26.6 |
10 | 10.3 | 17.5–24.5 |
11 | 1.1 | 17.4–24.4 |
12 | −7.5 | 17.4–24.4 |
Analogue Serial Number | Materials (From Outside to Inside) | Thicknesses (mm) | Heat Transfer Coefficient (k) K = 1/(0.15 + ∑R) (W/m2·k) | Thermal Inertia D = R × S | Thermal Comfort Time Percentage | |
---|---|---|---|---|---|---|
External wall | Standard | Brickyard | 450 | 0.54 | 16.981 | 24.03% |
1 | Brickyard | 400 | 0.6 | 15.094 | 24.03% | |
Brickyard | 500 | 0.49 | 18.868 | 24.13% | ||
Total thickness of the wall remains the same, changing the wall construction | ||||||
1 | Brickyard (430 mm) Extruded polystyrene foam (with skin) (20 mm) | 450 | 0.41 | 16.453 | 24.03% | |
Extruded polystyrene foam (with skin) (20 mm), Brickyard (430 mm) | 450 | 0.41 | 16.453 | 24.03% | ||
2 | Brickyard (410 mm), Extruded polystyrene foam (with skin) (20 mm), lime mortar (20 mm) | 450 | 0.42 | 15.944 | 24.03% | |
Changing the total thickness of the wall | ||||||
1 | Brickyard (450 mm), Extruded polystyrene foam (with skin) (20 mm) | 470 | 0.40 | 17.208 | 24.03% | |
2 | Brickyard (450 mm), Extruded polystyrene foam (with skin) (50 mm) | 500 | 0.29 | 17.548 | 24.03% |
Analogue Serial Number | Materials (From Outside to Inside) | Thicknesses (mm) | Heat Transfer Coefficient (k) K = 1/(0.15 + ∑R) (W/m2·k) | Thermal Inertia D = R × S | Thermal Comfort Time Percentage | |
---|---|---|---|---|---|---|
Roof | Standard | Concrete tiles (20 mm), Lime mortar (1) (20 mm), Grass-filled clay (ρ = 1400) (20 mm), Wooden boards (20 mm) | 80 | 1.74 | 1.301 | 24.03% |
1 | Concrete tiles (30 mm), Lime mortar (1) (30 mm), Grass-filled clay (ρ = 1400) (30 mm), Wooden boards (30 mm) | 120 | 1.27 | 1.951 | 24.03% | |
Changing the roof structure while keeping the total thickness of the roof structure unchanged | ||||||
1 | Concrete tiles (20 mm), Aerated concrete, foam concrete (ρ = 700) (20 mm), Grass-filled clay (ρ = 1400) (20 mm), Wooden boards(20 mm) | 80 | 1.51 | 1.399 | 24.14% | |
2 | Concrete tiles (20 mm), Lime mortar (1) (20 mm), Rigid-foam polyurethane sheet PUR (ρ ≥ 35) (20 mm), Wooden boards (20 mm) | 80 | 0.73 | 4.612 | 24.03% | |
Changing the total thickness of the roof and the thickness of the insulation | ||||||
1 | Concrete tiles (20 mm), Lime mortar (20 mm), Rigid-foam polyurethane sheet PUR (ρ ≥ 35) (1) (60 mm), Wooden boards (20 mm) | 120 | 0.33 | 11.770 | 24.35% |
Analogue Serial Number | Materials (From Outside to Inside) | Thicknesses (mm) | Heat Transfer Coefficient (k) K = 1/(0.15 + ∑R) (W/m2·k) | Thermal Inertia D = R × S | Thermal Comfort Time Percentage | |
---|---|---|---|---|---|---|
External wall | standard | Wooden, plastic-double-glazed windows (double-glazed spacing (100–140) | 2.50 | 24.03% | ||
1 | 6 mm + LE35AMARL film glass | 4.60 | 22.83% | |||
2 | Plastic +6Low-E + 12A + 6 mm white transparent insulating glass | 1.90 | 23.31% | |||
3 | [5 mm + 9A (air) + 5 mm] nano-coated (HJ-N-series) + 9A (air) + 5 mm white glass (warm edge sealing) | 1.56 | 24.09% |
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Zhang, M.; Shang, Z.; Luo, K.; Xie, K. New Insights into Traditional Construction Behind Sibe Dwellings with Swastika Kang for Space Heating in North China. Buildings 2025, 15, 795. https://doi.org/10.3390/buildings15050795
Zhang M, Shang Z, Luo K, Xie K. New Insights into Traditional Construction Behind Sibe Dwellings with Swastika Kang for Space Heating in North China. Buildings. 2025; 15(5):795. https://doi.org/10.3390/buildings15050795
Chicago/Turabian StyleZhang, Menglong, Zhiyuan Shang, Keqian Luo, and Kai Xie. 2025. "New Insights into Traditional Construction Behind Sibe Dwellings with Swastika Kang for Space Heating in North China" Buildings 15, no. 5: 795. https://doi.org/10.3390/buildings15050795
APA StyleZhang, M., Shang, Z., Luo, K., & Xie, K. (2025). New Insights into Traditional Construction Behind Sibe Dwellings with Swastika Kang for Space Heating in North China. Buildings, 15(5), 795. https://doi.org/10.3390/buildings15050795