Optimization and Renovation Design of Indoor Thermal Environment in Traditional Houses in Northeast Sichuan (China)—A Case Study of a Three-Section Courtyard House

The three-section courtyard is the most representative traditional residence in the traditional villages in northeast Sichuan. As a unique cultural landscape, it carries the local historical style and cultural connotation. However, the high temperature weather in summer leads to a poor thermal environment in traditional residential buildings, which cannot meet the needs of building users for human thermal comfort, and the wall is the most critical factor affecting the indoor thermal environment. Therefore, to optimise the indoor thermal environment of traditional residential buildings, this study designed four groups of wall renovation schemes according to the original traditional residential buildings and modern technology, and simulated and verified the feasibility of the building renovation schemes by using Design Builder. Then, the four groups of wall renovation schemes were compared and tested based on the Design Builder. Comparative results of the thermal-performance evaluation index revealed that compared with Case 1 and Case 2, the building refrigeration energy consumption of Case 3 in the hottest week was the least, only 427.7 kW·h, which indicates that the external wall renovation scheme using aerated concrete blocks had the best thermal insulation and energy-saving effects. The cooling energy consumption of Case 4 in the hottest week was 422 kW·h, which was 4.3 kW·h less than that of Case 3, indicating that the wall renovation scheme with an air inter-layer had better thermal insulation and energy-saving effects. The refrigeration energy consumption of Case 7 in the hottest week was only 409.8 kW·h, which was 4.19% lower than Case 3 (without insulation material), indicating that the scheme of selecting central insulation and extruded polystyrene board (XPS) had better thermal insulation and energy-saving effects in practical projects. In summary, the above transformation scheme not only improves the indoor thermal environment of traditional residential buildings, but also provides guidance for architectural designers on green, energy-saving and sustainable design.