By analyzing measurements of the thermal environment of a qilou (arcade building) street, this study used the relative warmth index (RWI) to evaluate the thermal comfort in the colonnade space of a qilou. The analysis of the influence of the temperature, humidity, and wind speed on the thermal comfort in the colonnade space of a qilou street was conducted, and it was shown that the ambient wind speed had a strong influence on the RWI, indicating that a proper increase in the wind speed positively affected thermal comfort in this space. Then, this study also analyzed the effects of different forms of qilou streets on the wind environment by employing computational fluid dynamics (CFD) and summarized the architectural design measures that can improve the thermal comfort, including adopting back chamfer, street gaps, and the appropriate sizing of building components. It was concluded that the wind environment of a qilou could be optimized in terms of these measures, and the average RWI value decreased by 0.06, effectively enhancing the thermal comfort in the colonnade space. The research findings are applicable toward designing a thermally comfortable environment in the transitional space.

By extracting and simplifying the characteristics of commercial streets with arcades (Qilou) in Nanning, the tissue map of Qilou streets which reflects the urban morphology, including the road network form, block scale, building scale and other characteristics in a hot and humid area is obtained. In addition, the sunshine simulation is performed by using sunshine design software in an environment comprising streets with arcades to simulate street sunlight environments under various conditions. The relationship among street height-to-width ratio, sunshine hours, and street orientation angle is achieved by nonlinear fitting analysis. Then, a model is established to adjust the street height-to-width ratio based on sunshine requirement and street orientation. The finding indicated that when the street is north–south, it is suggested that the street height-to-width ratio is 0.95–1.13 to reduce sunshine hours effectively, and when the street is east–west, it is proposed that one side of the street should have a recessed space to improve the thermal conditions. The results of this study can serve as the specific guidelines that can be adopted in the redesign and reformation of commercial streets with arcades to achieve thermal comfort of Qilou streets in hot and humid areas.