Effects of Street Orientation and Canyon Geometry on Thermal Improvement Efficiency of Retractable Sunshade Canopies at Pedestrian Level
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PUBLIC SUMMARY
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36 ENVI-met summer solstice scenarios simulate hourly AT, MRT & PET (6:00–20:00) for retractable building sunshades with varied street orientations, widths and canopy lengths.
Retractable canopies cut daily average PET by up to 4.67°C, mitigating extreme summer heat harm to residents and lowering buildings’ cooling energy demand.
E-W streets see linear thermal relief with longer canopies; 12m narrow streets with 3.0m canopies deliver the strongest cooling effect.
12m N-S streets with full-length canopies trap excess heat; the optimal N-S setup is 18m width + 3.0m canopies (max PET drop: -1.65°C).
Dynamic adjustable shading systems are superior to static fixed layouts for balancing pedestrian thermal comfort and building cooling loads.
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ABSTRACT
The extremely hot summer in China significantly exerts adverse impacts on residents' health and intensifies building cooling energy demands. This study quantifies the thermal effects of building-mounted, retractable sunshade canopies at the pedestrian level. Hourly values (6:00–20:00) of air temperature (AT), mean radiant temperature (MRT), and physiological equivalent temperature (PET) of 36 designed scenarios on the summer solstice were simulated via the ENVI-met software. The designed experimental scenarios integrated two street orientations (east-west and north-south), three street widths (D = 12, 18, 24 m), and five sunshade canopy lengths (d = 1.0, 1.5, 2.0, 2.5, 3.0 m). The results demonstrate that sunshade canopies can effectively improve the localized thermal environment, resulting in a maximum diurnal average PET reduction of 4.67°C. In the east-west street canyons, thermal mitigation effects exhibit a monotonic linear relationship with street canopy extension, with the peak efficiency occurred in the minimum D (12 m) coupled with the maximum d (3.0 m). A distinct adverse "heat retention" anomaly occurs in narrow north-south street (12 m wide) with maximal canopy length. Consequently, for north-south streets the optimal diurnal PET strategy shifts from the narrowest configuration to a medium D (18 m) combined with the maximum d (3.0 m), delivering a maximum local thermal comfort improvement corresponding to a PET reduction of -1.65°C. These empirical findings demonstrate the need to shift from rigid, static geometric layouts to dynamic and responsive shading regulation frameworks. This approach can synergistically optimize pedestrian-level outdoor thermal environment and cooling energy use of adjacent building. -
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REFERENCES
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Zhu Z., Wang D., Ma C., et al. (2026). Effects of Street Orientation and Canyon Geometry on Thermal Improvement Efficiency of Retractable Sunshade Canopies at Pedestrian Level. Energy Use 2:100058. https://doi.org/10.59717/ipj.energy-use.2026.100058
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Zhu Z., Wang D., Ma C., et al. (2026). Effects of Street Orientation and Canyon Geometry on Thermal Improvement Efficiency of Retractable Sunshade Canopies at Pedestrian Level. Energy Use 2:100058. https://doi.org/10.59717/ipj.energy-use.2026.100058
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Figure 1.
Location of Xi’an and the mean air temperature anomaly for the period July 6-August 4, 2025, relative to the 1991-2020 WMO baseline (July 6-August 4) (data source:National Climate Centre, https://cmdp.ncc-cma.net/cn/index.htm)
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Figure 2.
East-west air temperature variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 3.
North-south air temperature variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 4.
East-west MRT variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 5.
North-south MRT variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 6.
East-west MRT variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 7.
North-south PET variation:(A) D=12m, (B) D=18m, (C) D=24m.
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Figure 8.
Response surface of daily mean air temperature difference (°C) as a function of D and d: (A) for east-west streets, (B) for north-south streets. Response surface of daily mean radiant temperature difference (°C) as a function of D and d: (C) for east-west streets, (D) for north-south streets. Response surface of daily mean physiological equivalent temperature (°C) as a function of D and d: (E) for east-west streets, (F) for north-south streets