A Case Study on Energy-Saving Renovation Strategies for a Wind and Rain Sports Hall

Energy-efficient renovation of existing buildings is one of the important approaches to achieving sustainable development. This study takes a naturally ventilated sports hall (without heating or air conditioning systems) at a university in Weifang, Shandong Province, as the research object, where indoor thermal comfort levels remain low throughout most of the year. Adopting passive optimization as the core approach, the study aims to improve natural daylighting and winter thermal environment by adjusting window-to-wall ratio (WWR), window-to-floor ratio (WFR), skylight height, and glass thermal–optical parameters. The research methodology consists of two main stages: field measurement and multi-scenario simulation. On-site measurements were first conducted to ascertain the building’s actual usage patterns, existing daylighting conditions, and temperature distribution characteristics. Subsequently, six scenarios—including the original design, the current condition, and four differentiated optimization schemes (Schemes A, B, C, and D)—were quantitatively evaluated for indoor daylighting and thermal performance using Ecotect Analysis 2011 and eQUEST 3.65. The simulation models were calibrated against field measurement data to ensure result reliability. Key findings are as follows. In terms of daylighting, daylight factor and indoor average illuminance increase significantly with higher WFR, with this growth trend noticeably plateauing around a WFR of 0.7. Illuminance uniformity should be comprehensively assessed using both of its calculation methods; skylights provide more balanced daylighting than side windows, and combined side-window and skylight schemes yield far superior illuminance uniformity compared to single-type window arrangements. Regarding thermal performance, in schemes incorporating skylights, indoor temperature rises with increasing glazing area when WFR is below 0.7; however, when WFR exceeds 0.7, building heat dissipation surpasses solar heat gain, causing indoor temperature to decrease. Considering annual thermal comfort performance, Scheme C achieves the longest cumulative comfort hours and the most balanced year-round thermal performance, making it suitable for renovation projects pursuing stable indoor environments. Scheme A demonstrates significant winter warming effects but suffers from overheating defects during summer and transition seasons, thus requiring enhanced ventilation measures. After implementing increased ventilation (5 air changes per hour), Schemes A and C achieve 36.7% and 37.2% more comfortable hours during the building’s 10-month usage period, respectively, compared to the current condition. In conclusion, for large-space buildings such as sports halls, relying solely on increasing WFR and WWR for passive winter warming yields limited effects, and coordinated optimization of glass thermal–optical properties and ventilation strategies should be adopted.