The application of radiative cooling materials in buildings can effectively improve the indoor thermal environment in summer. This study used computational fluid dynamics (CFD) simulation to investigate the impact of transparent radiative cooling (T-RC) film on the indoor thermal environment of an office building in Nanjing, Jiangsu Province, China. The window-to-wall ratios (WWR) and orientations of the windows were also considered. The simulation results indicate that the best cooling effect of the T-RC film on indoor average air temperature is observed in the south room (1.91 °C), followed by the east room (1.59 °C) and then the west room (1.5 °C), while the cooling effect in the north room is limited (0.56 °C). The cooling effect of the T-RC film is best in the west room at WWR 50 %, while in the east and south rooms at WWR 75 %. The cooling effect of applying the T-RC film only to the south-facing windows is 61.4 % and 57.9 % of applying film to all windows for the west and east rooms, respectively. This study can provide a reference for the effects of applying the T-RC film to office buildings, inform the design or retrofit scheme of building windows, and provide helpful information for making a more comfortable indoor thermal environment.

Indoor respiratory airborne particles pose a significant threat to public health, especially in high-occupancy office spaces. In this study, Computational Fluid Dynamics simulations were conducted to investigate the transport characterization of airborne particles from nasal breathing under displacement ventilation (DV) with factors including air change rates (ACH), relative humidity (RH), diffuser configurations, and partition designs. The modified Wells-Riley model was used for risk quantification. Results indicate that under low-velocity DV, particles exhibit limited horizontal spread but accumulate vertically, forming bimodal distributions around 1.1 m and above 1.5 m. Under the baseline condition (5 ACH, 22 degrees C supply air temperature and 50 % RH), infection risk was significantly higher at standing height (1.6 m) than at seated height (1.15 m), with the maximum probability rising from 30.98 % to 60.48 % over 1800 s. Increasing ACH significantly enhances particle removal, while RH has minimal influence. Optimized diffuser placement and larger outlet areas were found to improve airflow distribution and reduce pollutant accumulation. Critically, while partition types have limited effect on airborne particle transmission, raising partition height from 30 cm to 70 cm cuts particle suspension by 42.5 % and increases deposition nearly 45-fold, demonstrating partition height greatly limits particle transmission. The study highlights the critical role of ventilation parameters and partition designs in DV offices. The findings offer concrete guidance for designing safer offices, prioritizing optimized ventilation and partitions of at least 50 cm in height to mitigate airborne particle transmission risks under real breathing conditions in DV offices.

The Spring Festival, a cornerstone of Chinese cultural heritage, fosters family reunions. However, its traditional practices, such as burning incense and setting off fireworks, generate severe air pollution and pose significant health threats. This presents a critical dilemma regarding how rural residents balance the imperatives of cultural preservation against environmental health risks. This study investigates this trade-off using a multidisciplinary approach. Field measurements within a rural household during the 2024 festival revealed alarmingly high indoor PM2.5 levels, peaking above 1000 μg/m3 on New Year's Eve and averaging over 600 μg/m3. Furthermore, a survey of 1035 residents across nine northern provinces found that 38.7% and 19.7% reported adverse physiological symptoms from high outdoor and indoor pollutant levels, respectively. Notably, of those experiencing symptoms, an overwhelming 81.8% were still willing to tolerate temporary air pollution for cultural fulfillment derived from the festival. This underscores that for these rural residents, the perceived value of traditional observance can outweigh immediate environmental health concerns. Therefore, policymakers must develop strategies that reconcile public health and cultural heritage. Effective interventions could include promoting eco-friendly fireworks, organizing pollution-free community events, and subsidizing advanced ventilation technologies.

With the increasing population and urbanization promotion, energy consumption and carbon emissions have increased, and concern for inefficient energy use and deteriorating urban environments is growing. The prediction of building energy consumption and environmental evaluation, especially at large scales, are considered to be a major challenge confronting the research community. An outstanding strategy for mitigating energy consumption and carbon emissions resides in the field of energy modeling. As a simplified building energy modeling model, resistance-capacitance (RC) network model has the applications in fast predicting building energy consumption. Notably, in recent years, there has been an evident absence of thorough review endeavors related to RC model for urban building energy loads and climate. This review systematically explores the application of low-order models and reduction methods for urban or regional energy simulation starting from the typical RC model for building. In summation, the challenges associated with employing this model for urban building energy loads and climate can be succinctly summarized as follows: the absence of a unified platform for RC modeling; insufficient readily applicable urban datasets; the need for modeling tools that facilitate cross-platform analyses in conjunction with existing Geographic Information Systems (GIS) and urban thermal environment simulation research platforms, and the essential requirement for seamless integration with other complementary modules.

Solar control films (SCFs) have been widely studied as energy-saving retrofitting for buildings. To investigate the cooling effect of SCFs, a series of reduced-scale outdoor experiments were conducted to analyse the cooling effects of different kinds and orientations of SCFs and the joint effect of SCFs and cool materials. The impact of various weather conditions and nighttime use of SCFs on indoor air temperature was also discussed. It was found that the unidirectional fluoroscopy grey film (UFF-G) had the best cooling effect, reducing indoor air temperature by up to 4 degree celsius. The maximum temperature difference in indoor air caused by SCFs on different orientations can reach 4.8 degrees C, with west or south-facing SCFs resulting in lower indoor temperatures. Additionally, using both SCFs and cool materials can result in a maximum temperature decrease of 4.5 degrees C compared to using SCF alone. The cooling effect of SCFs could decrease on overcast and rainy days, and buildings without SCFs have lower indoor air temperatures at night. Our experimental results can offer theoretical references for energy-saving renovation of glazing systems with SCFs, creating a more comfortable indoor thermal environment and energy-efficient buildings.

Traffic-related PM2.5 seriously endangers human health and affects the energy consumption of building ventilation systems. This study investigates the impact of different ventilation strategies caused by traffic-related PM2.5 dispersion on indoor PM2.5 concentration and building energy consumption of nine typical residential neighborhoods in Nanjing using EnergyPlus software. Results of a third-floor apartment in a six-story slab-type parallel layout residential neighborhood (6F-Sp) show that strategy 1 (window opening, OW) and strategy 7 (natural and mechanical ventilation, NV&MV-TC) can maintain indoor PM2.5 concentration below 25 μg/m3. The NV&MV-TC strategy is chosen to simulate indoor PM2.5 concentrations and cooling/heating energy consumption in nine neighborhoods. The building cooling energy consumption range is 21.2–41.5 kW•h/m2, while the heating energy consumption is 14.9–74.7 kW•h/m2. In the cooling season, the hybrid ventilation strategy shows the lowest cooling energy consumption, followed by window closure with operating indoor air purifiers. Apartments employing window closure with mechanical ventilation have the highest cooling energy consumption. In the heating season, the most energy-efficient strategy is window closure with operating indoor air purifiers, followed by the hybrid ventilation strategy. The indoor PM2.5 concentration negatively correlates with the frontal area index (λf). This study provides valuable information for residential ventilation strategies and guides residents' behaviors in cooling/heating seasons.

The Modelica language, developing from version 1.0 in 1997 to the current version 3.1, has become the preferred language for system simulation. Its advantages focus on high-level components' behavioral aspects without delving into complex algebraic equations. Modelica supports various modeling approaches, is open-source, and allows users to implement their compilation tools. Several topics related to this language have emerged, warranting further in-depth research and discussion. Notably, in recent years, there has been an evident absence of thorough review related to Modelica language in the building sector. This review provides a systematic overview of the development of libraries, applications at the building and district scale, coupling and comparisons with other software, and discusses boundary conditions, model optimization, and development status. The study identifies the current research limitations of Modelica and highlights the future focus on integrating renewable energy systems and advanced control systems. The review identifies challenges, including extensive learning costs, while emphasizing the need for future research to develop open-source libraries and complex models for broader applications in building systems.

Four building arrays, each comprising 25 building models, were utilized to investigate the effects of cool materials on building surface temperatures, indoor temperatures, and street microclimates in Guangzhou, China. The experiments are divided into three groups. The first group of the experimental models is used to investigate the cooling effect of the roof using cool materials on the roof surface and indoor environment. The results show that using cool materials on roofs can significantly reduce roof surface and indoor temperatures of the top floor by 13.5 degrees C and 3.9 degrees C at noon under an average global solar radiation (GSR) of 727 W/m2. The second group of experiments included four arrays: one control group without cool materials and three other arrays applying cool materials on the third, second, and first floors, respectively. Using cool materials on the fa & ccedil;ades of the third, second, and first floors reduced the indoor temperature by an average of 1.9 degrees C, 0.8 degrees C, and 0.5 degrees C (average GSR = 404 W/m2), respectively. As a result, higher floors receive more solar radiation, and cool materials show better cooling capacity. The third group is used to investigate the effect on street air temperatures when cool materials are used on all building fa & ccedil;ades. Overall, the effect of cool materials on the street air temperature is very small, with a maximum reduction of only 0.2 degrees C in the street air temperature.

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Traffic-related PM2.5 seriously endangers human health and affects the energy consumption of building ventilation systems. This study investigates the impact of different ventilation strategies caused by traffic-related PM2.5 dispersion on indoor PM2.5 concentration and building energy consumption of nine typical residential neighborhoods in Nanjing using EnergyPlus software. Results of a third-floor apartment in a six-story slab-type parallel layout residential neighborhood (6F-Sp) show that strategy 1 (window opening, OW) and strategy 7 (natural and mechanical ventilation, NV&MV-TC) can maintain indoor PM2.5 concentration below 25 mu g/m3. The NV&MVTC strategy is chosen to simulate indoor PM2.5 concentrations and cooling/heating energy consumption in nine neighborhoods. The building cooling energy consumption range is 21.2-41.5 kW center dot h/m2, while the heating energy consumption is 14.9-74.7 kW center dot h/m2. In the cooling season, the hybrid ventilation strategy shows the lowest cooling energy consumption, followed by window closure with operating indoor air purifiers. Apartments employing window closure with mechanical ventilation have the highest cooling energy consumption. In the heating season, the most energy-efficient strategy is window closure with operating indoor air purifiers, followed by the hybrid ventilation strategy. The indoor PM2.5 concentration negatively correlates with the frontal area index (lambda f). This study provides valuable information for residential ventilation strategies and guides residents' behaviors in cooling/heating seasons.