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This study aimed to determine whether canopy and air temperature difference (ΔT) as an existing simple normalizing index can be used to detect an increase in canopy temperature induced by soil drought in urban parks, regardless of the unique energy balance and three-dimensional (3D) structure of urban trees. Specifically, we used a thermal infrared camera to measure the canopy temperature of Zelkova serrata trees and compared the temporal variation of ΔT to that of environmental factors, including solar radiation, wind speed, vapor pressure deficit, and soil water content. Normalization based on a 3D energy-balance model was also performed and used for comparison with ΔT. To represent the 3D structure, a terrestrial light detection and ranging-derived 3D tree model was used as the input spatial data. The temporal variation in ΔT was similar to that of the index derived using the energy-balance model, which considered the 3D structure of trees and 3D radiative transfer, with a correlation coefficient of 0.85. In conclusion, the thermal-image-based ΔT performed comparably to an index based on the 3D energy-balance model and detected the increase in canopy temperature because of the reduction in soil water content for Z. serrata trees in an urban environment. [ABSTRACT FROM AUTHOR]

The escalating use of glass in an ever-evolving world poses a waste management challenge, with glass waste contributing to non-biodegradable landfill growth. Recycling glass waste emerges as a viable solution, combating the need for additional landfills and the environmental repercussions. This study employs a scientometric and content analysis from the Scopus bibliometric database and explores the functional feasibility and performance characteristics of recycled glass waste (RGW) in sustainable concrete production. Results indicate that Asia dominates research contributions to RGW for concrete production compared to other continents. Glass-mixed concrete properties depend on glass type, particle size, shape, surface texture, replacement ratio, and curing age. The pozzolanic reactivity of recycled glass is correlated with its relative fineness. Finer glass particles were considered more suitable for use due to the enhanced alkali-silica interaction. Utilizing glass powder and fine aggregates improves mechanical properties, but high replacement levels could affect concrete strength development. Additionally, using RGA as a cement and fine aggregate replacement reduces concrete's thermal conductivity. This scientometric analysis not only aids in understanding a comprehensive overview of incorporating recycled glass waste into concrete production but also identifies knowledge gaps, guiding sustainable concrete research and development for addressing waste management challenges linked to the growing use of glass in our contemporary society. [ABSTRACT FROM AUTHOR]

Affordable apartments in tropical developing countries generally have double-loaded corridors to maximise the total floor areas. Building designs with double-loaded corridors often suffer from poor environmental conditions. Passive design using a vertical void can help improve the natural ventilation in the such building design. This study investigates the effectiveness of vertical voids in enhancing the wind speed in the building. An experimental building with a vertical void, open pilotis, penthouse at rooftop and wind fin on the ground floor to help direct air to the void was constructed in Tegal, Indonesia. Five cases were considered by controlling the window openings, louver openings on the roof and change in fin size at pilotis. Wind speed and direction were recorded at one-second intervals. High wind speed was experienced in the pilotis and void when the wind direction is from the north and the wind speed in the void improved due to the wind fin being placed on the south corridor of the building. The results show the average wind speed in the void is twice as high as compared to the corridors. The building design performed best with high wind speeds in the void and corridores when all windows were kept open.

This paper focuses on clarifying the heat transfer coefficient necessary for determining the indoor temperature distribution during night ventilation using floor-level windows. Measurements were used to identify the factors that influence the vertical temperature distribution within a room wherein phase-change materials (PCMs) were installed at the floor level. The investigation revealed a temperature differential ranging from 1 °C to a maximum of 3 °C between the floor and the center of the room, attributable to external climatic conditions (outdoor temperature and wind speed). This variation was found to depend on the degree of mixing of indoor air currents. This deviation was critical because it significantly affected the phase-change temperature of PCMs, thereby impacting their thermal storage capabilities. Consequently, this study aimed to refine the predictive accuracy of indoor temperature distributions by proposing a modified vertical temperature distribution model that incorporated these findings. The results of this study are expected to provide better design strategies for building constructions that incorporate PCMs, and to optimize their functionality in passive cooling systems. [ABSTRACT FROM AUTHOR]

In the building sector, the low thermal conductivity of plastics makes them a viable option to increase the thermal resistance of construction materials. Incorporating recycled plastic in concrete panels can not only enhance the sustainability and circular economy of the buildings but also provide an affordable alternative to phase change materials (PCM) for thermal insulation. To evaluate the potential of waste plastic as a thermal insulation material, nine samples with varying thicknesses (1 mm, 2 mm, and 3 mm) and portions of shredded waste plastic were tested to determine their thermal and physical properties. The properties under investigation, such as density, water absorption, porosity, compressiveness, and thermal conductivity, have been tested. Upon completion of the physical and thermal assessments, it was determined that the PL.SH.layer.10% and PL.SH.layer.20% insulation samples exhibited higher thermal effective alternatives compared to the PCM samples. Additionally, the latter two options are deemed to be more cost-effective. Only the samples with with a melted plastic layer of 1 or 2 mm failed to boost their thermal efficiency in terms of heat insulation until the melted plastic was increased by more than 3 mm. The research emphasizes the capacity of recycled plastic to act as a cost-efficient substitute for thermal insulation. This substitution to boost the insulation of building envelopes, preserve energy, and enhance thermal comfort, boost increase the insulation of building envelopes, preserve maintain energy, and enhance thermal comfort, especially in hot developing countries. The results may provide valuable is for future investigations and advancements in sustainable construction materials, facilitating the shift towards a circular economic model. [ABSTRACT FROM AUTHOR]

Green roofs' (GR) positive impact on indoor thermal conditions in hot areas may have possible negative impacts during hot and cold weather. Most previous studies have focused on GR's positive effects as a standalone strategy without mitigating these side effects of GR application. This study contributes to a more comprehensive understanding of the impact of GR and how to mitigate the negative aspects by integrating it with other passive techniques (natural ventilation and thermal insulation). Therefore, this study experimentally compares the seasonal impact of various soil layer configurations, integrated with natural ventilation, on improving Indoor Thermal Comfort (ITC) throughout the day in summer and winter. Field experiments were conducted using two identical validated test boxes. The results revealed that clay soil reduced Indoor Air Temperature (IAT) during the daytime in summer by up to 4.7 and 4°C for low and high soil thickness, respectively. Increasing clay soil thickness improved average IAT during the daytime in summer and winter by up to 6.49% and 2.61%, respectively. Additionally, adding thermal insulation is preferred in winter, while uninsulated soil had a slight positive effect on IAT and Indoor Relative Humidity (IRH) in summer. The use of natural ventilation at night and closed-ventilated systems during the daytime in summer and winter is recommended. Clay soil could save cooling and heating energy by up to 34.8% and 12.18%, respectively. These findings might inform designers by adjusting different GR soil parameters and the importance of natural ventilation in improving multi-seasonal thermal and energy performance. [ABSTRACT FROM AUTHOR]

The number of scientific papers has dramatically increased in recent years; however, such a huge number of papers often become difficult to review qualitatively because of limited time and cost. A text-mining-based bibliometric analysis method is developed to provide a comprehensive overview of passive cooling methods used in buildings in hot and humid climates. First, a comprehensive overview analysis is conducted to clarify the trends in studies on passive cooling methods between 1970 and 2022, using 39,604 publications. Second, 15 coding rules are constructed to perform a detailed analysis, and possible combinations of passive cooling methods are discussed. The detailed analysis of the co-occurrence network based on the comprehensive overview and 15 coding rules shows that the recent studies on thermal energy storage have mainly focused on phase change material (PCM), which is a latent heat storage material, rather than sensible heat storage materials such as concrete. The analysis of the co-occurrence network indicates that natural ventilation maintains the vital role of passive cooling methods by improving thermal comfort in hot climates. The constructed method and possible combinations of passive cooling methods for hot and humid climates will help engineers find effective combinations in the planning stage. [ABSTRACT FROM AUTHOR]

Optimizing the thermal environment of a bedroom is desirable for good sleep. In moderate climatic conditions, natural ventilation is a viable method for enhancing the quality of sleep by improving indoor air conditions. This study examined the effects of air temperature and wind speed on sleep quality in naturally ventilated rooms with windows open and closed, during autumn. Thirteen young males in healthy conditions participated in this study. Two adjacent test rooms (for opened and closed conditions) were selected on a university campus, with standardized indoor conditions. Air temperature and wind speed were measured near the height of the participants' heads. Sleep efficiency and wake after sleep onset (WASO) were calculated using physiological wearable sensors based on heart rate and body movement. The participants completed questionnaires on thermal sensation and comfort before and after sleep. The results showed that the lowest percentage of WASO was observed when the nocturnal mean temperature was 23–24°C with a quadratic regression curve regardless of the window opening conditions. Conversely, subjective sleep satisfaction and WASO did not show any significant differences between the conditions. The results revealed no significant impact of varying thermal and airflow conditions during autumn on thermal/airflow comfort, although significant differences were observed in the thermal/airflow sensation before and after sleep. Thus, these results suggest that natural ventilation through the opening of windows might not affect thermal/airflow comfort, while a nocturnal indoor air temperature of 23–24°C is recommended for good sleep and thermal comfort, regardless of window opening conditions under moderate climate conditions. [ABSTRACT FROM AUTHOR]

Natural ventilation is a common passive cooling method for improving air quality and thermal comfort; however, hot temperatures in summer and safety and privacy issues at night often result in its unideal performance. Therefore, we proposed the use of floor-level windows, mainly combined with microclimate improvement, to improve the indoor thermal environment by enhancing the cooling effect of natural ventilation during summer. Our study area was a house in Machida, Tokyo. We evaluated the effectiveness of our method in improving the indoor thermal environment in summer and performed a numerical simulation, while illustrating the detailed horizontal and vertical distribution of airflow in the house through the floor-level windows. The influence of different window types and opening angles of floor-level windows on ventilation and cooling was determined using the simulation. We found that: (a) natural ventilation-based passive cooling methods reduced semi-outdoor and indoor temperature and increased the humidity; (b) the airflow formed an indoor wind path; south-westerly inflow was from western floor-level windows and the skylight, and the outflow was from northern floor-level windows; and (c) the side hung windows (with an opening angle of 60°) were an ideal option to improve indoor airflow. However, there was no improvement in the passive cooling performance, due to the inflow of warmer outside air. [ABSTRACT FROM AUTHOR]