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.

Urban surface albedo is important for investigating urban surface–atmosphere radiative heat exchanges. For modeling surface energy balance (SEB) at local and neighborhood scales, ground or unmanned aerial vehicle (UAV)-based multispectral remote sensing (RS) can be used to obtain high-spatial-resolution multispectral information for both horizontal and vertical urban surfaces. The existing narrow-to-broadband (NTB) conversion models, developed for satellite/high-altitude observation and large homogeneous rural/vegetated/snow zones, may not be suitable for downscaling to the local and neighborhood scales or the urban complex texture. We developed three NTB models following published methodologies for three common UAV-based multispectral cameras according to Sample_D, a sample group of extensive spectral albedos of artificial urban surfaces, and evaluated their performance and sensitivities to solar conditions and surface material class. The proposed models were validated with independent samples (Sample_V). A model considering albedo physics was improved by multiplying different variables with respect to the camera (termed as “Model_phy_reg”), which initially proved to be the most accurate with a root mean square error of up to 0.02 for Sample_D and approximately 0.029 for Sample_V, meeting the required accuracy of total shortwave albedo for SEB modeling. The accuracy of Model_phy_reg was not much prone to the solar conditions.

Previous measurements (Del Rio et al. 2019) have confirmed the formation of cool summer microclimates through a combination of passive cooling elements (i.e., evaporative cooling louver, vegetation, and sunscreen) in semi-outdoor building spaces in Japan. Computational fluid dynamics (CFD) simulation is useful to understand the contribution of each element to semi-outdoor and indoor microclimates with natural ventilation, and to determine their effective combination. To date, there have not been sufficient studies on the modeling and validation for the CFD simulation of microclimates by such elements. This study demonstrates the modeling method using literature-based values and field measurements. It also demonstrates model validity by comparing the obtained results with field measurements. The results show that CFD simulation with detailed modeling of these elements can replicate vertical temperature distributions at four different positions across the semi-outdoor space and indoor space. The maximum difference in air temperature between the measurements and simulation results was 0.7–1 °C. The sensitivities of each passive cooling element on the microclimates formed in both spaces were confirmed. The watered louver condition and shorter louver–window distance were most effective in cooling both spaces. These results indicate that the modeling method could be effectively applied to assess cool microclimates and formulate a passive cooling design.

The rapid urbanization in Southeast Asia has resulted in an increase in vertical apartment buildings, bringing notable changes in residents’ lifestyles accompanied by Westernized cultures. Focusing on Indonesia, this study delves into how residents adapt their behaviors, especially traditional floor-sitting behavior, to living in the different types of apartments. The study also explores energy consumption and thermal comfort in relation to floor-usage behaviors. We conducted a comprehensive questionnaire survey of more than 3300 respondents in Indonesia, with 1841 Jabodetabek samples used for analysis. The findings indicate that approximately 80% of lower-income apartment residents (Rusunawa) predominantly engaged in floor-sitting behavior and relied on fans for cooling. In contrast, approximately 75% of higher-income apartment residents (condominiums) preferred chair-sitting and used air conditioning (AC). Cluster analysis of three key factors—primary posture, foot covering, and floor covering—revealed four distinct groups. The clusters with a lower preference for floor-sitting exhibited approximately 50% higher annual electricity consumption due to AC usage, whereas the clusters favoring floor-sitting consumed less electricity, relying more on fans. However, despite variations in energy use, over 85% of respondents across all clusters were mostly reported as comfortable, indicating that behavioral adaptations with floor-sitting remain viable in achieving thermal comfort. While an increase in income level changes behaviors and energy use, the results suggest that floor-sitting is a traditional practice that serves as an effective low-energy strategy in hot and humid climates.