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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]

This study clarifies the contact cooling effect of bare feet on human thermal physiology and sensation using a floor cooling system under hot environments. An experiment was conducted with 14 healthy young men and women using a water-cooled floor panel to investigate the cooling effects under Japanese summer conditions. The results revealed that the influences of the room temperature on the physiological parameters including blood flow, mean skin temperature, and sublingual temperature were more sensitive than that of the floor temperature. Nevertheless, the contact cooling of the soles with the floor temperature of 28 °C reduced the percentage of "very hot" and "hot" sensations of the entire body by 15.5 % when the room temperature was 30 °C. Moreover, the contact cooling of the soles at the room temperature of 30 °C increased heat flow from the soles while maintaining constant blood flow when the floor temperature was decreased. Thus, contact cooling of the soles was confirmed to be effective for heat mitigation in hot environments. However, the contact cooling was likely to cause thermal discomfort owing to the cold sensation as the room temperature decreased to 24 °C. Individual differences, in addition to the sex differences, occurred in the contact cooling effects on blood flow and skin temperature. Individual differences in blood flow were primarily caused by differences in basal metabolism and muscle mass. Further energy savings for space cooling and improved thermal comfort will be achieved by considering the individual differences for the floor cooling systems. • Influence of contact cooling on thermal physiology and sensation was investigated. • Individual difference of physiological response to floor temperature was observed. • Muscle mass affected the blood flow trends, mainly caused by gender differences. • Contact cooling reduced hot sensation by 15.5 % when the room temperature of 30 °C. • Contact cooling caused thermal discomfort due to cold at room temperature of 24 °C. [ABSTRACT FROM AUTHOR]

Abstract Evaporative cooling is a widely used passive cooling method to mitigate high ambient temperatures in Japan during the hot and humid summer season. An evaporative cooling louver was developed by Hirayama et al. (2014) to create a cool microclimate in an urban residential outdoor space. This study investigated the potential of using passive cooling methods integrated with the louver to create a cool microclimate in a semi-outdoor space for natural ventilation. A field measurement was conducted to evaluate the microclimate in a semi-outdoor space under different amounts of solar radiation, surrounding vegetation, and distances from louver to window to find the best way that accumulates at most the cool air generated by the louver. Best results were found when the semi-outdoor space was exposed to low solar radiation, was fully surrounded by vegetation, and when the louver was closer to the window. Moreover, to use the cool microclimate created at the semi-outdoor space for natural ventilation, different ventilation settings such as window opening area, indoor cross ventilation, and stack ventilation with a sky window were incorporated and measured to find the best conditions to induce the cool air into the indoor space. Best results were found when the window was fully open and the wind speed of the air crossing the window was more than 0.2 m/s, which maintained a cooler vertical air temperature distribution inside the window. Highlights • We found an integrated passive cooling method to form a cool microclimate at a semi-outdoor space. • The ambient temperature was reduced by 1.0–4.0 °C when passing through the evaporative cooling louver. • Cool microclimate was formed when the semi-outdoor space was surrounded by vegetation. • Formed cool air was induced into the indoor space when wind speed crossing the window was more than 0.2 m/s. [ABSTRACT FROM AUTHOR]

We introduce a multilayer model to estimate mean radiant temperature (MRT) and evaluate the pedestrian thermal comfort in a street canyon. This multilayer MRT model (MMRT) is suitable for urban streets with varying building and tree heights. The model simulates shortwave and longwave radiation exchange for each urban element and area-weighted view factors, then finally obtains MRT of pedestrians on the sidewalk. Probability density profiles of buildings and trees enable the consideration of urban vertical heterogeneity. Furthermore, Monte Carlo ray tracing (MCRT) allows the model to evaluate the radiation transfer in complex urban areas. We verify the effectiveness of MCRT and the probabilistic density profile approach. A sensitivity test conducted in Seoul on September 1, 2017 using the MMRT reveals that MRT can be reduced by 23 °C as the tree leaf area density increases from 0 to 1, and by 18 °C as the tree height increases from 0 m to 12 m in 1300 LST. The model controls urban form and pavement parameters as well as tree parameters. We aim to use this model to compare diverse MRT mitigation strategies and confirm the best strategy for thermal-friendly street design. [ABSTRACT FROM AUTHOR]

This study aims to determine the optimum window-opening control that maximizes annual thermal comfort using ventilative cooling, i.e., night and comfort ventilation, in naturally ventilated buildings where phase change materials (PCMs) are used. A thermal energy simulation (TES) coupled with an airflow network model was constructed to evaluate the comfort ventilation and thermal storage effects of the PCMs by controlling the window-opening patterns. The EnergyPlus-based coupled TES model was validated by comparing with the field measurement results of a full-scale experimental building in Indonesia. The root-mean-square errors of the temperature and air speeds at the center of the target building ranged from 0.2 to 0.5 °C and 0.1–0.2 m/s, respectively. The accuracy of the coupled TES was similar to that of computational fluid dynamics coupled with the heat balance analysis, which can simulate the spatial distributions of temperature and air speeds. The annual simulation results showed that prioritizing the thermal storage effect of the PCMs in the morning and comfort ventilation in the afternoon increases the thermal comfort period. For the optimum window-opening control to maximize thermal comfort in the hot and humid climate, an indoor temperature of 27 °C can be considered a criterion to open the windows for comfort ventilation in addition to night ventilation for the thermal storage effect. When this criterion was applied, the thermal comfort period in the room with PCMs increased to 83.3 %. Accordingly, the reduction in electricity consumption for space cooling was 41 % less than that in a control room without PCMs. • A coupled TES model evaluating thermal comfort was constructed. • The coupled TES calculated wind speed accurately with the light calculation load. • The proposed system using PCM achieved thermal comfort period of 83 % for a year. • An optimum window-opening control to maximize annual thermal comfort was clarified. • Indoor temperature of 27 °C and nighttime can be criteria to open window. [ABSTRACT FROM AUTHOR]

Street and garden trees in urban areas are often exposed to advection of strong vapour pressure deficit ( VPD) air that can raise the whole-tree transpiration rate ( ET), known as the oasis effect. However, urban trees tend to have small soil volume compared with natural conditions, and so they are believed to strongly regulate stomata. ET characteristics of such urban trees have not been well understood because of a lack of reliable measurement methods. Therefore, we propose a novel weighing lysimeter method and investigate the whole-tree water balance of an isolated container-grown Zelkova serrata to examine (a) which biotic and abiotic factors determine ET and (b) which spatial and temporal information is needed to predict ET under urban conditions. Whole-tree water balance and environmental conditions were measured from 2010 to 2012. Although leaf area substantially increased in the study period, daily ET did not vary much. ET increased with VPD almost linearly in 2010 but showed saturation in 2011 and 2012. Root water uptake lagged ET by 40 min in 2012. These results suggest that the small planter box interfered with root growth and that hydraulic supply capacities did not increase sufficiently to support leaf area increase. From analysis of water balance, we believe that neglecting soil drought effects on street trees without irrigation in Japan will overestimate ET over 4-5 sunny days at the longest. This is unlike previous studies of forest. [ABSTRACT FROM AUTHOR]

We propose a multipoint measurement method for air temperature in outdoor spaces using polyvinyl chloride pipes with fan-aspirated ventilation. The method is applied to microclimate measurement in the outdoor space of a residential house, and the cooling effects of plants and natural ventilation on the house were evaluated. The accuracy of the proposed method was verified in the outdoor space. Average systematic errors of the method were 0.43 °C during daytime on sunny days and 0.16 °C on cloudy days. Application of the method to microclimate measurement shows that air temperatures were reduced by evapotranspiration of plants and watering in the planted space during daytime. By placing the plants near a floor-level window, wind speed inside the window was reduced, although the cooled air flowed into the indoor space through the window. The cooling effects of the plants and watering in the outdoor space kept indoor air temperature cooler during daytime. The period in which the sensible heat flux from the outdoor to indoor space showed positive values, i.e., when there was a sensible heat load in the room, diminished from 9 to 4 h through the cooling effects. [ABSTRACT FROM AUTHOR]

Air temperature is an important physical indicator of a built space. A novel method for remotely measuring the air temperature distribution using a thermal infrared spectroradiometer is evaluated, and an experiment using the maximum a posteriori method, which uses a priori information, is conducted with a heat source. The a priori information is the probabilistic information that the observer knows about the air temperature prior to the observation. Assuming an indoor scale (10 m), the air temperature distribution is estimated (i.e., retrieved) by discretizing the space into four layers. Accordingly, our method reduces the error in the air temperature estimation compared to the a priori information. When the layer of the heat source is known, the air temperature estimation is sensitive to the air temperature of the heated layer, even when the heat source is away from the sensor (2nd to 4th layers). The root-mean-square error (RMSE) of the heated layer decreased from 10 K (a priori) to 4.8 K. Although the RMSE of the temperature distribution was approximately the same regardless of the number of spectral channels used in the retrieval, the RMSE of the heated layer was smaller when ten spectral channels were used. In the case of a target space and spectrometer, as in this study, ten spectral channels were sufficient. These findings indicate the possibility of remotely measuring the air temperature distribution in a space with a local heat source (e.g., data centers), which is a relatively difficult case for remote sensing methods. • Air temperature distribution was remotely measured by a spectroradiometer. • Maximum a posteriori method was used as a regularization for this measurement. • The effectiveness of the proposed method was validated through the experiment. • Ten spectral channels were sufficient in the spectroradiometer for this method. • When a heat source location was known, sensitivity was seen away from the sensor. [ABSTRACT FROM AUTHOR]

This study investigated the applicability of a thermal energy simulation (TES) for a naturally ventilated building in which a phase change material (PCM)-based radiant floor cooling system was installed. The TES was conducted to determine influential factors to maximize the thermal storage effect of PCMs in the building throughout a year in a hot and humid climate. First, the thermal properties of a full-scale PCM product were measured using the heat flow method. This measurement clearly captured the hysteresis of the PCM depending on the heating and cooling rates; thus, the enthalpy–temperature curve under slow heating and cooling rates was determined for the TES. Based on the results of the PCM measurement, the EnergyPlus-based TES model was validated by comparing it with the results of field measurement at a full-scale experimental building with natural ventilation in Indonesia and a computational fluid dynamics (CFD) simulation coupled with the heat balance analysis. Good correlations (up to R2 = 0.99) were observed in the air and floor surface temperatures between the measurement and TES simulation. Additionally, the TES had a similar accuracy as the coupled CFD, which considers spatial wind and temperature distribution. The results of the annual simulation showed that the proposed PCM-based radiant floor cooling system with night ventilation achieved a thermal comfort period of up to 68.5% a year. Furthermore, a reasonable annual average utilization rate of approximately 70% can be determined to maintain a low floor surface temperature throughout a year. • A thermal energy simulation model considering hysteresis of PCM was constructed. • Two types of PCM measurement methods were compared to determine the thermal properties. • The proposed system using PCM achieved thermal comfort period of up to 68.5% a year. • The maximum liquid fraction influenced the retention of thermal storage effect of PCM. • A reasonable annual utilization rate can be determined as approximately 70%. [ABSTRACT FROM AUTHOR]

This paper presents a method for estimating the solar transmittance of urban trees using airborne light detection and ranging (LiDAR), and the radiative transfer simulation of vegetation. The leaf area density (LAD) distribution of trees with voxel size 1\ \textm\times 1\ \textm\times 0.5\ \textm is estimated using high-resolution and multireturn airborne LiDAR data. The LAD of voxels having few incident laser beams is corrected from the surrounding voxels. The LAD of the periphery of the crown is discretized into 0.5\ \textm\times 0.5\ \textm\times 0.5\ \textm voxels to accurately calculate the shaded area. The resulting LAD distribution is used in a radiative transfer simulation to calculate the solar transmittance of the trees. We verified the accuracy of the calculated transmittance by comparing it with empirical data for a Zelkova serrata. The comparisons were conducted under different angles of incidence of laser beams and solar radiation. When the angle between the incident laser beams and solar radiation was small, the transmittance could be accurately estimated. The LAD correction enabled the method to be applied to a broader range of the angle between beams and solar radiation. When the zenith angle of the incident laser beams was small (<\ 10^\circ) and the LAD correction was carried out, the errors in transmittance were within 0.06 for solar altitudes greater than 40°. Next, we examined the difference in solar transmittance among streets caused by the layout of trees and buildings and the growth condition of the trees. It was shown that the present method is able to quantify the solar shading provided by urban trees and take into account LAD, tree layout, and the spatial geometry of the surrounding buildings. [ABSTRACT FROM AUTHOR]

Mean radiant temperature (MRT) is the primary metric of radiant heat exchange between a human body and the environment, and it dominates human thermal comfort and heat stress. This study develops a new portable recording system for spherical thermography utilizing only commercial devices (an infrared thermal imaging camera and a portable rotation platform) and image processing for panorama synthesis. We use the system to estimate the MRT in a longwave radiation environment. A spherical thermal image is generated by synthesizing 24 source images on the basis of feature point identification. The longwave MRT and plane radiant temperature can be estimated from the spherical thermal image using image projection methods, including the orthographic projection and Lambert cylindrical projection. To validate the developed system, measurements were made using the system in outdoor and indoor environments with various radiant temperature distributions, including sunny built spaces and a tree-shaded space, and the results were compared with those obtained using pyrgeometers. The difference in longwave MRT between the estimation by the developed system with orthographic projection of spherical thermal images and the measurement by pyrgeometers for six directions was within 1 °C in most cases and 1.6 °C at maximum. The results show that the developed system has sufficient accuracy for longwave MRT estimation while evaluating the radiant temperature distribution and radiant asymmetry of spaces. • A portable recording system for spherical thermography was developed. • The developed system was validated for indoor and outdoor spaces. • Mean radiant temperature can be accurately estimated by the developed system. [ABSTRACT FROM AUTHOR]

Bio-receptive façade panels that support the natural growth of mosses, micro-organisms, and small plant species are potential alternatives than traditional green walls. Supporting the moss's development naturally could offer great potential for achieving ecologically richer, healthier, and zero-carbon cities. In particular, a limited amount of hydration is required for mosses to grow on these bio-receptive surfaces, which is ideal for the hot, humid environment of north Egypt. This review paper is aimed at identifying the feasibility and influencing factors of implementing such a façade innovation in a hot, humid climate as north Egypt. To investigate this feasibility, first, it is essential to compare the critical factors for moss growth with the target environmental conditions. These key feasibility factors for the approach were classified as environmental and physical growth factors. Second, a field study was undertaken to confirm the availability of such moss resources in north Egypt since the climatic conditions correspond to the acceptable range necessary for its application of the approach. This study resulted in promising families of mosses being available, in which great potential for the use of bio-receptive concrete with a cover of moss to expand the green areas vertically is expected. Especially, this green expansion will be with moss, which blooms randomly in the natural environment. This technique may bring additional advantages by generating new sustainable materials from low-cost and readily available resources. It is considered to be an approach to enhance greening and reduce urban environment's susceptibility to climate change without requiring extensive irrigation and maintenance. [ABSTRACT FROM AUTHOR]

Abstract: This paper focuses on the development of a thermal design tool for use in planning outdoor spaces by combining a heat balance simulation for urban surfaces, including buildings, the ground and greenery, with a 3D-CAD system that can be run on a personal computer. The newly developed tool is constructed by improving the previous simulation model, which uses the geographic information system (GIS) for the input data. The simulation algorithm is constructed so as to predict the surface temperature distribution of urban blocks while taking into account the actual design of the outdoor space using the 3D-CAD system. A method of multi-tracing simulation to calculate the sky view factor and radiative heat transfer is established. The optimal mesh size is examined for the tool so as to provide detailed spatial geometry within a suitable calculation time. The simulation model is integrated with an all-purpose 3D-CAD software, and the pre-processing method are constructed for practical use. The results obtained by applying this simulation tool to an area of detached houses reveals that the tool is able to evaluate the effects of building shape, materials, and tree shade on the surface temperature distribution, as well as the MRT and HIP, which are evaluation indices of the outdoor thermal environment. [Copyright &y& Elsevier]

We proposed a novel radiant floor cooling system using phase change materials (PCMs) with night ventilation in the hot and humid climate of Indonesia. This study aims to clarify the measures to ensure the thermal storage effect of the proposed cooling system during daytime for a naturally ventilated room within a relatively narrow diurnal temperature range, focusing mainly on the thermal properties of PCMs. We analyzed the relationship between the indoor vertical air temperature distributions and heat flows of the proposed system using an experimental building in Tangerang, Indonesia. The results confirmed that the thermal mass of PCMs and the cooling strategy for the floor structure at night strongly contributed to maintaining a low floor surface temperature during the subsequent daytime. Calm wind conditions and warm nocturnal ambient temperature, which was 0.7–3.2 °C lower than the set-point solidifying temperature and is common in the tropics, prevented PCMs from solidifying in case of natural ventilation for the underfloor space. In contrast, forced ventilation for the underfloor space attaching PCMs was effective in ensuring sufficient solidification. Furthermore, 95% of the thermal storage capacity of PCMs might be utilized when the ambient temperature was 2–3 °C higher than the set-point melting temperature during the daytime. The phase change temperature for PCMs can be determined based on the average ambient temperature, whereas a relatively wide diurnal ambient temperature range, at least 4.7 °C, was required to ensure the latent heat thermal storage effect caused by the supercooling. • Latent heat thermal storage was influential in lowering floor surface temperature. • Forced ventilation ensured the sufficient solidification of PCMs at warm nights. • Diurnal temperature range at least 4.7 °C was required to ensure phase changes. [ABSTRACT FROM AUTHOR]

Air temperature is an important physical indicator for urban and architectural environments; however, it is difficult to obtain its distributive characteristics by field measurements owing to the limitations of current measuring instruments. In this context, this study was conducted to demonstrate whether a small and portable ground-based thermal infrared spectroradiometer can be used to estimate the horizontal air temperature distribution in built spaces. For this estimation, we first calculated a forward model using radiative transfer simulations, and the air temperature distribution was inversely estimated from the observed radiance using the model. To regularize the estimated air temperature, we used the maximum a posteriori method, which uses prior information. To verify this estimation method, we conducted measurement experiments in two types of built spaces that had different air temperature distributions within spaces that were approximately 20 m long. Moreover, we conducted a parametric case study on the prior information. As a result, we were able to estimate the air temperature distribution with an average root mean square error (RMSE) of 1.3 °C for all cases when the average RMSE of the prior information for all cases was 2.1 °C. This improvement in the RMSE indicates that this method is able to remotely estimate the horizontal air temperature distribution in built spaces. [ABSTRACT FROM AUTHOR]

The combination of ventilative cooling and radiant cooling is a feasible approach for improving the cooling performance of buildings, thus achieving better thermal comfort of occupants in hot and humid climates. We propose a novel radiant floor cooling system using a phase change material (PCM) in Indonesia. This study aims to determine the window design that optimizes indoor air flow pattern to provide ventilative cooling, while maintaining the radiant cooling effect during daytime. We analyzed several window types through a field experiment using an experimental building in Tangerang, Indonesia. The performance of the windows was analyzed with an air flow pattern and was assessed in convective heat transfers on the floors and by the standard effective temperature (SET*) at the center of the room. The results showed that the horizontal pivot windows led to air inflows to the occupied level regardless of the outdoor wind conditions. The heat transfer coefficient on the floor was reduced by approximately 1.52 W/m2K compared with that of the simple opening. Nevertheless, the increase in thermal mass owing to the PCM had a greater effect on the retention of the floor cooling effect compared with the effect of the window type. Consequently, the SET* was reduced by approximately 0.79 °C during the daytime, showing that the proposed window design with the radiant floor cooling system achieved better thermal comfort in a hot and humid climate. Particularly, the horizontal pivot windows contributed to thermal comfort mainly because of the ventilative cooling effect. • A novel floor cooling system was proposed for a hot and humid climate. • Window type strongly affected indoor airflow pattern. • Heat transfer coefficient was reduced by 1.52 W/m2K by the horizontal pivot window. • Increased thermal mass maintained a cooler surface temperature. • SET* was reduced by 0.79 °C by the floor cooling system and horizontal pivot window. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Systematic simulations were performed in a city block in Yokohama, Japan, on a clear summer day to study the effects of building surface thermal properties on their radiative and thermal exchange with the atmosphere, and the surface energy balance (SEB) model sensitivity to these thermal properties. To study this practically and systematically, the thermal properties used were determined from a database of commonly used materials for building surfaces in urban Japan, characterizing the typical thermal property values and their combinations. Using suitable simplification and assumption, the main findings included: (a) a combined modification of thermal properties enlarges the cooling effects of individual modifications, reaching 131%–149% of the accumulated reduction in the emitted sensible heat flux (Q H); (b) the difference in the cooling effects of a high-albedo strategy applied to roofs between various thermal properties is up to 76 [W m−2] in Q H ; (c) the SEB model sensitivity of the surface temperature (T s) to thermal properties for the façade is close to that of the albedo, at up to approximately 0.1 °C for a thermal conductivity Δ λ c of 1 [W m−2 K−1] and a heat capacity Δ C a of 1 [kJ m−2 K−1]; (d) the range in root mean square error of the simulated daily, daytime, and noon Q H caused by generalizing the roof thermal properties is estimated to be 6%–41%, 7%–50%, and 7%–38%, respectively. Overall, the thermal properties of building surfaces are important for their thermal and radiative behavior, and therefore cannot be ignored in SEB modeling. • Importance of thermal property for surface heat balance is verified systematically. • Combined modification of thermal properties enlarges individual cooling effects. • Thermal properties cannot be ignored to evaluate the cooling effect of cool roofs. • Generalizing the thermal properties causes nonnegligible errors in SEB modeling. [ABSTRACT FROM AUTHOR]

We investigated the distribution of air temperature (T a ) and the factors affecting it in low-rise areas surrounding an isolated high-rise building during the Japanese winter. The study site was the central part of a regional city in Japan (36°5' N, 140°12' E), lying north-east of the Tokyo metropolitan area. The daytime surface temperature (T s ) in the shade is generally considered to be comparable to T a ; however, according to airborne remote sensing conducted in December 2009 where a multi-spectral scanner was installed on a fixed-wing aircraft, T s for pavements in the shade of a high-rise building was significantly lower than T a of sub-urban areas, indicating an influence of cold storage on T s . Then, we conducted mobile observations using instruments (thermocouple, four component radiometer, and so on) installed on a bicycle in January 2016 to investigate the detailed distribution of T a and the factors affecting it. The results showed the T a over the pavements in the shade of the high-rise building was lower than the T a of sunlit areas in the same urban area by -2 °C and lower than the T a of sub-urban areas by -1-1.5 °C, although the advection effect was large due to strong winds around the building. In conclusion, a locally lower T a compared to the surrounding areas can develop during the day in winter, even in spaces that are open to areas beyond the canopy., Competing Interests: The authors declare no conflict of interest.