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The quality of natural lighting within secondary school classrooms can significantly affect the physical and mental well-being of both teachers and students. While numerous studies have explored various aspects of daylighting performance and its related factors, there is no universal standard for predicting and optimizing daylighting performance from a design perspective. In this study, a method was developed that combines measurements and simulations to enhance the design parameters associated with daylighting performance. This approach facilitates the determination of precise ranges for multiple design parameters and allows for the efficient attainment of optimal daylighting performance. Daylight glare probability (DGP), point-in-time illuminance (PIT), daylight factor (DF), and lighting energy consumption were simulated based on existing control parameters of operational classrooms. The simulation results were then validated using field measurements. Genetic algorithms (GAs) were employed to optimize the control parameters, yielding a set of optimal solutions for improving daylight performance. The differences between daylighting performance indicators corresponding to the optimal solution set and those of the basic model were compared to test the performance of the optimized parameters. The proposed method is a robust process for optimizing daylight design parameters based on GAs, which not only enhances daylighting performance but also offers scientifically grounded guidelines for the design phase. It is a valuable framework for creating healthier and more productive educational environments within secondary school classrooms. [ABSTRACT FROM AUTHOR]

With the advancement of information technology, energy consumption prediction models are widely used for various types of buildings (office, residential, and commercial buildings) as guidance during the design and management stages. This article will establish an efficient building energy consumption prediction model for hotel buildings. To achieve this, we collected 78 architectural drawings of high-rise hotel buildings to establish 6 kinds of typical energy consumption models in 2 standard floor layouts and 3 public area levels. Then, on this basis, we used the total energy consumption calculated by EnergyPlus as an indicator to conduct sensitivity analysis on geometric feature parameters, internal heat source parameters, and thermal parameters, respectively. Finally, we generated a building database with 5000 samples through the R programming language to calculate and verify the energy consumption. As a result, it was proved that the energy consumption of hotel buildings can be predicted accurately, and that quadratic polynomial regression, with the best accuracy and stability, is the most suitable optimization model for hotel energy consumption prediction in Guangzhou. These conclusions provide a good theoretical basis for the analysis, prediction, and optimization of energy consumption in high-rise hotel buildings in the future. [ABSTRACT FROM AUTHOR]

Highlights • Data on the impact of four trees’ species on the UHI are obtained. • Three physiological and seven microclimatic parameters are studied. • Differences in cooling performance among the four trees’ species are assessed. • Ficus microcarpa has the best cooling performance (reduced PET by 32.4 °C). • Tree planting implications are discussed from a microclimatic perspective. Abstract Tree morphology and characteristics are quite different among different tree species, leading to large differences in cooling performance across tree species, particularly across different climatic regions. To obtain microclimatic characteristics and data on the influence of common subtropical tree species on the outdoor thermal environment, this study investigates, with field measurements, three physiological indices (leaf transpiration rate, leaf surface temperature, and leaf reflectance) and seven microclimatic parameters (solar radiation, long wave radiation, mean radiant temperature (Tmrt), ground surface temperature, air temperature, relative humidity, and wind speed) characterizing four common tree species in Guangzhou: Ficus microcarpa , Mangifera indica , Michelia alba, and Bauhinia blakeana. The Physiological Equivalent Temperature (PET) is calculated with the Rayman 12 tool to assess human thermal comfort. Special focus is set on the differences between these parameters in the presence and absence of tree cover. The results are as follows: Ficus microcarpa has the best cooling performance (reduced solar radiation by 1050 W/m2, reduced Tmrt by 14.8 °C, reduced PET by 32.4 °C). These trees have also some negative effects: reducing wind speed (2.83 m/s) and increasing long wave radiation (55 W/m2). It is expected that these data and results will shed some light on tree planting implications in subtropical areas. [ABSTRACT FROM AUTHOR]

Urban heat island (UHI) effects and heat waves (HWs) increase, posing a threat to human health and urban ecological systems. However, the synergistic mechanisms of UHI and HWs are yet to be fully elucidated. This study aims to assess the characteristics of UHI under HWs in different Local Climate Zones (LCZs) using temperature observations from Guangzhou, China. Fixed-point measurements were employed to simultaneously collect air temperature from nine LCZs in 2021. The results showed a localised interplay between HWs and UHI. During HWs, the UHI effect was significantly amplified in built-type LCZ, where the UHI intensity (UHII) was amplified by 0.1–0.5 °C throughout the day, 0.4–1 °C at night, but slightly reduced by 0–0.4 °C during daytime. The UHII was significantly reduced in land-cover type LCZ, and the urban cold effect was amplified during HWs. Furthermore, with strong solar radiation and low wind speed in HWs, the daily maximum UHII of LCZs increased 0.4–1.1 °C. Finally, correlations between UHII and morphological characteristics of LCZs are examined in HWs and non-heat waves (NHWs). During HWs, the increase in impervious surface fraction (ISF) and building surface fraction (BSF) and the decrease in sky view factor (SVF) exacerbate UHII, particularly at night. The augment in surface vegetation fraction (F v e g ), does not significantly contribute to reducing the UHI and is less effective than NHWs at night. Therefore, different measures should be taken in different LCZs to mitigate UHII amplification during HWs. This study can serve as a reference for preventing responses to climate extremes. • A localised interplay between heat waves and urban heat islands is observed. • A year of UHI observations in different Local Climate Zones (LCZs) were used. • The interactions between UHI and HW varies across different LCZs. • The daily maximum UHI intensity of LCZs increased 0.40–1.13 °C during HWs. • Correlations between UHII and morphological characteristics of LCZs are examined. [ABSTRACT FROM AUTHOR]

The Urban Heat Island (UHI) is a widely studied phenomenon, characterized by unique spatiotemporal variations depending on urban structure. Seeking a simple and rapid method to monitor the Urban Heat Island Intensity (U H I I) for local urban area with multiple inner morphology is essential for energy saving, citizen health, and urban planning. Hence, this study proposed a diagnostic equation for daily maximum urban heat island intensity ( U H I I max) based on routine meteorological data and basic urban properties. The applicability of equation, previously proposed by European scholars, was evaluated based on Local Climate Zone (LCZ) scheme by a long-term temperature observation experiment conducted in Guangzhou. Overall, the underestimation of U H I I max was caused by LCZ 1,2,3,4 , in which the morphological parameters were outside the application range of the original equation. Then, a revised equation was proposed by adding the impervious surface fraction (ISF) in morphological parameters based on the spatiotemporal variance of U H I I for different LCZ. The revised equation was evaluated against a year dataset and revealed a higher accuracy than the original one with a decrease of RMSE and MEAE at 0.4K, 0.15K, an increase of d r at 0.1. Moreover, the efficiency of the equations for all the seasons and LCZs were elucidated. In summary, the results can be used as a tool for monitoring the development of UHI in outdoor temperature studies. [Display omitted] • Diagnostic equation for maximum urban heat island intensity (UHII) is proposed. • Morphological characteristics of different Local Climate Zone (LCZ) were used. • Efficiency of equation for all the seasons and LCZs was elucidated. • Significant variance for UHII in spatiotemporal dimension is observed. [ABSTRACT FROM AUTHOR]

Applying vertical green facades (VGFs) on building envelopes is an effective design strategy to reduce building energy consumption and mitigate the urban heat island effect. Although many studies have investigated the cooling and energy-saving effects of VGFs, research on the long-wave infrared radiation properties of VGFs remains scarce, limiting the understanding and application of heat-transfer models of VGFs. Therefore, in this study, theoretical analyses and field measurements were performed in the subtropical city of Guangzhou, China, to examine the long-wave infrared radiation properties of VGFs. First, an observation platform was established using six plants commonly used for VGFs in subtropical regions. The long-wave infrared radiation and leaf temperature of these plants with different coverage rates were measured to investigate the effect of coverage rate on the radiation transfer of the vegetation canopy. A Fourier spectrometer was used to analyse the spectral features of the leaves in the long-wave infrared radiation band. Based on the observation data and radiation balance of the vegetation canopy, an empirical equation for transmitting long-wave infrared radiation was established. Moreover, the monthly variations in the leaf area index and coverage rate of the VGFs were recorded throughout 2021, and an exponential function was used to determine the relationship between them. A quantitative method was used to assess the accuracy of the long-wave infrared radiation model, and the results indicated that the calculated values were in good agreement with the measured values. • Long-wave infrared radiation properties of VGFs were investigated. • Experimental data were collected to fit the ambient equivalent temperature. • The long-wave infrared radiation transfer in an uneven canopy was modelled. • The correspondence between the coverage rate and the LAI was found. [ABSTRACT FROM AUTHOR]

• Study of two physiological and three microclimatic parameters of four tree species • A three-dimensional simulation mode has been developed • Model accuracy has been validated with field measurements • Model accuracy is related to light spots phenomenon and leaf area density • Differences between simulated and measured values are less than 20 W/m2 (R2 = 0.85) Shade creation and radiation modification by trees is an important way of alleviating the urban heat island and improving the outdoor thermal environment. However, a major challenge is still present in numerical models: How can shade creation and radiation modification by trees be realistically represented? To address this challenge, this paper proposes a new three-dimensional model of radiation modification by shade trees for four common tree species in Guangzhou, China: Ficus microcarpa , Mangifera indica , Michelia alba and Bauhinia blakeana. Its accuracy is verified with field measurements. The results show that the proposed model can accurately simulate the canopy attenuation of incoming solar radiation (SR) (d = 0.76∼0.93) and long-wave radiation (LWR) (RMSE = 2.7 W/m2∼12 W/m2) in the case of Ficus microcarpa , Mangifera indica , and Bauhinia blakeana. But for Michelia alba , the difference between measured and simulated values can be large (>60 W/m2), leading to a high RMSE (25 W/m2 ∼194 W/m2). The predictability of surface energy budget and thermal comfort in urban environments is enhanced by incorporating the proposed model into a heat balance model to obtain the mean radiant temperature (MRT). Future development and application of this numerical model will provide useful guidelines for urban landscape management and sustainable urban planning in terms of heat island mitigation. [ABSTRACT FROM AUTHOR]

The synergistic effect of heat waves and urban heat islands (UHI) adversely affect the urban environment, building energy consumption, and human health. The absorption and storage of short-wave radiation by hardened pavement is the primary reason for high-temperature heat waves and the UHI effect. Three mitigation strategies were assessed to alleviate the influence of high-temperature hardened pavement on the thermal environment and thermal comfort of pedestrians, water-spray vehicles (spray) and pavement watering (watering) to take advantage of evaporative cooling, and a fan based on convective heat transfer. In addition, the fan-spray and fan-watering combinations were evaluated to increase the evaporative cooling rate. Field measurements showed that the five heat mitigation strategies improved the thermal environment and reduced environmental thermal stress. The thermal sensation, comfort sensation, and mean skin temperature (MST) were analyzed in thermal perception experiments. The result indicated that the mitigation strategies changed the subjects' thermal perception. Moreover, regression analysis between the universal thermal climate index (UTCI) and the thermal response showed that the neutral temperature and the range of comfort threshold of UTCI and MST increased after implementing the mitigation strategies. • [problem definition] Five strategies (fan, spray vehicle, pavement-watering, spray + fan, watering + fan) were used to alleviate thermal environment of hardened pavement and improve thermal comfort of pedestrians. • [concept] The strategies based on evaporative cooling and convective heat transfer are beneficial to improve the thermal environment of hardened pavement. • [action] The fan could improve the evaporative cooling rate of mist-spray and pavement-watering. • [results] The heat mitigation strategies are found to significantly reduce the UTCI and increase the range of thermal comfortable threshold of UTCI. • [significance] The result of heat mitigation strategies to improve the thermal comfort of pedestrians is effective. [ABSTRACT FROM AUTHOR]