Search Results (1,074)

A whole series of factors influence the temperature of the soil surface and surface layers. The soil surface is heated by solar radiation during the day. It radiates some of the obtained heat at night. The heat exchange between the soil and the atmosphere depends on the air and soil temperatures and the speed of air movement. Precipitation may also affect surface soil layers, but this was not considered in this study. In the mentioned interaction, a specific temperature field of the surface layers of the soil is established. To increase the building’s energy efficiency, the aim is to optimize the operation of its heating and cooling systems and to reduce heat loss to the environment as much as possible. Heat loss through the floor of the building or the walls of the recessed part into the ground changes the established temperature field of the ground. The heat spreads in the soil and is given to the atmospheric air. During the research, to validate the numerical model, the heat flow density was analysed to determine how it changes while maintaining a constant temperature of the heating surface at a certain depth of the soil. It was found that the new thermodynamic equilibrium, depending on the seasonality, can be reached in a time interval of up to a week. The temperature change in the artificially limited volume of the ground under the building or next to it can be treated as the work of the ground thermo-accumulator: its charge or discharge by heat. This makes it possible to reduce the annual energy costs of the building by more than ten percent. Full article

Urbanization transforms landscapes from natural ecosystems to configurations of impervious surfaces and green spaces, leading to urban heat island effects that impact health and ecosystem sustainability. This study in Xiamen City, China, categorizes urban areas into functional zones, employs Random Forest and Stepwise Regression models to assess thermal differences, and proposes optimization measures for the building–green space landscape. The optimization involves altering the characterization of the building–green space landscape pattern. Results indicate: (1) due to the spatial heterogeneity of the building–green space landscape pattern in different functional zones, the surface temperature also shows strong spatial heterogeneity in different functional zones; (2) different optimization measures for the building–green space pattern are needed for different functional zones; taking the urban residential zone as an example, the Normalized Difference Vegetation Index (NDVI) in the hot spot area can be adjusted according to the value range of the cold spot area; (3) considering the solar radiation process, Sun View Factor (S_unVF) plays an important role in indicating the change in surface temperature in the commercial service area, and as S_unVF increases, the surface temperature of the functional zone tends to rise. This research offers insights into urban thermal environment improvement and landscape pattern optimization. Full article

Due to the supply problems of fossil-based energy sources, the tendency towards alternative energy sources is relatively high. For this reason, the use of solar energy systems is increasing today. This study combines experimental data and machine learning algorithms to evaluate the energy performance of four different photovoltaic (PV) panel designs (monocrystalline, polycrystalline, flexible, and transparent) under harsh environmental conditions on Horseshoe Island (Antarctica). In this research, the effects of environmental factors, such as solar radiation, temperature, humidity, and wind speed, on the panels were analyzed. Electrical power output of the PV panels are analyzed using six machine learning models. Random forest (RF) and CatBoost (CB) models showed the highest accuracy and reliability among these models. According to the experimental results, Monocrystalline PV provided the highest electrical power (20.5 Watts on average), and Flexible PV provided the highest energy efficiency (19.67%). However, Flexible PV was observed to have higher surface temperatures compared to the other panel types. Furthermore, using Monocrystalline PV resulted in an average reduction of 4.1 tons of CO₂ emissions per year, demonstrating the positive environmental impact of renewable energy systems. Thanks to this study, renewable energy research for temporary stations in Antarctica will focus on explainable and interpretable artificial intelligence models that will provide an understanding of the factors affecting the energy performance of PV panels. The research results will be an important guide for optimizing energy consumption, management, and demand forecasting in temporary research stations in Antarctica. Full article

Studying the potential of buildings for utilizing solar radiation would be helpful to decrease the energy consumption of buildings. The solar radiation acquisition (SRA) potential of building facades can be used to characterize the building’s SRA potential. A review of the existing literature shows that few performance indicators have been established to specifically evaluate and guide the design of the building facade form from the perspective of SRA potential. This study explores how to evaluate the form of building facades to affect their SRA potential. Two new indicators (ρ value—the surface density of solar radiation received by the facades—and α value—the correction coefficient for receiving solar radiation in the concave part of the facade) and one new path were constructed to evaluate the SRA potential of building facades. It was found that the ρ values can reflect the upper limit of solar radiation in the region itself and serve as a basis for measuring the building’s SRA potential in the region. It is only related to the shapes of buildings and not to their sizes, and the larger the ρ value of a building, the stronger its facade’s potential to receive solar radiation. The α values can intuitively show the discount of the SRA potential when adding a concave part into the architectural design. At the same time, the extent of the discount due to the elements of the concave part can be elucidated, which can help minimize the loss of solar radiation when designing the concave part in the architectural design process. It is only related to the shapes of building plans (which directly relate to the building facade) but not their sizes. The larger the α value of the concave part of the building facade, the stronger its potential to receive solar radiation. The method for identifying the proper range of ρ values and calculating the standard ρ values was proposed and utilized in Lanzhou city as an example. It reveals that, for Lanzhou city, the maximum ρ value (ρmax) is 670.98 kwh/m² and the average value of ρ value (ρave) is 592.47 kwh, which reflect the basic situation of buildings’ SRA potentials in this city. For the concave parts of the triangular facades in this specific region, the concave offset has almost no effect on their α value. When the concave part of the building facade is triangular, the further south the concave part (rectangular is up to 30° southwest), the smaller the CCS, the higher the concave HWR, the larger the correction coefficient, and the greater the SRA potential of the buildings’ facades. Full article

In this work, for the first time, the sorption behaviour of platinum and palladium on polyethylene microplastics (PE-MP) was studied. To simulate natural conditions, part of PE-MP was subjected to the ageing process in lake water under the influence of solar radiation. The original and aged PE-MP was characterised using elemental analysis, FT-IR, SEM-EDX, and nitrogen porosimetry methods. The studies on Pt and Pd sorption on PE-MP were carried out in batch mode in natural lake water at pH 7.6. It was found that the ageing process led to the degradation of the surface of the PE-MP and the formation of a biofilm. The sorption process of Pt and Pd on PE-MP particles proceeds according to pseudo-second-order kinetics. A good fit of the experimental data to the Freundlich and Langmuir isotherm model indicates the mixed nature of Pt and Pd sorption on PE-MP. It was clearly indicated that Pt and Pd sorption from natural waters can occur on the surface of inert polyethylene particles, which can lead to the preconcentration of these elements, even from waters with a very low content, and transferring them over longer distances. This poses a threat to the health of living organisms and humans. Full article

Contemporary environmental challenges are increasingly significant. The primary cause is the drastic changes in climates. The prediction of solar radiation is a crucial aspect of solar energy applications and meteorological forecasting. The amount of solar radiation reaching Earth’s surface (Global Horizontal Irradiance, GHI) varies with atmospheric conditions, geographical location, and temporal factors. This paper presents a novel methodology for estimating surface sun exposure using advanced deep learning techniques. The proposed method is tested and validated using the data obtained from NASA’s Goddard Earth Sciences Data and Information Services Centre (GES DISC) named the SORCE (Solar Radiation and Climate Experiment) dataset. For analyzing and predicting accurate data, features are extracted using a deep learning method, Deep-FS. The method extracted and provided the selected features that are most appropriate for predicting the surface exposure. Time series analysis was conducted using Convolutional Neural Networks (CNNs), with results demonstrating superior performance compared to traditional methodologies across standard performance metrics. The proposed Deep-FS model is validated and compared with the traditional approaches and models through the standard performance metrics. The experimental results concluded that the proposed model outperforms the traditional models. Full article

The synthesis of special photocatalysts of nanostructured functional ceramics (PNFC) under the ZKHM brand under the influence of concentrated solar radiation showed the effectiveness of these ceramic materials in multifunctional use, in particular as additives for coatings of welding electrodes. However, problems with producing these materials in solar ovens on an industrial scale did not allow the widespread use of this method. This problem was solved using the technique of PNFC synthesis, followed by activation by pulsed radiation generated by functional ceramics. The ceramic material obtained by this method under the brand name ZB-1 also showed its effectiveness when used as an additive in welding electrode coatings. A comparative analysis of the effectiveness of the actions of additives from the ZKHM and ZB-1 brands on the welding and technological properties of welding electrodes from the MR-3 brand was carried out. Comparative results for the formation of weld beads showed that beads with high-quality formation without external defects were achieved when surfaced with electrodes with additives from both brands at concentrations up to 1%. Also, at concentrations up to 1%, these additives increased the breaking length of the arc and the stability of arc welding. The different effects of these additives were observed in a comparative analysis of their impacts on the size of the visor at the end of the electrode, the coefficients of melting and surfacing, and the loss factor for fumes and splashing of electrode metal. Full article

Near-infrared light-triggered photocatalytic water treatment has attracted significant attention in recent years. In this novel research, rational sonochemical fabrication of Ag₂S/g-C₃N₄ nanocomposites with various compositions of Ag₂S (0–25) wt% was carried out to eliminate hazardous rhodamine B dye in a cationic organic pollutant model. g-C₃N₄ sheets were synthesized via controlled thermal annealing of microcrystalline urea. However, black Ag₂S nanoparticles were synthesized through a precipitation-assisted sonochemical route. The chemical interactions between various compositions of Ag₂S and g-C₃N₄ were carried out in an ultrasonic bath with a power of 300 W. XRD, PL, DRS, SEM, HRTEM, mapping, BET, and SAED analysis were used to estimate the crystalline, optical, nanostructure, and textural properties of the solid specimens. The coexistence of the diffraction peaks of g-C₃N₄ and Ag₂S implied the successful production of Ag₂S/g-C₃N₄ heterojunctions. The band gap energy of g-C₃N₄ was exceptionally reduced from 2.81 to 1.5 eV with the introduction of 25 wt% of Ag₂S nanoparticles, implying the strong absorbability of the nanocomposites to natural solar radiation. The PL signal intensity of Ag₂S/g-C₃N₄ was reduced by 40% compared with pristine g-C₃N₄, implying that Ag₂S enhanced the electron–hole transportation and separation. The rate of the photocatalytic degradation of rhodamine B molecules was gradually increased with the introduction of Ag₂S on the g-C₃N₄ surface and reached a maximum for nanocomposites containing 25 wt% Ag₂S. The radical trapping experiments demonstrated the principal importance of reactive oxygen species and hot holes in destroying rhodamine B under natural solar radiation. The charge transportation between Ag₂S and g-C₃N₄ semiconductors proceeded through the type I straddling scheme. The enriched photocatalytic activity of Ag₂S/g-C₃N₄ nanocomposites resulted from an exceptional reduction in band gap energy and controlling the electron–hole separation rate with the introduction of Ag₂S as an efficient photothermal photocatalyst. The novel as-synthesized nanocomposites are considered a promising photocatalyst for destroying various types of organic pollutants under low-cost sunlight radiation. Full article

Previous research has demonstrated that the multiple environmental benefits of green roofs are primarily associated with their evaporative cooling effect. However, current studies on green roof evapotranspiration (ET) mainly focus on extensive green roofs, and the evaporative cooling effect of intensive green roofs is still unclear. Using the intensive green roof of AQUA City in Nanjing as a case study, this research employs the three-temperature (3T) model combined with high-resolution thermal infrared imagery obtained via an unmanned aerial vehicle (UAV) to estimate the ET of different vegetation types. The study aims to explore the spatiotemporal variations in surface temperature, evapotranspiration (ET) rate, and evaporative cooling rate for various vegetation types under typical seasonal (summer and winter) and weather conditions (sunny, cloudy, and rainy before and after rainy days). The results showed that: (1) the ET rates and evaporative cooling effects of different types of vegetation differed significantly, with shrubs having the fastest ET rates, followed by arbors, and grasslands having relatively low ET rates. (2) Solar radiation and air temperature are the most crucial meteorological parameters for inducing ET on green roofs. In this study, the evaporative cooling performance showed the patterns of summer > winter and sunny > cloudy > rainy days. (3) In the spatial distribution of tree and irrigation plant groups, some low-temperature diffusion phenomena to the adjacent small microenvironments were evident, while the diffusion effect in winter is smaller and mainly shows the opposite warming characteristics. This study offers a valuable reference for quantifying the ET and evaporative cooling effects of various vegetation types on intensive green roofs, facilitating the optimization of vegetation configuration and supporting sustainable urban development. Full article

Phase-change material (PCM) can enhance the efficiency of photovoltaic (PV) modules by reducing their temperature and is widely studied for thermal management. However, their performance varies due to differences in local solar radiation and climate conditions. Previous studies have mainly focused on the thermal properties of PCM, but practical evaluation should consider specific local conditions. To investigate the thermal-management performance of PCMs in different zones and obtain optimal design parameters, this study investigated the temperature-control effect of PCMs on PV systems across different regions through experiments. The results revealed that the temperature-control performance of PCM was limited in cold regions. Furthermore, the study developed a PCM-PV model and employed response surface methodology along with an NSGA-II to analyze the temperature-control effectiveness of the PCM-PV system in nine regions of China. Pareto solutions were obtained for nine regions in China, balancing annual power generation and system costs. PCM effectiveness is limited in colder regions like Naqu, where it increases power generation by only 0.5%, while in other regions, it improves annual power generation by 1.4% to 3%, especially in areas with high temperatures and abundant solar resources. However, when considering life-cycle gains and initial investment, PCM technology may not always be economically efficient, highlighting the need for region-specific evaluations. Full article

Water management is a significant aspect of sustainable vegetable farming, especially in water-scarce regions. This, in addition to weed infestations, limits vegetable yields, which negatively affect food security in developing regions, particularly East Africa, where livelihoods chiefly depend on rain-fed agriculture. Vegetable farming, especially tomato cultivation, requires more water. By promoting mulching, a soil water conservation tool, we can control surface evaporation (E), which, together with irrigation, enhances effective water use and vegetable yields. The experiments for this study were conducted at the Tokyo University of Agriculture, Japan, to evaluate the influences of different irrigation conditions and poly-mulching on weed control, tomato yields, and water use efficiency. The study was conducted from May to September 2018 on a 30 m² plot in an open-ended greenhouse using drip irrigation for tomato cultivation. Three predetermined irrigation conditions of 4, 3, and 2 mm/day were applied on black poly-mulched and bare ridges. Data on soil conditions—soil temperature, as well as meteorological variables, including solar radiation and temperature—were measured using thermocouple sensors and micro-hobo weather stations, respectively, during the tomato cultivation, while yield components—growth, yield, water productivity, and sugar content—were determined after harvest. The results of a two-way ANOVA show that irrigation conditions with poly-mulching reduced the weed biomass significantly, and improved yields and water use efficiency compared to the irrigation conditions on bare ridges. The application of 4, 3, and 2 mm/day irrigation with poly-mulching significantly reduced the weed biomass by 5% compared to the same irrigation conditions on bare ridges. Similarly, 4 and 3 mm/day irrigation conditions with poly-mulching significantly increased the tomato yield by 5% compared to 2 mm/day on bare ridges. The bigger roots were concentrated and widely distributed at the shallow soil depth (0–20 cm) of the ridges with high irrigation amounts, while the small and thin roots were in deeper soil layers (30–45 cm). This study provides scientific knowledge on the application of predetermined irrigation conditions that can be (i) integrated into irrigation scheduling and (ii) adopted for regions facing water scarcity and limited or no in situ meteorological data, to improve water use efficiency for vegetable cultivation. Full article

Solar radiation is an important energy source, and accurately predicting it [daily global and diffuse solar radiation (R_s and R_d)] is essential for research on surface energy exchange, hydrologic systems, and agricultural production. However, R_s and R_d estimation relies on meteorological data and related model parameters, which leads to inaccuracy in some regions. To improve the estimation accuracy and generalization ability of the R_s and R_d models, 17 representative radiation stations in China were selected. The categorical boosting (CatBoost) feature selection algorithm was utilized to construct a novel stacking model from sample and parameter diversity perspectives. The results revealed that the characteristics related to sunshine duration (n) and ozone (O₃) significantly affect solar radiation prediction. The proposed new ensemble model framework had better accuracy than base models in root mean square error (RMSE), coefficient of determination (R²), mean absolute error (MAE), and global performance index (GPI). The solar radiation prediction model is more applicable to coastal areas, such as Shanghai and Guangzhou, than to inland regions of China. The range and mean of RMSE, MAE, and R² for R_s prediction are 1.5737–3.7482 (1.9318), 1.1773–2.6814 (1.4336), and 0.7597–0.9655 (0.9226), respectively; for R_d prediction, they are 1.2589–2.9038 (1.8201), 0.9811–2.1024 (1.3493), and 0.5153–0.9217 (0.7248), respectively. The results of this study can provide a reference for R_s and R_d estimation and related applications in China. Full article

Ideal black bodies absorb all electromagnetic energy without reflecting it. As it does not reflect or transmit light, it appears black when cold. Heated black bodies emit black body radiation, a temperature-dependent spectrum. This idea helps scientists and engineers comprehend heat radiation and design efficient solar desalination absorbers. This work uses the black body concept to create three non-contact nanostructured single-slope solar stills (NCNSSSs) with varied perforation diameters (2.4 mm, 3.2 mm, and 3.8 mm). The chemical oxidation of mirror-polished perforated stainless steel 304 sheets resulted in highly absorptive top surfaces with 90% absorptivity. The structures’ bottom surfaces were coated with a commercial high-emissivity coating to make them 85% emissive. The developed non-contact nanostructures absorbed maximum solar light and converted it into infrared radiation using a highly emissive bottom coating and a very absorptive top coating. Water, an excellent absorber of infrared (IR) radiation, readily absorbs the IR radiations and evaporates through the perforations, thus producing a desalination effect. Experiments were conducted parallelly in three NCNSSSs under the same weather conditions at three water depths. It was observed that non-contact nanostructure perforation diameters affected solar still performance. The NCNSSS-3 (3.8 mm) achieved a 9.89% and 13.47% higher productivity than the NCNSSS-2 (3.2 mm) and NCNSSS-1 (2.4 mm) at a 5 mm water depth. Additionally, fouling studies, expedited corrosion studies, and water quality assessments (TDS, salinity, fluoride, chlorides, nitrates, sodium) were performed. Water eminence examinations confirmed that the collected freshwater was bacteria-free and safe to drink. Full article

Rock varnishes, complex structures formed by long-term deposition on rocks, exhibit unique light absorption characteristics and are widely distributed across arid environments on Earth’s surface. The varnishes possess the ability to absorb and convert photons from solar radiation into electrons, which represents a newly discovered fundamental energy form in nature, with further elucidation required regarding the underlying mechanism of how semiconductor minerals respond to light radiation. The regulations governing the photoconductive responses of samples from the Alashan region in Gobi, China, and the mechanisms exhibited by rock rock varnishes under various bias voltages and irradiation wavelengths (532 nm, 808 nm, and 1064 nm) were studied. The photoconductivity response is positively correlated with the applied external bias, and the response caused by shorter wavelengths is larger. The synergistic effect was quantitatively assessed by monitoring and fitting the correlation between photoconductivity, temperature, and time during laser irradiation. As an effective method to study the fundamental physical properties of semiconductor minerals, the photoconductivity testing will help to establish a fundamental framework for investigating the intrinsic physical characteristics of natural rock varnishes. Full article

A flat-plate unglazed solar water heater (SWH) with a polymer thermal absorber was developed and experimented with. Polymer thermal absorbers could be a viable alternative to metal thermal absorbers for SWH systems. The performance of this polymer SWH system was measured based on inlet and outlet water temperature, water flow rate, ambient air temperature and solar irradiance. The polymer thermal absorbers were hollow Polyvinyl Chloride (PVC) tubes with a 20 mm external diameter and 3 mm thickness and were painted black to enhance radiation absorption. The pipes are arranged in a rectangular spiral inward–outward alternating-flow (RSioaf) pattern. The collector pipes were placed in a 1 m × 1 m enclosure with bottom insulation and a reflective surface for maximized radiation absorption. Water circulated through a closed loop with an uninsulated 16 L storage tank, driven by a pump and controlled by two valves to maintain a mass flow rate of 0.0031 to 0.0034 kg·s⁻¹. The test was conducted under a partially clouded sky from 9 a.m. to 5 p.m., with solar irradiance between 105 and 1003 W·m⁻² and an ambient air temperature of 27–36 °C. This SWH system produced outlet hot water at 65 °C by midday and maintained the storage temperature at 63 °C until the end of the test period. Photothermal energy conversion was recorded, showing a maximum value of 23%. Results indicate that a flat-plate solar water heater with a polymer thermal absorber in an RSioaf design can be an effective alternative to an SWH with a metal thermal absorber. Its performance can be improved with glazing and optimized tube sizing. Full article