Shading Effect Research Articles

Do we need a saw? Carbon-based analysis of facade BIPV performance under partial shading from nearby trees

Building integrated photovoltaics (BIPV) are becoming more common in urban spaces. The impact of shading from nearby trees on BIPV performance and the potential conflict between the carbon sequestration benefits of trees and the carbon mitigation benefits of BIPV is not well documented in research. Therefore, this paper investigates the cost-benefit relationship of the carbon storage potential of trees vs. their shading effects on a nearby BIPV facade from the perspective of a life cycle assessment (LCA) using a high-resolution BIPV model and temporally sensitive tree growth model. The study is based on a typical Swiss residential building with adjacent vegetation and includes various BIPV facade permutations with different cell types, module orientations, inverter types, facade azimuths, grid emissions profiles, and tree planting scenarios. The results indicate that the removal of trees does not necessarily influence the overall carbon balance when considering LCA to the same degree as other features of the model space such as the grid carbon intensity or the configuration of the BIPV array. Furthermore the parametric-based analysis enables reporting on which BIPV configurations operate with the highest system efficiency under partial shading.

A Low Power Photo-Voltaic Battery Charger With Improved Reliability and Functionality to Reduce Shading Effect

A Low Power Photo-Voltaic Battery Charger With Improved Reliability and Functionality to Reduce Shading Effect

Effects of slight shading in summer on the leaf senescence and endogenous hormone and polyamine contents in herbaceous peony

Herbaceous peony is a perennial root plant that likes light and is cold-resistant. During summer, high temperature and strong light intensity advance its entry into the leaf wilting stage, which limits the accumulation of nutrients and formation of strong buds and severely affects its growth and development the following year. In this study, the wild herbaceous peony species and two main cultivars, ‘Zifengyu’ and ‘Hongfengyu’, were subjected to slight shading and strong light environments in summer, and their effects on leaf senescence and endogenous hormone and polyamine contents were explored. Slight shading treatment significantly delayed withering, increased the leaf net photosynthetic rate, and increased the chlorophyll, soluble sugar, indole-3-acetic acid, zeatin, gibberellin, spermine, spermidine, putrescine, and polyamine contents. Additionally, slight shading significantly reduced the proline and abscisic acid contents. Slight shading during summer prolonged the green period and delayed leaf senescence. The tolerance of tested materials to strong light intensity in summer was ranked as follows: ‘Zifengyu’ > ‘Hongfengyu’ > wild species. In conclusion, this study revealed that summer leaf senescence is delayed in herbaceous peony through shading and growth regulators. Additional varieties should be evaluated to provide reference for high-efficiency, high-quality, and high-yield cultivation of herbaceous peony.

Design and evaluation of an agrivoltaic system for a pear orchard

Agrivoltaic systems are mostly deployed on arable farm land. An interesting application of agrivoltaics for permanent farming such as pear orchards, is in replacing the protective function of hail nets by semi-transparent PV modules. In this study, a theoretical framework is used to design the optimal agrivoltaic lay-out regarding the levelized cost of electricity, electricity generation and incident irradiance. This incident irradiance is modelled using a 3D light simulation tool, capable of including the light distribution within the canopy walls. Given the practical constraints (orientation, planting distance, maximum wind load, protection function), present in an existing pear orchard, a double-inclined PV structure with a PV module transparency level of 40% was used. This system was constructed in Bierbeek, Belgium. Results of the first year of operation are presented and the models used are validated. It is concluded that this application is promising, with positive effects of the climatological conditions, robust energy generation and a minimum loss of 16% on pear yield. Nevertheless, at this moment, the system is financially unviable and a long-term analysis of the shading effect on crop yield and quality is needed before the large-scale deployment of this technology.

Multidimensional optimization for accelerating light-powered biocatalysis in Rhodopseudomonas palustris

BackgroundWhole-cell biocatalysis has been exploited to convert a variety of substrates into high-value bulk or chiral fine chemicals. However, the traditional whole-cell biocatalysis typically utilizes the heterotrophic microbes as the biocatalyst, which requires carbohydrates to power the cofactor (ATP, NAD (P)H) regeneration.ResultsIn this study, we sought to harness purple non-sulfur photosynthetic bacterium (PNSB) as the biocatalyst to achieve light-driven cofactor regeneration for cascade biocatalysis. We substantially improved the performance of Rhodopseudomonas palustris-based biocatalysis using a highly active and conditional expression system, blocking the side-reactions, controlling the feeding strategy, and attenuating the light shading effect. Under light-anaerobic conditions, we found that 50 mM ferulic acid could be completely converted to vanillyl alcohol using the recombinant strain with 100% efficiency, and > 99.9% conversion of 50 mM p-coumaric acid to p-hydroxybenzyl alcohol was similarly achieved. Moreover, we examined the isoprenol utilization pathway for pinene synthesis and 92% conversion of 30 mM isoprenol to pinene was obtained.ConclusionsTaken together, these results suggested that R. palustris could be a promising host for light-powered biotransformation, which offers an efficient approach for synthesizing value-added chemicals in a green and sustainable manner.Graphical

Shading effect and energy-saving potential of rooftop photovoltaic on the top-floor room

Rooftop photovoltaic panels can serve as external shading devices on buildings, effectively reducing indoor heat gain caused by sunlight. This paper uses a numerical model to analyze rooftop photovoltaic panels' thermal conduction, convection, and radiation in hot summer areas as shading devices. The researcher builds an experimental platform to verify the model, exploring the potential for energy savings of photovoltaic rooftop units in the Wuhan area. The results show that after installing photovoltaic panels, the delay performance of the roof increases by 0.5 h, the roof heat flux is reduced by 41.7%, the peak temperature of the roof is reduced by 22.9 °C, and the daily heat gain is reduced by 74.84%. Finally, this paper discusses the impact of high-reflectance and low-reflectance roofs on the shading effect. The study finds that low-reflectance roofs are more energy-efficient in the hot summer, as high-reflectance roofs lead to a 10.8% increase in indoor heat gain when the photovoltaic panel is installed. Finally, a quantitative method for evaluating the comprehensive potential for energy savings is proposed, considering the electricity generation gain of photovoltaic panels and the comprehensive energy-saving efficiency of photovoltaic roofs, which generates a total potential for energy savings rate of 61.06%. The model presented in this paper provides theoretical guidance for analyzing the comprehensive energy-saving effects of photovoltaic rooftop systems and reveals the potential for energy savings of rooftop photovoltaic panels as external shading devices.

Effect of shading on the physiological and reproductive parameters in Nelore cows.

This study aimed to evaluate the physiological and reproductive parameters of Nelore cows under various microclimatic conditions. The experiment was performed in Central Brazil, which has a tropical climate with dry winters and rainy summers. The experimental groups were divided into an area with shading (5.8 trees/ha; n = 42) and an area with little shading (0.4 trees/ha; n = 42). The physiological (heart rate, respiratory rate, rectal temperature, surface body temperature, and vaginal temperature) and reproductive (estrus detection, conception rate, and rate of pregnancy loss) parameters were then assessed. The rectal temperature (p = 0.002); surface body temperature on the flanks, forehead, and shoulder (p < 0.001); and vaginal temperature (p < 0.001) of cows in the group with shading were significantly lower than those of cows in the group without shading. Estrus was higher (p = 0.08) in the shaded group; however, no effect was observed on conception and pregnancy loss rates. In conclusion, shading (5.8 trees/ha) provided better thermal comfort for Nelore animals in the tropical climatic region. However, this did not affect their performance after fixed-time artificial insemination.

Urban Building Energy Modeling with Parameterized Geometry and Detailed Thermal Zones for Complex Building Types

Urban building energy modeling (UBEM) has attracted wide attention to the requirement for global carbon emission reduction. This paper presents a UBEM tool, AutoBPS-Param, to generate building energy models (BEMs) with parameterized geometry and detailed thermal zones, especially for complex building types, considering the shading effect from surrounding buildings simultaneously. Three building number scales and four scenarios were analyzed in the hotel-related buildings in Changsha, China. For the prototype modeling of Scenario 1, eighteen prototype building energy models for six building types in three vintages were created, and their simulation results were aggregated based on their representative floor areas. For AutoBPS-Param of Scenario 4, the method created one EnergyPlus (Version: 9.3.0) model for each building. The geometry of the prototype model was scaled and modified based on the target building’s length, width, and number of stories. The surrounding buildings were also added to the AutoBPS-Param simulation to better capture the urban dynamic impact. The results showed that the annual electricity and natural gas energy use intensity (EUI) of the pre-2005 HotelOffice prototype model was 172.25 and 140.45 kWh/m2. In contrast, with the AutoBPS-Param method, the annual electricity EUIs of 71 HotelOffice buildings constructed before 2005 ranged from 159.51 to 213.58 kWh/m2 with an average of 173.14 kWh/m2, and the annual gas EUIs ranged from 68.02 to 229.12 kWh/m2 with an average of 108.89 kWh/m2. The proposed method can better capture the diversity of urban building energy consumption.

A novel shadow dispersion approach for solar PV modules in array using chess board game methodology: An experimental study

In the global scenario, photovoltaic (PV) systems contribute much power compared to other renewable energy (RE) sources due to their benefits, e.g., environmental friendliness, low maintenance, and the small investment required for efficient energy harvest. However, it experiences performance limitations due to adverse climatic conditions, i.e., temperature and sun irradiance variations. Partial shadowing circumstances (PSCs) have a negative effect on PV modules, leading to a shift in irradiance and diminished PV performance in terms of power loss (PL), performance ratio (PR), and reduced fill factor (FF). In this paper, the modification of PV module interconnections in an array system shows the power loss reduction under PSCs. The chess board game theory (CBGT) based PV array reconfiguration technique shows efficient results in terms of shade dispersion on the entire PV array to diminish the shading effect. Novel CBGT configuration (9 × 9 size) shows minimum PL and higher global maximum power point (GMPP) compared to existing series–parallel (SP), total-cross-tied (TCT), and puzzle-based Su-Do-Ku (SDK) and puzzle game theory (PGT) PV configurations. The CBGT configuration achieves higher performance in power GMPP (315.8 W, 273.6 W, 232.8 W, and 262.1 W) under four shading instances experimentally.

Thermal-dynamic coupling analysis of space truss antennas in actual space thermal environment

Space truss antennas may undergo thermally induced vibration due to temperature changes caused by thermal mutations in the space environment, which will result in antenna performance degradation or even vibration failure. This paper aims to investigate the thermal-structural coupled dynamics of a space truss antenna in the orbital space thermal environment. A spatial thermal analysis model is established based on the spatial heat flux model, Fourier-temperature element, finite element method (FEM) and astrometric model to calculate temperature variation of the antenna structure during its operation in orbit. In this model, the effective solar heat flux received by the antenna structure is calculated on the basis of an astrometric model, with consideration of the Earth's shadow effect and the shading effect of the reflective surfaces. Additionally, a thermo-structural coupled dynamic model of the antenna structure is constructed considering the coupled effects of structural deformation and absorbed effective solar heat flux, which was validated using a finite element shell model. Numerical cases are arranged to comparatively analyze the thermal-structural coupling effects, light shading by reflective surfaces, and thermodynamic response during the space operation cycle, respectively. It is demonstrated that both the earth shadow effect and the shading effect of components have great effect on the temperature distribution and variation of the antenna structure. Moreover, significant vibrations will occur at certain moments especially when the thermal radiation flux to the structural components changes suddenly due to light shading from the earth shadow and reflective surfaces. The thermal-structural coupling dynamic model of the antenna structure presented in this work can provide guidance for thermal compensation and thermal-induced vibration attenuation of truss antenna structures.

Thermal fluid dynamics of the effect of filler wire on deposition rate and bead formation intending plasma arc-based DED

The influence of filler wire configuration, such as size and geometry, on the deposition rate (DR) and bead formation, has been studied in wire arc-based directed energy deposition (WADED), but the fundamental physics underlying its effect on wire melting and melt pool dynamics remains unclear. In this paper, a series of plasma arc-based DED (plasma-DED) experiments were conducted to investigate the impact of five different filler wire configurations on DR and bead dimensions. The coupling behaviours of wire melting, metal transfer and melt pool dynamics under the five filler wire configurations were also simulated numerically using the authors' recently developed wire-feeding model. The calculated wire melting and bead cross-sections are consistent with the experimental images and measurements. The results demonstrate that the filler wire significantly affects the highest DR by altering wire melting and metal transfer behaviours through changes in arc energy absorption. The filler wire with a rhombus geometry which is closer to a Gaussian-like arc distribution than the flat wire was shown to get higher DR and more stable metal transfer. Furthermore, different filler wire configurations lead to distinct melt pool behaviours, including temperature distribution and flow velocity, due to various metal transfer behaviours and arc shading effects. This study sheds light on the fundamental physics underlying the impact of filler wire on wire melting and bead formation for the first time. The methods and findings can guide improving DR and controlling bead shape in the plasma-DED process.

Performance evaluation of semitransparent PV window systems employing periodic thermal model

A conventional window system can be replaced by a semitransparent PV window system, which generates electrical energy, provides natural daylighting, and improves the building's overall energy efficiency. The present study evaluates the performance of three different types of PV window systems, namely, STPV (Semitransparent Photovoltaic), SAG (Semitransparent-photovoltaic-Airgap-Glass), and VSAG (Ventilated Semitransparent-photovoltaic-Airgap-Glass) operating in heating and cooling mode, for the climatic conditions of Calgary, Canada. Periodic mathematical thermal models based on the energy balance equations of the window systems are developed to evaluate the systems' performance under the shading and non-shading effects of a curtain. The results indicate that the VSAG window system can be operated in heating mode to increase the room air temperature and in cooling mode to decrease the room temperature. Additionally, the curtain's transmissivity, PV modules' packing factor, and airflow rates could be used as a controlling measure to keep the room temperature within a comfortable range in different climatic conditions. Reducing the transmissivity of the curtains by 20% lowers the room temperature by 2.5 °C while decreasing the packing factor by 10% increases the room temperature by 4.8 °C.

Effects of polyethylene microplastics with different particle sizes and concentrations on the community structure and function of periphytic biofilms

The widespread use of microplastics (MPs) inevitably lead to their release into aquatic environment, where they are likely to encounter the periphytic biofilms, leading to changes in microbial community structure and function. However studies on the toxicity of MPs with different particle sizes and concentrations to biofilms are still lacking. Here, the effects of polyethylene (PE) MPs with three sizes (10, 40 and 120 µm) and two concentrations (2 and 20 mg/L) on biofilm communities were investigated in microcosms over a 28-day incubation period. High-throughput sequencing showed that the alpha and beta diversity of biofilm community were significantly altered by MPs, depending on their size and concentration. Typically, larger particle sizes and higher concentrations resulted in more significant changes in biofilm community structure, indicating a stronger shading effect of larger particles. Compared to the controls, 120 µm MPs treatments significantly reduced the Chao1 and Shannon index of biofilm community regardless of the concentration, while 40 µm MPs reduced the Shannon index only at high concentrations. Moreover, MPs resulted in the changes in the abundances of bacterial communities, with the abundance of Cyanobacteria increasing significantly while that of Proteobacteria and Bacteroidetes decreasing in all treatments. Interestingly, functional analysis by FAPROTAX suggested that a decrease in the abundance of chemoheterotrophy genes and an increase in photoautotrophic- and nitrification-associated genes were observed after exposure to MPs, leading to potential changes of the carbon and nitrogen metabolism of biofilms. These results highlighted that MPs exposure had negative impacts on microbial community structure and function, which in turn affects microbial-mediated processes.

Distributed photovoltaic power output prediction based on satellite cloud map video frames

To address the challenge of predicting distributed photovoltaic (PV) power output for improved system integration and stability, this study proposes a novel method. Given the expanding scale of distributed PV systems and their economic constraints, accurate power output prediction becomes pivotal. Conventional prediction methods are hindered by the lack of meteorological stations at most distributed PV stations. In response, we present a dynamic convolutional generative adversarial network (DC-GAN) approach coupled with satellite cloud map video frames. By extracting shading features from satellite cloud images and utilizing DC-GAN, our method forecasts short-term cloud shading effects on future radiation. We further integrate radiation data from centralized PV stations, spatial correlations of distributed PV stations, and cloud shading characteristics. This information is used to construct a predictive model combining Convolutional Neural Networks (CNN) and Long short-term memory (LSTM), enhancing prediction accuracy. Comparative experiments confirm the superiority of our proposed method over traditional approaches, substantiating its effectiveness and practicality. Our method achieves notable accuracy improvements, establishing its value in predicting distributed PV power output. This research’s findings offer a valuable contribution to the field of renewable energy integration. In numerical assessments, our method demonstrates a significant increase in prediction accuracy, outperforming conventional techniques by 3.3%. This underscores the practical relevance and efficiency of our proposed approach in enhancing distributed PV power output prediction.

Effect of shading and fertilization with iron and sulfur on some vegetative growth and leaves mineral content of Gardenia jasminoides Ellis.

This study was conducted in a glass house, Dept of Hort. and Landscape, College of Agriculture, Univ. Anbar, during the 2021-2022 growing season, to investigate the influence of shading and fertilization on the growth and leaf mineral content of gardenia plants. This study included two factors: two levels of shading at 0 (S0), shading 50 % (S1) and four treatments of fertilizations, control (F0), chelated iron spray at 2 ml.L-1 (F1), addition of magnesium sulfate to pots at 7 gm.plant-1 (F2) and chelated iron spray at 2 ml.L-1 + addition of magnesium sulfate to pots at 7 gm.plant-1 (F3) and their interaction. Treatments were replicated three times at Split plots design (Shading is the main plot) in an RCBD. The number of plants used was 36 plants. The results showed that interaction treatment (S1F3) significantly increased the plant height by 6.517 cm, the highest increase in shoot length of 11.267 cm, and the number of 94.107 leaves.plant-1 , highest leaf area of 9437.463 cm2 , highest leaf nitrogen content of 1.877 % and highest leaf potassium content of 0.561 %, while lower values of these traits were in interaction treatment (S0F0). Keywords: iron, sulfur, vegetative growth, Gardenia jasminoides Ellis

Insights into heat islands at the regional scale using a data-driven approach

Urban heat island (UHI) phenomenon is crucial in the context of climate change. However, while substantial attention has been given to studying UHIs within cities, our understanding at the regional level still needs to be improved. This study delves into the intricate dynamics of the regional heat island (RHI) by examining its relationship with land use/land cover (LULC), vegetation, and elevation. The objective is to enhance our knowledge of RHI to inform effective mitigation strategies. The research employs a data-driven approach, leveraging satellite data and spatial modeling, examining surface and canopy-layer regional heat islands, and considering daytime and nighttime variations. To assess the impact of LULC, the study evaluates three main categories: anthropized (urbanized), agricultural, and wooded/semi-natural environments. Furthermore, it delves into the influence of vegetation on RHI and incorporates elevation data to understand its role in RHI intensity. The findings reveal meaningful variations in heat islands across different LULCs, providing essential insights. Although urbanized areas exhibit the highest RHI intensity, agricultural regions contribute notably to RHI due to land use changes and reduced vegetation cover. This emphasizes the significant impact of human activities. In contrast, wooded and semi-natural environments demonstrate potential for mitigating RHI, owing to their dense vegetation and shading effects. Elevation, while generally associated with reduced heat island, shows variations based on local conditions. Ultimately, this research underscores the complexity of the RHI phenomenon and the importance of considering factors such as different temperatures and their daily variation, landscape heterogeneity, and elevation. Additionally, the study emphasizes the significance of sustainable spatial planning and land management. Targeted efforts to increase vegetation in high daytime land surface temperature areas can reduce heat storage and mitigate RHI. Similarly, planning for agroforestry and green infrastructure in agricultural areas can significantly increase resilience to climate.

Optimal installation and operation planning of parking spaces for solar-powered electric vehicles using hemispherical images

This study aimed to select the optimal installation of parking spaces for solar-powered electric vehicles using hemispherical images and to suggest operation plans. Hemispherical images were captured in parking spaces to generate shading matrices. The parking space suitability index was introduced to quantify the ratio of direct and diffuse solar insolation that is diminished by shadows during the operational hours of the parking space designated exclusively for solar-powered electric vehicles. Spatially adjacent parking spaces were grouped using a genetic algorithm to assign multiple solar-powered electric vehicles-only parking spaces. Finally, the optimal installation sites with the highest parking space suitability index were selected as the parking space dedicated to solar-powered electric vehicles. This approach was applied to 69 parking spaces in an off-street parking lot at Pukyong National University. The calculated parking space suitability index of parking spaces for four seasons showed that the shading effects were the same in the summer season (spring and summer), and in the morning and afternoon of the winter season (autumn and winter). It was more appropriate to park in different spaces during the summer, winter morning, and winter afternoon because of the shading effect.

Numerical Analysis of Temperature Deformation Characteristics for Super-High Arch Dams considering Solar Radiation Effects

Considering that the effect of solar radiation on the super-high arch dam temperature field remains poorly studied, the calculation accuracy of dam temperature deformation is unable to be guaranteed accordingly. To address the issue, the solar radiation effect is adequately taken into consideration by proposing a practical calculation method based on the ray-tracing algorithm, the precomputation algorithm, and the ASHRAE clear sky model in this paper. With the aid of the ASHRAE clear sky model, the solar radiation received by the super-high arch dam and reservoir water is calculated. The shading effects are calculated by means of the ray-tracing algorithm, and the precomputation technology is introduced to further enhance the computational efficiency. Finally, to guarantee the authenticity of the calculation results, the dam thermodynamic parameters are inversed by employing the hybrid genetic algorithm. Based on the application in a real-life case, we concluded that around one third of the entire dam radial temperature deformation was attributable to solar radiation during continuous sunny days. The analysis results signify a critical role for taking account of the solar radiation in dam deformation calculation. Furthermore, the practicability and utilization prospect of the proposed method was verified.

Geospatial segmentation of high-resolution photovoltaic production maps for Switzerland

Until last year, most of Switzerland’s photovoltaic (PV) installations were built on roof tops. But the amount added is not enough to reach the country’s energy transition goals. With the adjustments of September 2023, the government incentivizes large-scale, free-standing photovoltaic installations. It is now essential to identify the best installation locations and to accurately estimate their production potential. Past studies have assessed different landcover classes, but much of the efforts have gone into separating out zones that are not suitable for PV plants; for technical, economical and also legislative reasons. All along, the underlying radiation data that was used to compute the local energy yield remained at a spatial resolution &gt; 1 km. Given the complex terrain of the southern half of the country, this resolution is not high enough to capture the local variability in production potential. Our study introduces a new methodology to derive solar irradiance at a very high resolution of 25 m. Satellite data is combined with high resolution terrain information to compute accurate horizons and to account for local shading effects. These base radiation maps are then converted into potential electricity production from a PV panels. A comparison of the production from a typically chosen panel tilt with the production that can be achieved when the tilt is locally optimized based on the high-resolution radiation maps underlines the value of our new method. In a first application, this data set was used to estimate the lumped production potential of two major landcover classes in Switzerland: agricultural land and water surfaces, each of them divided into two subclasses. The geospatial segmentation was based on land use maps and the total available area within each class was calculated. Comparing the results to the production potential from Swiss roofs shows that these newly incentivized installation areas have a much higher production potential than the conventional roofs; both, in an absolute sense of total potential production (roofs: 120 TWh/a, agricultural: 2,250 TWh/a, water: 210 TWh/a), and in a relative sense of energy yield per installed capacity, especially in winter (roofs &lt;50kWh/m2, agricultural &gt;100kWh/m2, water ≈100kWh/m2).

Silicon Spraying Enhances Wheat Stem Resistance to Lodging under Light Stress

In recent years, the decrease in solar radiation has led to insufficient light, resulting in a shading effect on crops and a deterioration of stem quality, which seriously affects wheat yield. In this experiment, two different lodging-sensitive wheat varieties, SN16 (SN16) and SN23 (SN23), were selected as experimental materials, and two treatments were set up, with 50% shade (S1) and natural light as control (S0) from the jointing stage to the maturity stage. Two treatments, spraying 400 mg L−1 (C1) silicon fertilizer and spraying water as control (C0), were set up at the jointing stage of wheat. The effects of spraying silicon fertilizer on the yield, morphological and mechanical characteristics of the stem, and lignin content of winter wheat under low-light stress were investigated. The results showed that spraying silicon fertilizer increased the lignin content of the stem and improved stem lodging resistance mainly by improving the degree of lignification. An effective cultivation measure for wheat’s resistance to lodging can be provided by spraying silicon fertilizer when future low-light stress occurs.