Shading Rate Research Articles

Comparative Study of the Effect of Shading Rate on the Electrical Parameters of CIGS and CdTe/CdS Solar Modules

In this paper, a comparative study of the maximum power on the shading rate on the maximum power of thin film PV modules. Thus two thin film PV modules of type Copper indium gallium selenide, CIGS, of 90W power and a CdTe (Cadmium telluride)/CdS (Cadmium sulfide) module, of maximum power 75 W. These modules, reference SN-CIGS90 and CX3 75 were tested under the conditions of the installation site to ensure their proper functioning and to determine the initial values of electrical parameters before shading. The results obtained are as follows: for the CIGS: Pm (80.717 W); Vco (23.06 V), Icc (3.5 A) and for the CdTe:Pm (54.914 W); Vco (35.52 V), Icc (1.546 A). After this characterization test, the modules are exposed to real operating conditions at the Center for Study and Research on the renewable energy (CERER), Cheikh Anta Diop University in Dakar. Four types of shading are performed on each module with the same mask: partial shading at 25%, 50%, 75% and complete shading at 100%. The comparison of the variation rates obtained on the experimental values of the 4 types of shading carried out on each module, shows that, the phenomenon of shading constitutes an environmental factor which influences negatively the maximum power of the thin film PV modules. But this reduction depends on the surface of the shaded module, the nature of the mask but also the technology used. Indeed, for a shading of 25% of the surface of the two modules, we note a reduction of 21.32% of power for the CIGS, against 40.53% for the CdTe/CdS, that is to say a difference which approaches 20%.

사막기후 스마트팜 적용 냉방패키지시스템의 냉방효과 비교분석

The purpose of this study was to shorten the uncultivated period from about 5-6 months to 2 to 3 months. The uncultivated period of 5-6 months was due to midday temperature in the UAE soaring up to 47℃ and the high solar radiation causing problems in crop cultivation. This study intended to compare the effect of reducing high temperature and cooling load of greenhouse through simulation with covering material, external shading, and fan & pad evaporative cooling system to be applied to the UAE smart farm and use it to select equipment capacity such as chiller and cold storage tank. The average indoor illuminance and the peak cooling load were compared according to the type of covering material and the shading rate. When a fan & pad system was applied, the peak cooling load was reduced by 42.9% or 69.4% compared to the typical glass greenhouse (case 1) when the fan & pad system efficiency was 60% or 80%, respectively. It is expected to reduce the capacity of equipment for heat sources such as chiller and cold storage as much as the peak cooling load reduction.

Perceptual model for adaptive local shading and refresh rate

When the rendering budget is limited by power or time, it is necessary to find the combination of rendering parameters, such as resolution and refresh rate, that could deliver the best quality. Variable-rate shading (VRS), introduced in the last generations of GPUs, enables fine control of the rendering quality, in which each 16×16 image tile can be rendered with a different ratio of shader executions. We take advantage of this capability and propose a new method for adaptive control of local shading and refresh rate. The method analyzes texture content, on-screen velocities, luminance, and effective resolution and suggests the refresh rate and a VRS state map that maximizes the quality of animated content under a limited budget. The method is based on the new content-adaptive metric of judder, aliasing, and blur, which is derived from the psychophysical models of contrast sensitivity. To calibrate and validate the metric, we gather data from literature and also collect new measurements of motion quality under variable shading rates, different velocities of motion, texture content, and display capabilities, such as refresh rate, persistence, and angular resolution. The proposed metric and adaptive shading method is implemented as a game engine plugin. Our experimental validation shows a substantial increase in preference of our method over rendering with a fixed resolution and refresh rate, and an existing motion-adaptive technique.

Experimental investigation on photovoltaic source performances in case of degraded operating conditions for an integration feasibility in Algerian agricultural farms

The accumulation of sand particles and all impurities that can cover the PV panel plans (Tree leaves, birds ejections) will reduce the electric performances of these generators. The main objective of this work is to study the performance of a PV generator affected by several real shading scenarios (total, partial or random) for possible integration in Algerian agricultural farms. For this purpose, we exposed a monocrystalline silicon PV generator to the different artificial shading configurations mentioned above and tested under three specific irradiance levels. For each studied configuration, five shading cases were considered (25%, 50%, 75% and 100% of the generator surface were shaded, add to those, the PV generator's healthy case). Performance measurements have been made, and quantitative comparisons between different studied configurations were carried out. More than 25% (22%) of PV power can be gained respectively at 25% (50%) of shading rate, if a partial shading has been occurred instead of total shading. The PV efficiency drop obtained in the case of random shading represents almost 67% of PV efficiency with total shading, while it represents more than 74%, of PV efficiency with partial shading; these were the drawn significant conclusions.

Simulation Analysis of Daylight Characteristics and Cooling Load Based on Performance Test of Covering Materials Used in Smart Farms

In this study, seven of the most commonly applied covering materials in smart farms are selected as the representative samples for analysis, namely, glass, soft film (polyethylene, PE), soft film (polyolefin, PO), rigid plastic film (ethylene tetra fluoro ethylene, ETFE), rigid plastic sheet (poly methyl methacrylate, PMMA), rigid plastic sheet (polycarbonate, PC double layer), and woven film. For each covering material, visible light transmittance and reflectivity, solar radiation transmittance and reflectivity, thickness, solar heat gain coefficient, and the coefficient of heat transmission are measured according to the test methods in the Korean Industrial Standards (KS) to derive input data for the respective materials. In addition, using the optical and thermal input data as derived above, simulations are performed on the cooling load and daylight characteristics of smart farms to derive basic reference data for the selection of adequate covering materials for the design. Based on the analysis result of the daylight characteristics for each covering material, for a shading rate of 60%, the average values of indoor illuminance were 19,879 lux, 20,012 lux, 19,393 lux, 19,555 lux, 16,560 lux, 16,228 lux, and 11,173 lux for glass, PE film, PO film, ETFE, woven film, PMMA, and PC double layer, respectively, between 6 a.m. and 8 p.m., which correspond to the hours when daylight enters indoor spaces. Considering the target light intensity for strawberry growth at 10,000–40,000 lux, the above results confirm that all the sample covering materials had an indoor illuminance level above the lower limit range of the target light intensity. For the cooling load evaluation, the PC double layer had the lowest value of 482.8 W/m2, and PO film had the highest value of 633.8 W/m2. The difference between the cooling loads of the PC double layer and the PO film is 151 W/m2, which amounts to 23.8%, thus indicating that the selected covering material significantly impacts the cooling load. The cooling load exhibited a pattern similar to that of the coefficient of heat transmission and solar heat gain coefficient, which are key influencing factors for most of the sample materials. However, for PMMA, the cooling load was low because it had a higher coefficient of heat transmission than other materials, but its solar heat gain coefficient was relatively low. Another possible reason for the difference is that the solar heat gain coefficient impacts the cooling load. When the cooling set temperature was controlled from Case 1-1 to Case 1-2, the cooling load decreased by 10.7% on average. In addition, when the cooling set temperature changed from Case 1-1 to Case 1-3, the cooling load decreased by 26.1% on average. For cooling set temperature control, maintaining the temperature around the lower temperature range of the optimal growth temperature of the plants increases the yield, but it also incurs increased cooling load and cost. In terms of cost only, while maintaining the cooling temperature for 24 h at 30 °C, which is the upper limit of the optimal growth temperature, would be advantageous, it will lead to a deterioration of the quality and reductions in yield. Therefore, as follow-up studies for further investigation of the findings of this research, there is the need for an evaluation of the yield and quality with respect to the range of cooling set temperatures. When the internal shading rate was increased to 40% (Case 2-2) with reference to Case 2-1, which was a greenhouse without the application of internal shading, the cooling load decreased by 27.4% on average. Furthermore, when the internal shading rate increased to 50% (Case 2-3) with reference to Case 2-1, the cooling load decreased by 29.3% on average. When the internal shading rate increased to 60% (Case 2-4), the cooling load decreased by 31.5% on average.

A comparative study of the seedling production technology of Picea obovata L. in the forest-steppe ecotone of northern Mongolia

The success of reforestation largely depends on the quality of the seedling. This study focuses on comparative assessments of the experimental planting of Picea obovata seedlings under various growing conditions, including in a greenhouse and open field. The objectives were to carry out a comparative study of the effect of different care regimes on the growth of seedling, and to choose the most optimal treatment that accelerates the growth of seedlings on the basis of the results taken from the comparative analysis. The study was carried out in the Experimental Forest Nursery of the Institute of Geography and Geoecology, MAS in the period between 2018 and 2020. The experimental planting design included four treatments with varying irrigation norms, air temperatures, air relative humidity, shading rates. Two of these experiments were put in greenhouses, and the remaining two treatments were in the open field. Repeated measurements and sampling were performed at the end of each growing season. The results showed high variation in seedling height (p < 0.0001; F = 38.6) and diameter (p < 0.0001; F = 43.2) growth and biomass accumulation (p < 0.0001). These variables therefore, positively corresponded to the air temperature, air relative humidity and moisture sufficiency in the soils. We found that the seedlings had faster growth in height (52.4%) and diameter (62.3%), and there was more biomass accumulation (128.1%) under greenhouse conditions than outdoors. With regard to the biomass allocation, a three-year observation showed a greater proportion of stem biomass in the total biomass, and, conversely, the predominant proportion of needle biomass accounted for open field treatments. However, the creation of stable condition in the greenhouse with a high relative humidity (more than 75%; daily watering norm of 20 liters per day) and an internal temperature of 25°C (40% shading) had the most positive effect on the growth and accumulation of biomass of seedlings. Consequently, we conclude that to meet the existing needs for seedlings for the restoration of natural Picea obovata forests, seedling production in greenhouses should be recommended.

Effects of Light Condition on Growth and Physiological Characteristics of the Endangered Species Sedirea japonica under RCP 6.0 Climate Change Scenarios.

This study was conducted to evaluate the physiological and growth responses of Sedirea japonica cultured in chambers under RCP 6.0 and different light conditions. S. japonica was grown in a soil–plant daylight system chamber under two treatments, a control (CO2 = 400 ppm) and a climate change treatment (CCT) (CO2 = 650 ppm, temperature = control + 3 °C), and three different shading treatments (60%, 90%, and no-shading). S. japonica showed the characteristics of typical Crassulacean acid metabolism (CAM) plants. As the shading rate increased, it increased chlorophyll content, leaf area, and leaf dry weight to efficiently absorb and use light. The CCT had a lower CO2 absorption rate, stomatal conductance, and growth rate and slightly higher water utilization efficiency than the control. This was because stomatal closure occurred in the CCT to reduce water loss due to a relatively higher temperature. As CO2 fixation decreased and consumption increased due to respiration, the overall growth was inhibited. The CCT without shading revealed a dynamic photoinhibition phenomenon showing a significant increase in ABS/RC, TRo/RC, ETo/RC, and DIo/RC and a decrease in PI ABS and DF ABS. In this group, leaf, root, and total dry weight, chlorophyll content, and carotenoid content were the worst growth indices.

Cooling effects of a mist-spraying system on ethylene tetrafluoroethylene cushion roofs in hot-humid areas: A case study in Guangzhou, China

Ethylene tetrafluoroethylene (ETFE) cushion roofs are used for improving indoor natural lighting. However, their poor thermal insulation compromises the indoor thermal environment. Water spraying offers promising potential in roof cooling, but its cooling and shading effects on ETFE cushion roofs have not been examined. This paper on roof-mount spraying systems aimed to address this gap with numerical simulation and a full-scale field experiment. Our findings indicated that exterior surface temperatures of ETFE cushion roofs should be kept below 33.7°C to establish a thermally tolerable indoor environment. Secondly, under limitations of field conditions, decreases in exterior and interior surface temperatures yielded by the spraying system respectively ranged from 4.8°C to 19.5°C and from 0.2°C to 4.9°C. Thirdly, the shading effects generated by spraying have been insignificant, with the average solar radiation shading rate being only 0.23. Lastly, decreases in temperatures for both exterior and interior roof surfaces could be expressed as a function of only four parameters with good accuracy (R2 = 0.93 and 0.87, respectively). Decreases in exterior surface temperatures were most affected by exterior surface temperatures, followed by solar radiation, wind speed, and lastly the wet-bulb temperature, whereas decreases in interior surface temperatures were most affected by solar radiation.

Analysis of the Rice Yield under an Agrivoltaic System: A Case Study in Japan

Agrivoltaic systems, comprising photovoltaic panels placed over agricultural crops, have recently gained increasing attention. Emerging interest in these systems led us to investigate their influence on rice crops. Various factors affecting rice crop yield, including fertilizer application, temperature, and solar radiation, were directly observed, and measured to evaluate changes associated with the shading rates of photovoltaic systems installed above rice crops. The results suggest that the allowable upper limit of the shading rate for agrivoltaic installations ranges from 27 to 39%, which sustains at least 80% of the rice yield, a condition set by the Japanese Ministry of Agriculture, Forestry and Fisheries for these systems. If such systems are applied to rice paddies in Japan at 28% density, they could generate 284 million MWh/yr. This is equivalent to approximately 29% of the total Japanese electricity demand, based on 2018 calculations. This projection indicates the potential of agrivoltaic systems for efficient land use and sustainable energy generation.

Effects of reduced solar radiation on photosynthetic physiological characteristics and accumulation of secondary and micro elements in paddy rice.

Atmospheric haze pollution is a popular environmental issue in recent years. The aerosols reduce solar radiation reaching land surface, with consequences on the growth of crops. In order to examine the effects of low solar radiation intensity on the physiological characteristics and mineral nutrition of grain crops, the random designed field experiment of rice cultivar 'Nanjing 5055' planted under different shading degrees (CK, natural sunlight control; Y1 and Y2 were treatments with shading rates of 19% and 45%, respectively) were conducted. The response of chlorophyll content (SPAD), leaf area index (LAI), net photosynthetic rate of leaves, grain yields and secondary/micro element contents (Ca, Mg, Fe, Zn, Mn, Cu) in rice were measured during key growth stages (jointing, heading, and grain filling stages). Results showed that, shading treatments inhibited the synthesis of photosynthetic products and reduced the LAI during the whole growing period, but at the early stage it did not affect the chlorophyll content, which was significantly increased at the late growth stage. Compared with CK, the 1000-grain weight of rice was decreased by 14.4% and 18.4%, and seed setting rate was decreased by 4.3% and 12.9%, which resulted in rice yield reduction. With the increases of shading rates, rice yield was decreased by 58.5% and 66.4%, respectively. The nutrient concentrations, especially for the micro-elements, in brown rice and glume were increased. Shading had a negative effect on rice growth, which would eventually reduce the crop production. The higher contents of heavy metals such as Cu and Mn would be a pollution risk for human health. Therefore, the impacts of weakened solar radiation on quantity and quality of crops need comprehensive evaluation.

무늬 관엽식물 선호도의 변화 및 색채 조화미 분석 - 최근 유통되는 무늬 관엽식물을 중심으로

In this study, we comparatively analyzed the preference of pattern foliage plants to provide the basic data for the status of current use of pattern foliage plants by researching and analyzing changes in the preference of such plants in the years 2010 and 2020. We also analyzed the color-harmonious beauty of pattern foliage plants currently distributed in the market. This study targeted 18 species used for a survey on the preference of pattern foliage plants, and eight species of pattern foliage plants in 2020. For the research and analysis of preference, three surveys were conducted. For the measurement of plant color, the plants were domesticated in a greenhouse (shading rate: approximately 40%) for a week. After taking a photograph of each individual plant in a light room on the basis of day light, the color was measured by correcting it to a standard color using the Adobe Photoshop Program. The results of analyzing the preference of pattern foliage plants using the above method were as follows. Firstly, it was clear that the preference of green-patterned plants was higher than that of red-patterned plants. Secondly, in the plants with red and yellow patterns, the preference was low when the brightness difference was larger. In plants with the same green patterns, the preference was shown regardless of the brightness difference. Moreover, when the difference in chroma was greater, the preference was low. Thirdly, color had the highest influence on the preference of plants. In the case of pattern plants with the same group of colors, the form of pattern and color arrangement rate had a higher influence on the preference than color. As the preference of plants is different at different times, and the preference should be quickly understood to use it for marketing strategies, there should be continuous research on the preference of plants in the future.

城市居住区多功能绿地景观的景感生态学效应

作为居住区绿地景观重要的组成要素，公共活动空间是居民最为频繁使用的空间，对提高绿地生态系统文化服务，改善人居环境与提高居民健康具有重要意义。基于居民休闲娱乐文化感知，探讨居住区绿地公共活动空间的景感生态学效应，揭示多功能绿地景观对生态系统文化服务和景感营造的影响，可为居住区绿地的景观规划与设计提供重要的参考依据。以郑州市26个居住小区80个公共活动空间为研究对象，结合景感生态学理念，基于小区绿地公共活动空间的景感特征（植被覆盖、基础设施、遮荫率、管理水平、公共活动空间面积与类型）以及内部居民休闲娱乐文化活动特征的调查分析，探讨了城市居住区绿地公共活动空间的景感效应对绿地生态系统文化服务的影响。结果表明：（1）小区绿地不同类型公共活动空间提供的景感效应存在显著差异，水体的自然属性使其景感效应更丰富，文化服务价值最高。（2）小区绿地公共活动空间面积越大，居民的心理感知越强，景感体验越丰富，文化服务价值越高，增加公共活动空间面积是构建多功能绿地景观的直接通道。（3）公共活动空间的植被覆盖营造的视感与遮荫率营造的风感生态学效应较为显著，而基础设施的触感与清洁度的视感并未存在显著影响。（4）结合小区社会经济数据的多元回归分析结果表明，由公共活动空间面积营造的多样化景感对居民活动量的贡献最大，其次为公共活动空间的类型与小区户数。运用景感生态学理论和景感营造原则，在有限的空间内通过景观设计实现了景感载体化，改善和增加了绿地生态系统服务，能够缓解城市绿地的不公平性。未来城市居住区特别是高密度居住区应尽可能设置大面积的具有多功能特征的公共活动空间，而低密度居住区在绿地面积充足的前提下，可设置大面积自然水体和增设多类型的公共活动空间，以提高景感效应。;Public activity space within the urban residential green space is the most frequently used space for residents' leisure and entertainment activities, which are substantial in the improvement of the cultural ecosystem services of green spaces and the amelioration of the neighborhood environment and the residents' physical and mental health. Focused on the residents' perception of leisure culture, our study explored the effects of the landsenses ecology on the public space of residential areas. We also revealed the effect of multifunctional green space landscapes on ecosystem cultural services and landsenses creation to provide important directions for the planning and the design of green space in residential areas. This paper selected 80 public activity spaces in 26 residential communities in Zhengzhou as research objects. The following results were obtained. (1) The significant differences were observed in the sense of landscape effect provided by different types of public activity spaces in residential green spaces. The natural attributes of water bodies enriched the sense of landscape effects and had the highest cultural ecosystem service value. (2) A large public green space in the residential area resulted in strong psychological perception of the residents, rich sense of scenery experience, and high value of cultural ecosystem services. Increasing the area of the public activity space was a direct channel to build a multifunctional green space landscape. (3) The ecological effects of the visual sense created by the vegetation coverage and shade rate created by the public event space were significant, but the tactile sense of the infrastructure and the visual sense of cleanliness did not exist. (4) Combining with the social and the economic data of the community, the results of multiple regression analysis showed that the diverse sense of landscape created by the public activity space had the largest contribution to the amount of residents' activities followed by the type of public activity space and the number of households in the community. The theory of landscape ecology and the principles of sense of landscape creation were applied, and the landsenses carrier was achieved through the landscape design in a limited space, thereby improving the green space ecosystem services and alleviating the unfairness of the urban green space. Finally, high-density urban residential areas were suggested to be provided with large public activity spaces with multifunctional characteristics as much as possible, and low-density residential areas were suggested to be provided with large-scale natural water bodies and additional multiple types of public activity paces to enhance the effect of scenery.

Effects of shading on photosynthetic characteristics and yield at different growth stages of potato.

We examined the effects of shading photosynthetic characteristics, yield, and tolerance to low light in two potato varieties (Jizhangshu 12 and Jizhangshu 8) at four growth stages (seedling, seedling/budding, budding/early flowering and flowering/harvest). There were three shading treatments (0(CK), 20% and 50%). The results showed that at both 20% and 50% shading rates, the SPAD value (a measure of leaf cellular chlorophyll content) of the two varieties decreased significantly at the seedling stage compared with CK treatment. No significant change in the SPAD value occurred at the seedling/budding stage or the budding/early-flowering stage. However, the SPAD value increased marginally after shading at the initial flowering stage. Under the 50% shading regime, the SPAD values of both varieties followed the same trend as the 20% regime. The range of changes at different growth stages remained similar. The only exception was that shading at the beginning of flowering increased SPAD value. Shading had little effect on leaf stomatal conductance (gs) at each developmental stage. There was no significant difference between all treatments and the control, except that the gsvalue of Jizhangshu 8 decreased significantly (43.9%) compared with the control under 50% shading at the beginning of flowering. After the shading treatment, the intercellular CO2 concentration (Ci) of leaves showed an upward trend. 50% shading at the seedling and seedling/budding stages could significantly increase Ci, but not at other stages. The net photosynthetic rate (Pn) of the four periods were all decreased after 15 d of shading. The Pn reduction of the two varieties, 50% shading, was greater than 20% shading. The decline range of Pn of Jizhangshu 12 was less than that of Jizhangshu 8 at all stages, except for that at the seedling stage. The yield of shading treatments decreased in all four stages, with the decrease rate of 50% shading treatment being greater than that of the 20% shading treatment. 'Jizhangshu 12'was not tolerant to low light at the seedling stage but performed better than 'Jizhangshu 8' at other stages. The comprehensive analysis of two test varieties implied that varieties with strong tolerance to low light experienced a smaller boost in intercellular CO2 concentration and a smaller drop in net photosynthetic rate, stomatal conductance, and yield post-shading.

Application of Photovoltaic Systems for Agriculture: A Study on the Relationship between Power Generation and Farming for the Improvement of Photovoltaic Applications in Agriculture

Agrivoltaic (agriculture–photovoltaic) or solar sharing has gained growing recognition as a promising means of integrating agriculture and solar-energy harvesting. Although this field offers great potential, data on the impact on crop growth and development are insufficient. As such, this study examines the impact of agriculture–photovoltaic farming on crops using energy information and communications technology (ICT). The researched crops were grapes, cultivated land was divided into six sections, photovoltaic panels were installed in three test areas, and not installed in the other three. A 1300 × 520 mm photovoltaic module was installed on a screen that was designed with a shading rate of 30%. In addition, to collect farming-cultivation-environment data and to analyze power generation, sensors for growing environments and wireless-communication devices were used. As a result, normal modules generated 25.2 MWh, bifacial modules generated 21.6 MWh, and transparent modules generated 25.7 MWh over a five-month period. We could not find a difference in grape growth according to the difference of each module. However, a slight slowing of grape growth was found in the experiment group compared to the control group. Nevertheless, the sugar content of the test area of the grape fruit in the harvest season was 17.6 Brix on average, and the sugar content of the control area was measured at 17.2 Brix. Grape sugar-content level was shown to be at almost the same level as that in the control group by delaying the harvest time by about 10 days. In conclusion, this study shows that it is possible to produce renewable energy without any meaningful negative impact on normal grape farming.

Contracts as Reference Points: A Replication

We replicate two treatments of an experimental theory test (Fehr et al., 2011) studying Hart and Moore (2008)’s idea that contracts serve as reference points in trading relationships. In contrast to rigid contracts, flexible contract terms may be perceived in a self-serving manner and, therefore, the contract parties might form subjective entitlements. This reference-dependent perception of flexible contract terms leads to a trade-off of the contractual form. While flexible contracts are, in theory, deemed preferable to rigid contracts, frustrated subjective entitlements may lead to perfunctory performance and shading behavior that is absent in rigid contracts. The results of our replication are mixed. On the one hand, we find that sellers under flexible contracts shade more often than sellers under rigid contracts and our replication analysis suggests replication success. On the other hand, our analysis does not indicate a meaningful positive effect of removing ex ante competition on shading rates under rigid contracts. Our replication analysis does not unambiguously suggest replication success here. Thus, we do not find supporting evidence for the idea that competition creates objectivity and enhances perceived fairness of the contract terms.

차광형태와 기간이 천궁의 고온피해 경감에 미치는 효과

Background: Cnidium officinale is a medicinal crop sensitive to high temperature. It is necessary to develop environment control technology that can reduce environmental stresses such as high temperature. This study was conducted to develop technology for stable production of Cnidium officinale by reducing damage owing to high temperature by applying shading treatment of varying duration, and structure.BRMethods and Results: Black shading nets were used from May to September or November; shading structures such as pillar, flat roof, and tunnel type structures were installed. Environmental changes, rate of photosynthesis, and growth characteristics were investigated. The shading treatment reduced temperature by 3℃. The rate of photosynthesis and yield with shading treatment were higher by 134% and 127%, respectively, than those with full sunlight. The ratio of shading area ranged from 50% to 71% according to the type of shading structure. The effect of environmental control on growth varied depending on the type of shading structure.BRConclusions: The shading treatment reduced damage owing to high temperature, shading rate of 55% - 75% was recorded between the period May - September, and the flat roof type shading structure was considered the most suitable among shading methods.

Impact of Shading Net on Photovoltaic Cells Performance

The output of the photovoltaic cells such as voltage and current is an essential parameter to assess the performance of photovoltaic cells. The performance of photovoltaic cells depends on the intensity of solar irradiation and the cleanliness conditions of cells. One of the factors that influence the performance of photovoltaic cells is shading. It can reduce the intensity of solar irradiation on the cells. In this study, the measurement system used two units of current and voltage sensors that simultaneously measures the performance of photovoltaic cells. In photovoltaic cells covered by a shading net with nominal shading rates of 50% and 90%, the average efficiency is 6% and 2% respectively. Meanwhile, for photovoltaic cells without covering by a shading net, the average efficiency is 11%.

Thermo-environomic assessment of an integrated greenhouse with an adjustable solar photovoltaic blind system

Optimum energy consumption and renewable energy utilization reduce environmental impacts and are cost-effective. They are the key aspects of achieving sustainable energy management, such as in the agricultural industry. The contribution of the horticultural section in the global energy demand is approximately 2%, and among its various sections, greenhouses are one of the main systems in modern agriculture that have a great share on energy consumption. In this study, a rose greenhouse is examined and modeled in EnergyPlus as a greenhouse reference (GR). Validation of the developed greenhouse model is carried out with a site experimental measurement. Using the GR as the basic model, 14 various configurations of greenhouses have been assessed by considering a solar photovoltaic blind system (SPBS) in checkerboard arrays 1 m above the greenhouse roof. These modified greenhouses called solar-blind greenhouses (SBGs) have different shading rates and SPBS sizes. To perform a Thermo-environomic assessment, the effects of various parameters, including temperature, relative humidity, natural gas consumption, electricity consumption, and carbon dioxide (CO2) emission reduction, are studied. Results indicate that covering 19.2% of the roof, with no significant change in the illumination level on the plant canopy, will annually reduce natural gas consumption, electricity demand, and CO2 emission by 3.57%, 45.5%, and 30.56 kg/m2, respectively. Moreover, with the SPBS, the annual electricity production is approximated at 42.7 kWh/m2.

영농형 태양전지 스트링 구성에 따른 발전량 및 농업생육환경 분석

The distributed solar module composition in small size is necessary for simultaneous crop cultivation and power generation in agrophotovoltaic (APV). The purpose of this study is to compare and analyze PV power generation and agricultural environment changes according to different cell string composition (3×12 and 4×9 module). Ground solar radiation was simulated and a test-bed was constructed, with 30% shading rate, to collect monthly power and agricultural environment data for 10 months. The 3×12 module had a 0.7% higher ground solar radiation value than the 4×9 module in the simulation results. In test-bed, though the 4×9 module may be considered for use in the APV in terms of power production, ground solar radiation, and soil humidity, the 3×12 module should be considered that the damage of crops caused by waterdrop can be mitigated when the PV module has fewer strings. These results can contribute for the selection of standard APV module design in terms of installing 10GW of APV by government vision.

Identification of Partial Shading Conditions for Photovoltaic Strings

Under partial shading conditions (PSC), the power-voltage (P-V) characteristic curve of photovoltaic (PV) strings exhibits multiple peaks. Such mismatching phenomenon brings challenges in controlling the output power. To analyze the electrical characteristics of PV strings in complex environments, a quantitative analysis method is required to characterize the PSC. This paper introduces the shading matrix to describe the shading rate and shading strength information. The proposed shading matrix would provide maximum power point tracking (MPPT) controllers with the essential environmental information to improve the global maximum power point (GMPP) tracking performance. A modified Tabu search (MTS) based identification method is proposed to estimate the shading matrix. The proposed modified method involves a preselection process of updating the Tabu list to optimize the searching efficiency. The accuracy and efficiency of the proposed analytical estimation expression are validated through simulations and experiments. By comparing with binary search (BS), golden-section search (GS) and Tabu search (TS) algorithms, the proposed MTS algorithm is demonstrated to perceive the shading information at least 18.75% faster.