Distributed modeling of direct solar radiation on rugged terrain of the Yellow River Basin

Due to the influences of local topographical factors and terrain inter-shielding, calculation of direct solar radiation （DSR） quantity of rugged terrain is very complex. Based on digital elevation model （DEM） data and meteorological observations, a distributed model for calculating DSR over rugged terrain is developed. This model gives an all-sided consideration on factors influencing th a resolution of 1 km × 1 km for thDSR. Using the developed model, normals of annual DSR quantity wie Yellow River Basin was generated, with DEM data as the general characterization of terrain. Characteristics of DSR quantity influenced by geographic and topographic factors over rugged terrain were analyzed thoroughly. Results suggest that： influenced by local topographic factors, i.e. azimuth, slope and so on, and annual DSR quantity over mountainous area has a clear spatial difference; annual DSR quantity of sunny slope （or southern slope） of mountains is obviously larger than that of shady slope （or northern slope）. The calculated DSR quantity of the Yellow River Basin is provided in the same way as other kinds of spatial information and can be employed as basic geographic data for relevant studies as well.

Estimation of Direct Solar Radiation of Chad

The aim of this paper is to estimate the direct solar radiation on a horizontal plane in five regions of Chad using the Liu and Jordan’s model in view of the installation of a thermo-solar power plant. For this purpose, the HelioClim-3 Data Base of Solar Irradiance V5’s is used. All the results presented in this paper were obtained using Microsoft Excel software 2015. These results show that compared to the other regions considered for this study, the direct solar radiation on a horizontal plane in Moundou is less.

Highly efficient energy harvest via external rotating magnetic field for oil based nanofluid direct absorption solar collector

Nanofluids based direct absorption solar collectors(DASCs) are considered as the important alternative for further improve the utilization of solar energy. However the low-quality energy and aggregation of nanoparticles obstructs their large-scale application. In this work, a new method of using magnetic nanofluids in DASCs is proposed. By this method, not only high-quality energy is got as well as the problems of blockage and corrosion in heat exchanger are well avoided. The result shows that the maximum temperature can reach 98℃ under 3 solar irradiations and the photothermal conversion efficiency can be further increased by 12.8% when the concentration is 500 ppm after adding an external rotating magnetic field. The highest viscosity of working fluid reduced by 21% when the concentration is 500 ppm at 95℃ after separating the Fe_(3)O_(4)@C nanoparticles from the nanofluids via magnetic separation technology. Meanwhile, the obtained pure base liquids with high temperature flow to heat exchanger, which also reduces the flow resistance in pipeline and avoids the problems such as blockage and corrosion in heat exchanger. This research promotes a new way for the efficient utilization of solar energy.

Optimum Design of Tilt Angle and Horizontal Direction of Solar Collectors under Obstacle’s Shadow for Building Applications

Solar collectors can provide clean, renewable, and domestic energy. The tilt angle and horizontal direction of solar collectors significantly affect its efficiency. There are many good methods to search the optimum tilt angle and horizontal direction to realize the maximum total radiation on the solar collector within a particular day or a specific period. However, it is hard to realize it when solar collectors are placed under obstacle’s shadows;especially when some obstacles, such as trees, have irregular shapes. This paper presents algorithms to achieve the best tilt angle and horizontal direction for solar collector’s performance under the free-form surfaces 3D obstacle’s shadow. The solution process is composed of 4 steps. First, it creates a 3D scene, in which a unique color is given to the solar collector. Second, it employs orthographic projection from the point of view to get an image of the scene. Third, the number of pixels is used to represent the efficiency of the solar collector by counting the pixels of the unique color. Fourth, the efficiency of solar collector in each direction in a period of time is calculated with many images to further select the best direction.

The Characteristics of the Evaporator/Evaporator for Direct Expansion Solar Assisted Heat Pump System

Direct expansion solar assisted heat pump (DX-SAHP) technology is developed by combining solar energy heat utilization with heat pump energy saving technology. The experimental researches of the DX-SAHP hot water system are conducted in this paper, and overall performance of DX-SAHP is analyzed with three different structures of collectors/evaporators, namely a bare-plate collector, a glass-plate collector and double collectors/evaporators (a bare-plate collector and a glass-plate collector). The influence factors and overall performance are studied, which show that the overall performance of the system is mainly influenced by solar irradiation intensity and the collector area. Comparing with glass-plate collector in similar conditions, bare-plate collector system COP is higher. While increasing collector area is conducive to improve the system COP, but will reduce the collector efficiency and increase the workload of the compressor by comparing the bare-plate collector with double-plate collectors.

Assessment of the Direct Sun-Light on Rural Road Network through Solar Radiation Analysis Using GIS

The movement of vehicles on the roads, during summer, can sometimes hide risks involved in direct sunlight. In places where the relief is complicated, road network usually consists of a road complexity. This complexity in conjunction with the motion of a vehicle on a road and the position of the sun at the same time may result in the loss of vision in some sections of the road. This paper describes a GIS-based methodology of the spatiotemporal analysis of this phenomenon. Thus, for a given study area, in this case ofMilos Island,Greece, the geometry of the road network, the terrain morphology and the solar radiation (in specific time intervals during summer) have been analyzed. The result of this procedure is a map illustrating the sections of the road where direct sunlight includes a serious amount of risk for the drivers. Applying this methodology for long periods of time may lead to prevention policies adoption related to accidents of direct exposure to sunlight. Moreover, this methodology could be an additional module in car navigation systems.

基于物联网远程监控的太阳能定向跟踪系统设计

设计了一种基于物联网远程监控的太阳能定向跟踪系统,分别对太阳能定向跟踪系统本体和远程监控系统进行了设计与开发,采用离线和实时控制两种方式,通过监控数据计算当前的太阳高度角和方位角,调整光伏板的倾角,从而提高太阳能光伏板的发电率。对该装置设备层的太阳能定向跟踪系统本体采用框架式结构设计,并通过模糊PID算法对跟踪装置电机进行调控;对应用层的远程监控系统采用B/S架构设计,使用MQTT协议与云平台进行数据交互,用户可直接通过浏览器访问监控系统,实现太阳能定向跟踪系统的远程状态检测、实时控制、数据管理等功能。经测试,用户能通过该监控系统控制和监控太阳能定向跟踪系统的运行,满足太阳能定向跟踪系统远程监控的要求,系统具有较高的实用性。

基于三端柔性直流的光热储能站与新能源场站功率协同控制策略

新能源基地大多经传统交流方式接入高压交流或直流外送通道,为解决大规模新能源经交流接入方式下并网容量小、损耗大,以及功率波动对电网稳定性影响等问题,构建了一个基于柔性直流输电并网的风电和光伏、光热储能及电网三端柔性直流系统。基于直流电压-有功功率特性,提出一种适用于该系统的站间协调控制策略,根据柔性直流输电系统的直流电压波动情况,调整光热储能机组的出力,以平抑风、光功率波动,降低其对电网的影响。针对光热储能侧换流站,采用直流电压裕度下垂混合控制策略,通过控制器参数配置,抑制控制模式切换过程中的暂态过电压,提高系统响应速度。最后,在PSCAD/EMTDC中搭建三端柔性直流系统仿真模型,验证所提控制策略的有效性。

太阳能热化学转化技术研究进展

利用热化学反应将太阳能转化为易存储的化学产品,是实现太阳能大规模连续利用的有效方式。聚光器和反应器是太阳能热化学转化系统的核心设备。该文首先基于热化学反应进行温度的不同,对典型的低、中、高温太阳能热化学转化系统进行介绍,并对不同温度段系统中常用的聚光器类型进行总结,同时简要评述不同太阳能热化学转化系统的优缺点和发展趋势;然后基于太阳能热化学转化过程中传热方式的差异,对直接辐射加热型和间接辐射加热型太阳能反应器的种类、结构、工作原理和研究进展进行阐述。

唐山地区日光温室番茄东西垄向栽培模式研究

为解决日光温室内南北垄向栽培模式不利于机械化作业、人工费用高等问题,以唐山当地传统番茄品种“铁皮西红柿”为试材,在日光温室内春茬番茄种植密度3.3株/m^(2)条件下,试验设东西垄向双行定植(株距35.0 cm,垄距120 cm,垄上行距20 cm、采用“品”型定植)、东西垄向单行定植(株距17.5 cm,垄距120 cm)、南北垄向双行定植(株距30.0 cm,垄距30 cm,垄上行距20 cm、采用“品”型定植)和南北垄向单行定植(传统种植模式,CK,株距15.0 cm,垄距30 cm)4个处理,分析不同垄向与定植方式对番茄农艺性状、净光合速率(Pn)、产量以及起垄—定植人工成本的影响。结果表明:东西垄向栽培模式与南北垄向栽培相比,番茄单花序显著增长,植株提前进入始花期,其中单行定植的效果优于双行;坐果期和收获期Pn显著提高,其中单行定植收获期的叶面积和Pn显著高于其他处理;成熟期茎粗和两果间距显著增大,其中单行定植的效果优于双行;产量提高,但与CK差异不显著,其中单行定植的效果优于双行;起垄—定植人工用时大幅度减少,成本是南北垄向栽培模式的8.8%。相关分析结果表明:番茄单位面积产量与收获期的Pn和茎粗呈显著正相关,与收获期的两果间距呈极显著正相关。在唐山地区日光温室内,采用东西垄向栽培番茄技术可行,单行定植模式优于双行。

建筑“光储直柔”系统中直流家用电器技术及标准进展研究

随着能源革命的深入进行,用电终端也将迎来新的变革,建筑“光储直柔”系统中直流家用电器具备储用一体、直流、柔性等典型特征。该文围绕直流家用电器相关的技术和标准,梳理了国内外相关标准制定情况,依据上述研究构建了直流家用电器的标准体系,并分析阻碍直流家用电器及相关领域产业化的核心技术,提出技术标准重点研究内容。最后对未来研究方向进行展望,以期为“光储直柔”直流家用电器的进一步深入研究、探索提供参考。

智能技术在直膨式太阳能热泵效能优化中的应用

阐述人工智能驱动下的直膨式太阳能热泵系统在效能提升方面的应用和成果。通过人工智能在系统中的应用,实现对太阳能资源的监测和预测、控制算法、能耗优化和协调管理的改进。

果园直流电自动灌溉系统实现与应用研究

应用光伏、计算机等先进技术,建设一套不依赖市电、可无人值守、分布式控制、效率较高、绝对保证生产安全的自动化节能喷灌系统。该系统通过光伏实现了各工作站的独立供电,并通过对工作站中无线传感网节点的编程,实现了对机电设备分布式控制,保证了系统布设低成本与灵活性。同时,全系统使用直流设备,通过合理的电路设计,在确保系统正常工作的同时,实现了节能和保障人员安全的目标。此外,系统通过水锤泵与溢流管的使用,将灌溉系统的蓄水端与供水端解耦,不仅降低了系统的建设与运行费用,还简化了系统实现自动控制的逻辑,减轻了开发人员的负担。

Performance Assessment of Motorized Solar Photovoltaic Louvers System Using PVSYST Software

In the realm of technological market penetration of solar photovoltaic louvers(PVL)addressing environmental difficulties and the industrial revolution,a new avenue of renewable energy is introduced.Moreover,solar energy exploitation through building façades was addressed through motorized solar photovoltaic louvers(MPVL).On the other hand,proponents exalted the benefits of MPVL overlooking the typical analyses.In this communication,we attempted to perform a thorough industrial system evaluation of the MPVL.This communication presents a methodology to validate the industrial claims about MPVL devices and their economic efficiency and the insight on how geographical location influences their utilization and augment their potential benefits.This task is carried out by evaluating the extent of solar energy that can be harvested using solar photovoltaic system(PVSYST)software and investigating whether existing product claims are associated with MPVL are feasible in different locations.The performance and operational losses(temperature,internal network,power electronics)were evaluated.To design and assess the performance of different configurations based on the geographical analogy,simulation tools were successfully carried out based on different topographical locations.Based on these findings,various factors affect the employment of MPVL such as geographical and weather conditions,solar irradiation,and installation efficiency.tt is assumed that we successfully shed light and provided insights into the complexity associated with MPVL.

光热电站主机直接空冷系统优化探讨

光热发电是一种比较有发展前景的可再生能源发电形式,具有良好的储能和调峰能力。受制于水资源条件,目前我国光热电站的主机冷却系统多采用直接空冷系统。直接空冷系统配置对机组经济性和盈利能力均会产生较大影响。在总结和分析光热电站投资构成及运行特点的前提下,依托某案例工程进行直接空冷系统优化计算和分析。对光热电站直接空冷系统气象数据选取与处理、以及电价敏感性分析进行初步探讨。由于上网电价及成本电价普遍较高,与常规火电厂直接空冷系统相比较,光热电站直接空冷系统配置倾向于初始温差(ITD)值较低、风速较小、空冷凝汽器面积较大的方案。

太阳能PV/T+相变能与直蒸式水源热泵供热(冷)系统特性分析

为解决河北农村建筑清洁供暖问题和太阳能利用具有不稳定性问题,设计了太阳能PV/T+相变能与直蒸式水源热泵供热(冷)系统进行实验研究。实验结果表明,冬季典型日系统发电量为4.453kWh,制热系数COP平均值3.41;夏季典型日系统发电量为5.945kWh,制冷系数EER平均值3.2;将发电量用于系统运行,制热系数COP为4.22,制冷系数EER为4.19,分别提高了23.75%和30.12%;夏季单纯PV/T太阳能电池发电量5.537kWh,本系统的发电量提高了7.37%。该系统经济效益高,运行稳定,是一种实现河北农村清洁供暖有效途径。

分水闸门采用直流供电系统的设计研究

水利输水工程中采用风光互补直流供电的闸门测控系统已在国内诸多输水工程项目中开展了试验性应用,系统采用直流直驱方式进行闸阀门监控,系统配备视频监控、水情、水力监测、信息化传输等功能的系统化输水测控方案已得到较为成熟的应用,并具备推广应用条件,系统的新能源供电和直流直驱闸门测控方案可有效解决水利工程存在的市电供应成本高、安全环保成本大、管理维护困难等突出问题,为有效推进水利信息化建设提供了基础保障,对智慧水利建设提供了技术支撑,为分析风光互补供电的直流闸门测控系统特征,在工程实际项目中进行针对性地系统设备选型,通过实际系统工程建设、试验运行,表明风光互补供电的闸门测控系统可实现稳定运行要求,在特定环境和设计配置使用条件下有必要进行针对性设计选型。

CFD Simulations of Wind Effect on Net Solar Heat Gain of South Walls with Internal Insulation

Computational fluid dynamics( CFD) techniques are used to investigate effects of both wind direction and wind speed on net solar heat gain of south wall with internal insulation in winter.Results show that wind effect has a significant influence on the net solar heat gain,where the impact of wind direction is stronger than that of wind speed. For regions in lower reaches of the Yangtze River,difference of their average net solar heat gains( NSHGS) is about 20% due to various wind speeds and wind directions.Buildings in districts with a dominant wind direction of north achieve the highest solar energy utilization.

Solar Photocatalytic Degradation of Textile Dyes in TiO_2 Suspended Solutions

The degradation and decolourization of direct dye(Everdirect supra turguoise blue,FBL),acidic dye(Isolan orange S-RL) and vat dye(Indanthren red FBB) have been investigated by solar/TiO2 process.The effects of solution pH,dye concentration,dosage of TiO2 and nano-size of TiO2 have been studied.The increase in initial pH(3,5 and 11) and dye concentration decrease the removal rate.The treatment for FBB and FBL dye solutions is more efficient than that of S-RL.Under optimum conditions,the color removal is found to be almost complete for FBB and FBL while that of S-RL also reaches 95%.Langmuir adsorption isotherm and modified Langmuir-Hinshelwood kinetic model(L-H model) have been fitted to the experimental data and found to correlate the adsorption patterns as well as the kinetics of the dyes studied.

Exergetic Analysis of Solar Energy drying Systems

An exergetic analysis of three basic types of solar drying systems is presented. The analysis is used to find the available useful energy and the quality of energy that is obtainable from the dryers. The dryers were installed side by side and tested simultaneously to eliminate influence of solar radiation and environmental changes in comparing their performances. The results obtained show that mixed mode and indirect mode solar dryers are more effective in utilizing the captured energy than direct mode dryer, and mixed mode has a slight edge in superiority over indirect mode system. 78.1% and 77% of energy collected in the mixed mode and indirect mode systems, respectively, were available as useful energy, while direct mode system could only convert 49.3% of collected energy to useful energy. The overall exergetic efficiencies of mixed mode, indirect mode and direct mode systems were found to be 55.2%, 54.5% and 33.4%, respectively.