菲涅尔透镜聚光光伏光热耦合系统性能模拟研究

建立带有嵌入式流道结构的低倍菲涅尔透镜聚光的光伏光热耦合系统数学模型,分别从聚光比、换热流体质量流量、几何和环境参数角度研究了耦合系统的光热光电性能。结果表明:随着聚光比增加,系统的热性能提升而电性能降低,且低Re数下聚光比对系统性能影响显著;系统各性能参数在小流量阶段变化剧烈,但变化速率逐渐减缓,直至趋于稳定;流道宽度w_1的不同造成系统性能随流道深度h变化特征的差异,根据Re数与换热面积所占比重可分为4个不同阶段;当太阳电池覆盖率Pa相同时,随着风速的增加,系统热性能参数缓慢降低,而电性能几乎不变。     

光伏光热一体化组件性能实验探究与分析

通过搭建PV/T一体化组件性能测试实验台,测试在不同进口水温、不同一体化组件倾角和不同流量时PV/T一体化组件的热、电效率。结果表明,在进口水温30℃工况下一体化组件拥有最优的热效率值和输出电功率值,其日总热效率为35.97%,对应的输出电功率范围为29.40~30.51 W;45°倾角放置的一体化组件可接收到较多的太阳辐照度,且具有最优的光热性能,对应的日总热效率为32.65%;流量85 L/h工况下一体化组件拥有最优的热效率值,对应的日总热效率值为25.89%,串联50Ω电阻时组件的输出电功率随流量的增大而增大,但变化较小,流量120 L/h工况下一体化组件拥有最优的输出电功率值,对应的输出电功率值范围为24.02~29.19 W。     

机油滤清器耐低温性能评价

介绍了目前机油滤清器耐低温性能评价方法,通过改进NBR配方和采用玻璃化温度Tg评价很好解决了机油滤清器耐低温性能测试不能反映实际使用状况的问题,提出了从NBR密封圈和机油滤清器检测改进机油滤清器耐低温性能评价的方法.     

光伏光热系统导热流道传热性能的数值模拟

对光伏光热系统实体模型进行简化处理,并建立了包含单条流道、带翅片的单条流道、单侧排列两条流道的三种型式导热流道的物理模型。以20℃蒸馏水为流动工质,借助FLU-ENT分别对三种不同型式的导热流道的传热性能展开数值模拟研究,分析了导热流道的出口平均温度和壁面导热速率。     

Performance Optimization of Water-Cooled Concentrated Photovoltaic System

In this paper, a three-dimensional computational fluid dynamics model is developed to predict the thermal and electrical performance of a water-cooled concentrated photovoltaic (CPV) system. Based on the good agreement between the numerical results and experimental data from literature, an attempt was made to improve this system performance. Indeed, as the developed model is able to predict the thermal behavior of the different system components, many hot spots were detected in the cell module. In order to avoid this disadvantage while promoting solar cell cooling, the number of water cooling pipes of the CPV module was first increased and then a rectangular channel was employed. Numerical simulation results indicate the potential of the different modified systems for reducing these hot spots and the CPV module temperature, thus providing increased electrical and thermal efficiencies. The optimum design, which presents a solar cell temperature of 315.15 K and respectively a thermal and combined (thermal plus electrical) efficiency of 74.2% and 83.5%, is also evaluated.     

陶瓷过滤器脉冲清灰系统的性能测定与分析

在由3根滤管组成的高温陶瓷过滤器实验装置上,测定了不同过滤气体温度下滤管脉冲反吹系统的循环性能．比较不同直径的喷嘴在不同脉冲宽度和反吹温度下的气体耗量,利用加尘实验得出各操作参数对过滤循环稳定性和清灰性能的影响规律．实验结果表明,喷嘴每次反吹的气体消耗量与脉冲宽度近似呈线性关系;适当增大喷嘴直径能提高清灰效果,延长反吹周期,但气体消耗量也随之增加．利用已建立的脉冲反吹系统动态模型,对脉冲反吹系统进行了模拟计算,得出了脉冲反吹系统的储气罐容积、管线直径对反吹气体流量和气体消耗量的影响规律．这些结果可用于高温陶瓷过滤器的工程设计和脉冲反吹系统的优化．     

Thermal Performance Prediction of Two-Phase Closed Thermosyphon Using Adaptive Neuro-Fuzzy Inference System

In this paper the Adaptive Neuro-Fuzzy Inference System (ANFIS) is used for the prediction of thermal efficiency and thermal resistance of a two-phase closed thermosyphon (TPCT). Aqueous suspensions of pristine multiwalled carbon nanotubes (CNTs) and functionalized CNTs with ethylene diamine were used as nanofluid in the TPCT. The experimental results regarding the TPCT performance including thermal efficiency and thermal resistance were modeled by the ANFIS technique. The ANFIS network was initiated by 70% of experimental data, and 30% of primary data were considered for testing and checking the suitability of the ANFIS model. The modeling results were compared with five arithmetical criteria. The arithmetical criteria suggested that the obtained modeling by ANFIS is valid and it could be expanded for other conditions. Also, to determine optimal ranges of experimental conditions, three-dimensional diagrams were traced by the modeling data. The proposed method of ANFIS modeling may be applied for optimization of other TPCTs with different configurations.     

硅油风扇离合器结构参数对其性能的影响

作者对硅油风扇离合器的主从动件工作面结构形状、端面间隙、柱面间隙、回油孔尺寸、硅油量、主从动件速度差等结构参数对性能的影响进行了试验研究;为设计硅油风扇离合器提供了有用的数据。     

太阳能光伏光热建筑一体化系统的研究

太阳能光伏光热一体化不仅能够有效降低光伏组件的温度,提高光伏发电效率,而且能够产生热能,从而大大提高了太阳能的转换效率。对光伏光热建筑一体化(BIPV/T)系统的两种主要模式:水冷却型和空气冷却型系统的工作原理和系统模型进行了理论介绍,详细说明了两种系统中热产品在家庭中的应用。并对目前研究情况下两个系统中存在的问题提出了改进方案。与常规建筑相比,光伏光热建筑减少了墙体得热,改善了室内空调负荷状况,提高了建筑节能效果。     

Performance investigation and optimization of the Trough Concentrating Photovoltaic/Thermal system

The overall performances of a 10 m² Trough Concentrating Photovoltaic/Thermal (TCPV/T) system with a Super cell array, a GaAs cell array and a concentrating silicon cell array are investigated. The experimental results show that the average electrical efficiencies of the TCPV/T system with the three types of solar cell arrays are 3.63%, 8.94%, and 3.67% respectively in typical synoptic condition. The thermal efficiencies of the TCPV/T system with the three types of solar cell arrays are 45.17%, 41.69%, and 34.53% respectively after the TCPV/T system runs over 5 h. The TCPV/T system with the three types of cell arrays is also evaluated based on the electricity generation costs. From the point of the performance price ratio, the concentrating silicon cell array is preferable for the system with a middle or low concentration ratio.In order to improve the performance of the TCPV/T system, a 2 m² experimental system utilizing the mirrors with a higher reflectivity is built. In concentrating irradiance, when the mirror reflectivity increases from 0.69 to 0.92, even the area of the reflecting mirrors reduce, the maximum powers of the cell arrays increase. The electrical efficiencies of the system using a Super cell array, a GaAs cell array and a concentrating silicon cell array rise by 0.9%, 2.62% and 5.47% respectively. The high reflectivity of the parabolic mirror is pursued. All these works are helpful to the further study on the trough concentrating system.     

太阳能光伏光热系统性能预测研究

建立了太阳能光伏光热(PV/T)系统的BP神经网络预测模型,通过对比不同优化算法、影响因素、数据量等来寻求最佳预测精度的模型.结果表明:在选用RMSprop这种参数优化算法下,输入5因素和2600条数据量得到的模型精度较优.     

热分离式机油滤清器的试验分析

现介绍一种新型热分离式机油滤清器，它采用电加热方法汽化水和其它易挥发性液体，同时采用滤芯去除固体颗粒，从而达到清除机油中固体杂质，又分离机油中液体污物的目的。     

柴油机磨损的油料光谱分析

本文用油料光谱法分析了不同粒度的灰尘对柴油机主要摩擦副的磨损情况。实验结果表明,不同粒度的灰尘对柴油机的磨损不同,根据油料光谱分析结果,可以准确得到发动机的磨损状况,该方法是对柴油机进行故障诊断的有效工具。     

油液光谱分析比例模型的建立

针对油液光谱分析中数学分析模型的建立问题，分析了现有光谱数据数学分析模型的不足，提出了比例模型的概念，介绍了比例模型的建立过程，给出了比例模型界限值的制定方法，并应用比例模型对某型发动机进行实际磨损状态监测。     

低温地热ORC-AHT联合循环系统热力性能分析

为充分回收利用低温地热,利用第二类吸收式热泵升温原理,提出一种新型低温地热ORC-AHT联合循环发电热力系统。根据热力学第一、第二定律,建立热力学模型,编制计算程序并进行热力性能分析,结果表明:净输出功、热效率和火用效率随蒸发温度升高呈现先增加后减小的趋势,且随热源温度升高而增加。根据热力学模型设定条件,从T-Q图中可看出,与单级ORC系统相比,耦合系统可降低火用损失,提升联合系统热力性能。热源温度为373、383和393K时,耦合系统净输出功较单级ORC系统分别增加30.48%、21.9%和17.7%;热效率较单级ORC系统分别增加11.6%、7.25%和4.19%;火用效率较单级ORC系统分别增加45.45%、53.95%和60.05%。     

Modeling and Dynamic Performance of a Self-Commutated Photovoltaic Inverter System

Interest in utility-interactive photovoltaic (PV) inverter systems has increased over the past decade and numerous central-station PV systems have been installed. It is anticipated that as PV system costs decrease, residential systems will be installed in increased numbers. Although a substantial amount of literature is available concerning the design, protection, safety, economics, and operating experience of residential and central-station PV systems, little information is available regarding their dynamic electrical characteristics and the computer modeling of these systems. Moreover, most of the available literature concerning modeling and/or dynamic performance focuses either upon the long-term dynamic behavior as it affects power system scheduling or upon the steady-state harmonic characteristics. In recent work, highly detailed computer models of a representative set of PV systems have been developed and several of these models have been verified by comparison with system measurements [1, 2]. However, the models described in [1, 2] are more complex than necessary for large-scale power system studies in which the fast switching transients associated with the dc-to-ac inverter are of little concern and only the slower cycle-to-cycle behavior of the PV system is of interest. In fact, it is not possible to incorporate these detailed models into conventional transient stability programs due, in part, to the very small time-step requirements associated with these models. In this paper, a three-phase self-commutated utility-interactive photovoltaic inverter system is described including its associated control system. A schematic diagram of the selected PV inverter system is depicted in Fig. 1.     

Modeling and Dynamic Performance of a Line-Commutated Photovoltaic Inverter System

Interest in utility-interactive photovoltaic (PV) inverter systems has increased over the past decade and numerous central-station PV systems have been installed. It is anticipated that as PV system costs decrease, residential systems will be installed in increased numbers. Although a substantial amount of literature is available concerning the design, protection, safety, economics, and operating experience of residential and central-station PV systems, little information is available regarding their dynamic electrical characteristics and the computer modeling of these systems. Moreover, most of the available literature concerning modeling and/or dynamic performance focuses either upon the long-term dynamic behavior as it affects power system scheduling or upon the steady-state harmonic characteristics. In recent work, highly detailed computer models of a representative set of PV systems have been developed and several of these models have been verified by comparison with system measurements [1, 2]. However, the models described in [1, 2] are more complex than necessary for large-scale power system studies in which the fast switching transients associated with the dc-to-ac inverter are of little concern and only the slower cycle-to-cycle behavior of the PV system is of interest. In fact, it is not possible to incorporate these detailed models into conventional transient stability programs due, in part, to the very small time-step requirements associated with these models. In this paper, a three-phase line-commutated utility-interactive photovoltaic inverter system is investigated. A schematic diagram of the selected PV inverter system is depicted in Fig. 1.     

有机朗肯循环与再热式循环低温热源发电系统热力性能研究

针对120℃以下的低温余热热源,探讨了基本有机郎肯循环发电系统和再热式有机朗肯循环发电系统模型的基本原理.从热力学第一定律角度出发,研究了纯工质R245fa和非共沸混合工质R21/R245fa在基本有机郎肯循环系统中,以及纯工质R245fa在再热式有机郎肯循环系统中,三种形式的有机郎肯循环系统热力性能随蒸发温度的变化情况.与纯工质基本有机郎肯循环系统相比,再热式有机郎肯循环最大可提高系统净输出功7.08％,而混合工质对提高整个系统热力性能具有较大的优势,净输出功和热效率最大可提高4.67％和2.91％.     

以挖掘数据替代测点失效值的热力系统性能研究

为解决机组热力系统测点参数失效致使其性能计算模型不能作出正常评估的问题,基于相似性原理,利用某600MW机组热力系统历史正常运行数据建立了其动态超球预测模型,获得了该机组热力系统性能计算模型所需的预测值及相似度曲线,验证了性能计算模型预测值的可靠性,并以测点预测值作为挖掘数据替换其失效值.结果表明:合理选择和适当补入历史正常运行数据,可降低预测值的相对误差,并将其控制在工程允许范围内,提高其替代失效值的可靠性;当输入的热力系统测点参数因测量系统等引起随机波动甚至个别参数失效时,该方法仍可实现对机组热力系统运行性能的正常实时评估和故障诊断.     

燃油燃烧器喷嘴的性能分析

文章详细介绍了燃油燃烧器高压雾化型喷嘴的基本原理和运行规律，着重分析了燃油的性质和运行工况参数对喷嘴性能的影响。文章同时给出了选择喷嘴的具体建议，具有一定的指导意义。