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针对以水为传热介质真空管太阳能集热器存在的低温冻裂、过高温炸裂和使用间断性等问题,将太阳能集热器的真空管进行改进设计,并在其中设置相变蓄能棒,采用空气为传热介质,研制了一种新型空气式太阳能集热器。实验测试表明:在平均辐照强度为727 W/m2条件下,可延长供热3 h,并随着辐照强度增加供热时间延长;无相变材料的真空管太阳能集热器平均集热效率为36%,相变蓄能棒平均等效集热效率为60%,新型蓄能型空气式太阳能集热器综合集热效率为96%;与传统以水为介质的内插式真空管太阳能集热器平均集热效率为58%相比,该新型集热器集热效率有显著提高。 相似文献
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一种高效平板太阳能集热器试验研究 总被引:11,自引:0,他引:11
性能良好的太阳能集热器是太阳能空调的关键设备之一,广东省江门市太阳能空调系统采用了一种高效的平板集热器,其主要技术特垂直 是增加了一块聚碳酸脂(PC)透明隔热板,本研究通过对比试验,确定了一种高交平板太阳能热器的技术方案,并测定了效率曲线,其热损系数仅为2.90W/(m^2.℃)。 相似文献
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以丽江市某农村居住建筑为研究对象,设计了一种微通道平板集热器太阳能热水系统,并使用TRNSYS仿真软件建立了该系统仿真模型,采用控制变量法模拟分析了不同集热器设计参数对集热器出口温度及集热效率的影响。结果表明:集热器面积分别为2 m2、3 m2、4 m2时,集热器最大出口温度分别为58.2℃、77.6℃、95.7℃,最大集热效率分别为67.6%、63.5%、59.4%;集热器进口温度分别为15℃、20℃、25℃时,集热器最大出口温度分别为58.2℃、62.4℃、66.5℃,最大集热效率分别为65.6%、64.4%、63.1%;集热器进口流量分别为20 kg/h、25 kg/h、30 kg/h时,集热器最大出口温度分别为58.2℃、50℃、44.5℃,最大集热效率分别为65.6%、66.6%、67.2%;集热器倾角分别为30°、45°、60°时,集热器最高出口温度分别58.8℃、61.4℃、54.0℃,最大集热效率分别为66.9%、70.7%、59.6%。 相似文献
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In this paper we present a theoretical model of the black liquid flat plate solar energy collector. Numerical calculations have been performed corresponding to the experiments of Minardi and Chuang (1975). The present model has a good agreement with the experiments of Minardi and Chuang. A study of the effects of varying parameters, such as the liquid flow rate, radius and length of the tube has been made corresponding to the average solar intensity and ambient temperature data of 20 June 1974 in Ohio, U.S.A. The system's performance has also been studied for tropical climates. 相似文献
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In this note an analysis of an inverted flat plate solar collector has been presented. Effect of various parameters, namely thickness of the insulation, air conductance between flowing water and top of the bottom insulation, length of the collector and flow velocity of water on the performance of the collector have been studied. Numerical calculations have been made for typical cold day in Delhi, namely 26 January 1980. 相似文献
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This paper presents the transient performance of a single basin solar still coupled with a flat plate collector. The average daily production of distilled water has been found to be 24% higher than for a simple single basin solar still 相似文献
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This paper deals with the design of a single glazed flat plate Photovoltaic-Thermal (PV-T) solar collector. First, the thermal and electrical performances of several single glazed flat plate PV-T concepts based on water circulation are investigated, using a simple 2D thermal model, then different ways of improvement are presented. It mainly consists in focusing on the heat transfer between PV cells and fluid, and also on the optical properties of materials. Thus, the most appropriate concept configuration has been identified and suitable material properties have been selected. A prototype collector has been designed, built and tested. A high thermal efficiency was reached at zero reduced temperature. For this level of thermal efficiency, the corresponding electrical efficiency has is lower than efficiency of a standard PV panel using the same technology. However, this solar PV-T collector is reaching, in these standard conditions, the highest efficiency level reported in the literature. 相似文献
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The problem of flat plate solar energy collector with water flow is simulated and analyzed using computational fluid dynamics (CFD) software. The considered case includes the CFD modeling of solar irradiation and the modes of mixed convection and radiation heat transfer between tube surface, glass cover, side walls, and insulating base of the collector as well as the mixed convective heat transfer in the circulating water inside the tube and conduction between the base and tube material. The collector performance, after obtaining 3-D temperature distribution over the volume of the body of the collector, was studied with and without circulating water flow. An experimental model was built and experiments were performed to validate the CFD model. The outlet temperature of water is compared with experimental results and there is a good agreement. 相似文献
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构建表面积为1.50 m×1.50 m的小型实验用盐梯度太阳池,并与平板太阳能集热器配合使用,分别对普通太阳池和集热增强型太阳池进行了储热、放热实验。实验研究与理论分析表明:单独盐梯度太阳池的放热量为3.5×103k J,热效率为13.6%;集热增强型太阳池放热量可以达到4.8×103k J,且热效率增至28.1%。另外后者下对流层温度最高可提升10℃以上,从而证明太阳能集热器可以有效提高太阳池热效率,增加下对流层储热量。此外,考虑了放热过程换热器对太阳池下对流层的扰动,对比实验前后的溶液浓度,可以看出实验后太阳池盐度曲线合理,非对流层呈良好梯度分布,太阳池稳定性并未遭到破坏。 相似文献
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Effect of magnetic field on the thermal performance of a ferrofluid-based solar flat plate collector
Mohammed Asfer Atyan Alatyan Danvendra Singh Mohammad T. Haweel Balkrishna Mehta 《亚洲传热研究》2022,51(5):3999-4011
In this paper, the effectiveness of ferrofluid as a working fluid for solar flat plate collectors (FPCs) is studied. A mini-ferrofluid-based solar FPC is designed and tested under laboratory conditions. The thermal performance of the designed solar FPC is evaluated under different conditions and it is observed that it provides higher efficiency for the case of ferrofluid in the presence of a magnetic field. The thermal efficiency is observed to increase by 54% for ferrofluid in presence of a magnetic field as compared to no magnetic field. The thermal efficiency is observed to increase further with the increase in the magnetic field. The increase in thermal efficiency is attributed to the combined effects of higher thermal conductivity and magnetohydrodynamics of ferrofluid, which result in higher convective heat transfer from the riser tube walls into ferrofluid. The higher heat transfer for ferrofluid with a magnetic field is established by calculating the Nusselt number numerically using COMSOL. Simulation results show an increase in Nusselt number for ferrofluid with magnetic field and hence higher thermal efficiency for the solar FPC. The designed FPC provides simple modifications to conventional FPCs to use ferrofluid with magnetic field for higher thermal efficiencies. 相似文献
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The performance of a heat-pipe solar collector was investigated experimentally using refrigerants R11 as the working fluid. The unit is fabricated locally and its performance is evaluated under Beirut Solar conditions. The heat transfer from the heat pipes to the hot-water storage tank took place through a circular end condenser section of the heat-pipe integrated within the collector frame. Tests of single heat pipes showed that the thermal performance of the heat pipe were dependent on its tilt angle, condenser section length and configuration, and type of internal wick used. A circular condenser end of the heat-pipe performed better than a straight condenser due to increased surface area for heat transfer. The R11-charged solar collector with integrated condenser for secondary cooling of water had an efficiency in early operation hours that reached values higher than 60% for the forced circulation mode. The instantaneous system efficiencies varied from 60 to 20%, which are in the range of conventional water solar collectors. System response was fast and sensitive to the incident solar radiation. The thermosyphonic mode of the system operation generated build up of stored energy in the condenser, resulting in oscillating-type flow thus reducing system efficiency below values obtained with forced circulation. © 1998 John Wiley & Sons, Ltd. 相似文献