| 严寒地区小型线性菲涅尔聚光集热器末端损失与补偿 |
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| 引用本文： | 闫素英,陈壮,赵晓燕,马靖,吴玉庭,田瑞.严寒地区小型线性菲涅尔聚光集热器末端损失与补偿[J].农业工程学报,2019,35(6):206-213. |
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| 作者姓名： | 闫素英 陈壮 赵晓燕 马靖 吴玉庭 田瑞 |
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| 作者单位： | 1. 内蒙古工业大学能源与动力工程学院，呼和浩特 010051；2. 内蒙古可再生能源重点实验室，呼和浩特 010051；,1. 内蒙古工业大学能源与动力工程学院，呼和浩特 010051；,1. 内蒙古工业大学能源与动力工程学院，呼和浩特 010051；,1. 内蒙古工业大学能源与动力工程学院，呼和浩特 010051；,3. 北京工业大学环境与能源工程学院，北京，100124,1. 内蒙古工业大学能源与动力工程学院，呼和浩特 010051；2. 内蒙古可再生能源重点实验室，呼和浩特 010051； |
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| 基金项目： | 国家自然科学基金资助项目（No.51766012）；内蒙古财政创新资助项目（2017年度）；内蒙古工业大学科学研究项目（A类）（No.X201606） |
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| 摘 要： | 针对严寒地区线性菲涅尔聚光集热器末端损失严重的问题,该文以呼和浩特地区小型线性菲涅尔聚光集热系统为研究对象,根据不同季节太阳位置的变化,理论分析并计算了沿水平南北轴放置的线性菲涅尔集热器自东向西跟踪过程的末端损失,得到其变化规律及补偿方法,并进行了试验验证。结果表明,一天中末端损失随时间的变化趋势与太阳高度角的变化趋势相同,与太阳方位角变化趋势相反,正午时刻末端损失最大,早晨和傍晚时刻末端损失最小;不同季节相同时间段内的末端损失,冬季最大,夏季最小,春季和秋季几乎相等;镜场调节试验结果表明,增大反射镜北端与水平面的夹角可以补偿末端损失,在夏至前后正午,当镜场北端抬高20°时,末端损失减少至集热器长度的1/10左右,瞬时集热效率达到65.9%,与反射镜调节前相比,正午瞬时集热效率提高54.5%,下午时间段内瞬时集热效率提高20%左右。研究结果可为减小严寒地区小型线性菲涅尔聚光集热器末端损失提供理论参考。
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| 关 键 词： | 太阳能 传热 末端损失 严寒地区 线性菲涅尔聚光集热器 反射镜调节 |
| 收稿时间： | 2018/12/4 0:00:00 |
| 修稿时间： | 2019/1/30 0:00:00 |
End-loss and compensation for small linear Fresnel collectors in severe cold area |
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| Yan Suying,Chen Zhuang,Zhao Xiaoyan,Ma Jing,Wu Yuting and Tian Rui.End-loss and compensation for small linear Fresnel collectors in severe cold area[J].Transactions of the Chinese Society of Agricultural Engineering,2019,35(6):206-213. |
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| Authors: | Yan Suying Chen Zhuang Zhao Xiaoyan Ma Jing Wu Yuting and Tian Rui |
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| Institution: | 1. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China; 2. Inner Mongolia Renewable Energy Key Laboratories, Inner Mongolia University of Technology, Hohhot 010051, China;,1. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;,1. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;,1. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;,3. College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China and 1. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot 010051, China; 2. Inner Mongolia Renewable Energy Key Laboratories, Inner Mongolia University of Technology, Hohhot 010051, China; |
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| Abstract: | Abstract: The linear Fresnel solar concentrating collector has been widely used in the field of solar heat source utilization due to its compact structure, easy manufacture and low price. Because there is a certain distance between the primary mirror and the collector, the position of the sunlight after reaching the collector changes with the incident angle of the sun, and a part of the reflected light will run out of the collector end to form the end-loss. For the large linear Fresnel collector systems, the end-loss length accounts for a small proportion of the length of the collector, while for the small linear Fresnel systems, the end-loss length accounts for a large proportion of the length of the collector, it has a great influence on the heat collection performance of the collector, so it is particularly important to reduce the end loss. According to the geographical location, the end-loss length of a north-south linear Fresnel mirror field is difference. Based on this, aiming at the serious end- loss of linear Fresnel collector in severe cold area, taking the small linear Fresnel collector system in Hohhot area(north latitude 40.87°) as the research object, the end-loss of linear Fresnel collector placed along the horizontal north-south axis and its adjustment and compensation method were studied and verified by experiments in this paper. The experiment bench was developed on a building roof. The linear Fresnel experimental system was mainly composed of a primary mirror, a compound parabolic secondary mirror and a glass-metal vacuum heat collecting tube. After the light reflected by the plane mirror, part of the light was directly absorbed by the vacuum heat collecting tube, and the other part was absorbed by the vacuum heat collecting tube after the secondary reflection of CPC(compound parabolic collector). The change of end-loss in different seasons and different collector heights was analyzed and calculated theoretically, a method of adjusting reflectors to compensate end-loss was proposed. The focal spot length of collector at different time before and after end-loss compensation was captured by infrared thermal imager, and the change of instantaneous heat collection efficiency before and after reflectors adjustment was analyzed. The results showed that the end-loss length was mainly caused by the horizontal distance from the mirror field to the collector, the height of the collector, the solar azimuth angle and height angle. The end-loss length could be reduced by raise the height of the collector under the premise of avoiding the occlusion and shadow loss between the mirror elements. Meanwhile, the end loss could be reduced by increasing the angle between the mirror and the north-south horizontal plane according to the seasonal variation, and the angle should be kept within the theoretical range. The length of the end-loss decrease to about 1/10 of the collector length after the northern end of the mirror field was raised to 20°at summer solstice afternoon, and the instantaneous heat collecting efficiency increased to 65.9% at noon, which was 54.5% higher than that of before compensation. The change trend of the end-loss with time was the same as that of the sun altitude angle in the middle of the day, contrary to the change trend of the sun azimuth angle, the end-loss at noon was the largest, and the en-loss at morning and evening was the smallest. In the same period of time, the end-loss was the largest in winter, the smallest in summer, and almost the same in spring and autumn. The study provided a theoretical reference for reducing the loss-end length of small linear Fresnel concentrating collectors in severe cold area. |
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| Keywords: | solar energy heat transfer end-loss severe cold area linear Fresnel concentrating collector reflector adjustment |
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