镜面积尘对线性菲涅尔镜场反射比及系统集热性能的影响
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摘要
针对线性菲涅尔镜场镜面积尘所导致的聚光损失问题,建立镜场积尘数学模型,通过理论分析和试验测试,分析平面镜积尘遮挡机理及积尘前后相对反射比变化规律,实验测试积尘对不同波长太阳辐射的反射规律,以及积尘时间对系统反射比及热性能影响进行分析。结果表明:随着太阳入射角的增大,相对反射比呈递减趋势;随着积尘密度的增加,相对反射比降低;积尘密度为1 mg/cm2时,相对反射比由0.63降至0.24;在无降雨自然积尘10 d后,镜元相对反射比降低,系统瞬时集热效率降低29.37%;降雨使镜元积尘密度减小,但同时会使积尘形态发生变化,相对反射比降低,瞬时集热效率减小。
A mathematical model of the dust accumulation on the mirror field was established in order to study the dust accumulation mechanism and the spot light loss of the linear Fresnel plane mirror with dust accumulation. The change of the thermal properties and the relative reflectance of mirror field were studied in the linear Fresnel system with dust accumulation. Meanwhile,the change of solar radiation at different wavelengths was measured with dust accumulation.The results showed that the relative reflectance was decreased with the increasing of solar incident angle when the dust density was constant. While the relative reflectance displayed a decreasing tendency when the dust density was increased and this phenomenon was obvious when the solar incident angle became bigger. Specifically,the relative reflectance was reduced from 0.63 to 0.24 when the dust density was 1 mg/cm2. The relative reflectance was decreased after 10 days of natural dust deposition without rainfall,and the instantaneous heat efficiency of the system was decreased by 29.37%compared with clean mirror filed. The dust accumulation form was changed due to rainfall when the dust accumulation density decreased,while the instantaneous heat efficiency was decreased with the relative reflectance decreasing.
A mathematical model of the dust accumulation on the mirror field was established in order to study the dust accumulation mechanism and the spot light loss of the linear Fresnel plane mirror with dust accumulation. The change of the thermal properties and the relative reflectance of mirror field were studied in the linear Fresnel system with dust accumulation. Meanwhile,the change of solar radiation at different wavelengths was measured with dust accumulation.The results showed that the relative reflectance was decreased with the increasing of solar incident angle when the dust density was constant. While the relative reflectance displayed a decreasing tendency when the dust density was increased and this phenomenon was obvious when the solar incident angle became bigger. Specifically,the relative reflectance was reduced from 0.63 to 0.24 when the dust density was 1 mg/cm2. The relative reflectance was decreased after 10 days of natural dust deposition without rainfall,and the instantaneous heat efficiency of the system was decreased by 29.37%compared with clean mirror filed. The dust accumulation form was changed due to rainfall when the dust accumulation density decreased,while the instantaneous heat efficiency was decreased with the relative reflectance decreasing.
引文
[1]Katzan C M,Edwards J L.Lunar dust transport and potential interactions with power system components[R].NASA CR-4404,1991.
[2]Al-Hasan A Y.A new correlation for direct beam solar radiation received by photovoltaic panel with sand dust accumulated on its surface[J].Solar Energy,1998,63(5):323-333.
[3]李剑,张文基,孙清,等.灰尘对全玻璃真空太阳集热管热性能的影响[J].农业工程学报,2008,24(3):228-231[3]Li Jian,Zhang Wenji,Sun Qing,et al.Influence of dust on the thermal performance of all-glass evacuated solar collector tube[J].Transactions of the CSAE,2008,24(3):228-231.
[4]Hegazy A A.Effect of dust accumulation on solar transmittance through glass covers of plate-type collectors[J].Renewable Energy,2001,22(4):525-540.
[5]李念平,马俊,刘刚,等.平板型太阳集热器表面积尘对其热性能影响的分析[J].太阳能学报,2013,34(7):1197-1201.[5]Li Nianping,Ma Jun,Liu Gang,et al.Analysis of the effect of dust accumulation on thermal properties of flat plate solar collectors[J].Acta Energiae Solaris Sinica,2013,34(7):1197-1201.
[6]刘刚.平板型太阳能集热器表面积灰对系统热性能影响的分析[A].中国建筑学会暖通空调分会、中国制冷学会空调热泵专业委员会.全国暖通空调制冷2008年学术年会论文集[C],中国建筑学会暖通空调分会、中国制冷学会空调热泵专业委员会:中国制冷学会,2008.[6]Liu Gang.Analysis of the Influence of Surface Area Ash of Flat Solar Collector on Thermal Performance of the System[A].HVAC Branch of China Architecture Society,Air Conditioning Heat Pump Committee of China Refrigeration Society.Proceedings of National Annual Conference of HVAC Refrigeration in 2008[C],China Architecture Society HVAC Branch,China Refrigeration Society Air Conditioning Heat Pump Professional Committee:China Refrigeration Society,2008.
[7]刁荣丹,李金平,马思聪,等.紧凑式全玻璃真空管热水系统热性能影响因素研究[J].太阳能学报,2016,37(1):110-115.[7]Diao Rongdan,Li Jinping,Ma Sicong,et al.Thermal performance influential factors of compact all-glass vacuum tube solar water heating systerm[J].Acta Energiae Solaris Sinica,2016,37(1):110-115.
[8]闫素英,常征,王峰,等.积尘对槽式太阳能聚光器焦面能流密度分布的影响及聚光优化[J].光学学报,2017,37(7):231-238.[8]Yan Suying,Chang Zheng,Wang Feng,et al.Effect of dust accumulation on focal energy flux density distribution of trough solar concentrator and concentration optimization[J].Acta Optica Sinica,2017,37(7):231-238.
[9]El-Nashar Ali M.The effect of dust accumulation on the performance of evacuated tube collectors[J].Solar Energy,1994,53(1):105-115.
[10]Hamdy K.Effect of dust on the transparent cover of solar collectors[J].Energy Conversion and Management,2006,47(18):3192-3203.
[11]杨艳,王杰,田明中,等.中国沙尘暴分布规律及研究方法分析[J].中国沙漠,2012,32(2):465-472.[11]Yang Yan,Wang Jie,Tian Mingzhong,et al.Distribution characteristics and research method of sandstorms in China[J].Journal of Desert Research,2012,32(2):465-472.
[12]臧建彬,王亚伟,王晓东.灰尘沉积影响光伏发电的理论和试验研究[J].太阳能学报,2014,35(4):624-629.[12]Zang Jianbin,Wang Yawei,Wang Xiaodong.Computation model and experiment of dust deposition affecting transmittance of photovoltaic module[J].Acta Energiae Solaris Sinica,2014,35(4):624-629.
[13]闫素英,李彦洁,田瑞,等.菲涅尔聚光PV/T系统热电输出特性分析[J].太阳能学报,2018,39(6):1552-1558.[13]Yan Suying,Li Yanjie,Tian Rui,et al.Analysis of thermoelectric output characteristics Fresnel concentrating PV/T system[J].Acta Energiae Solaris Sinica,2018,39(6):1552-1558.
[2]Al-Hasan A Y.A new correlation for direct beam solar radiation received by photovoltaic panel with sand dust accumulated on its surface[J].Solar Energy,1998,63(5):323-333.
[3]李剑,张文基,孙清,等.灰尘对全玻璃真空太阳集热管热性能的影响[J].农业工程学报,2008,24(3):228-231[3]Li Jian,Zhang Wenji,Sun Qing,et al.Influence of dust on the thermal performance of all-glass evacuated solar collector tube[J].Transactions of the CSAE,2008,24(3):228-231.
[4]Hegazy A A.Effect of dust accumulation on solar transmittance through glass covers of plate-type collectors[J].Renewable Energy,2001,22(4):525-540.
[5]李念平,马俊,刘刚,等.平板型太阳集热器表面积尘对其热性能影响的分析[J].太阳能学报,2013,34(7):1197-1201.[5]Li Nianping,Ma Jun,Liu Gang,et al.Analysis of the effect of dust accumulation on thermal properties of flat plate solar collectors[J].Acta Energiae Solaris Sinica,2013,34(7):1197-1201.
[6]刘刚.平板型太阳能集热器表面积灰对系统热性能影响的分析[A].中国建筑学会暖通空调分会、中国制冷学会空调热泵专业委员会.全国暖通空调制冷2008年学术年会论文集[C],中国建筑学会暖通空调分会、中国制冷学会空调热泵专业委员会:中国制冷学会,2008.[6]Liu Gang.Analysis of the Influence of Surface Area Ash of Flat Solar Collector on Thermal Performance of the System[A].HVAC Branch of China Architecture Society,Air Conditioning Heat Pump Committee of China Refrigeration Society.Proceedings of National Annual Conference of HVAC Refrigeration in 2008[C],China Architecture Society HVAC Branch,China Refrigeration Society Air Conditioning Heat Pump Professional Committee:China Refrigeration Society,2008.
[7]刁荣丹,李金平,马思聪,等.紧凑式全玻璃真空管热水系统热性能影响因素研究[J].太阳能学报,2016,37(1):110-115.[7]Diao Rongdan,Li Jinping,Ma Sicong,et al.Thermal performance influential factors of compact all-glass vacuum tube solar water heating systerm[J].Acta Energiae Solaris Sinica,2016,37(1):110-115.
[8]闫素英,常征,王峰,等.积尘对槽式太阳能聚光器焦面能流密度分布的影响及聚光优化[J].光学学报,2017,37(7):231-238.[8]Yan Suying,Chang Zheng,Wang Feng,et al.Effect of dust accumulation on focal energy flux density distribution of trough solar concentrator and concentration optimization[J].Acta Optica Sinica,2017,37(7):231-238.
[9]El-Nashar Ali M.The effect of dust accumulation on the performance of evacuated tube collectors[J].Solar Energy,1994,53(1):105-115.
[10]Hamdy K.Effect of dust on the transparent cover of solar collectors[J].Energy Conversion and Management,2006,47(18):3192-3203.
[11]杨艳,王杰,田明中,等.中国沙尘暴分布规律及研究方法分析[J].中国沙漠,2012,32(2):465-472.[11]Yang Yan,Wang Jie,Tian Mingzhong,et al.Distribution characteristics and research method of sandstorms in China[J].Journal of Desert Research,2012,32(2):465-472.
[12]臧建彬,王亚伟,王晓东.灰尘沉积影响光伏发电的理论和试验研究[J].太阳能学报,2014,35(4):624-629.[12]Zang Jianbin,Wang Yawei,Wang Xiaodong.Computation model and experiment of dust deposition affecting transmittance of photovoltaic module[J].Acta Energiae Solaris Sinica,2014,35(4):624-629.
[13]闫素英,李彦洁,田瑞,等.菲涅尔聚光PV/T系统热电输出特性分析[J].太阳能学报,2018,39(6):1552-1558.[13]Yan Suying,Li Yanjie,Tian Rui,et al.Analysis of thermoelectric output characteristics Fresnel concentrating PV/T system[J].Acta Energiae Solaris Sinica,2018,39(6):1552-1558.
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