太阳能菲涅尔线聚焦集热器与中温蓄热装置研究
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摘要
本文针对太阳能中温集热技术和应用需求,围绕菲涅尔线聚焦集热器以及蓄热装置进行研究。论文设计构建了一种线聚焦菲涅尔太阳能集热器,分析了菲涅尔线聚焦集热器热损失系数以及集热效率。利用Tracepro计算表明,所研究的菲涅尔线聚焦集热器最大光学效率为75.5%;针对此类集热器建立了菲涅尔柱面镜的光线踪迹法模型,得到柱面镜宽度、吸收器高度、光斑宽度、光斑能量密度分布之间的优化关系;搭建了14.4m2菲涅尔线聚焦集热器测试平台,测试实际光学效率为55.7%,150℃时的集热效率为36.6%,单位长度吸收器热损失系数为110.0W/m。
论文还针对集热温度在80～250℃之间的蓄热需求,研究了包括石英砂与钢砂混合材料显热蓄热、KNO_3/LiNO_3共晶盐、季戊四醇(PE)/三羟基乙烷(PG)固固相变材料等,其中利用成型膨胀石墨制取PE/PG复合材料使其导热性能增加6倍以上。考虑加工工艺等问题,采用石英砂和钢砂的混合材料作为蓄能材料,结合蛇形盘管换热器设计加工了2kWh的蓄能装置,并连接菲涅尔与槽式集热器进行测试。以火用效率、热效率以及集热效率为指标,建立相应模型得到以下结论:集热蓄能装置充放热的综合热效率为81.3%,火用效率为52.3%,蓄热体积与集热器面积之比在80L/m2时为最优值。上述结论对于工业中太阳能中高温应用具有指导价值。
In this paper, for the solar medium temperature thermal technology, Linear Fresnel lens solar collector and thermal storage were studied. A linear Fresnel collector was designed and established. Then, the optical, heat loss and thermal efficiency of Fresnel lens collector were defined, and the maximum of optical efficiency was 75.5% by Trace-pro optical software. Meanwhile, the light trace of Fresnel lens mirror was modeled, the optimized relation of mirror’s width, receiver’s height, beam’s width and energy density were studied. Then, The 14.4m2 prototype of Fresnel lens solar collector was established, the test result showed that the practical optical efficiency is 55.7%, the efficiency of collector is 36.6% at 150℃and the heat loss of the receiver is 110.0w/m。
Furthermore, in order to find a suitable the thermal storage for medium temperature solar collector, mixture material of quartz sand and steel shot , KNO_3/LiNO_3 molten salt and solid phase change material were studied. Then, a composite material comprised of solid phase change material and expanded graphite was developed and its heat conductivity was increased 6 times. Finally, a 2kWh sensible thermal storage which is combined with serpentine heat exchangers was established. According to the thermal efficiency, exergy efficiency and collector efficiency, the results showed that the thermal efficiency of heat storage is about 81.3%, exergy efficiency is about 51.3%, The optimized thermal storage volume-to-parabolic trough collector area ration is 80L/m2 by coupled heat transfer model, and the desired heat transfer area could reduce a lot when the heat conductivity increases to 2.0 W/(m·℃). The solar indutrail thermal application could benefit from the above conclusion.
论文还针对集热温度在80～250℃之间的蓄热需求,研究了包括石英砂与钢砂混合材料显热蓄热、KNO_3/LiNO_3共晶盐、季戊四醇(PE)/三羟基乙烷(PG)固固相变材料等,其中利用成型膨胀石墨制取PE/PG复合材料使其导热性能增加6倍以上。考虑加工工艺等问题,采用石英砂和钢砂的混合材料作为蓄能材料,结合蛇形盘管换热器设计加工了2kWh的蓄能装置,并连接菲涅尔与槽式集热器进行测试。以火用效率、热效率以及集热效率为指标,建立相应模型得到以下结论:集热蓄能装置充放热的综合热效率为81.3%,火用效率为52.3%,蓄热体积与集热器面积之比在80L/m2时为最优值。上述结论对于工业中太阳能中高温应用具有指导价值。
In this paper, for the solar medium temperature thermal technology, Linear Fresnel lens solar collector and thermal storage were studied. A linear Fresnel collector was designed and established. Then, the optical, heat loss and thermal efficiency of Fresnel lens collector were defined, and the maximum of optical efficiency was 75.5% by Trace-pro optical software. Meanwhile, the light trace of Fresnel lens mirror was modeled, the optimized relation of mirror’s width, receiver’s height, beam’s width and energy density were studied. Then, The 14.4m2 prototype of Fresnel lens solar collector was established, the test result showed that the practical optical efficiency is 55.7%, the efficiency of collector is 36.6% at 150℃and the heat loss of the receiver is 110.0w/m。
Furthermore, in order to find a suitable the thermal storage for medium temperature solar collector, mixture material of quartz sand and steel shot , KNO_3/LiNO_3 molten salt and solid phase change material were studied. Then, a composite material comprised of solid phase change material and expanded graphite was developed and its heat conductivity was increased 6 times. Finally, a 2kWh sensible thermal storage which is combined with serpentine heat exchangers was established. According to the thermal efficiency, exergy efficiency and collector efficiency, the results showed that the thermal efficiency of heat storage is about 81.3%, exergy efficiency is about 51.3%, The optimized thermal storage volume-to-parabolic trough collector area ration is 80L/m2 by coupled heat transfer model, and the desired heat transfer area could reduce a lot when the heat conductivity increases to 2.0 W/(m·℃). The solar indutrail thermal application could benefit from the above conclusion.
引文
[1] IEA国际能源署《2010能源展望报告》何梓年.太阳能热利用[M].合肥:中国科学技术大学出版社;2009:7,28
[2]国际铜业协会.中国工业领域太阳能热利用现状及前景调研报告.上海:国际铜业协会,2009.
[3]王如竹,代彦军.太阳能制冷[M].化学工业出版社,2007.1
[4]徐建中.关于我国能源发展战略的思考,中国科学院院刊, 2005, 20(5):359-361.
[5]罗会龙,王如竹,代彦军,吴静怡,沈家敏,张彬彬.太阳能制冷低温储粮应用效果初探[J],中国农学通报. 2005,9(21):400–402,442.
[6] Dr. Schubert.德国太阳能空调系统最新实例.太阳能学报.1998(3):18.
[7] Klogirou S. Use of parabolic trough solar energy collectors for sea-water desalination. Applied Energy,1998, 60(2):65–88.
[8]殷志强,严习元,陈腾华,赵铁松,安瑞红,唐轩.太阳吸收涂层与真空集热管的热性能[J].,太阳能学报. 1996.1.
[9] Window B. Heat extraction from single ended glass absorber tubes[J]. Solar Energy,1983,31(2): 159-166.
[10] M.A. Minn, K.C. Ng, W.H. Khong, T. Melvin. A distributed model for a tedlar-foil flat plate solar collector[J]. Renewable Energy. 2002,27:507–523.
[11] Rabl A. Optical and thermal properties of compound parabolic collectors[J]. Solar Energy 1976,18:497–511.
[12] N. Fraidenraich. Simulation model of a CPC collector with temperature-dependent heat loss coefficient[J]. Solar Energy 1999,65(2),18:99–110.
[13] D.R.Mills. Project Proposal for a Compact Linear Fresnel Reflector Solar thermal Plant in the Hunter Valley[EB].
[14]张寅平.相变贮能[M].合肥:中国科学技术大学出版社;1996:21,28
[15] Doerte Laing. Sensible heat storage for medium and high temperature[J]. Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement,2007;2732.
[16]张焘,曾亮,张东.膨胀石墨、石墨烯改善无机盐相变材料热物性能[J];无机盐工业; 2010, 42(5): 3-4
[17]夏莉,张鹏,王如竹.具有自由表面的固-液相变的数值模拟与实验研究[J];热能工程;2010, 25(5):2-3
[18] S.S. Mathur, T.C. Kndpal, B.S. Negi. Optical design and concentration characteristics of linear Fresnel reflector solar concentrators—I. Mirror elements of varying width [J]. Energy convers Mgmt, 1991, 31(3); 205-219;
[19] S.S. Mathur, T.C. Kndpal, B.S. Negi. Optical design and concentration characteristics oflinear Fresnel reflector solar concentrators—II. Mirror elements of equal width[J]; Energy conversion and management, 1991, 31(3); 221-223;
[20] N. Velázquez. Numerical simulation of a Linear Fresnel Reflector Concentrator used as direct generator in a Solar-GAX cycle[J]. Energy Conversion and managemen; 2010, 433-440;
[21] Gabriel Morin. Road map towards the demonstration of a linear Fresnel collector using a single tube reciver[EB].
[22] Andreas H?berle. The solarmundo line focusing Fresnel collector optical and thermal performance and cost calculations[EB].
[23] Jorge Faca?o and Armando C. Oliveira. Simulation of a linear Fresnel solar collector[J]. International Journal of Low-Carbon Technologies Advance Access,2010.
[24]熊亚选张丽娜吴玉庭. LiNo3热物性参数及热稳定性试验研究[J].工程热物理学报, 2008;
[25]翟辉.采用腔体吸收器的线聚焦太阳能集热器的理论及实验研究[D].上海:上海交通大学,2009.
[26]张丽英.聚焦型集热器中腔体吸收器的热性能研究[J].太阳能学报,2008, 29(7); 2
[27] Angela M. Patnode. Simulation and Performance Evaluation of Parabolic Trough Solar Power Plants[C].2006.
[28]张鹤飞.太阳能热利用原理与计算机模拟[M].西安:西北工业大学出版社; 204:97-127
[29]黄犊子.采用HOTDISK测量材料导热系数的实验研究. ?刊号,年份,页码!
[30]白涛.太阳能线聚焦腔体吸收器热迁移因子分析及集热器应用研究[D].上海:上海交通大学机械与动力工程学院,2010.
[31]谢刚.熔融盐理论与应用[M] .北京:冶金工业出版社, 1998: 1- 9.
[32]张太平.固一固相变贮热的研究[J].华中师范大学学报. 1994, 28(1); 2,3
[33]樊耀峰.有机固一固相变材料的研究进展[J].材料导报. 2003, 17(7); 2,3,4
[34]康艳珍.贮热材料PG PE二元体系相图的构筑[J].河北师范大学学报. 2004, 28(2); 1
[35] Ahmet Sar?. Thermal conductivity and latent heat thermal energy storage characteristics of paraffin/expanded graphite composite as phase change material[J]. Applied thermal engineering. 2007;1271-1277.
[36] R. Pokhrel. Analysis and Design of a Paraffin/Graphite Composite PCM Integrated in a Thermal Storage Unit[J]. Solar energy engineering. 2010, 132.
[37] Andrew Mills. Thermal conductivity enhancement of phase changematerials using a graphite matrix[J]. Applied Thermal Engineering, 2006; 1652–1661
[38] Xavier Py, Regis Olives, Sylvain Mauran. Paraffin/Porous-graphite-matrix composite as a high and constant power thermal storage material[J]. Heat and mass transfer. 2001,44;2727-2723
[39] S. Pincemina, R. Olivesa, X. Pya, M. Christb. Highly conductive composites made of phase change materials and graphite for thermal storage[J]. Solar energy materials and solar cells. 2008, 92(6): 604,608.
[40]杨世铭,陶文铨.传热学.高等教育出报社,北京,1998.
[2]国际铜业协会.中国工业领域太阳能热利用现状及前景调研报告.上海:国际铜业协会,2009.
[3]王如竹,代彦军.太阳能制冷[M].化学工业出版社,2007.1
[4]徐建中.关于我国能源发展战略的思考,中国科学院院刊, 2005, 20(5):359-361.
[5]罗会龙,王如竹,代彦军,吴静怡,沈家敏,张彬彬.太阳能制冷低温储粮应用效果初探[J],中国农学通报. 2005,9(21):400–402,442.
[6] Dr. Schubert.德国太阳能空调系统最新实例.太阳能学报.1998(3):18.
[7] Klogirou S. Use of parabolic trough solar energy collectors for sea-water desalination. Applied Energy,1998, 60(2):65–88.
[8]殷志强,严习元,陈腾华,赵铁松,安瑞红,唐轩.太阳吸收涂层与真空集热管的热性能[J].,太阳能学报. 1996.1.
[9] Window B. Heat extraction from single ended glass absorber tubes[J]. Solar Energy,1983,31(2): 159-166.
[10] M.A. Minn, K.C. Ng, W.H. Khong, T. Melvin. A distributed model for a tedlar-foil flat plate solar collector[J]. Renewable Energy. 2002,27:507–523.
[11] Rabl A. Optical and thermal properties of compound parabolic collectors[J]. Solar Energy 1976,18:497–511.
[12] N. Fraidenraich. Simulation model of a CPC collector with temperature-dependent heat loss coefficient[J]. Solar Energy 1999,65(2),18:99–110.
[13] D.R.Mills. Project Proposal for a Compact Linear Fresnel Reflector Solar thermal Plant in the Hunter Valley[EB].
[14]张寅平.相变贮能[M].合肥:中国科学技术大学出版社;1996:21,28
[15] Doerte Laing. Sensible heat storage for medium and high temperature[J]. Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement,2007;2732.
[16]张焘,曾亮,张东.膨胀石墨、石墨烯改善无机盐相变材料热物性能[J];无机盐工业; 2010, 42(5): 3-4
[17]夏莉,张鹏,王如竹.具有自由表面的固-液相变的数值模拟与实验研究[J];热能工程;2010, 25(5):2-3
[18] S.S. Mathur, T.C. Kndpal, B.S. Negi. Optical design and concentration characteristics of linear Fresnel reflector solar concentrators—I. Mirror elements of varying width [J]. Energy convers Mgmt, 1991, 31(3); 205-219;
[19] S.S. Mathur, T.C. Kndpal, B.S. Negi. Optical design and concentration characteristics oflinear Fresnel reflector solar concentrators—II. Mirror elements of equal width[J]; Energy conversion and management, 1991, 31(3); 221-223;
[20] N. Velázquez. Numerical simulation of a Linear Fresnel Reflector Concentrator used as direct generator in a Solar-GAX cycle[J]. Energy Conversion and managemen; 2010, 433-440;
[21] Gabriel Morin. Road map towards the demonstration of a linear Fresnel collector using a single tube reciver[EB].
[22] Andreas H?berle. The solarmundo line focusing Fresnel collector optical and thermal performance and cost calculations[EB].
[23] Jorge Faca?o and Armando C. Oliveira. Simulation of a linear Fresnel solar collector[J]. International Journal of Low-Carbon Technologies Advance Access,2010.
[24]熊亚选张丽娜吴玉庭. LiNo3热物性参数及热稳定性试验研究[J].工程热物理学报, 2008;
[25]翟辉.采用腔体吸收器的线聚焦太阳能集热器的理论及实验研究[D].上海:上海交通大学,2009.
[26]张丽英.聚焦型集热器中腔体吸收器的热性能研究[J].太阳能学报,2008, 29(7); 2
[27] Angela M. Patnode. Simulation and Performance Evaluation of Parabolic Trough Solar Power Plants[C].2006.
[28]张鹤飞.太阳能热利用原理与计算机模拟[M].西安:西北工业大学出版社; 204:97-127
[29]黄犊子.采用HOTDISK测量材料导热系数的实验研究. ?刊号,年份,页码!
[30]白涛.太阳能线聚焦腔体吸收器热迁移因子分析及集热器应用研究[D].上海:上海交通大学机械与动力工程学院,2010.
[31]谢刚.熔融盐理论与应用[M] .北京:冶金工业出版社, 1998: 1- 9.
[32]张太平.固一固相变贮热的研究[J].华中师范大学学报. 1994, 28(1); 2,3
[33]樊耀峰.有机固一固相变材料的研究进展[J].材料导报. 2003, 17(7); 2,3,4
[34]康艳珍.贮热材料PG PE二元体系相图的构筑[J].河北师范大学学报. 2004, 28(2); 1
[35] Ahmet Sar?. Thermal conductivity and latent heat thermal energy storage characteristics of paraffin/expanded graphite composite as phase change material[J]. Applied thermal engineering. 2007;1271-1277.
[36] R. Pokhrel. Analysis and Design of a Paraffin/Graphite Composite PCM Integrated in a Thermal Storage Unit[J]. Solar energy engineering. 2010, 132.
[37] Andrew Mills. Thermal conductivity enhancement of phase changematerials using a graphite matrix[J]. Applied Thermal Engineering, 2006; 1652–1661
[38] Xavier Py, Regis Olives, Sylvain Mauran. Paraffin/Porous-graphite-matrix composite as a high and constant power thermal storage material[J]. Heat and mass transfer. 2001,44;2727-2723
[39] S. Pincemina, R. Olivesa, X. Pya, M. Christb. Highly conductive composites made of phase change materials and graphite for thermal storage[J]. Solar energy materials and solar cells. 2008, 92(6): 604,608.
[40]杨世铭,陶文铨.传热学.高等教育出报社,北京,1998.