Analysis and optimization of the flow rate of the PV/T system

doi:10.16085/j.issn.1000-6613.2017-2473

Abstract

Abstract: Numerical and experimental analyses of a water-cooled PV/T hot water system was conducted in this paper. Power generations, heating energy collected by PV/T system, and power consumption of pump were three main characteristics to evaluate the effect of flow changes on the system performance. In addition, the mathematical model was verified and compared with the experimental data. Results indicated that the optimal flow rate value, which maximized the overall efficiency of a water-cooled PV/T system, did exist. Hence, the optimal flow rate value and the solar radiation intensity have a positive linear relationship and the optimal flow rate under typical summer condition of Nanjing is about 0.02 kg/(s·m²). Furthermore, a variable-flow operation mode was proposed to optimize the performance of system, where operating flow is adjusted according to the solar radiation intensity to ensure that water-cooled PV/T system can operate at the highest overall efficiency all day. The results showed that variable-flow mode can receive 19808J more energy than that of constant-flow mode in which flow rate is kept at 0.072m³/(h·m²). Therefore, analysis and optimization of flow rate in PV/T system is of practical significance and the application of variable-flow operation is promising.

Key words: water-cooled PV/T system, simulation, optimum flow rate, vary flow rates operation

摘要： 建立水冷型PV/T热水系统模型并搭建实验台，从发电量、集热量和水泵耗电量各方面考虑，模拟计算流量变化对系统性能的影响，并结合相对应工况下的实验数据进行对比分析。结果表明：存在最佳流量值使得水冷型PV/T系统综合效率最大，最佳流量值大小与太阳辐射值为正系数线性关系，南京夏季典型工况下系统的最佳流量在0.02kg/（s·m²）左右。以此为基础，本文提出了变流量运行方式优化系统性能，即根据太阳辐射强度调整系统运行流量使水冷型PV/T全天运行时刻处于最高综合效率，结果表明：以实际工程0.072m³/（h·m²）定流量运行为参照实验，全天运行变流量系统实际能量比其多收益19808J。因此，对PV/T系统流量的分析和优化是极有意义的，变流量运行有实际应用前景。

关键词: 水冷型PV/T系统, 模拟, 最佳流量值, 变流量运行

CLC Number:

TK519

WANG Bofei, LI Shuhong. Analysis and optimization of the flow rate of the PV/T system[J]. Chemical Industry and Engineering Progress, 2018, 37(10): 3826-3831.

王博飞, 李舒宏. 光伏光热一体化系统流量的分析与优化[J]. 化工进展, 2018, 37(10): 3826-3831.

References

[1] 王宝群, 姚强, 宋蔷.光伏/光热(PVT)系统概况与评价[J]. 太阳能学报, 2009, 30(2):193-200. WANG Baoqun, YAO Qiang, SONG Qiang. Photovoltaicthermal(PVT) system and their evaluation[J]. Acta Energiae Solaris Sinica, 2009, 30(2):193-200.
[2] 张凇源, 关欣, 王殿华.太阳能光伏光热利用的研究进展[J].化工进展, 2012, 31(1):323-327. ZHANG Songyuan, GUAN Xin, WANG Dianhua. Research development of solar thermal utilization and photovoltaic power generation[J]. Chemical Industry and Engineering Progress, 2012, 31(1):323-327.
[3] JI J, CHOW T T, HE W. Dynamic performance of hybrid photovoltaic/thermal collector wall in Hong Kong[J]. Building & Environment, 2003, 38(11):1327-1334.
[4] 徐国英, 张小松, 赵善国. 平板型太阳能光伏/光热一体化热泵热水系统特性[J]. 化工学报, 2012, 63(s2):136-141. XU Guoying, ZHANG Xiaosong, ZHAO Shanguo. Performance of flat-plate PV/T integrated heat pump water heating system[J]. CIESC Journal, 2012, 63(s2):136-141.
[5] 余长富, 阮应君, 吴家正. 太阳能光伏光热一体化系统性能影响因素[J].热力发电, 2015, 44(11):20-25. YU Changfu, RUAN Yingjun, WU Jiazheng. Experimental study on performance of hybrid PV/T solar system and its influencing factors[J]. Thermal Power Generation, 2015, 44(11):20-25.
[6] 荆树春, 朱群志, 王文婷. 采用铝方管结构的光伏光热一体化系统的研究[J].太阳能学报, 2014, 35(9):1639-1645. JING Shuchun, ZHU Qunzhi, WANG Wenting. Investigation on photovoltaic/thermal solar system utilizing aluminum square tube[J]. Acta Energiae Solaris Sinica, 2014, 35(9):1639-1645.
[7] 肖文平, 陈思铭, 张立荣.基于对流传热分析的PV/T优化设计与实验[J]. 建筑电气, 2017(3):63-68. XIAO Wenping, CHEN Siming, ZHANG Lirong. Optimal design and experiment of PV/T based on convective heat transfer analysis[J]. Building Electricity, 2017(3):63-68.
[8] KALOGIROU S A. Use of TRNSYS for modelling and simulation of a hybrid PV-thermal solar system for Cyprus[J]. Renewable Energy, 2014, 23(2):247-260.
[9] FUDHOLI A, SOPIAN K, YAZDI M H, et al. Performance analysis of photovoltaic thermal (PVT) water collectors[J].Energy Conversion & Management, 2014, 78(1):641-651.
[10] 陈剑波, 于海照, 岳畏畏. 太阳能光伏光热一体化组件的应用特性实验研究[J]. 太阳能学报, 2015, 36(1):154-161. CHEN Jianbo, YU Haizhao, YUE Weiwei. Experimental research on application characteristic of solar photovoltaic and photothermal integration components[J]. Acta Energiae Solaris Sinica, 2015, 36(1):154-161.
[11] YAZDANIFARD F, EBRAHIMNIA-BAJESTAN E, AMERI M. Investigating the performance of a water-based photovoltaic/thermal (PV/T) collector in laminar and turbulent flow regime[J]. Renewable Energy, 2016, 99:295-306.
[12] HERRANDO M, MARKIDES C N. Hybrid PV and solar-thermal systems for domestic heat and power provision in the UK:techno-economic considerations[J]. Applied Energy, 2016, 161:512-532.
[13] 梁子伟, 简林桦, 闫金州. PV/T集热器优化设计及实验[J].化工进展, 2016, 35(5):1326-1331. LIANG Ziwei, JIAN Linhua, YAN Jinzhou. Optimization design and experimental study on collector of photovoltaic/thermal[J]. Chemical Industry and Engineering Progress, 2016, 35(5):1326-1331.
[14] 于国清, 汤金华, 邹志军. 太阳能热水系统蓄热水箱温度分层作用研究[J].建筑科学, 2007, 23(4):70-73. YU Guoqing, TANG Jinhua, ZOU Zhijun. Research on the effect of temperature stratification in water tank in solar domestic hot water system[J]. Building Science, 2007, 23(4):70-73.
[15] 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, 2012. ZHANG Hefei. Principle and computer simulation of solar heat utilization[M]. Xi'an:Northwestern Polytechnical University Press, 2012.
[16] DUFFIE J A, BECKMAN W A, MCGOWAN J. Solar engineering of thermal processes[J]. Journal of Solar Energy Engineering, 1994, 116(1):549.
[17] 任仁良, 魏恩震. GB12497-1995与GB/T 12497-2006三相异步电动机经济运行判别方法比较[J].标准科学, 2011(6):66-68. REN Renliang, WEI Enzhen. Comparison of the judgment of three-phase induction motor's economic operation between GB/T12497-1995 and GB/T12497-2006[J]. Standard Science, 2011(6):66-68.
[18] 郑瑞澄.民用建筑太阳能热水系统工程技术手册[M].北京:化学工业出版社, 2011. ZHENG Ruicheng. Engineering technical manual of solar hot water system for civil buildings[M]. Beijing:Chemical Industry Press, 2011.