摘要
针对太阳辐射间歇性、不稳定性导致槽式太阳能集热系统热性能波动的问题,以采光面积15.3 m2的槽式集热系统为研究对象,采用二元硝酸熔盐(ω(KNO_(3))40%+ω(NaNO_(3))60%)作为相变材料(PCM),构建相变热缓冲层,WRY-320型导热油为传热工质,通过实验验证与数值模拟相结合的方法,探究PCM层添加及不同厚度对系统热力特性的影响。结果表明:数值模型与实验数据的均方根误差(RMSE)为0.032,验证了模拟方法的可靠性;添加PCM层可显著抑制系统温度波动,加热停止后60 min内,无PCM系统导热油平均温度降低7.5℃,而含PCM系统温度升高2.3℃,冷却阶段平均降温速率仅为无PCM系统的3/5,总储热量增加33.2 MJ,储热效率提升18.5%;PCM层厚度在2.6~32.6 mm范围内,导热油提热量与加热结束时平均油温呈“先升后降”趋势,总储热量与储热效率持续上升,其中22.6 mm厚PCM层可兼顾正常用热需求与高储热效率,综合性能最优。研究结果为槽式太阳能集热系统的储热结构优化提供了量化依据。
Aiming to address the fluctuation in thermal performance of parabolic trough solar collector(PTSC)systems induced by the intermittency and instability of solar radiation,this study is conducted on a PTSC system with a solar aperture area of 15.3 m2.Binary nitrate molten salt(ω(KNO_(3))40%+ω(NaNO_(3))60%)is utilized as the phase change material(PCM)thermal buffer layer,and WRY-320 heat transfer oil serves as the heat transfer fluid(HTF).A combined approach of experimental verification and numerical simulation is employed to systematically investigate the effects of adding a PCM layer and varying PCM layer thicknesses on the thermodynamic characteristics of the collector system.The results indicate that,the root mean square error(RMSE)between the numerical model and the experimental data is 0.032,validating the scientific rigor of the simulation method.Incorporating a PCM layer can significantly mitigate the impact of solar radiation fluctuations on the system.Within 60 minutes after heating cessation,the average HTF temperature in the PCM-free system decreased by 7.5 ℃, whereas that in the PCM-equipped system increased by 2.3 ℃. The average cooling rate during the cooling phase was only 60% of that in the PCM-free system. Compared with the PCM-free system, the total heat storage capacity increased by 33.2 MJ, and the heat storage efficiency was enhanced by 18.5%. When the PCM layer thickness ranged from 2.6 mm to 32.6 mm, the HTF heat gain and average oil temperature at the end of heating exhibited a trend of first increasing and then decreasing, while the total heat storage capacity and heat storage efficiency increased continuously. Among all tested thicknesses, the 22.6 mm-thick PCM layer can balance normal heat demand and high heat storage efficiency, achieving the optimal comprehensive performance. Collectively, experimental and numerical results confirm that the binary nitrate molten salt-based PCM layer effectively mitigates PTSC system thermal performance fluctuations caused by solar radiation intermittency. The 22.6 mm-thick PCM layer is identified as the optimal thickness balancing heat demand and storage efficiency, providing a quantitative basis for the optimization of heat storage structures in PTSC systems.
作者
邢雯清
王华
王迪
XING Wenqing;WANG Hua;WANG Di(School of Mechanical and Power Engineering,Henan Polytechnic University,Jiaozuo 454003,Henan,China)
出处
《能源研究与管理》
2025年第4期33-42,共10页
Energy Research and Management
基金
河南省科技攻关项目(232102321088)。
关键词
槽式太阳能集热系统
相变储热
二元硝酸熔盐
热力特性
PCM层厚度
parabolic trough solar collector(PTSC)system
phase change heat storage(PCHS)
binary nitrate molten salt
thermodynamic characteristics
phase change material(PCM)layer thickness
