CIESC Journal ›› 2023, Vol. 74 ›› Issue (S1): 132-140.DOI: 10.11949/0438-1157.20221538

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Performance simulation of paper folding-like evaporator for solar evaporation systems

Zhanyu YE(), He SHAN, Zhenyuan XU()   

  1. Institute of Refrigeration and Cryogenic Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
  • Received:2022-10-30 Revised:2022-12-02 Online:2023-09-27 Published:2023-06-05
  • Contact: Zhenyuan XU

用于太阳能蒸发的折纸式蒸发器性能仿真

叶展羽(), 山訸, 徐震原()   

  1. 上海交通大学制冷与低温工程研究所,上海 200240
  • 通讯作者: 徐震原
  • 作者简介:叶展羽(1997—),女,硕士研究生,yezhanyu@sjtu.edu.cn
  • 基金资助:
    国家自然科学基金项目(51976123)

Abstract:

Solar vapor generation, as a carbon-free and sustainable freshwater production approach, exhibits considerable potential for alleviating the global freshwater crisis. However, the conventional evaporators that adopt the one-dimensional structure have faced a theoretical upper limit evaporation rate of 1.47 kg·m-2·h-1 for solar evaporation due to the solar energy conversion efficiency. Differently, the three-dimensional evaporator can surpass the evaporation limit by exploiting environmental heat and enhancing solar capture, realizing a higher evaporation rate and energy efficiency. Herein, we explore the performance and advantages of the three-dimensional (3D) paper folding-like evaporator in comparison with one-dimensional flat evaporator enabled by the multiphysics simulation method via COMSOL software. Meanwhile, we study the influences of ambient air speed, relative humidity, and solar incident angle on the overall evaporation performance. The results show that the evaporation rate of the paper folding-like 3D evaporator is averagely increased by 1.20 times in comparison with the flat evaporator, reaching 1.53 kg·m-2·h-1, meanwhile the dynamic solar energy capture performance is improved by 32.07%. The ambient with high wind speeds and low relative humidity can increase the overall evaporation rate, finally reaching the calculated evaporation rate of 3.07 kg·m-2·h-1 at the relative humidity of 20% and the airflow rate of 1.0 m·s-1. We anticipate that our designed structure and simulation results could provide design ideas for the subsequent three-dimensional evaporator and its practical applications.

Key words: solar energy, evaporation, numerical simulation, three-dimensional structure

摘要:

太阳能驱动水蒸发技术是一种零碳、可持续从海水与污水中获取清洁水的方法,逐渐成为缓解全球水资源危机的有效途径之一。目前用于太阳能水蒸发过程的蒸发器多采用一维界面蒸发结构,其最大蒸发速率受限于太阳能利用的热力学极限,而三维结构界面蒸发器可借助于光的多次折射和捕捉与环境能量的利用,实现太阳能蒸发速率和能量利用效率的提高。为了探究折纸阵列型三维蒸发器的性能与优势,采用COMSOL有限元仿真方法对高宽比3∶2折纸蒸发器模型进行研究。通过对温度场、速度场以及蒸汽浓度场的传热传质分析,对比讨论了该结构相比平面蒸发结构的优势及其原因,并探究了环境风速、环境相对湿度及太阳入射角等多种因素对蒸发器性能的影响。结果表明,单阵列折纸型三维蒸发器相比于平面蒸发器纯蒸发速率平均提高1.20倍,达到1.53 kg·m-2·h-1,同时可将动态太阳能捕捉性能提升32.07%。环境风速与低相对湿度环境将对蒸发速率产生增益,在低相对湿度20%与环境风速1.0 m·s-1下可达3.07 kg·m-2·h-1的理论蒸发速率。所设计的结构及仿真结果为后续三维蒸发器及其高效蒸发提供了设计思路。

关键词: 太阳能, 蒸发, 数值模拟, 三维结构

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