Using renewable energy, especially solar energy, is an essential requisite for preventing global warming and climate change. Solar-powered steam generation is one of the recent solutions to the problem of environmental pollution and can be a promising way to generate clean energy. In this study, the superficial and volumetric approaches of the zinc oxide nanoparticles (ZnO) in solar vapor generation have been compared experimentally. For the volumetric approach, the nanofluid performance at different mass concentrations (0.001%, 0.002%, and 0.004%) on the solar vapor generation was examined. For the superficial approach, the evaporative performance of delignified mulberry wood coating on ZnO nanoparticles as an absorbent (ZnO-Wood) was investigated. Moreover, the effect of nanoparticle size on optical and evaporative properties was evaluated. Finally, the economic performance of the ZnO nanofluid was compared to the other nanofluids. The results indicated that the evaporative efficiency of the nanofluids containing ZnO(50nm) nanoparticles at 3 suns (3kW/m²) was approximately two times greater than that of water (18%). However, the evaporative efficiency of ZnO-Wood was 3.15 (56%) times greater than that of water.In addition, the results of the nanoparticle size effect showed that increasing the size of nanoparticles from 20 nm to 50 nm in the superficial and volumetric approaches increases the evaporative efficiency by roughly 10% and 3%, respectively. Finally, the cost analysis of nanofluid for solar vapor generation illustrated that ZnO nanoparticles are cost-effective compared to other nanoparticles presented in the literature.

使用可再生能源，特别是太阳能，是防止全球变暖和气候变化的必要条件。太阳能蒸汽发电是解决环境污染问题的最新解决方案之一，并且可能是产生清洁能源的一种有前途的方式。在这项研究中，通过实验比较了氧化锌纳米粒子（ZnO）在太阳蒸气产生中的表面和体积方法。对于体积方法，检查了在不同质量浓度（0.001％，0.002％和0.004％）下对太阳蒸气产生的纳米流体性能。对于表面方法，研究了脱木的桑木涂层在作为吸收剂的ZnO纳米颗粒（ZnO-Wood）上的蒸发性能。此外，评估了纳米粒度对光学和蒸发性能的影响。最后，将ZnO纳米流体的经济性能与其他纳米流体进行了比较。结果表明，含有ZnO（50nm）纳米颗粒的纳米流体在3个太阳（3kW / m）下的蒸发效率²）大约是水（18％）的两倍。然而，ZnO-Wood的蒸发效率是水的蒸发效率的3.15倍（56％）。此外，纳米粒子尺寸效应的结果表明，纳米粒子在表面和体积上的尺寸从20 nm增加到50 nm两种方法分别将蒸发效率分别提高了约10％和3％。最后，用于太阳能蒸汽产生的纳米流体的成本分析表明，与文献中介绍的其他纳米颗粒相比，ZnO纳米颗粒具有成本效益。