ABSTRACT

Regarding water scarcity in recent decades, solar stills due to their environmental compatibility and economic viability received more attention. Through the current study, the performance of weir-type cascade solar still equipped with different phase change materials (PCMs) especially Nano-PCMs is evaluated. The utilized phase change materials are Stearic acid, Paraffin, and some kinds of PCMs that are enhanced with Nanoparticles of different materials. The Nano-enhanced PCMs are consisted of nePCM I (Paraffin+$\mathrm{T}\mathrm{i}{\mathrm{O}}_2)$, nePCM II (Paraffin+CuO), and nePCM III (Paraffin+GO). The novelty of the present work can be attributed to the exegetic and energetic analysis of cascade solar still equipped with Nano-enhanced PCM as well as investigating the effects of climatic parameters on the performance of the system. Regarding the results, in brackish water mass flow rate of 0.07 and 0.4 kg/(m².min), the system equipped with nePCM II has the energy and exergy efficiencies of 63.55, 6.4181, 56.79%, and 5.387, respectively. Moreover, for the mass flow rate of 0.2 and 0.3 kg/(m².min) the nePCM I show higher energy efficiency compared to others. The maximum distilled water production belongs to nePCM II in the mass flow rate of 0.07 kg/(m².min), which is 9.28 kg/(m².hr). Besides, the results showed that at the ambient temperatures lower than 29°C, the system equipped with Stearic acid has better performance from an energetic and exergetic point of view. Finally, the best Azimuth angles for the system in the presence of different PCMs presented.

摘要

关于近几十年来的水短缺，由于其环境相容性和经济可行性，太阳能蒸馏器受到更多关注。通过当前的研究，评估仍然配备有不同相变材料（PCM），尤其是纳米PCM的堰式级联太阳能的性能。所使用的相变材料是硬脂酸，石蜡和某些用不同材料的纳米颗粒增强的PCM。纳米增强PCM由nePCM I（石蜡+$\mathrm{Ť}\mathrm{一世}{\mathrm{Ø}}_2）$，nePCM II（石蜡+ CuO）和nePCM III（石蜡+ GO）。当前工作的新颖性可以归因于仍然配备纳米增强PCM的级联太阳能的能量学和能量分析，以及研究气候参数对系统性能的影响。关于结果，在微咸水质量流量为0.07和0.4 kg /（m ² .min）的情况下，配备nePCM II的系统的能量和火用效率分别为63.55、6.4181、56.79％和5.387。此外，与0.2和0.3 kg /（m ² .min）的质量流量相比，nePCM I显示出更高的能量效率。最高蒸馏水产量属于nePCM II，质量流量为0.07 kg /（m ² .min），即9.28 kg /（m ².hr）。此外，结果表明，在低于29°C的环境温度下，从高能和高能的角度来看，装有硬脂酸的系统具有更好的性能。最后，在存在不同PCM的情况下，给出了系统的最佳方位角。