This experimental study aims to reveal the negative effect of the external condenser (EC) on the conventional solar still (CSS) performance. A new EC design was proposed and integrated into a single-slope, basin type CSS. The EC's negative aspect is demonstrated through a comparative study between the CSS and the modified solar still (MSS) in the same outdoor weather conditions. The experimental results show that adding an EC to the CSS is not always positive and the still performance is closely related to the weather conditions. The EC positive effect appears in moderate weather conditions, where its contribution to improving MSS productivity reaches 29%. While in very cold or hot weather days, the EC affects adversely the still productivity, which decreases to about 16.5% against that of the CSS. It was found that the natural circulation mode (NC) is the dominant mass transfer process, which contributes by about 63% to 80% to the water vapor transfer toward the EC. The results show also that the maximum daily energy and exergy efficiencies for the MSS and CSS are 23.2% and 1.9%, respectively, while for the CSS, they are 18.25% and 2.4%, respectively.

这项实验研究旨在揭示外部电容器（EC）对常规太阳能蒸馏器（CSS）性能的负面影响。提出了一种新的EC设计，并将其集成到单斜面盆地型CSS中。通过在相同的室外天气条件下，将CSS与改良的太阳蒸馏器（MSS）进行比较研究，可以证明EC的负面影响。实验结果表明，在CSS中添加EC并不总是积极的，并且静止性能与天气状况密切相关。EC的积极作用出现在中等天气条件下，对提高MSS生产率的贡献达到29％。在极冷或炎热的天气中，EC对静止生产率产生不利影响，相对于CSS而言，生产率降低至约16.5％。发现自然循环模式（NC）是主要的传质过程，其贡献了约63％至80％的水蒸气向EC的传递。结果还显示，MSS和CSS的最大每日能量和火用效率分别为23.2％和1.9％，而CSS的分别为18.25％和2.4％。