A novel fractional model based on the Riemann Liouville fractional derivative to simulate the thermal performance of conventional solar still and show the effect of using hybrid nanofluid on the desalination system is presented. The results of the fractional model are compared with the results obtained from the classical model, then compared to real experimental data under various climate conditions of Upper Egypt. The theoretical results reveal a perfect agreement between the proposed fractional model and the experimental data of the still with a percentage of error reached 1.486% in summer and 3.243% in winter compared to an error percentage of 24.1% and 20.08%, in case of applying the classical. Moreover, the performance of the modified solar still after adding hybrid nanoparticles is also compared with the conventional solar still. The model is implemented using a hybrid nanofluid of alumina and copper oxide (Al₂O₃-CuO) with a concentration of 0.025% for each nanoparticle. The results show that using hybrid nanofluid raises the still daily productivity to 5.5239 kg/m²·day in summer and 3.1079 kg/m²·day in winter of an enhancement in the still output yield of 27.2% and 21.7% compared with still without nanoparticles. The average energy efficiency of the still in summer is also increased to 49.54% and 23.212% in summer and winter, respectively, with an augmentation of 12.6% and 11.85% in hot and cold climate conditions, respectively. In addition, the average exergy efficiency is raised by 22.5% in summer and 13.4% in winter by using hybrid nano.

提出了一种基于Riemann Liouville分数导数的新型分数模型，用于模拟常规太阳能蒸馏器的热性能，并展示了使用混合纳米流体对脱盐系统的影响。将分数模型的结果与经典模型的结果进行比较，然后与上埃及各种气候条件下的实际实验数据进行比较。理论结果表明，所提出的分数模型与蒸馏器的实验数据完全吻合，其误差百分比在夏季达到1.486％，在冬季达到3.243％，而在应用的情况下，误差百分比为24.1％和20.08％。古典。此外，还添加了混合纳米颗粒后的改性太阳能蒸馏器的性能与常规太阳能蒸馏器的比较。₂ O ₃ -CuO），每个纳米粒子的浓度为0.025％。结果表明，使用混合纳米流体提高了仍然每天生产率5.5239公斤/米² ·天在夏季和3.1079公斤/米² ·天在27.2％和21.7％的静止输出产率的增强的冬季仍然没有比较纳米粒子。夏季和夏季，静止的平均能量效率分别提高到49.54％和23.212％，在炎热和寒冷的气候条件下分别提高12.6％和11.85％。此外，通过使用混合纳米技术，夏天的平均火用效率提高了22.5％，冬天的平均火用效率提高了13.4％。