Enhancing the solar still performance via rotating wick belt and quantum dots nanofluid

Two designs of rotating wick solar stills are investigated under the same operating conditions. The first design is a called L-RWSS, where the wick belt of black jute cloth is designed to be rotated inside the solar still in a path of an “L” character. The second design is called LC-RWSS, where the wick belt is designed to be rotated in a path of an “L” character with a chamfer at the bottom end. The rotation of the wick belt is under ON time of 5 min and different OFF times (zero, 10, 20, 30, 40, 50, and 60 min). In addition, the effect of using quantum dots nanofluid on the performance of LC-RWSS is studied. Results revealed that the optimum thermal performance of LC-RWSS is obtained at 30 min OFF time either with or without nanofluid. Besides, the total accumulated daily productivity of LC-RWSS is higher than that of L-RWSS by 19% and 17% with and without nanofluid, respectively. The productivity of L-RWSS and LC-RWSS reached 8200 and 9600 mL/m².day, respectively. The thermal efficiency of LC-RWSS is 88 and 86% with and without nanofluid respectively compared to 82% for L-RWSS under 30 min OFF time. Moreover, the cost of distilled water from LC-RWSS and L-RWSS is 0.019 and 0.022 $/L, respectively.