Augmenting the Thermal Efficiency of Solar Stills Using Phase Change Material on a Rotating Hollow Cylinder

Jun 30, 2025

Journal International Journal of Heat and Technology

DOI https://doi.org/10.18280/ijht.430336

Issue 3

Volume 43

This study presents an experimental investigation into enhancing solar water desalination using phase change materials (PCMs) and geometric modifications in a double-slope solar still. Paraffin wax was employed as a thermal energy storage medium, encapsulated in copper tubes mounted on a revolving hollow metal cylinder to simulate the climate of Kirkuk, Iraq. The system was designed to increase the surface area of the basin water through a thin water film inside the rotating cylinder and to utilize the stored thermal energy during off-sunshine hours, thereby sustaining water evaporation and enhancing distillate output. Results showed a marked improvement in productivity: while the conventional solar still produced 410 mL/day in December 2024, the enhanced still operating at 0.25 rpm achieved a yield of 3400 mL/day. These findings demonstrate that integrating PCM with mechanical rotation significantly improves the performance of solar desalination systems, offering a sustainable solution for freshwater generation in arid regions.

Evaluating the heat transfer characteristics of hybrid nanofluid flow in circular ducts with constant heat flux

Oct 27, 2023

Journal https://doi.org/10.59018/0823235

DOI https://doi.org/10.11648/j.ajset.20230803.16

Issue 16

Volume 18

Researchers have recently been interested in introducing solid nanoparticles into thermal systems in order to improve their thermal performance as a nanofluid. Researchers have investigated nanoparticle types, sizes, and concentrations using theoretical, numerical, and experimental approaches. In the present study, a hybrid nanofluid was utilized in two concentrations, namely (0.5% ZnO+0.5% SiO2-distilled water) and (1% ZnO+1% SiO2-distilled water), in a 45o inclined heated pipe at a constant heat flux of 12000 W/m2 and a range of 4000 to 12000 for the Re number.Initially, the performance of the test apparatus was evaluated using distilled water in the same conditions as the hybrid nanofluids experiment, and its results were compared to an empirical relation to ensure accurate results. The experimentation results indicated that the nanofluids significantly improved heat transfer coefficients when nanoparticle concentration increased in hybrid fluids. This indicates that increasing nanoparticle concentrations can substantially improve heat transfer coefficients. Using hybrid nanofluids with a concentration of (0.5 and 1)% increases the heat transfer coefficient by 1.2 and 1.4 times compared to distilled water.

Furqan Haider Mohammed Ali, Ehsan Fadhil Abbas, Iesam Jondi Hasan, Shahen Mohammed Fakhraldin

Aug 28, 2023

Journal American Journal of Science, Engineering and Technology

DOI https://doi.org/10.11648/j.ajset.20230803.16

Issue 3

Volume 8

Given the significance of improving heat transfer in thermal engineering equipment, researchers in this field have developed numerous methods for heat transfer improvement. These methods are classified as active and passive. Several researchers consider the use of forced vibration in improving heat transfer to be one of the most significant topics in the applied field. This is because some thermal equipment has this feature due to its nature. As a result, the current study emphasizes research dealing with mechanical vibration in enhancing heat transfer in free convection conditions. The results of these studies agreed that heat transfer by free convection and vibration contributed to improving the thermal performance of thermal equipment compared to its at-rest condition. These studies' findings indicate an increased heat transfer coefficient as frequency is raised, particularly in forced convection heat transfer. However, the limited vibration amplitude has an impact on heat transfer. In some studies, the fin slope was studied in addition to vibration. These studies showed that fin tilting reduces heat transfer optimization value with fin tendencies that produce vibrations. Furthermore, while the vibration process does enhance heat transfer capacity, it is accompanied by certain drawbacks. These include the generation of noise, which can disturbance to humans, as well as potential damage to mechanical components of the equipment.