In arid and semi-arid regions, access to clean drinking water remains a persistent challenge despite the abundance of solar energy. This study investigates the performance enhancement of single-slope solar stills (SSSS) by integrating hybrid phase change material (PCM) composites composed of paraffin wax and graphite nanoparticles. The experiments were conducted in Tanta, Egypt (30°47′ N, 31° E), under typical summer conditions in August and October 2017. Three identical SSSS units were tested with varying mass concentrations of graphite nanoparticles—0%, 5%, 10%, 15%, and 20%—mixed into paraffin wax to form hybrid thermal storage materials. The results demonstrate a direct correlation between nanoparticle concentration and distillate production. The maximum accumulated yield reached 8.52 liters per square meter per day at a 20% graphite concentration, representing a 43.3% increase over the conventional system without hybrid PCM. The addition of graphite significantly enhances thermal conductivity, enabling faster heat transfer from the absorber plate to the PCM and improving the rate of evaporation. Moreover, the improved thermal diffusivity reduces temperature gradients within the basin, leading to more uniform heating and higher vapor generation efficiency. The average daily efficiency also increased from 51.5% in the base case to 62.3% at 20% nanoparticle loading. These findings highlight the effectiveness of nano-enhanced PCMs in overcoming the inherent limitations of traditional paraffin wax, such as low thermal conductivity and slow response time. The use of hybrid composites allows for greater energy absorption during daylight and sustained release during nighttime, extending the operational window and increasing overall productivity.
Thermal Dynamics and Heat Transfer Enhancement
The integration of graphite nanoparticles into paraffin wax fundamentally alters the thermal dynamics of the solar still system. Pure paraffin wax has a low thermal conductivity (approximately 0.2 W/m·K), which limits its ability to rapidly absorb and distribute heat. By incorporating graphite nanoparticles—known for their exceptional thermal properties—the effective thermal conductivity of the composite increases significantly. At 20% mass concentration, the thermal conductivity reaches levels sufficient to promote rapid heat propagation throughout the PCM matrix. This enhanced heat transfer mechanism ensures that the entire volume of PCM participates efficiently in the energy storage process, minimizing thermal lag and hotspots. During the day, the PCM absorbs solar radiation and undergoes phase transition from solid to liquid, storing latent heat. At night, the stored energy is released gradually, maintaining elevated basin water temperatures and enabling continued evaporation even after sunset. The experimental data show that the temperature difference between the basin water and the glass cover remains consistently high throughout the 24-hour cycle when using the 20% composite, directly contributing to higher condensation rates. Additionally, the presence of nanoparticles improves the wettability and surface interaction between the PCM and the absorber plate, further enhancing heat transfer efficiency. The optimized thermal behavior translates into measurable gains in both hourly and cumulative freshwater output, validating the role of nanotechnology in advancing solar desalination systems.
Economic and Environmental Implications of Nano-Enhanced Systems
The economic analysis reveals that while the initial cost of hybrid PCM composites is higher than that of pure paraffin wax, the long-term benefits justify the investment.PAK1 Antibody MedChemExpress The total lifetime production of the 20% graphite composite system reaches approximately 19,350 liters/m² over a 10-year period, compared to 12,423 liters/m² for the conventional still.TRIM22 Antibody manufacturer At a market price of $0.PMID:35222794 093 per liter in Egypt, the revenue generated is nearly 60% higher. The payback period for the enhanced system is estimated at around 420 days, which is competitive given the substantial increase in output. Furthermore, the reduced need for mechanical or electrical components aligns with the goal of off-grid, sustainable water solutions. Environmentally, the system operates entirely on renewable solar energy with no emissions or chemical byproducts. The use of non-toxic, recyclable materials such as paraffin wax and graphite minimizes environmental impact. The produced freshwater meets all national safety standards for TDS (≤500 ppm), pH (6.5–8.5), hardness (≤179 mg/L), and clarity (≤1 NTU), ensuring suitability for human consumption. This study demonstrates that hybrid PCM composites offer a scalable, efficient, and eco-friendly pathway to improve solar desalination performance. Future research should focus on optimizing nanoparticle dispersion techniques, exploring alternative nanomaterials, and developing modular designs for easier maintenance and deployment in remote communities.MedChemExpress (MCE) offers a wide range of high-quality research chemicals and biochemicals (novel life-science reagents, reference compounds and natural compounds) for scientific use. We have professionally experienced and friendly staff to meet your needs. We are a competent and trustworthy partner for your research and scientific projects.Related websites: https://www.medchemexpress.com