Microencapsulated thermal storage materials for solar desalination process: an advanced technique for hygienic water production
Dilshad Ali, ... B. Srinivasarao Naik, in Water, The Environment, and the Sustainable Development Goals, 2024
18.2.3.1 Macro encapsulation
The PCM is encapsulated in 1 mm or 1 cm of the shell. The growth and effectiveness of the SD process are significantly influenced by the choice of PCM and shell materials for macro encapsulation. This method can contain a sizable amount of PCM.19 Macro encapsulation of PCM in SD, copper, or aluminum containers is required for PCM’s thermal conductivity enhancement.
As discussed in Table 18.1, the organic PCMs have less thermal conductivity. Lower thermal conductivity PCM may affect sustainable water productivity. The thermal conductivity of containers has been provided in Table 18.2 for a better understanding of the materials.
Container for PCM | Thermal conductivity (W/m.K) |
---|---|
Aluminum | 235 |
Copper | 401 |
Elashmawy et al.21 filled PCM in aluminum containers to improve heat transfer and copper rods were placed inside aluminum tubes. The outcomes demonstrated a significant improvement in SD system performance and distillation productivity at a cheap cost. The effectiveness and productivity of the designed system were increased by 38.3% and 40.5%, respectively. Additionally, the designed system’s yield, efficiency, and price per litre are 5.6 L/m2 day, 44.0%, 0.008 USD, and 4.0 L/m2 day, 32%, 0.02 USD, respectively. Kabeel et al.22 also tested with PCM in a copper tube to improve diurnal and nocturnal distillation. They reported a considerable increase in productivity using copper-filled PCM in tubes. Time, container thickness, and PCM mass are vital in the system’s design. PCM and non-PCM water distillation productivities were about 5780 and 5331 mL/m2 day, respectively. Additionally, solar still with PCM had 8% higher production efficiency than traditional ones (non-PCM).23 The daily efficiency for developed tubular SS and traditional SS with PCM range from 37.2% to 38.1% to 44.2%–45.3%. It means that water productivity with PCM depends on solar still design.