**4.2 Advantage of solar still with PCM over ordinary solar still**

The potential advantages of solar still with PCM (phenol) are numerous, including flexibility, processability, low material cost, and independence on scarce resources. The flexibility as an advantage is shared with solar cells and solar energy storage panels and is a feature allowing the solar stills with PCM to be incorporated into applications where flexibility is an advantage. Such solar stills that can be rolled out onto a roof or other surfaces are one option. Processability is another major selling point of PCM infused solar stills. Both solar stills with and without PCM depend on distillation methods wherein sunrays are concentrated by glass requiring massive amounts of energy; with PCM based solar cells, on the other hand, energy is stored and for distillation, which yields distillate of desalinated water and complete setup are have a possibility of implementation on a larger platform. Flexibility and more energy storage capacity allows for up-scaling the production and thus reducing the cost per area of PCM solar stills. The promise of low material cost and minimal use of scarce materials can be realized with optimized PCM solar stills.

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**Nomenclature**

**C** constant

**d** the depth of the water (m)

glass (W/m2

**E** energy of incident radiation

**Ta** ambient air temperature (°C) **Tb** basin temperature (°C)

**k** thermal conductivity (W/m °C) **L** latent heat of vaporization (J/kg)

**A** area of the basin (m<sup>2</sup>

**Gr** Grashoff number (dimensionless)

*Water Desalination Using PCM to Store Solar Energy DOI: http://dx.doi.org/10.5772/intechopen.92597*

**5. Conclusion and future scope of work**

the distillate production.

The rationale behind this research work is to apply and analyze the thermal energy engendered by the PCM using the incident solar radiation. The practical work conducted at two water depths concludes the inverse proportionality between the water level and heat released by water; we relate this to the volume occupied by the water in the still. It also follows that, as the water depth decreases, the distance between the top condensing cover and surface of the water also increases, affecting

• The cumulative distillate yield at 0.05 m in the double-slope solar still was 1595 mL, and 1788 mL when the experimented with no PCM, phenol as PCM.

1333 mL, and 1478 mL, when the experimented with no PCM and phenol as PCM,

• The effectiveness of PCM to be used to enhance solar distillation intersected with the depth of water in solar still as the efficiency of still changed.

The data available could be used to prepare the theoretical model to predict the performance of solar stills for solar distillation under the climatic condition in the parts

Efficient and optimized stills and solar distillation systems are projected as replacing wood with carbon fiber or a more effective insulator. As we can observe in the world map, near the tropic of cancer where solar radiation is potent, and seashore is close, solar distillation is a viable option in case of water shortage. Solar stills are subject to further analysis to separate dirt particles and impurities. Stills can also be used in groundwater as well as tap water to improve the quality of water by removing dirt and unwanted particles. In essence, solar distillation would play a vital role in meeting world freshwater supply demands. The data obtained could be used to investigate the scope of solar distillation further. From this investigation, we discovered that for domestic application, double-basin single-slope cascade solar still is a suitable and economical design.

/day).

• The cumulative distillate yield at 0.07 m in the double-slope solar still was

• Phenol gave an increase of distillate yield of nearly ~11.5%.

of the world (where the intensity of solar irradiation is around 5.44 kWh/m2

**b** average spacing between water and glass surface (m)

°C)

**Pg** partial vapor pressure at glass temperature (N/m<sup>2</sup>

**Pw** partial vapor pressure at water temperature (N/m2

**mw** yield of still per unit area per hour (kg/m2

) **hcw** convective heat transfer coefficient from water surface to

/h)

)

)

*Thermodynamics and Energy Engineering*

*Cumulative distillate collected results.*

**Table 5.**

**Figure 14.**

*Cumulative distillate collected at two heights.*

and the rate of hot water leaving the unit. Accordingly, the productivity of the unit decreases since the vapor pressure decreases. One also can notice (**Figure 11**) that the rate of production is significant during the day time and gets lower after sunset. The outcome of variation of height is that the amount of distillate collected reduced

**S. No. Height (m) PCM Distillate collected (mL)**

 0.05 No PCM 1595 0.05 Phenol 1788 0.07 No PCM 1333 0.07 Phenol 1478

with the increase in the height of water in the solar still (**Figure 14**) [31, 32].

The potential advantages of solar still with PCM (phenol) are numerous, including flexibility, processability, low material cost, and independence on scarce resources. The flexibility as an advantage is shared with solar cells and solar energy storage panels and is a feature allowing the solar stills with PCM to be incorporated into applications where flexibility is an advantage. Such solar stills that can be rolled out onto a roof or other surfaces are one option. Processability is another major selling point of PCM infused solar stills. Both solar stills with and without PCM depend on distillation methods wherein sunrays are concentrated by glass requiring massive amounts of energy; with PCM based solar cells, on the other hand, energy is stored and for distillation, which yields distillate of desalinated water and complete setup are have a possibility of implementation on a larger platform. Flexibility and more energy storage capacity allows for up-scaling the production and thus reducing the cost per area of PCM solar stills. The promise of low material cost and minimal use

**4.2 Advantage of solar still with PCM over ordinary solar still**

of scarce materials can be realized with optimized PCM solar stills.

**182**
