A solar still purifies water using a natural process similar to how rain is formed, effectively separating pure water from impurities. Here's a breakdown:
The Solar Still Process
The core of a solar still's operation lies in the principles of evaporation and condensation:
- Evaporation: Impure water is placed outside a transparent collector (like a glass or plastic cover). The sun's energy passes through this collector and heats the water, causing it to evaporate. The water turns into water vapor, leaving behind the impurities like salts, minerals, and bacteria.
- Condensation: This pure water vapor rises and makes contact with the cooler inside surface of the collector. The cooler temperature causes the vapor to condense back into liquid water.
- Collection: The condensed pure water then drips down into a collection tank, ready for use.
Key Components and Functions
| Component | Function |
|---|---|
| Transparent Cover | Allows sunlight to pass through and heat the impure water, facilitating evaporation. |
| Impure Water Source | Provides the water that needs purification. |
| Collection Tank | Gathers the purified water after it has condensed. |
| Insulation (Often Optional) | Helps retain heat within the system, improving the efficiency of evaporation. |
Practical Insights
- Solar stills are useful in areas where clean water is scarce and sunlight is abundant.
- The simplicity of their design makes them affordable and easy to build using readily available materials.
- The purification method doesn’t require electricity, making it an environmentally friendly solution.
- Example: A basic solar still can be made using a glass container, a smaller container to collect water, and a cover.
Distillation & Rain Formation
The solar still utilizes the process of distillation, just like how nature creates rainwater:
- The sun's heat evaporates water from bodies of water like oceans and lakes.
- This water vapor rises and condenses in the atmosphere to form clouds.
- The condensed water then falls as pure rainwater.
The solar still replicates this natural process on a smaller scale to provide clean drinking water.
