How to DIY a solar still

Table of Contents

• Introduction
• Understanding Solar Stills
• Materials and Tools
• Step-by-Step Guide
• Using Your Solar Still
• Maximizing Efficiency
• Conclusion

Imagine you’re on a remote backpacking trip when your water supply runs low. The nearest source is a murky stream, but is it safe to drink?

Fear not! There’s a simple tool you can build yourself to turn that questionable water into clean drinking water: a solar still.

This DIY marvel utilizes sunlight to purify water, making it a valuable skill for emergencies, camping, or even off-grid living. It’s low-cost, requires minimal resources, and can be a lifesaver in a survival situation.

Understanding Solar Stills

The science behind it

Our handy solar still relies on a fundamental scientific principle: evaporation and condensation. Here’s the breakdown:

1. Sunshine Power: Sunlight acts as the driving force. When sunlight hits the transparent cover of the solar still, it warms the dark-colored base (usually a container filled with water).

2. Evaporation Takes Center Stage: As the base heats up, the water inside begins to evaporate, leaving behind dissolved salts and other contaminants that can’t turn into vapor.

3. Condensation Captures the Clean Stuff: The water vapor, being lighter than air, rises and comes into contact with the cooler transparent cover. This cooler surface causes the vapor to condense back into liquid water.

4. Clean Water Collection: The condensed clean water then trickles down the inner surface of the cover and collects in a separate container at the bottom. This container holds your hard-earned purified water!

Voila! Through the magic of solar energy, we’ve separated the clean water from the contaminants, making it safe for drinking.

Different Solar Still Designs

Create a Material List

For the Bowl and Cup Design (Simple & Quick):

• Large Bowl: Choose a clear or light-colored bowl with a reasonably large diameter (think soup bowl size or larger) to hold the contaminated water.
• Smaller Bowl or Cup: This will act as the collection container for the purified water. Ideally, it should fit snugly inside the larger bowl, leaving some air space between them.
• Transparent Plastic Sheeting: A clean sheet of plastic wrap or a clear plastic bag large enough to cover the larger bowl comfortably.
• Optional: Black construction paper or dark cloth (to increase heat absorption if desired).

Note: Ensure all containers are clean and free of debris before using them in your solar still.

In addition to the materials listed earlier, you might need a few basic tools:

• Sharp Knife or Scissors: For cutting the plastic sheeting to the desired size.

Step-by-Step Guide

Step 1: Prepare the Larger Bowl

Fill your large bowl with the water you want to purify. If using saltwater or heavily contaminated water, consult additional resources for pre-treatment methods (boiling might be necessary).

Step 2: Position the Collection Cup

Carefully place the smaller bowl or cup in the center of the larger bowl filled with water. The smaller cup will collect the purified water. Ideally, there should be a small air gap between the two bowls.

Optional Step 3: Enhance Heat Absorption (for Faster Results)

Cut a piece of black construction paper or dark cloth to a size slightly smaller than the bottom of the larger bowl. Place this dark material under the larger bowl to absorb sunlight and heat the water more efficiently.

Step 4: Secure the Transparent Cover

Carefully stretch the clean plastic sheeting over the top of the larger bowl, creating a loose tent-like cover. Use the knife or scissors to trim any excess plastic around the rim of the bowl.

Step 5: Seal the Deal (Optional, for Improved Efficiency)

For better results, try to create a slight seal around the rim of the bowl where the plastic sheet meets the edge. You can use pebbles, rocks, or even clothespins to gently weigh down the edges and create a tighter seal.

Step 6: Find a Sunny Spot!

Place your completed solar still in a location with direct sunlight for most of the day. The more sun exposure, the faster your still will produce clean water.

Pro Tips and Variations for Your Solar Still

Maximizing Efficiency:

• Transparent Cover Choice: While plastic wrap works well, consider using a clear plastic bag (bread bag size) if available. It can create a more inflated “dome” effect, maximizing condensation and potentially increasing water production.
• Double Up the Bowls: If you have two identical bowls, you can use them both! Fill one with saltwater and place the empty bowl upside down inside the first bowl to collect the purified water. This variation helps separate the contaminants further from the clean water vapor.
• Solar Reflector Boost (Optional): For an extra efficiency boost, consider creating a reflective surface around your solar still using aluminum foil or reflective emergency blankets. Position the reflector to direct additional sunlight towards the base of the still, enhancing heat absorption.

Material Variations (Based on Availability):

• Bowl Substitutes: No bowls available? Get creative! Use large, clean tin cans or even a baking dish lined with plastic wrap as your water container. Just ensure the chosen container is heat-resistant.
• Transparent Cover Alternatives: In a pinch, a clear plastic shower cap or even a tightly stretched layer of clear plastic wrap on a frame (made from sticks or twigs) can serve as a makeshift cover.

Remember: While these variations might not be as efficient as the original design, they can still provide a means to purify water in a survival situation when resources are limited.

Using Your Solar Still

Location, Location, Location

Now that you’ve built your solar still, it’s time to find the perfect spot for it to work its magic. Remember, sunlight is the key ingredient for our little water purifier, so location plays a crucial role in its effectiveness. Here’s why:

• Sunshine Makes the Clean Water Flow: The more direct sunlight your solar still receives throughout the day, the faster it will produce clean water. Sunlight heats the water inside, promoting evaporation, which is the first step in the purification process.
• Aim for Sun Exposure Throughout the Day: Ideally, position your solar still in an open area that receives sunlight for most of the day, especially during the peak sun hours (typically midday). Avoid shady areas or locations with obstructions that might block sunlight throughout the day.
• Southward Facing is a Sweet Spot (Northern Hemisphere): In the Northern Hemisphere, a southward facing location is generally best for maximizing sun exposure. This allows your solar still to capture the sun’s rays for a longer duration throughout the day.
• Northward Facing for the Southern Hemisphere: If you’re in the Southern Hemisphere, flip the script! A northward facing location will provide the best sun exposure for your solar still.

Remember: Even a slight adjustment in the positioning of your solar still can significantly impact its water production rate. So, take some time to observe your surroundings and choose the sunniest spot available for optimal performance.

Operation and Maintenance

Your DIY solar still is ready! Now, let’s put it to the test and see how it transforms murky water into something safe to drink.

Filling Up:

1. Choose Your Water Source: Fill the larger bowl of your solar still with the water you want to purify. Remember, the dirtier the water, the slower the purification process might be. For heavily contaminated water, consider pre-treatment methods like boiling before using the solar still (consult additional resources for specific pre-treatment techniques).
2. Fill it Up, But Not Too Much: Don’t overfill the larger bowl. Leave some space at the top to allow for air circulation and prevent the plastic cover from touching the water directly.

Positioning for Sunlight:

1. Sun Seeker: As discussed earlier, finding the perfect sunny spot is crucial. Look for an open area with unobstructed sunlight for most of the day, ideally facing south in the Northern Hemisphere or north in the Southern Hemisphere.
2. Adjusting the Angle (Optional): For even better results, you can try tilting your solar still slightly towards the sun. This helps capture more direct sunlight throughout the day, especially during peak sun hours.

Collecting the Clean Water:

1. Patience is Key: Solar stills are not instant water purifiers. The amount of clean water produced will depend on various factors like sunlight intensity, ambient temperature, and the amount of water you started with. Be patient and let the sun work its magic.
2. Checking for Condensate: Periodically check on your solar still throughout the day. You should see water droplets forming on the underside of the plastic cover. This is the purified water!
3. Collecting Your Reward: Once you’ve collected a sufficient amount of clean water in the smaller cup, carefully remove the plastic cover and enjoy your hard-earned reward!

Pro Tip: If you notice the plastic cover sagging due to accumulated water droplets, carefully remove some of the water with a clean spoon or straw to prevent the cover from touching the water in the larger bowl.

Safety Considerations

While your DIY solar still is a valuable tool, it’s important to prioritize safety when using it. Here are a few things to keep in mind:

• Not All Water Sources Are Created Equal: Avoid using your solar still with heavily contaminated water sources, especially water suspected of containing harmful bacteria or industrial pollutants. Pre-treatment methods like boiling might be necessary before using the solar still for such water.
• Solar Stills Are Not Sterilizers: The water produced by your solar still is purified, but not necessarily sterilized. Boiling the collected water for an additional minute (especially if the source water is questionable) is recommended for added safety.
• Temperature Matters: Solar stills rely on sunlight for heating. In very hot climates, the water inside the still might reach high temperatures. Be cautious when handling the still and avoid drinking excessively hot water.

Maximizing Efficiency

Factors Affecting Performance

We’ve built our solar still, found the perfect sunny spot, and now it’s time to see how much clean water it can produce. But several factors can influence the efficiency of your solar still, impacting the rate at which it purifies water. Here’s what you need to know:

• Sunshine Intensity: This is the main driver! The brighter and more direct sunlight your solar still receives, the faster it will heat the water, leading to more evaporation and ultimately, more purified water production. So, sunny days are your still’s best friend.
• Ambient Temperature: Just like sunlight, warmer ambient temperatures can also boost your still’s efficiency. Think of it like this: the hotter the surrounding air, the easier it is for the heated water in your still to evaporate. So, using your solar still during hot days can lead to faster water production.
• Wind Speed: While a gentle breeze might not significantly impact your still, strong winds can actually be detrimental. Wind can cool down the heated water in the still, hindering evaporation and slowing down the purification process. If you find yourself in a windy location, try creating a wind barrier around your still using blankets or cloths to minimize the cooling effect.

Additional Factors to Consider:

• Color of the Base Container: A dark-colored base container absorbs heat more efficiently from the sunlight, leading to faster water heating and evaporation. Consider lining the bottom of your still with black construction paper or using a dark-colored container for optimal heat absorption.
• Size of the Water Container: While a larger water container allows you to purify more water in one go, it also takes longer to heat up. Conversely, a smaller container heats up faster but produces less purified water. Finding a balance between water capacity and heating efficiency is key.
• Insulation (Optional): Insulating the sides of your solar still with reflective materials (like aluminum foil) can help trap heat inside, further increasing its efficiency. However, this is an optional step and might not be feasible for all designs.

Tips for Improvement

We learned about the factors influencing your solar still’s performance. Now, let’s put that knowledge into action with some practical tips to maximize its efficiency and get you more clean water!

Heat Absorption Champions:

• Embrace the Dark Side: As discussed earlier, a dark-colored base container absorbs heat from the sun more efficiently. If your still uses a clear or light-colored container, consider lining the bottom with black construction paper or dark cloth. This simple step can significantly improve heat absorption and speed up the water purification process.
• Double Duty with Aluminum Foil: Get creative! Line the outside walls (not the bottom) of your solar still with reflective aluminum foil. This creates a reflective barrier, trapping the sun’s heat inside the still and further enhancing water heating.

The Greenhouse Effect Advantage:

• Clear Wrap It Up: Remember the “tent-like” plastic cover you created for your solar still? Upgrading to a thicker, clear plastic wrap can be beneficial. A thicker plastic sheet helps create a mini greenhouse effect within the still. This traps the warm, humid air inside, promoting faster evaporation and condensation, ultimately leading to more purified water.
• Inflate for Efficiency (Optional): If using a clear plastic bag as your cover, try to inflate it slightly. This creates a more prominent “dome” effect, maximizing the condensation surface area and potentially increasing water production. However, be mindful not to over-inflate and risk bursting the bag.

Optimizing Water Capacity and Management:

• Right-Size Your Still: Remember, a larger water container takes longer to heat up. If you need purified water quickly, consider using a smaller container for faster initial production. However, be prepared to refill it more frequently.
• Partial Shade, Partial Fill: If you find yourself in a location with partial shade for some parts of the day, adjust your water level accordingly. Filling the container only halfway allows for faster heating during the sunny periods and optimizes water production even with limited sun exposure.

Bonus Tip: Monitor your still’s performance throughout the day. If you notice the plastic cover sagging due to accumulated water droplets, carefully remove some of the clean water with a clean spoon or straw. This prevents the cover from touching the water in the larger bowl, which can hinder evaporation.

Conclusion

Congratulations! You’ve built your very own solar still, a powerful tool that harnesses the sun’s energy to transform potentially unsafe water into clean drinking water. Remember these key takeaways:

• Simple Yet Effective: Solar stills are a low-cost, low-tech solution for purifying water in emergencies, off-grid situations, or even for camping adventures.
• Science in Action: The basic principles of evaporation and condensation are at play, making the purification process understandable and empowering.
• Design Flexibility: From the simple bowl and cup design to the inclined solar still, you can choose a design that suits your needs and available resources.
• Efficiency Matters: Sunlight intensity, ambient temperature, and even the color of your container can all influence your still’s performance. By understanding these factors and implementing efficiency hacks, you can maximize your clean water output.

It’s important to be aware of the limitations of solar stills:

• Slow and Steady Wins the Race: Solar stills have a slower water production rate compared to other purification methods. Be patient and realistic about the amount of clean water you can collect, especially in a short timeframe.
• Sunshine Dependent: Solar stills rely on sunlight for operation. They won’t be effective at night or during cloudy periods.

While solar stills are a fantastic DIY option, it’s important to be familiar with other water purification methods that might be more suitable depending on the situation. Here’s a quick rundown of some alternatives:

• Boiling: This is the simplest and most effective way to kill harmful bacteria and parasites in water. Simply bring the water to a rolling boil for at least 1 minute (at higher altitudes, boiling for a longer duration might be necessary).
• Water Filters: Various portable water filters are available, ranging from simple straw filters to more complex pump filters. These filters remove contaminants through physical and/or chemical processes, making them a convenient option for on-the-go purification.
• Chemical Purification Tablets: Chlorine dioxide or iodine tablets are effective against bacteria and some parasites. However, always follow the manufacturer’s instructions carefully when using these tablets, as improper use can be harmful.
• Ultraviolet (UV) Water Purifiers: These purifiers use ultraviolet light to deactivate harmful microorganisms in water. They are typically battery-powered and offer a relatively quick purification method.

Check out this post for a more detailed treatise on the different water purification methods: https://deals-here.com/survivalpreppers/how-to-purity-water-in-a/!

Remember: The best water purification method depends on the specific situation, water source, and desired level of purification. Consider solar stills as a valuable tool in your arsenal, but be sure to explore alternative methods to ensure you have a well-rounded approach to safe drinking water, especially in emergencies.

Also, a disclaimer!! The information provided in this blog post regarding DIY solar stills and water purification methods is for educational purposes only. It is not intended to be a substitute for professional medical advice or instruction from qualified survival or water treatment specialists. Always prioritize your safety and well-being in emergency situations. Consult with a medical professional or qualified personnel for guidance on water treatment and purification methods in critical situations.

HOWEVER: Are You Ready to Give It a Try?

We’ve provided you with the knowledge and tools to build your own solar still. Now it’s your turn to take action! Head out there, gather your materials, and put your newfound skills to the test. You never know when such a skill might be put to the test one day.

Share Your Experience!

We’d love to hear about your solar still adventures! Did you build the bowl and cup design? Did you try any of the efficiency hacks? Share your experiences, tips, or even challenges you faced in the comments section below. Let’s create a community of solar still enthusiasts and empower each other with the knowledge of harnessing the sun’s power for clean water!