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Large Scale No Power Solar Still

Perfect for clean easy water in rural areas with no power or outside assistance.

Photo of Christian
8 2

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The main problem that most large water assistance programs have is that they require large funding and once that funding dry's up (pun intended) so does the water. We need a way for the locals to manage for themselves after the initial funding has been used.

This large scale solar still solves many problems. First moving the water. As you can see the water is moved from the river/pond/lake to a tank. This is done through a animal powered pump. The reason for that and not an electric one is quite obvious. Rural India doesn't have the best power situation, so having to base your most basic need on it is a little reckless. A simple pump like the one in Figure 1. shows how such a system can work. It is very basic and uses materials that the locals would not have a hard time getting their hands on, also, any bush mechanic would be able to fix and broken parts with ease. Next the tank. It's made of Aluminium for a number of reasons.

1) This will better transfer the heat of the sun to the water and allow for a quicker transfer to the holding tank

2) Heating a plastic tank may add other chemicals to the water that aren't very appealing

3) Aluminium is cheap and durable, it wont rust and is easily repaired. In an industrial country like India, supply isn't much of a problem.

4) The tank will need to be cleaned and repaired, so it needs to be light to allow it to be moved easily

Once the water is heated and evaporates it travels to a large above ground holding tank made of Concrete. It's like this, again, for a number of reasons:

1) Concrete is very cheap and easy to work with

2) Having it above ground lowers the risk of flood waters entering the tank should that be a problem in the area

3) The large access hatch will allow for someone to get inside and clean the tank (as someone who has worked in all tanks, trust me it needs to be here)

Once the water is in the tank it can be used for either drinking, livestock, or watering crops. If more water is required, another heating tank can be put into place. This system will help the villager's GET and STORE fresh clean water. By utilizing very simple systems, the villagers can handle their own water needs exactly as they need it.

The system can be used by a single person who then can sell the water. In densely populated areas on the river banks, individual families may not be able to set up the system there due to many different reasons (space, home not located on the river, etc.). But a young entrepreneur could set up the system and use it to produce clean water to then sell to the community. This way it even those in large communities can be given fresh water and will help facilitate job creation in some of the poorest regions. Once one person sets up it will show that other systems could be set up. This will completely eliminate the need for outside support (except for maybe the initial costs) and help create a market where one is greatly needed. The only problem would be the fact that the storage tank would be a security risk in larger communities from anyone who didn't/couldn't pay for the water. But with the very low start up costs and running costs the water should be able to be sold for quite cheap. People could bring by their own water jugs and have the water sold that way.

If the water production needed to be increased for any reason, the erection of mirrors directed at the tank would greatly increase the temperature inside and cause the water to evaporate faster, thus increasing the amount of water produced.

The problem I haven't solved yet is that in the holding tank the water is a perfect place for mosquitoes to breed. Any solution to the problem of keeping the water from remaining still with out the use of power is welcome.

How would you describe the stage of development of your idea?

  • Conceptual Development

Explain the sustainability aspect of your idea

This allows the people of India to take charge of their own water issues and doesn't rely on the continued in flux of money.

What types of financing would be required for your idea to be successful?

Individuals as well as charities could put of initial cost of materials and allow volunteers along with locals build the system so that they know how it works.

In-country experience

  • Not yet

Is your organization currently legally registered in India?

  • No

Tell us a bit about yourself.

Water is the most basic necessity of life and seeing those without clean water is vey difficult. I am a hydrological consultant in the Caribbean and a small business owner. I love to try and give back to anyone.

8 comments

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Photo of Cory Mogk
Team

Good idea - a couple questions:

1. Could a human operate the pump instead of an animal? I'm thinking like a traditional well with a hand pump? Maybe simpler and could reduce cost?

2. I presume one needs to remove organic material and pollutants from the still - any challenges there with operation, potential for leaks or disruption to the system?

3. For standing water and mosquitos I wonder if there is a filter that might go on either end of the system that could prevent them from getting in?

Photo of Christian
Team

1) Traditionally wells tend to have better water quality than surface water, but India is currently having a problem with their well water so the system could change and be used at  well. The pump could be configured to allow for a human to operate it, but it would require quite a lot of effort to move the amount of water. If the system was scaled down (which is very easy) then that could solve the problem for a single house hold who isn't looking for water to irrigate crops but more to bath and drink. It is something to think about as a large portion of the water that people still get its from wells.
2) Yes, once the water is heated, what is left over will need to cleaned from the tank. Due to the smoothness of the tank however this will make it hard for any containments to be stuck to the walls of the tank. The tank will not need to be cleaned everyday, and it would greatly depend on the level of water contamination. But with the tank being so light, it could be moved onto its side and cleaned very easily by wiping down the inside and removing leaves, stains and other contaminates.
3) Once the surface of the water is not stationary then they will have a much harder time trying to get a foot hold. It will only take one person to leave the hatch open for a couple minutes before they can get in and once they are in you will have to drain the entire tank to remove them. As for the filter its self I don't think one will be needed from the heating tank since the temperatures in there will not really be able to harbour much life, but certainly getting one for the outflow can be nothing but a benefit. As long as it can be easily gotten in the area. Were you thinking like a small micron filter bag? Or move of a cloth just to prevent things from living in any pipes?

Photo of Greg Lesher
Team

Yes, it could be as simple as pouring in water by hand or opening a valve to collect the purified water. A simple 5 watt panel and pump could operate it, cheap and simple. Also, the unit is air tight. No bugs in, none out.

Photo of Greg Lesher
Team

I am sure I have solved the problem, the "large scale solar water still" really did not exist due to design flaws. This is no longer the case. The high cost of RO put me into a mission mode. After spending $10,000 on a small home sized unit, I realized this was no answer. First it required large quantities of power just to operate the unit. The fuel/power consumption was crazy. I found it was cheaper to haul water from 30 miles away and store it. Second, there was no place to drain the rejected concentrate with out heavy damage to the surrounding land. So I set out on a mission to desalinate my well that had a saline concentration that rivaled the dead sea. I was able to re design the concept and make it work. If you google "large scale solar water still" the video pops up first. The output from this $800 US dollar still "passive version" reviled the RO unit with no operational costs. It even works well in the freezing, snowing winters. And I have now developed a form of concentrated solar still that will change everything water. It does not require grid or generator power to operate. It does not require multi flash distillation or vacuum pressures to operate, it is totally off grid and does not require power generation in any way other than low voltage solar panels. (the non passive version)

Photo of Andreea
Team

Hello Christian,

This is a great idea. Did you do any calculations on this? Do you think a single family in India might be able to afford this?
Thanks,
Andreea 

Photo of Christian
Team

Well pricing is a little difficult due to the fact that I don't know for sure what the pricing for materials is on the ground in India. The Heating tank will by far be the most expensive piece of the project but as I said it is easily available almost everywhere. But based on Industrial Pricing over there it should be around $150-$200USD for a 1500gal tank. The other materials can be made in small machine shops for very cheap as they are not complex. If I had to estimate, I would say the whole system would cost around $500-$900USD depending on the size of the system. I am thinking of it more as a village operation though, with more people it would be a lot easier to get the money together. But even given as a donation, the maintenance on the system would be very cheap as the parts are everywhere (concrete, smaller pieces of aluminium for patching, rope, small metal pieces, PVC pipe).

Photo of Andreea
Team

For a family, you could have a smaller tank which could bring the cost down. This is a great idea for schools, parks, community places in small villages. Thanks. Andreea

Photo of Christian
Team

I think that a single family in an area could very easily get a smaller tank and it would well be within there ability. But yes I hadn't thought of schools or other community places, it can defiantly work there too. Thanks!