Water Desalination by Using the Sun - Will it Work ?

[mintyspilot]

Originally Posted by anjou

Ken Hom has reported to police that several woks have been stolen from his garage.

Maybe we can avoid Mr Hom by using a rectangular parabolic reflector (about 2 minutes in)

YouTube - Solar Water Heater Steam Parabolic Mirror Trough

[kistinie]

Hi ,

if evaporation is searched, you should have a full passive device with "belier pumps" and capillarity to raise water up and evaporation glass.

If you want new smart technology
Eole Water - Give us wind, we give you water | Accueil

Regards !

[Tellie]

Originally Posted by mintyspilot

Indeed, but it does rather neatly illustrate the amount of energy that can be gathered and how intense it can be.

Just think, if one could really make this work why stop at water making. Perhaps bringing back a better steam engine to replace your diesel would be more of an accopmplishment.

[mintyspilot]

I suspect that your reply is a bit tongue-in-cheek, but the spaniards are trying something along these lines.

BBC NEWS | Science/Nature | Power station harnesses Sun's rays

The daytime energy is "collected and stored" as steam in oversize thermos flasks which provides a rather minimal "night service".

[Kristian]

Thanks a lot for your thinking on if this far shot can work or not!

With the inputs so far I have a strong belive that the tube going from the Sun heated boiler shoud be as short as possible , going at a rather steep slanted angle downward and ending in a condensing box/ freshwater collector. The box should of course be tightly fitted with the hull and thus cooled by the sea.

The Vaccum generating and supporting as before but no use bringing the vapour up the mast.

Please give more inputs , I´m going to have two Doctors of Technology from Chalmers in Gothenbourg for dinner this weekend and must get this at least presentable if daring to show them the concept....

How to collect the salt to finance the crusing will have to be a later task!!
I belive half of the market value (at least) is generated by the packaging and of course the marketing but that might be a suitable thread on how to get financially independent as a cruiser.....

Thanks all

Kristian

[Kristian]

Nice thinking Tellie!

The problem is that if I´m not wrong you want as much pressure as possible in a steam engines boiler to be able to use that pressure driving a turbine or an old fashioned piston..

Here in this thing we want the water to boil at a temperature as low as possible. It will be a bennefit bpth when it comes to boiling and also bringing the vapour back to water.

I think the same goes for any other energy storing idea. The vapour produced in this way has a very much lower energy potential.

Rgds

Kristian

[mintyspilot]

Given that in one of the videos the tube temperature was 300F, I do not think you need to worry about reducing pressure to make it boil. I would think that a thin tube would be better than a thicker one as there would be less water to heat. The amount of energy required to heat a liquid is

J = mct (c is a constant - the specific heat capacity. For water it is 4186 J/kg/K)

(the "t" is normally written as a greek theta.... ) so if we have a constant amount of energy (J) and we have a desired temperature difference (t) then we want the mass of water to be low (m). So a narrower tube would allow a jet of steam to be fed directly into a condenser. The tube could be self filling by having a reservoir at the correct height attached to one end. The condenser could run back through the reservoir allowing the cold salt water to condense the new fresh water.

I wish it was warmer outside - the UK is not that much warmer than Sweden and I rather fancy building a prototype of this to try it out.

[Kristian]

You do have a good point there Mintyspilot!

My thinking and reason to use the low press approach is twofold:

1) Capturing the same amount of sun energy would produce 30% ?? more water.
2)On days with a little less permanent sunshine you might be able to keep the temperature above lets say 55 degrees celsius and still get a good production.

My "in head" prototype would not be automatic but close to since all you really need to do is open a valve to the sea water supply hose and fill the sunheater with sea water by using the vacuum pump after you have emtied the freshwater collector.

I´m also looking forward to some heat so the prototype can be built and tested!

By the way , since I´m a Swede needing to learn a lot of things every day, the expression tounge in the cheek does it mean ironic or something like that?

Rgds

Kristian

[anjou]

Your grasping the nettle very well Kristian.

[mintyspilot]

Kristian - "tongue in cheek" is an expression which is used when someone is not really being serious about something and may even be using gentle sarcasm. So your description of "ironic" is close enough.

I'm prepared to wager a large amount of money that your english is a lot better than my swedish. I can get by in French and even have a smattering of Esperanto but I have never tried swedish.

[Kristian]

Thanks for the introduction on how you britts handle your tongues.

I get the meaning now by imagining someone doing just that together with your explanation.

I´m really impressed by your knowledge in Esperanto , must admit I never have been even close to hearing it spoken but the idea of a second language we can communicate in all over he world is fantastic.

Today I feel that English has taken that position and I´m even more impressed with your effort in learning Esperanto!

Rgds

Kristian

[mintyspilot]

Originally Posted by Kristian

I´m really impressed by your knowledge in Esperanto , must admit I never have been even close to hearing it spoken but the idea of a second language we can communicate in all over he world is fantastic.

Dankon. mi neniam farig tre bona ce gi</span>. Mi ne havis iun</span> praktiki kun.

Originally Posted by Kristian

Today I feel that English has taken that position and I´m even more impressed with your effort in learning Esperanto!

I agree with your comments about english. It is the most geographically widely spoken language and the most common second language. I suppose it has become a modern day version of Latin.

On the good side it means I get to travel around without all that tedious bother of having to learn another language. On the bad side it means that I miss all the fun of having to learn another language.

I'll just have to improve my french. At least I can get by in rural France, especially after a week or two totally immersed in a non-english environment.

[Jolly Roger]

I’ve been reading this thread with interest, because we are going on an ocean voyage soon, but I can’t make head-nor-tail of it, (that’s another Brit moment for you Kristian). Then the language diversion interested me; the reason why English is spoken everywhere is because Englishmen went everywhere in ships—without distillation systems or water-makers. What’s wrong with the good old fashioned water tank, and Jerry Cans strapped to the rail with lots of frayed rope, which are filled up every time it rains—which is always on Englishmen? If you are of other less sodden nationalities, how about a hand operated water-maker or, heaven forbid, a proper modern device. I don’t know much about energy coefficients, but wouldn’t it be possible for you guys to work out how much energy was required to earn enough money to buy a water-maker? Then you wouldn’t have to worry about capsizing or people thinking you were a steam boat or brewing moonshine.

[mintyspilot]

Originally Posted by Jolly Roger

I’ve been reading this thread with interest

That's a relief ;-)

Originally Posted by Jolly Roger

the reason why English is spoken everywhere is because Englishmen went everywhere in ships

Usually transporting good solid chaps with red uniforms and bayonets to keep the natives in line. What-ho Chaps! Spiffing!!

Originally Posted by Jolly Roger

... without distillation systems or water-makers. What’s wrong with the good old fashioned water tank, and Jerry Cans strapped to the rail with lots of frayed rope, which are filled up every time it rains

That's a good point actually, catching washoff rainwater is a good way to collect lots of fresh water.

Originally Posted by Jolly Roger

which is always on Englishmen?

Ter's me problem, begorrah. Himself isn't English...

Originally Posted by Jolly Roger

If you are of other less sodden nationalities

Sodden? How did whiskey (with an "e" you'll notice) get into this thread?

Originally Posted by Jolly Roger

but wouldn’t it be possible for you guys to work out how much energy was required to earn enough money to buy a water-maker? Then you wouldn’t have to worry about capsizing or people thinking you were a steam boat or brewing moonshine.

We don't need to work that one out. There's price lists available but the reverse osmosis stuff can be costly in a lot of ways - filters, cleaning, power to drive compressors etc. Boats are surrounded by water and tend to spend time in sunny locations, therefore........

[Kristian]

Jolly Roger, nice with even more of what I think you call an idiomatic scentence.

That one I have heard before and I sure do understand that you wonder where this thread is leading or what to get out of it.

It might be due the fact that it started out as a question regarding if we can get our fresh water any other way than the traditional.

Of course you can go anywhere using tanks and betting on your good fortune in finding fresh water or using a genset and watermaker or anything in between.

Personally I´m a bit tired in the complexity involved with all this gear even though I must admit it is nice fireing the genset up and producing water , cooling the cabin and topping the batteries up.
The downside is servicing the genset and the watermaker and having to go and fill the diesel regulary.

The post is really about if it is possible to find another sollution using the combined knowledge in a community like this.

I hope that finally there will be a conclusion to the original question.

If the awnser is yes - fine then lets try it out in real life , if the awnser is no then at least I do not have to try it just to find what you all could have told me in the first place!

I do have to take responsibility for not having produced anything of an easy to understand sketch.

Will try to do so after this weekend!

Perhaps you could call this idea a version of a hand and sun driven watermaker depending if you use an electric or hand driven pump to initiate the vacuum.


I would say that you then do not have to worry about no working genset ,watermaker , diesel shortage or the financial worries of keeping these things running.

The brewing moonshine aspect I do not take as a thing to worry about , it might even be a possibillity........for those so inclined.

Hope your ocean crossing is in a warm , nice and cosy place of the planet.

Rgds

Kristian