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Simple, solar-powered water desalination

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Re: Simple, solar-powered water desalination

#51

Post by numbsafari »

numbsafari wrote: post #32
symplee wrote: post #24

>> 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area. So a football field could collect around 8,000 gallons of water per hour. Let's say you can get 5 hours of good sunlight per day = 40,000 gallons of water. >> The team’s demonstration device can achieve an overall efficiency of 385 percent in converting the energy of sunlight into the energy of water evaporation. >> Theor…

If I am reading [1] correctly, NYC needs approx. 1 billion gallons of water per day. So, they would need an array of 12,500 football fields to meet their needs. [1] https://data.cityofnewyork.us/Environment/Water-Consumption-...

Per the original comment about 5 sq mi:

Based on this random article I found from 2015 [1], the average cost per build able sq ft in Manhattan was getting to $1200.

So, if you magically found 5 sq miles in NYC, it’d cost around $167.3B just for the land [2].

I’m guessing you’d want to build it outside the city and pump it in via aqueduct.

Following the article, an array of off-shore desalinated that pumped water back to the city would probably be the most economically viable solution and could probably be built with other kinds of offshore utility systems to try and share costs.

[1] https://therealdeal.com/issues_articles/486631/ [2] https://www.wolframalpha.com/input/?i=%241200+per+square+ft+...

Re: Simple, solar-powered water desalination

#53

Post by kragen »

SCAQTony wrote: post #34

A lot of lithium batteries are making their way onto both sailboats and yachts. With significant advantages come equal disadvantages, and those disadvantages are the risk of potential battery fires, which only a Class D fire extinguisher can snuff out. The Dive boat fire in San Diego, where 34-persons perished, is one example.

You don't need batteries to run a reverse osmosis desalinator from solar panels; you can run the desalinator when the sun is shining and store the water.

I'm surprised boats are already moving to lithium. I wonder if it would be worthwhile to tow the batteries in a separate buoy behind the boat?

Re: Simple, solar-powered water desalination

#54

Post by ebg13 »

zamalek wrote: post #40
numbsafari wrote: post #32

Earlier quoted context omitted.

If I am reading [1] correctly, NYC needs approx. 1 billion gallons of water per day. So, they would need an array of 12,500 football fields to meet their needs. [1] https://data.cityofnewyork.us/Environment/Water-Consumption-...

> 1 billion gallons of water per day * How much of that water need be drinkable? * How much of that water can be salinated (e.g. for flushing)? * How much of that water can be partially desalinated (e.g. for showering)?

Indeed. If you do only the drinking water, 2L per person per day for 20 million people is only 10566000 gallons or 132 football fields.

Re: Simple, solar-powered water desalination

#56

Post by ChuckMcM »

This is pretty cool. It also could solve one of the seasteading problems (water production) in a way that is more scalable. Certainly if they can produce a robust version of this you could pack it into lifeboats so that the first thing you did after abandoning ship would be to toss this overboard and unfold it so that it could be filling/refilling the boat's water tanks.

I am not to sure about it on a metropolitan scale though, that is a lot of surface area per person. One sq kilometer is a pretty big patch for serving up water for about a million people. Call it 800K for losses due to transport.

Re: Simple, solar-powered water desalination

#57

Post by aaronax »

SCAQTony wrote: post #34

A lot of lithium batteries are making their way onto both sailboats and yachts. With significant advantages come equal disadvantages, and those disadvantages are the risk of potential battery fires, which only a Class D fire extinguisher can snuff out. The Dive boat fire in San Diego, where 34-persons perished, is one example.

Most boats (recreational "cruisers" at least, which is what I am most familiar with) are using LiFePO4 chemistries which are much less likely to start fires. ReLiOn, Victron, BattleBorn, and MasterVolt for example as some of the leading vendors.

Re: Simple, solar-powered water desalination

#58

Post by [deleted] »

r-bryan wrote: post #27
hinkley wrote: post #20

Earlier quoted context omitted.

It takes 1 watt-hour to produce about 3.5 BTUs. With a heat pump, for instance, you might be able to produce 5BTUs per watt-hour, because you're extracting heat from the environment (a very large heat source), which would be 140% efficient. The paragraph you excerpted has your answer: > The key to the system’s efficiency lies in the way it uses each of the multiple stages to desalinate the water. At each stage, heat…

You mean BTU/hour.

[deleted]

Re: Simple, solar-powered water desalination

#60

Post by hinkley »

riazrizvi wrote: post #48
hinkley wrote: post #20

Earlier quoted context omitted.

It takes 1 watt-hour to produce about 3.5 BTUs. With a heat pump, for instance, you might be able to produce 5BTUs per watt-hour, because you're extracting heat from the environment (a very large heat source), which would be 140% efficient. The paragraph you excerpted has your answer: > The key to the system’s efficiency lies in the way it uses each of the multiple stages to desalinate the water. At each stage, heat…

I really enjoy artful displays of mental gymnastics, so thank you. A watt is a unit of power , a BTU is a unit of energy , and a watt hour is also a unit of energy . If you can show me how solar watt hours are converted into BTU's at an equivalent rate of 3.85 to 1, I will short sell all the energy stocks using my children as collateral.

So that's how this is gonna be.

Good luck.

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