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Simple, solar-powered water desalination

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Re: Simple, solar-powered water desalination

#31

Post by pfdietz »

sacred_numbers wrote: post #26

Efficiency in desalination is measured by comparing the energy expenditure to the enthalpy of vaporization of water (basically the energy required to distill water by boiling it). The current state of the art reverse osmosis desalination plants use about 3.2 KWh of electricity per cubic meter of fresh water ( https://pdfs.semanticscholar.org/d4d7/821d585699719289dddd10... ). This technology uses about 173 KWh of sola…

One fascinating (well, to me) component of modern RO desalination systems is the rotary pressure exchanger. Such a simple device, but so important. It looks like something from the 19th century, but the base patent was issued in 1988.

https://en.wikipedia.org/wiki/Pressure_exchanger

Re: Simple, solar-powered water desalination

#32

Post by numbsafari »

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-...

Re: Simple, solar-powered water desalination

#33

Post by zzzeek »

DanTheManPR wrote: post #23
worik wrote: post #9

"than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area." Units, people. Units. Be imperial. Be metric. Hey! Be both!

It comes out to about 0.4 liters per square foot, for those of you who are confused.

im sorry it's 1.25419 gallons per square yard

Re: Simple, solar-powered water desalination

#34

Post by SCAQTony »

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.

Re: Simple, solar-powered water desalination

#35

Post by driverdan »

worik wrote: post #9

"than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area." Units, people. Units. Be imperial. Be metric. Hey! Be both!

From the paper's abstract:

> 5.78 L/m^2/h

Whoever wrote this PR is responsible for the mix and match units.

Re: Simple, solar-powered water desalination

#38

Post by [deleted] »

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-...

[deleted]

Re: Simple, solar-powered water desalination

#39

Post by jfengel »

worik wrote: post #9

"than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area." Units, people. Units. Be imperial. Be metric. Hey! Be both!

I guess it's not really surprising for American engineers. Food and drink are measured in Imperial units. Technical doodads are measured in metric.

You don't really need them to be compatible in this case: even though it appears that you're talking about multiples of units of length, you don't really compare them. You're not going to do the calculation that this is "1.58 micrometers per second" or ".447 feet per day", which is what this is.

I mean, I guess if it helps you visualize a half-foot of water growing on top of the object every day, great. But I feel like "volumes of water" and "areas of solar panel" are quite different units, and it's kinda helpful that the system distinction helps make that clear.

Re: Simple, solar-powered water desalination

#40

Post by zamalek »

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-...

> 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)?

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