"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!
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It comes out to about 0.4 liters per square foot, for those of you who are confused.
That means for every square rod of surface area, this unit produces over 11,000 hogsheads of water! Impressive.
What, per millifortnight? cf. https://news.ycombinator.com/item?id=22270160
A millifortnight turns out to be just over 20 minutes...
How much water can I get in a moon?
If by 'moon' you mean our Moon, it has a volume of 2.1958×10^10 km3. Although, how much of that will hold water, we don't know. Anyway, a jerrycan is probably a lot more convenient ... holds 4.4 imp gals.
I really meant a month, but that was good :)
> 4.4 imp gals
That's 0.062 cubic Flemish ells, for those who were wondering.
To fit my Excel model, I really need to know how many barn-megaparsecs of water this produces per square smoot.
https://en.wikipedia.org/wiki/Smoot
https://www.google.com/search?q=barn%20megaparsec&oq=barn%20...
Matt Groening would be so proud of you right now.
Firkin hell
What's that in bathtubs per football field?
EDITED:
bathtub ≈ 302 liters
football field = 5351 square meters
They achieved 5.78 L/m^2/h
So 5351 m^2/football field * 5.78 L/m^2/h = 30928.78 L/h/football field
30928.78 L/h/football field / 302 L/bathtub = 102.4 bathtubs/football field/hour
h/t to brudgers for the correction about football field surface area!
A football field is 5351m^2. Futbol pitches vary.
The Canadian Football League would like a word with you.
I'm available right after fourth down.
Go Argos?
Oooh, thanks! Updated!
Layman's Explanation Greatest Hits right there. Except I was actually curious so I converted it. Assuming a 30-gal tub, it's about 267 tubs/field-hour.
Hrm - "To start, the standard bathtub will hold roughly around 80 gallons (302 liters) of water. Much smaller bathtubs can only hold around 40 gallons (150 liters) of water, which typically are more suited for smaller children or function more as a shower space."
30 gal seems too small.
well an NFL football field is approximately 5351 m2 so about 8000 gallons. not sure how big your bathtub might be though
im sorry it's 1.25419 gallons per square yard
It also makes the Kessel run in 1.21 JiggaParsecs.
Or, let's see... 5.7 millimeters!
(Per day, one assumes...)
From the paper's abstract:
> 5.78 L/m^2/h
Whoever wrote this PR is responsible for the mix and match units.
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.
Given the increasing popularity of 500 mL and 1 L units of bottled water, and the ubiquity of the 2 L HDPE beverage bottle, I think it would have been safe to measure the potable water output in liters. About the only things still sold by whole gallons any more are milk, water, iced tea, and lemonade, in the 1 gal jugs, or water in the 5-gal water-cooler jugs.
I'm more confused by the efficiency numbers exceeding 100%, which seems wrong. A theoretical efficiency of 100% would find the solar irradiance energy of 1 m^2 and then find the volume of fresh water per hour that produces an equal amount of energy when its salinity is increased to the mean salinity of seawater (about 3.5%). So if you can get 5000 Wh/m^2/day from insolation, and the energy difference between salt and fresh water is 0.810 W * h/L, 100% efficiency would be a 1 m^2 area producing 6173 L/day of fresh water. You're just dividing the daily energy of sunlight on your panel in Watt-hours by that 0.810, to get L/day.
The units in the article are all wrong anyway. They say "a rate of 5.78 liters per square meter", but there is no time factor mentioned whatsoever. An MIT roof gets mean 4.59 kWh/m^2/day of solar energy, so 100% efficiency would be 4590 * 1000/810 = 5667 L/m^2/day (1 m^3 = 1000 L). If the number given was per day, that's 0.1% efficient. If it's per hour, that's 2.4% efficient.
Servings of beverages in the US are still mostly in imperial measures. A can of soda is 12 ounces; so are most bottles. Beer in restaurants is usually a pint; if not, they'll specify ounces. A Starbucks venti is so called because it's 20 ounces; a tall is defined as 12 ounces. And American recipes still use cups and tablespoons (where the rest of the world has gone almost exclusively to grams, and not volume at all).
The soda industry went to 2 liter bottles back when the country tried to go metric, and it stuck. But most things haven't, including the individual serving sizes. So people never really got the feel for anything smaller than a liter.
Alcoholic beverages sold in containers are almost exclusively in metric. The old standard size was a fifth of a gallon, or 757 ml. When going metric this was reduced to 750 ml which is close enough that nobody would notice. Since it was ever so slightly smaller there was no pushback from the producers. https://en.wikipedia.org/wiki/Fifth_(unit)
Bottled water is often in metric too, even for single serving sizes.
Recipes elsewhere in the five eyes still use cups, tablespoons and teaspoons as well, although they're not the same size everywhere (eg. a metric cup is 250ml).
Containers marked in liters are very common in America, but every once in a while you'll run into some loud-mouthed boomer who starts feigning metric ignorance in a bizarre quasi-patriotic display, often while badmouthing the French. I believe that avoiding this nuisance is the primary reason why imperial volume units are still used at all.
The engineers don't enter into it; they used metric, of course.
I think it is important to use SI units, because it allows you to do comparisons between different approaches to desalination more easily, as I did in my comment https://news.ycombinator.com/item?id=22270160
> Technical doodads are measured in metric.
Not always. I would wager that you are using an electronic device whose circuit board was dimensioned in 'mils', which are not millimeters but thousands of an inch.
> Food and drink are measured in Imperial units.
Maybe if you don't mind losing your global Mars orbiter you don't:
http://edition.cnn.com/TECH/space/9909/30/mars.metric.02/
_everything_ is measured in metric, period.
The next time I'm supplying my orbiter with beverages, I'll keep that in mind.
Don't forget, 10 hours in a day, 100 minutes in a hour and 100 seconds in a minute (1 metric second = .864 imperial seconds)
... and that is why computers traditionally saved 32-bit seconds since the epoch ("Unix time"). These days we have 64-bits typically but the principle is similar. Only use the funny human units when setting stuff that's visible in the UI; in the back we avoid it.
I prefer all measurements of mass converted to stones, and volume converted to the volume of a 1-stone stone from the nearest drystane wall, provided the stone is one-hand wide and high.
How about 5.67812 liters for every 10.7639 square feet?
1.5 gal/(m²s) or 1.58 µm/s
Sort-of related: https://what-if.xkcd.com/11/
But is that a US gallon (3.79L) or an Imperial Gallon (4.55L)?
Do municipal water engineers still think in terms of acre-feet, or has everyone converted to cubic meters?
Mixing cultures makes everyone nicer.