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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 m

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.

jfengel 7y ago
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.
- mark-r 7y ago
  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) https://en.wikipedia.org/wiki/Fifth_(unit) Bottled water is often in metric too, even for single serving sizes.
- caf 7y ago
  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).
catalogia 7y ago
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.

jfengel 7y ago

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.

mark-r 7y ago
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) https://en.wikipedia.org/wiki/Fifth_(unit) Bottled water is often in metric too, even for single serving sizes.
caf 7y ago
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).

catalogia 7y ago

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.