solar water heater

BFL13 wrote:
It was all over for us in 1975, on day one, when they tried to report newborn babies, instead of being 8 lbs, it weighed 30,000 kilopascals or whatever. That did it. Total failure of another government program.

Probably grams. 8 lbs = 3,632 g. Pascals are units of pressure, not mass. Decimal system is more accurate - kilometer, meter, millimeter and kilogram, gram, milligram. Units smaller than "milli" are easily made by adding "micro" or "nano". When manufacturers really need accuracy, they switch to "kind of decimal" system, ex. 0.0007834 inches. Decimals are easy to compare and calculate, 0.59 vs 0.58 is obvious, 19/32 vs 37/64 is not. There are 2 or 3 different "gallons" and "ounces", people are using these terms without clear understanding. Boaters are measuring speed in "knots" - nautical miles per hour, and distance - in "land miles" aka statute miles, and it takes some head scratching or calculator to convert one "mile" to another.

Back to the topic - yes, morning use of hot water is what makes solar heater impractical. Installing it for only afternoon use seems like too much trouble. "Solar pump" is particularly bad idea, it will let you down more than once. Like "solar fountain" indeed - my neighbor has one, doesn't work half the time. Though pump can be fixed by running it from 12V battery. The very idea of water on the roof doesn't sound right for a movable rig.