Solar water heaters were cool in 1980s. They could be again.
Solar water heaters were cool in 1980s. They could be again.
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We have one, it works reliably for many years, even in winter when there is sun - problem is sunny days are too rare here from Nov to Jan. If you get one, get a big tank, and optimise setup for winter (low sun angle), more than enough hot water in summer.
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yeah, a very big tank (more than 2000L) of warm water can last a few days which is important for intermittent sunlight.
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How big are we talking here, really? Or should insulation be considered too?
I have two tanks in my house that are heated by different elements of the (fossil fuel based, unfortunately) heating system - the stove and the furnace, which used to burn coal, but now we're doing wood and briquettes.
Either one of those can be heated to near boiling temperatures in about an hour, carry about 100-150 liters of hot water, but sadly will cool down over less than 24 hours so if it's freezing, but not "fuck my balls are going to fall off" freezing, I have to use the electric boiler at great expense. But both of those are bare metal tanks, no insulation at all AFAIK.
PS: House was built by grandparents, I'm too broke to put 10-30 grand on either an air to water or ground to water heat pump right now, but if anyone's interested, I can tell horror stories about the current heating system and house altogether. Soviet era design choices and modern prices for literally everything make for an uh... interesting combination. When it hit -28C (around -18F), I was up all night fueling the furnace, literally feeling myself burn through money.
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Due to economics, using photovoltaic solar panels and an electrical heater is actually cheaper. Which is a bit stupid of course. I think water heater are more compact but more expensive. And they need a pump and a heat pump and more maintenance with moving parts and antifreeze etc.
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I have tried to think about the feasibility in installing a solar water heater on a monolithic dome styled house.
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They are still cool. I just recently installed one :)
The vacuum tube ones are IMHO the best, but there are also ones that circulate a heat exchange fluid in panels for direct connection to a heat-pump. The advantage of the latter is that you get good efficiency out of them in the winter, but it also means that the heat-pump has to run all the time. My vacuum tubes work fine most of the year with only a small circulation pump running (and smaller systems with a thermo-siphon don't even need that).
What did you end up spending for it? Are you using it paired with an existing hot water heater?
It's combined with a stand alone air-to-water heat-pump that shares a hot water storage container with the solar thermal panels. Prices are hard to compare and I actually got a small government subsidy for it as well, but the solar thermal vacuum tubes alone should be less than $500 for a typical family home.