Mastodawn

With a little regulatory nudge there might be a market jumpstarted where one could choose and purchase an integrated pump/heat exchanger/drainback tank package for a solar hot water system [and reasonably priced thanks to economy of scale].

But no. It all has to built from scratch*. Between labor hours and parts purchased in disadvantageous quantities there ends up being no economic advantage in deploying such a system.

But it's still richly satisfying to organize sunlight into domestic hot water.

There's no economic advantage in reading poetry, either-- but we do. :-)

* Drainback tanks alone are available but are very crude in terms of thermodynamic performance, and absurdly expensive for what they deliver.

#SolarDHW

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LorenAmelang Nov 5, 2023

@Doug_Bostrom
Interesting! My first system 35 years ago was drain-back. The pump required to lift water ~10' was so noisy you could hear it 100' away outdoors. Tried drain-down, the valves failed every year or so due to hard water (no exchanger required in US). So I added an exchanger and glycol beyond it. But the domestic water was in the big part of the exchanger tank, and eventually corroded it into leaking. Now I have a dual exchanger - glycol coil, domestic coil, and ~100 gallons of "dead" rainwater for heat storage. The domestic water is heated as it is used, passing through five parallel coils.

On any sunny day all year, it provides all my hot water, and sometimes floor or hot tub heat. If no sun, there is a gas heater and an outdoor wood boiler in the glycol system. (I'm totally #OffGrid )

Somehow it doesn't gain much without direct sunlight, though. I'm 39° N, and when a tree shades the panels it stops.

#solarDHW #SolarHotWater