overcomplicated

[Christ]

Ryland - I don't currently have the setup I explained, because I don't live in my own home. Trying to talk the owner of the house into anything that he doesn't understand (with his 5th grade education) is like putting spikes into rocks with a feather. You just can't hit it hard enough.

That said, I've built two similar systems for people using old fuel tanks, recycled steel/iron and copper tubing, and left over glass window panes. Sometimes, I wish I'd taken pictures of them. I get asked about them alot, and it's a PITA to draw it out for everyone.

Anyway, the system requires no pump at all, only that the solar collector be downhill from the inlet of the water tank. Obviously, the larger the bulk tank is, the larger the collector has to be, or the longer you'll wait for full heat after depleting it. (If you do).

It works on the thermosiphon principle, so as the coolant mix (recycled) heats up in the collector, it travels up the pipe, into coils in the bulk tank, transferring the heat to the usable water in the tank. As the coolant fluid cools in the coils, it flows back down into the collector to be reheated. If any valves are necessary, they're just shutoff valves for servicing purposes. The on demand heater is run inline with the bulk tank, and is only used when the hot water supply isn't "hot enough" using only the solar collector. I've never installed an on-demand system before, one of the people I built a solar collector for was having family over and ran out of hot water from everyone's wasteful showering practices. It took him some time to get the bulk tank up to temp again, so he decided that instead of risking that, he'd install a propane-fueled on-demand heater on the output line of the bulk tank.

Nobody out here gets billed for their water, we all have septic systems, which I'm sure you're familiar with. As such, it's basically irrelevant to make mention of "wasting water" when you're waiting for the hot water to reach the faucet that you've just turned on. It goes right back where it came from, it just takes a few days and some ground filtering to do it.

Hopefully, I've explained it better this time, so that you understand that it's the type of thing that just about anyone could do, probably in their spare time, if they'd taken the time to search for the materials, which are almost always available, if anyone wants to actually look for them. Sometimes, they can be had completely free!

Thermal control cannot really be had using this system, unfortunately, without additional cost. You have to learn to adjust your cold/hot setting as you need hot water, so you don't burn yourself. For only slightly more cost, (or free, depending) a valve could be added to bypass the bulk tank once it reaches a certain temp (which could be made automatic via temp swich) and transfer the heated fluid into another medium, such as your home's floors, during colder months.