Solar Hot Water System

[dancor01]

An easy way I did install in 2012 and still working fine, was cheap also. Less then $250 back then.


https://shop.heliatos.com/MH-38-Sola...ls-0710029.htm
China solar water heater Micro DC pump,China water heater DC pump,Topsflo.


For the hose use car tubing for the heater.

[Jef & Marin, Netherlands]

I once investigated sticking a copper plate and copper tubing to the back of a solar panel, but I never got around to actually build it.
I did not proceed to the point where I did the optimization of the distance between the tubes and the thickness of the copper plate.
Of course aluminium would be better than copper, but the welding is less simple than soldering.

I was planning to use this pump:
https://www.amazon.com/temperature-1...=cm_cr_pr_pb_t

[tomtriad]

A friend of mine installed a small tank under his deck with a black plexiglass light flush mounted on deck. Gravity feed from overhead down a tube with conventional hand held showerhead attached. Thermometer inserted in tank from the side to check temperature so as not to scald yourself with overly hot water (boat lives in the Caribbean). Cold water pumped up to reservoir with a hand or foot pump in the head compartment. The other ingenious feature was a Y valve on a gusher type pump which would clear out the sump under the shower area (no shower water into bilge) or evacuate the Lavac head. No electricity, minimal plumbing, nice hot showers.

[mako]

Originally Posted by ssmoot

A 2m² thermal heating panel will heat about 50 gallons of water in a tropical area. It would take about 10kWh to do the same job.

So it's much much more efficient to heat with thermal panels.

I think this common trend has more to do with the fact that houses don't really lack for installation space, and the cost of extending an existing solar electric design with another 2 or 3kW of solar electric panels is lower than the labor cost of plumbing in a secondary thermal system.

On a boat, where space is limited, I think the gunwale idea is one of the more clever ones I've ever seen.

A hot water panel is probably multiple times more efficient at transferring solar energy to water versus going the electricity route. No argument.

And your comments were basically my response also, to my architect as well.

The issue is that you and I were both looking at this from a tiny perspective. Think of this more holistically. You use only a small amount of hot water daily, even in a home. Yet that solar panel up there is sitting there, wasting the sun's energy all day long. Day after day. With an electric-methodology, the electricity is being transferred to the grid, your batteries, your inverter loads, etc., day after day after day.

So it is a much more efficient/effective use of space and investment of money.

However your comment smoot about boats being different than a huge house roof is very much noted. Especially on a small sailboat with low electric demands and little room for panels. I like the idea of hanging a long, skinny black collapsible tube vertically by the halyard. Hoisting it up. Perhaps tied into a water tap on deck - gravity hot water!

[simonpickard]

One question (hopefully related to this).
If you have a lot of free solar can you use an inverter to heat the hot water? Are any systems designed like this?

Regards,
Simon

[mako]

Sure. Great idea for excess power. Just make sure your battery bank is disconnected from the inverter first. Or you can goto Harbor Freight Tools or Walmart and buy a cheapo MSW inverter that is dedicated to the heater

[senormechanico]

Originally Posted by simonpickard

One question (hopefully related to this).
If you have a lot of free solar can you use an inverter to heat the hot water? Are any systems designed like this?

Regards,
Simon

That's what we do as have several others on CF.