hot water from fire and sun

Hello great people.

Is it ok to ask if anyone here has experience with heating water with water pipes behind glass (home made or commercial) and/or copper pipes around stove pipe?

I would like to put these two systems, in front of our propane powered hot water tank to save some money.

System One: heating water in poly or copper pipes behind glass (home made or commercial)

System Two: heating water in copper pipes or SS around stove pipe or within burn chamber

I looked for a suitable forum and if this has a thread but could not find?
Please re-direct me if i have missed something.

Thank you!

I found quite a few threads searching with "solar water".  This one :
https://permies.com/t/57410/Solar-water-heater-plans-safe
Seems to discuss quite a few ideas.
Whatever you do you'll have to think about winter cold as well as solar heat.  
I'd really love to add a solar heating system onto our property.  Unfortunately all the useful roofs face E/W, which makes it less viable.  Although in the summer (when we run the cooker which heats the water less) there is much more angle of sun and daylength.  We are 57+ degrees North.

I have used copper pipe around the flue of a wood heater.
I wrapped a full roll of 1/2 inch pipe and led it to a gravity hot watertank
I am not sure a LPG heater will have the same ability to heat the ater

Here's a great reference for anyone thinking about a DIY solar thermal system.
https://www.builditsolar.com/Projects/WaterHeating/water_heating.htm