combination passive solar collector + rocket stove water heater design / critique

hello permies !

looking to get some feedback on this novel solar / wood fired combination water heater design

this will go into a straw bale house at 8000' in southern colorado, design priority places an emphasis on anti-fragility

primary heating element : a passive solar heat collector using a thermosiphon glycol loop copper tubing heat exchanger inside the water tank, preferably WITHOUT a pump involved. would also like to have the ability to further heat the water using an integrated rocket stove, for cloudy days or occasions when more hot water or hotter water are desired

- will commission a welder build / modify a custom water tank that allows the upper end of the rocket stove barrel to to nest under it for conduction heating
- solar loop in / out connects to a large passive solar water heater on the outside of the south-facing wall

have seen quite a lot of rocket stove water heater vids on youtube but most of those are using copper tubing to make a heat exchange loop around the rocket stove interior J-flue. have not seen anyone attempt to nest the barrel under a water tank for direct heating via conduction, which seems like a simpler approach. can't imagine why it wouldn't work ?

( see attached illustrations )

some considerations :

- water tank will obviously need an aperture at the top to prevent pressure build-up
- this system is envisioned as very hands-on / monitored while heating using the stove - if temp gets too high / water boils solution is to let the rocket stove fire die and manually add more water from the well inlet
- rocket stove exhaust outlet run under a short ( likely cob ) bench and up through the roof
- weight of water tank is supported on ring stand with legs / rocket stove bears no weight
- water tank will be well insulated

- servicing the interior of the rocket stove barrel will prove challenging in this setup. if the j-shaped chimney inside it built of high quality refractory bricks how likely / often would one expect this to pose an issue ?

purpose of this water heater : provide hot water to the kitchen sink, bathroom sink, and a small soaking tub

- soaking tub will be insulated and exposed to incoming sunlight on the south side, so it should be possible to get the water in there lukewarm by end of day before adding any solar / wood heated water to bring it up to soaking temperature

- daily use will require filling the water tank in the morning so the solar collector can heat the water and using the soaking tub in the evening

anything i'm missing / misconstruing / missed opportunities before i attempt this ?

thanks for your time and attention ! 🙏 ✨