What do you all think of this concept?

I am considering building an earth-sheltered, passive solar multi-family dwelling that is much wider than it is deep, and built along an East-West axis.

I like the idea of a Trombe wall but I think I would like to make a greenhouse/conservatory style sunspace instead that doubles as both Trombe wall and a hallway. I had it in mind that instead of building a super-thick wall as thermal mass, using water to store thermal energy would be highly efficient. At first, erecting sealed water barrels came to mind, but then I thought of aquaponics. What if I built a long aquaponics trough in this indoor space?

Thoughts on this idea?

Moisture issues? Other than that,one more system to deal with.
Perhaps a vermiculture grey water system would be better, as in easier to maintain.

It's a good point to consider, but not a deal-breaker, I think. In fact, I'm looking at this in the Midwest, where our winters are quite dry. Adding some moisture to the air isn't a bad thing. Properly vented, an intake at the top of inner wall can draw in the warm, moist air, and return cooler air at the bottom. I'd still need to carefully consider air exchange to prevent mold.

In summer, which is warm and humid, we can remove the "glazing" to create an open-air system, as well as provide seasonal shading to prevent overheating.