Why did you use circulators to control every room in your home instead of using a manifold and TRV's?
to answer your questions
I would come off of my primary loop to a circulator and then directly into a manifold, so 2 manifolds I would have 2 circulators,
I suppose you could come off of the primary loop through the circulator, and tee to 2 manifolds.
I currently have 2 - 14-15k BTU radiators, 2 - 9-10k BTU radiators, 1 - 10.5k BTU radiator, A Vaughn Top Performer 70 gallon 150k BTU indirect water heater. I'm going to be picking up some more radiators in the next few weeks.
The long term plans are that the additions box most of the east and west sides of the stone house, making exterior walls interior walls. The south side is going to get a solarium. I would want the new construction to e controlled by one circ/manifold, and the stone house controlled by the other.
I see our posts crossed, so let me get this one
1. Why circulator to every zone- Each zone has a thermostat and circulator. When a zone is triggered, the primary pump runs, too (and boiler if it needs to), until the zone is satisfied. Using closely spaced tees allows each zone to be independent, not really required to be "balanced" against other zones in the system. Each zone takes the same amount of flow as it returns, leaving the water cooled slightly (based on volume, heatload of that zone, etc), but essentially unaffected balance-wise.
Using different length zones with different piping, number of radiants, mixing baseboard with convectors with radiators or whatever is all simple. Each zone uses split tees, so I balance the zone with ball valves to get equal flow (precision not required) and that's it.
Adding or removing zones or loads don't bother the main system/primary loop at all.
2. Why not TRVs- IMHO, they are much less capable than thermostats. For not much $$, you can have time of day, day of week, vacation setbacks, turn it up when using that room (ie this Christmas we had lots of company, so turned up temp in dining room/kitchen). Much better control over zone temps to meet our needs. Eventually we plan to have a system-wide electronic control setup.
TRVs are PHYSICAL valve devices. I have seen them and standard valves fail, both from constant use and then from use after not being used for a while. Some have had good luck with them, look to them for experience in that area. I'd much rather stick with on/off of circulators. (In all fairness, a similar comment is possible about zone valves, but not exactly)
3. Power usage- since you want to be off-grid, that is a question you will have to answer. If not for that single (very LARGE) requirement, the simple solution would be just buy circulators and use them. Keep one spare that will swap into any position and be done with it. But that may not be your best solution, power wise?
Some folks may be very good at balancing a shared circulator (describing the situation, not sure that is a valid term) system, or even gravity flow systems. I am not.
IF you were able to get it all gravity flow and working without any circulators, that would be ideal, but that's a pretty lofty goal, loaded with gotchas. I personally wouldn't tackle that. Our needs and house changes/remodel would likely make it impossible anyways, LOL.
If I had to be completely off-grid, I'd be looking hard at battery storage capacities, the daily usable solar window, historical "days without generation" etc. and then still have an alternative (generator?) for emergencies. Clearing snow from collectors is not an unimportant task in the winter.
Bear in mind that "no hydronic heat circulation" doesn't just translate into "cold" it can cause freeze damage(!) I'd certainly be using anti-freeze additive (some here can better direct you), in case you have to cut back heating certain areas in the winter.
We have 2 ventless propane free-standing stoves that are attractive and can provide livable warmth in a pinch. I figure we have 3-4 days before the thermal mass of our house puts our hydronic lines under threat, and then I can simply isolate those high risk areas with valves if it really comes down to that. But by then we'd either have the generator going or move portable propane/kerosene heaters into the basement to mitigate.
Big long story, I know, but being off-grid is a MAJOR factor that you'll want to consider in all areas of your system design.
Hope this gives you at least a little bit of help