> Assuming no losses, That could heat many dozens of typical Canadian suburban homes all winter.
This honestly seem incredibly optimistic to me. Even a high-end thermos will lose its heat in less than a day. Faster in a cold environment. And afaik, temperature loss is proportional to temperature difference, so the hotter the liquid the faster it cools.
While literally zero loss is a violation of thermodynamics, with a really large tank and good insulation, it gets to self-discharge rates lower than most battery chemistries. A few percent per month. There's a small district heating system in Alberta driven with solar thermal power. It uses a large insulated soil heatsink. Most of the energy input is in the summer and it took four years to fully charge up to operating temperature. It holds enough heat to provide all required heating through the winter for ~50 large houses.
The thermal time constant for a sphere scales as radius squared (one factor of r due to volume/surface area, and one factor due to the temperature gradient scaling as 1/r). Your thermos is quite small.
This honestly seem incredibly optimistic to me. Even a high-end thermos will lose its heat in less than a day. Faster in a cold environment. And afaik, temperature loss is proportional to temperature difference, so the hotter the liquid the faster it cools.