Not really - its not a pressurised system.
The device above is really just to keep the boiler (the water part) hot as, otherwise, the boiler would heat at the same rate as the thermal store.
If this were the case, you would have a cold 'lump' in your fire, which would cool the burn. If a fire burns cool, then half of the combustible stuff just vaporises, and goes up the chimney, without actually burning (ie giving off the energy - the bit you want).
So, the idea is that the unit keeps the back boiler, or water jacket as hot as is feasible before gradually letting the hot water creep into the thermal store. If you stoke the fire more, it opens up to compensate, but, if the fire dies back, it reduces the flow, so as to always (try) not to cool the burn.
Ahh, but maybe you were commenting on the thermal store? In which case, yes.
You burn the fire fierce (and efficient) for a short time, store the heat in the thermal store (also called accumulator tanks, or buffer tanks) and then the fire goes out, and you still have the heat.
Our thermal store will be about 900ltrs. I have not done the sums, but that's not even a great deal of volume (they're often 1500ltrs or more).
The rayburn in the photos is old tec, and about 4kw to the water, so not much (and it will probably be on a lot of the time) but we have another log burner which is 17kw to the water.
I worked out our homes energy consumption, and its about 60kw / day in the winter (high - it still has holes in the floor) - this means that a burn of about 4hrs on the larger stove should run the house for 24hrs.
