flu pipe heating coil

Good day all
i have a wood stove on the ground floor with a section of exposed flu pipe that i could wrap a coil around to capture heat for the next floor up. I was wondering what a simple system may look like with a coil, two radiators, an expansion and emergency pressure release. I was wondering if it i should consider water or oil for the heating fluid? any help appreciated..... I also have underfloor heating ran off an on demand baxi boiler but it would probably be more difficult to integrate into that system and part of the idea is to leave that on low and use the wood stove to quickly take the cold nip out of the air. ...... just in case as well i would probably want to have three or possibly 4 radiators (the top floor consists of two bedrooms, a landing and a bathroom), as they would all be at the same level i guess i would also need some kind of pump ran off a thermostat?
Cheers all
Tonino

That is a catch 22 because if you put in a coil and it is effective, it is probably going to draw down the heat in the stove pipe so bad that it starts getting poor draft, or becomes a creosote-maker; neither of which is good. Yet if a person maintains good draft, then the heat pulled is often not really worth the time and expense of doing!

As I said, a catch-22.

Sadly, there is no replacement for BTU's. If a house is cold, then it needs o be upgraded to a larger heating appliance, or a secondary one added.

It is possible that one area of the house is overheated, and another area underheated, at which a homeowner has to figure out a way to move the heat from the too hot area, to one that is too cool. That statement does not dispense with the first rule cited of having no replacement for btu's, because a person is just moving heat around better. That can take the form of duct work, fans, or in terms of boilers, plumbing and valves.

I tried using tubing on a flu pipe and it had troubles absorbing heat.  I used 50ft of ½” copper tube.  I would have to get the flu about red hot to make the water 130 deg f.  I improved it by rapping it with copper sheeting to catch more heat and add it to the outside of the tubing.  I used a little taco pump that sucked from a tank that was vented. I ended up using a small ball valve to slow the flow down to pick enough heat up.  It worked, but not as well as I hoped.  

thanks for the reply guys! hmmmm.....  i do have underfloor radiant which is heated by an on demand boiler and this does heat the house even, it is just that i keep it at a constant temperature and when we get a cold day or night snap then i use the log burner to take the nip out of the air but it needs to run for a long time before the ceiling fills up and it can get out the double doorway size opening threshold. May be the best thing to do would be to install some kind of hood over the top of the wood burner to collect and divert some of the air to the floor level above, the chimney has an extra chase i can use for it; i guess a low flow fan could also be incorporated and as the chimney is in the middle of the house i can vent to both sides upstairs.???

What I am heating is that the in floor radiant heating system take 2 plus to warm up and you want something to warm up in an hour or so. There is hope you can improve the system by:

A) Increase the flow rate of water in the system. with less dwell time, the temp of the exit water can be 110F
B) Increase the input temperature of the water. with higher input temp, the temp of the exit water can be 110F
C) Increase the BTU/heat per hour of the hot water heater, install 2 unit vs just 1, or get a higher powered on demand/small tank unit.
D) Increase the amount if loops in the floor
E) Place a new loop/fan-coil unit/radiator on the wall or ceiling.