I have a 30x40 woodworking shop, I installed a small cast iron stove, that I burn scrape wood in, on days when the temp. is down in the teens it takes for ever to heat the shop to a temp. that I can work,I wondered if a heat exchanger would be worth while.
Heat transfers through the metal surfaces of the stove and as it travels up the flue (vent) pipe. Consider venting through lots of vent pipe that has a lot of surface area to transfer the heat into the room. The vent pipe can be the heat exchanger you speak of. If the heat were to be vented out in a direct straight shot, that would let the heat escape before transferring to the room. If it winds through lots of vent that is in the room, that will allow more transfer to the room.
That is a big shop for a small cast iron stove. Roosters idea could cost a lot of money by the time you put in all the 90% and cut all the short pipe. The box fan is a better idea. The scrap wood from your shop might plug a heat exchanger. Look for reason in your flue, if there is not a lot make sure you have a fan pushing air through the heat exchanger.
I LOVE IT, THAT KIND OF STOVES THAT IS. I JUST USE A BOX FAN IN FRONT OF THE STOVE TILL THE AIR IS CIRCULATED IN THE ROOM. ONCE THE ROOM IS WARM I USUALLY HAVE TO SHUT IT OFF BECAUSE IT GET TO HOT TO STAND
