Flue heat recovery

chrisgeary

I have a newish boiler (Promax SL). It heats the radiators and a hot water cyclinder. The heat from the flue is fairly hot. It is installed in the kitchen which currently has no radiator. When the kitchen is in use, be it cooking or tumble drying, the temperature in there is pleasant. When the kitchen has been idle for a while, the rest of the house is a nice temperature but the kitchen is chilly. I'm debating whether to put in a small radiator (the only place it could go is under the boiler) but then got to thinking about heat recovery.

Most of the systems I've seen seem to be heat recovery to hot water. Does anyone know if heat recovery to a small radiator is possible... or even just to air? Seems wrong to pump out hot air while the very same room could do with that heat in winter time.

John

You would need somewhere to store the recovered heat, hence why it tends to be used to heat stored hot water.

Plumb in a rad

danmc_82

If the boiler newish it should be a condensing boiler which means no hot air would escape through the flue.

If you don't have enough space for a rad. try a plinth heater instead. Goes under your kitchen cupboards and plumbed in like a normal rad.

http://www.heatandplumb.com/acatalog/Smiths_Space_Saver_SS3_Plinth_Mounted_Hydronic_Fan_Convector_with_Brushed_Steel_Grille.html

kindlereader

Here is another alternative: heat exchanging ventilator: HR200WK - Vent-Axia

Axnxdxy

I've been looking at the vent axia heat exchanges like that one to resolve some humidity issues. My understanding is that won't create extra heat for a room, it will retain 60-70% of the heat from the air in the room but pull it through fresh air from outside. So by itself you'll be colder not warmer.

chrisgeary

I don't imagine it is safe to use a heat exchanging ventilator on a boiler flue. Unless the vented air heated recycled interior air. That'd work. But its the sort of thing that I'd like to use in bathrooms

Axnxdxy

No. Apart from anything those are designed to go through the external wall of the house!