Underfloor (and radiator) heating plan

[alifraser88]

Hi Canalword!

 

Friday scheming/dreaming...

 

In our boat, we have a little Torgem multifuel stove in the bedroom, which is to the bow. Then, going aft, there is a loo on one side and a shower on the other, followed by the lounge area and finally the galley then the cruiser stern. The heat from the stove has a terrible time getting out of the bedroom, and an eco fan doesn't seem to do the job (we may also get a bigger eco fan). This is the reason we are considering replacing the Torgem with something with a back boiler (unless you can retrofit a back boiler?).

 

The plan is to run a back boiler system with pipes through the shower, to 'radiator 1' in the lounge and 'radiator 2' in the galley (optional, as in, it can be cut off or opened as a part of the circuit in an overheating event/when the water becomes really hot). However, from rad 1, the outlet would go under the floor (we have great access to the cabin bilge via sections that can be lifted), through some coiled up tubes and back up by the stove, pretty much all circulating on thermosyphon principle. I'm pretty sure that won't be enough to keep the water flowing, especially if the return pipes make a trip under the floor... so, an impeller on the return just before re-entry into the back boiler - powered by TEG (peltier chip) with the cool water on one side and the hot fire/back boiler on the other side?

 

Haven't really thought about the specifics in too much detail, but if there are any glaring holes in my plan please point them out. this is more like a theoretical exercise, as we've got loads of more pressing jobs to do... and apologies for the diagram...

 

Thanks,

Alistair

oops, here's the diagram

[canals are us?]

Header tank needs to be at the highest point to release trapped air in the system. Personally I wouldn't run the pipework through from one rad to the other. It would be better if you used 28mm copper and tee off this gravity pipe to each radiator top tappings controlled by full bore lever valves. I personally wouldn't install the undefloor coil as unless rigorously insulated you would get condensation on the baseplate. Running the return pipework under the floor may impede gravity circulation. it would be much better if you ran the return from the second rad sloping down to the stoves return inlet on the boiler. This way you wouldn't need a pump.

 

James

[Robbo]

The stove will be too hot for connecting directly to the UFH, you'll get a warped floors if you do that. If you look at UFH systems you'll see they have a pump and thermostatic mixing valve.

[Tiggs]

I personally wouldn't install the undefloor coil as unless rigorously insulated you would get condensation on the baseplate.

James

Agreed - not a good idea.

28mm copper

 

Yes, large dis pipes are key to convection circulation