Is a triple coil calorifier overkill?

[nb Innisfree]

I have been pondering the heating design for our new boat and am still undecided which route to follow.

 

As far as I can see the main options are:-

 

Diesel boiler i.e. Webasto.

Engine heating

Immersion heater

Solid fuel backboiler.

 

All appear to have their own benefits depending on the situation. (and the associated drawbacks).

 

The boat will be a liveaboard and there will be times when we are cruising but I imagine most of our time will be spent moored up.

 

The ideal for me would to have the engine provide hot water when cruising, the back boiler during the winter, the webasto for convenience during the summer or if needed in the mornings before the fire is stoked and/or if away from a shore supply and the immersion for when hooked up.

 

I have found a website that will supply a triple coil tank for an additional £50+VAT so in theory I could have all the systems installed and pick which ever one is needed at the time.

 

Has anyone tried this and if so do you think it's worthwhile going to the extra expense?

We have used 2 single coil calorifiers plumbed in to CH, these can be heated by Mikuni, engine, or immersion heater. Only drawback is having to turn rads on and off in the spring/autumn. Intend to fit backboiler to SF stove and circulate with Mikuni pump

 

 

It's been done and Chris Pink would be a good person to ask about the technicalities, however you'd have to be quick as amongst the new stove installation guidelines -which if you search for "don't complain"- you might find-; banning pressurised systems running from fires is one of the less draconian measures that are mooted. They're not law yet and whether you'd keep any transitional protection is subject to debate.

I can't see why a s/s backboiler couldn't be used to gravity circulate water around a calorifier, it would need an auto air vent to keep it air free, no reason why pressurised water can't thermosyphon. Existing PRV would act as safety valve in the normal way.

[steelaway]

I thought of that but was told that calorifiers did not work well trying to achieve a heat transfer function.

 

Rather than engine heat just supplying a calorifier coil, I fitted a Bowman tubular heat exchanger in the CH circuit so that the engine heats the whole CH system, radiators and calorifier, still using the engine calorifier connections. An engine probably generates more waste heat than a dedicated CH boiler.

 

 

Hi

 

I have just fitted a Webasto circulating pump into the CH coil (top one) of my calorifier.

I am amazed at the amount of heat exchanged by the calorifier water heated by the engine coil (bottom one).

The CH rads are all hot after only 45minutes and if you do need the CH boiler when you stop, the water is already pre-heated.

You must have a switch to stop the pump or you will steal all the hot water when the engine is stopped.

I piped mine into the tee of to the calorifer from the CH boiler, the pump will probably stop the circulation of the CH boiler to the calorifier coil but never have the boiler heating the water. The boiler (4.5 Kw Eberspacher) is only just good enough to supply the CH.

Obviusly the temperature of the rads is governed by the engine temperature - so if you run at 70c thats the temperature of the rads, although mine gets up to 80c - so its toasty.

Well worth the £50 it cost to install.

 

Alex