Runing radiators from calorifier

[Strettonman]

Hi all, 

 

I’m planning to gut an old boat I’ve just bought and thinking about the appropriate water and heating solution. We plan to cruise rather than live aboard and space is tight so I don’t want to have a boiler and the log burner is not a back boiler so I’m thinking the main heat source will be from the engine with a back up immersion in a calorifier (I’m thinking of having 3 or 4 big leisure batteries). 

For the heating we’ll normally rely on the log burner but need radiators in the bathroom and bedroom (and maybe in the lounge) to take the chill off before we go to bed and first thing in the morning. Ideally I don’t want to run the engine so I wondered whether it would be appropriate to use the second coil of the calorifier that is normally used to add heat to the tank by a boiler to run it through the radiators. I guess I would need a small radiator pump and size the calorifier as large as possible so as not to reduce the hot water temperature too much. 

Really I wanted to know whether this is a good idea or fraught with problems.

[Tony Brooks]

The heat stored in a calorifier is probably no where near enough to warm a bathroom and bedroom - think of the water capacity of the calorifier when compared with the rads and then how log the rads would need to stay hot to warm the rooms. The calorifier will be cold by morning and you will need to run an electric pump.

 

Immersion heaters  are the finest way to ruin battery banks UNLESS you run them off a shoreline, generator, or excess solar power but the latter will not be available for most of the winter.

 

1. Do a power and charging audit for your electrical needs - then modify your needs until you get some kind of balance.

 

2. Sell your stove and get one with a back boiler - pipe the rads to run by gravity circulation rather than being pumped if possible (electricity use).

 

3. Find space for a boiler be it gas or diesel but remember most boilers also demand electricity to run so back to the power audit

 

 

Sorry but its a steep learning curve this boating lark.  You can run radiators from the engine but they will only be heated when the engine is running there are several ways of doing this and one involves the calorifier but that is not the best method and is a bit of a cludge although it does use excess engine heat but again only when the engine is running.

[Momac]

I don't think the residual heat in a calorifier is going to provide much energy after an overnight stop.

You would be better having a diesel heater , of which there are hot air and hot water types.

[koukouvagia]

If I turn off the diesel heater (a Refleks) and forget to turn off the central heating pump, by the morning  heat has been transferred from the calorifier leaving it and the radiators stone cold.  As others have said I doubt your idea will work.

[Dr Bob]

You can't run the immersion heater from batteries. You'd need many more than what you have and then how do you replace that power? 

A lot of peeps have a solid fuel stove to heat the lounge end of the boat and an eberspacky/ webastuff sort of heater to do the rest of the boat by radiators and heat the cauliflower. Siiiiimple.

[blackrose]

49 minutes ago, Strettonman said:

... so I’m thinking the main heat source will be from the engine with a back up immersion in a calorifier (I’m thinking of having 3 or 4 big leisure batteries). 

 

It I've understood correctly you're thinking of heating water with your batteries (via an inverter to the mains immersion)? 

 

If that's the case it's a bad idea. You can use batteries/inverter to run high power mains appliances for a short time (i.e. a toaster) or for a longer time (washing machine) with the engine running to charge the batteries at the same time, but I really wouldn't set up a system that plans to do this for a long time every day. If you're not on a mooring with shore power then save your batteries for low power draw items like lighting, etc.

Edited February 17, 2019 by blackrose

[Strettonman]

Thanks all for your comment. 

I will go back to the drawing board - that’s the beauty of this forum ?. 

Ive been considering a diesel heater next to the engine but there seem to be concerns about noise - comments like sounds like a jet engine. 

Are there good alternatives for compact gas boilers in the kitchen - but my main concerns is the space a hassle of a flue. 

 

[Dr Bob]

8 minutes ago, Strettonman said:

 

Ive been considering a diesel heater next to the engine but there seem to be concerns about noise - comments like sounds like a jet engine. 

 

 

Yes but that is the norm. Prolly the best way to 2ndry heat a boat. 

[Boater Sam]

The best way to heat a boat by far is a good solid/multi fuel burner with a back boiler feeding radiators and calorifier by gravity only, easily available fuel and no battery drain.

[Flyboy]

47 minutes ago, Strettonman said:

Thanks all for your comment. 

I will go back to the drawing board - that’s the beauty of this forum ?. 

Ive been considering a diesel heater next to the engine but there seem to be concerns about noise - comments like sounds like a jet engine. 

Are there good alternatives for compact gas boilers in the kitchen - but my main concerns is the space a hassle of a flue. 

 

My Webasto Top C is fitted with the correct air intake & exhaust silencers and is hardly noticeable when running.  Too many diesel heaters are unsilenced & have very poor instalations that get them a bad name.

[roland elsdon]

Our water heater is  a 12v 10 litre mains/ battery operated rv device.

 

its 300w at 12v so 25 amps approx 

its only turned on when the engine is running and the batteries have been on charge for at least an hour so the advec  doesnt add to the load.

 

the heat produced at the alternator is phenomenal ( well 300w plus losses) alternator life is reduced.

 

induction heaters do not work well of 12v.

 

( and yes i know but we boat long days ,have little room  a solid fuel stove and aircooled engine., dont  live on the boat in the winter, the planned rebuild includes a refleks stove and calorifier somewhere)

[Sea Dog]

3 hours ago, Strettonman said:

...thinking about the appropriate water and heating solution.

Don't think about anything to do with your boat with  a clean piece of paper in front of you. Research ad infinitum what's popular or standard practice, look at other folk's innovative ideas and how they got on, then see what best fits your boat and situation.  Don't try to be innovative yourself until you are experienced and really familiar with the issues because, at this stage of the game, if you feel you need to invent it's quite likely you're missing something.

 

[system 4-50]

33 minutes ago, Sea Dog said:

Don't think about anything to do with your boat with  a clean piece of paper in front of you. Research ad infinitum what's popular or standard practice, look at other folk's innovative ideas and how they got on, then see what best fits your boat and situation.  Don't try to be innovative yourself until you are experienced and really familiar with the issues because, at this stage of the game, if you feel you need to invent it's quite likely you're missing something.

 

This is the absolute nub of the matter.  It needs to be carved in steel letters sixteen metres high next to the angle (90degrees) of the north (assuming the pole hasn't moved over the weekend). No, but really.  It needs refinement from a good wordsmith and compacting, until it becomes an industry proverb known to everybody.  "Do not invent new solutions until you know exactly why everbody else does it differently unless you have money that you can afford to waste". 

On reflection, si ti sa tcefrep si it.

[Johny London]

As others have said - just get a Webasto. It will heat your water and your rads. They are not noisy actually - there is a wind like roar that comes from the exhaust but it isn't very loud nless you put your head down by it (don't 'cos the exhaust is hot!), the only thing you will hear inside the boat is the tick tick tick of the pump pump pump.