Running water-filled radiators off a water-heater/califorier??

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MYStargazer

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Has anyone tried installing small water-filled radiators running off the hot water supply coming from a combined water-heater/califorier?

It's got to be more efficient to heat water using the electric element, then let it circulate around the boat, rather than use a diesel-powered heater, shirley?

Would it need to be pumped around?

I'm thinking mainly of liveabords in Northern climes...
 
hwmbo said:
Has anyone tried installing small water-filled radiators running off the hot water supply coming from a combined water-heater/califorier?

It's got to be more efficient to heat water using the electric element, then let it circulate around the boat, rather than use a diesel-powered heater, shirley?

Would it need to be pumped around?

I'm thinking mainly of liveabords in Northern climes...
Click to expand...

I just did a quick calculation, and my heater - Mikuni MX60 uses 0.58L/hr (High) / 0.29L/hr (Low) High being 7KW and low being 3.5KW - so it would be more expensive to heat water at that rate by electricity for me - plus I could not do it while not on shore power. - How may people heat radiators with electricity in their homes?
Yes it is pumped around but the electricity required to do so in negligible.
 
Did think of going water heater/radiators route.
Would give the option of heating via engine, electric (which some Ebers have I think?) and diesel.

Ended up going blown air....
 
Yes we do, but in a slightly different manner.

We run 4 1/2 kW radiators with the water that is used to heat the Calorifier. So on your boat this would come from the diesel engine.

We have a diesel fired stove (Dickinson Adriatic) this heats water that supplies the Calorifier then the rads then back to the stove on a pumped closed loop. Works a treat. Shirt sleeve environment all year round.

We live aboard, River Medina, Isle of Wight.

Simes
 
Mate was buying a 27ft Swedish boat and asked me to give it a look over. Heat was by a parrafin stove, which self convected hot water through finned pipes under the berth fronts. We didn't try it (Algarve) but if it worked for Sweden, I imagine it would be good for UK. No 'lecky needed.
 
I know a chap who has done it on a Freeman 26. Using direct cooled engine water.

You need a high point that the water can run over at the end of the loop or the system may drain down every time you stop pumping.... just give that a bit of thought. He just put a pipr up the inside of his towel rail top the top, so the system stayed full.
 
About one half of the energy in the fuel becomes heat, of which about 40% ends up in the cooling water. So for every horsepower about 300W of heat enters the cooling circuit. The heat can obviously be used but you wouldn't want the engine to run cool and the other problem would be that to get maximum heat you will need to waste a great deal of fuel and power turning the propeller and going nowhere (unless you were in fact going somewhere).
 
An alternative is to heat with an Eberspacher Hydronic unit. Many are fitted to cars, trucks and motor caravans and they often appear on Ebay very reasonably. The 5 kW unit is compact, comprising the fuel pump, burner and water pump. They can be combined with small domestic radiators but I propose buying a couple of these very compact heaters.
 
My recently acquired Gladiateur 33 came with a rad located under the saloon table, a looped towel rail type heater in the hanging locker and pipework for another small rad in the forward cabin, ( removed by previous owner) all heated by the engine via the calorifier. They certainly do heat up well after running the engine for say 30 mins or longer so in that sense it is "free heat". However rads on board strike me as being similar to a car heater - you have to have the engine running to have a heat source. It is probably best as a partial heat source, used in combination with an air blower.
Also I will be draining down the system after lift out next week. I hope that is successful as these type of systems can be difficult to fully drain. I suspect that the rad removed by the previous owner may have suffered frost damage, maybe not....
 
Like the look of the mini-heater - neat and compact. I don't like the 2.2kW claim when they don't specify the input conditions, though, probably a bit optimistic in our sort of applications.

I've got a Hydronic unit somewhere, fell off the bottom of a Transit van. The mini-heater would allow me to site the heat exchanger in a central location so ducting to either end would be more efficient. It's probably much easier and cheaper to insulate water pipes than air ducts - builders merchants have all the gear on the shelves with no marine surcharge. People with a twin coil calorifier could use a Hydronic as a heat source when the engine isn't required.

Canal boats typically use a coal-fired, pot-bellied stove with back heater and convection flow along the line of radiators, rising from the stove in the bows to the saloon in a straight line. Most sailing boats would not be easy to fit such simple plumbing - we just don't have a nice flat wall to string it along. A small circulation pump should be able to feed small radiators for background heating, though.

Using engine cooling water shouldn't over-cool the engine as it should have already performed that function to pick up the heat! It should be diverted after the heat exchanger and manifold - so it will only be cooler than usual at the exhaust injection point.

Rob.
 
Last edited:
rob2 said:
Using engine cooling water shouldn't over-cool the engine as it should have already performed that function to pick up the heat! It should be diverted after the heat exchanger and manifold - so it will only be cooler than usual at the exhaust injection point.

Rob.
Click to expand...

This may well depend on the engine in question. I believe that running a calorifier from a single cylinder engine can reduce its operating temperature significantly. There has to be a point on any engine where the heat extracted by external devices cannot be balanced by the input from the engine.
 
[Quite, but car heaters divert it before the thermostat so the heater warms up faster. So on a boat, if the engine is big enough to have heat to spare at low outputs, then the circuit should tapped off before the heat exchanger. No point in warming up the exaust injection water. If anything, it might slow the corrosive effect on the elbow if cooler.
 
We are currently fitting a Refleks which also heats radiators. Stove is fitted just need to get a header tank for the deisel fitted and plumbed....
What im looking for now are suitable radiators, no more than 300mm high
and upto a max of 1500mm long. Anybody recommend a type/source for them?
When complete the set up will give us another source of hot water, engine and 240 being the others. and only power draw will be a little circulation pump for the heating.
Cant wait to get it up and running :)
 
I have abandoned the idea of using radiators as I haven't found anything suitable for my boat.
I have an Eberspacher D5W set up in the garage at the moment on test. The plan is to heat the calorifier which is already installed and a fan driven heat exchanger (I do like the look of the mini version but I have already bought a larger version).
The exchanger would provide forced hot air to the aft cabin and heads. The saloon has a drip-feed Taylors which is sufficient for the main space and forecabin.
I will not plumb the engine to the system as experience suggests I need warmth when at anchor or on the mooring.
I could be swayed back to radiators if I could find something suitable.
 
I am currently installing a 2kw electric heating boiler into my water radiator circuit, I intend to use it, along with a 240v domestic circulation pup while in port and mains electric. is available. By fitting a couple of diverter valves, a quick turn of each and when away from mains I can use the diesel boiler and 12v circulation pump. IO tried a smilar set up last winter on a temporary basis and it worked fine, t even heats the omestic water, but that does need a bit of a
 
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