Efficient Diesel Heating

westernman

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I see a lot of people on here have no end of trouble with various heating systems such as Webasto and others.

It seems to me that things would be much simpler with a simple hot water based radiator system with the heat provided by the generator heat exchanger.

If the generator does not run enough to provide enough heat, then use the generator to power an electric heating element for the hot water. The heating element can be sized so that you can optimally load the generator. That way it will heat the water up with a combined efficiency (electric plus heat exchanger) of around 85% which is close to what you can get out of a decent domestic central heating boiler.

The rest of the time (when you need the generator or main engine for other things) the heat is for free!

Where is the down side?

Why do people install complicated Webastos, Mukinis or whatever?
 
Where is the down side?

A generator is a diesel engine, which are known to cause trouble? :-) Also quite noisy, unless you have a fancy one in a hush box, and that costs more than a diesel heater.

If you want to learn about efficient and reliable diesel heaters, look to places where it's really cold. Baltic fishermen love their Refleks drip diesel stoves. No electronics, no pumps (ok, fuel may need to be raised into a day tank or some such, but that could be done with a simple hand pump), no arm thick ducting snaking through the whole boat. On larger boats, I've seen the setup where a copper spiral is inside the Refleks, which circulates hot water through radiators, so you're onto something with that part of your idea.

And there is a hot plate for a kettle on top, so you always have hot water for tea.

The Wilts, a famous German cruising couple, which unfortunately doesn't write in English, but did spend an arctic winter on Deception Island also swore by their Refleks, as well as a simple wood/coal burning stove (fired with coal dug up from an abandoned English research station that was buried under ashes when the local volcano last erupted - it's a fun place that island). They had an Eber/Webasto (forgot which) on the boat as well, which died from water ingress before they even got there.

Strandung%2063.jpg
 
Apart from the problem of finding room for radiators, not all of us have generators which, when running, are almost as noisy, smelly and anoying to vessels moored nearby as a main engine.
 
Most people get their eberbastos to work reliably.
The downside of generators is that they are noisy on a small boat.

The talk of optimally loading the generator doesn't wash, the heater matrices or rads will only take the heat they need, so your engine will either be running light or short cycling.
Once the heating is up to temp, you may only want 1 kW or so.
I think this scheme only makes sense on a big boat with effective soundproofing.
Unless you can create a small truly quiet engine to run on red diesel.
Wispergen stirling engines never seemed to sell?
 
My Webasto has been used a lot for 10 years. I sent it off to JPC in Norfolk to get an F10 fault issue looked at. Came back £50 inc postage.
Not expensive or unreliable.
I wouldn't mind a radiator setup though, which would also do the hot water.
 
I see a lot of people on here have no end of trouble with various heating systems such as Webasto and others.

It seems to me that things would be much simpler with a simple hot water based radiator system with the heat provided by the generator heat exchanger.

If the generator does not run enough to provide enough heat, then use the generator to power an electric heating element for the hot water. The heating element can be sized so that you can optimally load the generator. That way it will heat the water up with a combined efficiency (electric plus heat exchanger) of around 85% which is close to what you can get out of a decent domestic central heating boiler.

The rest of the time (when you need the generator or main engine for other things) the heat is for free!

Where is the down side?

Why do people install complicated Webastos, Mukinis or whatever?

I assume you already have a generator fitted as otherwise it would be a poor investment to fit one and run it purely for the hot water. Not a very efficient use of the diesel fuel. I love my eberspacher. It works perfectly. Most problems that people have with eberspachers, and the other makes, are related to poor installations or poor maintenance. Please do fit the optional silencer to to exhaust of the eberspacher otherwise you annoy your neighbours ☺

Colin. Www.solocoastalsailing.co.uk
 
My Webby has been used a lot and is utterly reliable, efficient (uses a tiny amount of diesel) is quiet, heats the boat toasty warm in a few minutes. Don't think it could be any better really. I love it.



There, that's done it. Bet it will blow up now.
 
I ran my last Eber D4 on kerosene which keeps the burner clean and the exhaust outside the boat smells sweeter. This advice was from the US Espar website, but wasn't shown anywhere on the Eu site.

Didn't have that much use from it, but when ever I started it it always started first time and ran very well.
 
I assume you already have a generator fitted as otherwise it would be a poor investment to fit one and run it purely for the hot water. Not a very efficient use of the diesel fuel. I love my eberspacher. It works perfectly. Most problems that people have with eberspachers, and the other makes, are related to poor installations or poor maintenance. Please do fit the optional silencer to to exhaust of the eberspacher otherwise you annoy your neighbours ☺

Colin. Www.solocoastalsailing.co.uk

But it is efficient - if you use the heat from the generator to heat the water as well.

Actually the real problem might me that you need a rather small generator to make this work.
A 4KW generator will at 75% load generator generate 3KW of electricity and about 6KW of heat of which you could probably recover up to 4.5 - 5KW through the heat exchanger.

You need a rather big yacht to need that amount of continuous heating. And that rather big yacht probably has a much bigger generator........
 
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I owned a Swedish built boat, 30 ft, fully encapsulated keel (there were / are many boat builders over there). It has gas fired central heating built in. Low level radiators. Absolutely brilliant. Can't remember the brand....Gastherm or something similar.
 
Please do fit the optional silencer to to exhaust of the eberspacher otherwise you annoy your neighbours ☺

Colin. Www.solocoastalsailing.co.uk

I'm sure that there have been warnings posted in the past (from our resident Eber dealer/expert whose name I can't recall) that you must not fit the Eber exhaust silencer in a boat installation because its simple crimped construction means that it isn't gas-tight. It was designed for mounting underneath vehicles and would be dangerous inside a boat - possible CO poisoning etc.
 
Eberspacher and similar heaters are close to ideal for the job they do - a lightweight, compact package heating a relatively small space quickly, economically and cheaply. Mine has been installed for something like 15 years and was initially used a great deal. We have never had any problems with it. However truck drivers who use them for overnight heating might well use them daily for weeks or months at a time, presumably with near-total reliability.
 
I'm sure that there have been warnings posted in the past (from our resident Eber dealer/expert whose name I can't recall) that you must not fit the Eber exhaust silencer in a boat installation because its simple crimped construction means that it isn't gas-tight. It was designed for mounting underneath vehicles and would be dangerous inside a boat - possible CO poisoning etc.


They do two types of silencer, one with rolled edges and one welded.

Regarding radiators... Why not just cut out the need for a generator
http://www.eberspacher.com/applications/marine/hydronic-water-heaters.html
 
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