How long can you idle a diesel for the hydronic heat?

[chrisncate]

How long can you idle a diesel for the hydronic heat? I am thinking about going at the heating issue at anchor in two ways, one being a hydronic heater and the other being a solid fuel bulkhead heater.

The thought being that the wood heater could suffice most of the time, but for the really cold nights and coldest part of winter, a hydronic heater that runs off the engine heat for real btu's. Can you safely idle a Yanmar 2GMF20 all night long occasionally, or even consistently for a month or longer?

A hydronic heater that puts out 40k btus is under $500 from defender, and the small solid fuel newport is probably about $550 with all the hardware needed.

For an Alberg 30 btw..

?

[centaursailor]

Can,t beleive this a serious enquiry from an enviromental perspective.
Running any disel engin for prolonged periods with little or no load is not recomended.
Bore glazing would damage the engin and is very costly to repair.
The low levels of fuel efficiency for running the engin to produce heat which is a by-product of propulsion must be staggering. There are several disel cabin heaters that run independent of the engin and have relativly high efficiency ratings
Any alternative must be a better proposition.
Regards
Brian

[LakeSuperiorGeezer]

Unlike gasoline engines, diesels are very efficient at idle. Not enough heat is generated to bring the engine up to temperature. I am saying this because I know at rest areas where trucks park, it is known fact that you cannot heat a cab with an idling engine. Combustion is going to be incomplete and you can get slobbering; also you can get plugged exhaust ports in the engine.

[ffiill]

Confused-surely hydronic heaters are the likes of Webasto Thermotop?
which is a minature version of your keroscene fired central heating boiler or in a more basic form the pressurised keroscene/diesel stove.
Fuel oil is pumped under pressure through a jet and ignited by a spark plug.There are the versions which then provide blown air but in the Hydronic version it circulates engine cooling water from an indirect cooled engine through minature radiators with or without fan blowers.
Primarily was designed to keep automobiles and trucks warm overnight in arctic conditions without having to plug into a mains water heater.
Having said all of this I find my gas cooker loaded with a couple of dense concrete building blocks very effective.
If I were however living aboard I would go for the Davys Hotpot solid fuel stove made over here in UK but I believe marketed world wide.A lovely marine minature solid fuel stove which lives up to its name.
I live with a multifuel cast iron box stove at home and guarantee there is still nothing like them to space heat whether by wood;coal or smokeless fuel..

[bacampbe]

Originally Posted by ffiill

Having said all of this I find my gas cooker loaded with a couple of dense concrete building blocks very effective.

Interesting. Can you elaborate?

[Faster]

Originally Posted by ffiill

Confused-surely hydronic heaters are the likes of Webasto Thermotop?
which is a minature version of your keroscene fired central heating boiler

Our last boat had a fan-equipped heating coil in the engine FWC circuit - similar to whats known as a 'bus heater' and pretty much what's in any vehicle for interior heat. These will only provide heat when the engine is running at temp.

There are, of course, diesel fired hydronic heating systems as you describe that are independant of the engine for a heat source. Sounds like the OP has the former.

I'm not sure the glazing issue (often debated, btw) is as much of a concern at low revs that at high revs unloaded, but as mentioned from an environmental angle (not just smell/emissions, but noise and vibration) running the engine solely for that purpose doesn't make much sense. I suspect it would be a rather expensive method as well, if you crunched all the numbers (added hours, maintenance, fuel etc)

For a bit more money the Dickinson Propane fireplaces are the deal, perfect for an Alberg 30, with it's limited interior volume, fully vented and safe to use and if you already have propane on board for cooking, the fuel system is already there. Also, the package includes everything you need, including the deck vent/intake, dual flue and mounting plate. Be sure to price any other system on the same basis.

http://www.dickinsonmarine.com/Specs...9-P12-2008.pdf

[jrd22]

Unfortunately, as others have said, you won't get much heat out of the bus heater you are talking about unless you run the engine rpm's high enough to open the thermostats. In cold weather you would probably have to put the transmission in gear and run the engine at full cruise speed to generate enough heat. Been there, done that (one very cold night in our crab boat).

Faster's suggestion about the propane Dickinson is a good way to go.

[dupek]

As truck driver, I can said that you can idle for any prolonged time you want and does heat cabin ( as someone stated opposite) in cold night. The only requirement is "bump" the RPM. On truck normal RPM is 550, but need to be bump to 750-800. On small engine, I would bump 50 rpm and should work as long as you have a fuel. The problem arise from ecological point of view. Air and surrounding pollution. At low rpm, some unburnt fuel will go to water. No good.
LP gas generator would be the answer, but it is expensive.
I would choose LP gen to heat up the boat with ceramic heaters.

[P35juniper]

If you can find a way to load you engine, say add a generator to it, for a 2GM20F it would be about 8KW, draw about 6KW as electric heat and recover the heat from the engine, its called combined heat and power, this setup is very efficient, diesels combust very efficient when loaded, better then 90% burn, you get about 20% rotation, the rest being heat, so with a CHP unit it is better then most house heaters,
next question, do you want to run up 720 hours amonth on your engine?

[ffiill]

Originally Posted by bacampbe

Interesting. Can you elaborate?

Got the idea from what over here in UK are called night storage heaters-at night electric element draws energy from cheap rate electricity and heats up a load of concrete blocks inside heater. During day heat is released.
So same concept but you heat up blocks and cabin space in your oven during day and let them release heat with no danger of carbon monoxide at night when its at its coldest.
If you regularly use oven its a problem!