Let's talk about heating with diesel.

[TMG51]

As I ponder my next vehicle home, I would like to use diesel to replace propane in all appliances.

1. I'm certain I've seen diesel wall-mount heaters for RV or marine use, but now I'm having trouble finding them. Any pointers?
2. Am I correct to assume that a diesel heater will produce moisture, just like burning propane does?
3. Are there diesel water heaters available? (When I search for this, I get results for water heaters for the engine, not an RV appliance.)

I see plenty of diesel forced air furnaces available, but that's not what I want. I never use the propane furnace I have now because of the battery draw. Instead I use my catalytic heater or stove top.

I have a tentative idea in my head to use a diesel water heater and tubing throughout the floor for radiant heating. It would require a small pump to circulate hot water. I'm not certain how well it would work, and I would want a wall mount heater for more immediate heat output regardless, but, I kinda want to try it. I think this could be a good source of even heating, and potentially without excess moisture if the water heater is vented. That's if a diesel water heater is an option, of course.

 

[TMG51]

Here's one.
http://dickinsonmarine.com/

Guy

Neat!

Expensive, but may be the best solution. I notice also it says "dry heat" and will dry out a cabin. I wonder, is this because of how it is vented, or does burning diesel not produce moisture the way other combustible fuels do?

 

[tx2sturgis]

2. Am I correct to assume that a diesel heater will produce moisture, just like burning propane does?
 

No because all diesel heaters intended for living space are vented. You do not want to breathe concentrated direct fumes from diesel combustion, in a small space. Diesel that we buy for land vehicles has some additives that cause the fumes to be even more unsafe for inhaling. 

But besides that, the diesel heaters I see for small boats all have a minimum output of 6500 BTU...which is just too much for a constant flow of heat in a van or small to mid size RV, unless you are boondocking in the great white north. 
Of course a diesel furnace could have a higher output since it will be cycled on and off to maintain the set temperature, but yes, it will use DC battery power. 

And repeating my statements in other threads, if you heat with motor fuels, you pay highway-use motor fuel taxes to heat your living space with. I hate that.

Now if you want to keep a supply of Jet-A, farm diesel, marine diesel, kerosene or home heating oil to run that diesel heater with, now we can get on the same page. 

And yes, some states DO offer refunds for motor fuel tax when the fuel is used for other purposes, but what a pain that can be for personal use.

 

[TMG51]

But besides that, the diesel heaters I see for small boats all have a minimum output of 6500 BTU...which is just too much for a constant flow of heat in a van or small to mid size RV, unless you are boondocking in the great white north. 
Of course a diesel furnace could have a higher output since it will be cycled on and off to maintain the set temperature, but yes, it will use DC battery power. 

And repeating my statements in other threads, if you heat with motor fuels, you pay highway-use motor fuel taxes to heat your living space with. I hate that.

Now if you want to keep a supply of Jet-A, farm diesel, marine diesel, kerosene or home heating oil to run that diesel heater with, now we can get on the same page. 

And yes, some states DO offer refunds for motor fuel used for other purposes, but what a pain that can be for personal use.

I'm intending to build something that will give me the option of staying in the cold northeast, if I choose.

I'm not especially concerned about the cost of fuel. Moreso, that I would have many gallons of it on hand in the vehicle's fuel tank. Although, now that I say that, I wonder if these heaters are designed to pull from a separate tank or be topped off in their own reservoir... hmmm... I do believe diesel induction stove tops are designed to be plumbed up to a tank.

 

[Motrukdriver]

Webasto or Espar units

https://www.webasto.com/au/markets-.../heating-solutions/space-air-heaters/air-top/

https://www.eberspaecher-na.com/products/fuel-operated-heaters/applications/marine.html

 

[TMG51]

Webasto or Espar units

https://www.webasto.com/au/markets-.../heating-solutions/space-air-heaters/air-top/

https://www.eberspaecher-na.com/products/fuel-operated-heaters/applications/marine.html

Hm.

So if I'm understanding this correctly, these units install in the engine bay, and deliver heat through the cab air vents, as well as pre-heat the engine to negate cold start.

Interesting. That might be an ideal solution, except that it incurs battery power consumption. Still an interesting option regardless.

 

[skyl4rk]

I had a Fab-All diesel heater in my sailboat. This is similar to the Dickinson model here:

http://dickinsonmarine.com/product/newport-diesel-heater/

It would work well in an RV. It might be more heat than needed in a van. Some other names to search on are SigMar, Refleks, Fab-All. I got mine used off of ebay for less than half the new price. They are vented, and I set up an outside air intake so it would burn better in heavy wind.

You will want the smallest one you can get. They have cookstoves as well but they are expensive.

 

[John61CT]

Hm.

So if I'm understanding this correctly, these units install in the engine bay, and deliver heat through the cab air vents, as well as pre-heat the engine to negate cold start.

Interesting. That might be an ideal solution, except that it incurs battery power consumption. Still an interesting option regardless.

There are air-blower only units, mount anywhere, ideall outside the living space.

As well as the coolant/block heater ones, can also make hot water, radiators / exchangers in multiple locations "hydronic" setups.

 

[skyl4rk]

The Dickinson diesel heaters are pot-burners, which have a steel bowl about the size of half a beer can. It has an adjustable fuel metering device sort of like a carburetor but no air flows through it. It will send fuel at a rate of a drop every second or every few seconds (more or less). The fuel is delivered in the bottom of the pot. The pot is hot and the fuel is vaporizing (boiling) while burning, so there is diesel in liquid and gas state. The flames are burning vaporized fuel, not liquid fuel.

The pot-burners must be preheated and started on very low settings to allow the pot to heat up. It takes about 15 minutes to get hot enough to be really warm. I would prime the heater with a half shot glass of alcohol, and light it with a long lighter. After 5 minutes, open up the diesel feed on a low setting. Ten minutes later, it would be hot enough to turn up the diesel feed. The heat is reliable but it does tend to stratify with cold air at the floor if you do not use a fan.

The pot-burners are best in situations where they will be left on for at least several hours. They are ideal for running all winter without a stop.

They are not good if you just want to heat up the cabin for a few minutes, or if you need to start it up to cook a meal. It takes too long to heat up. Also, if you are using it to cook in hot weather, it will be heating up your cabin the whole time.

Propane is much more convenient for cooking and instant heat.

 

[Motrukdriver]

Hm.

So if I'm understanding this correctly, these units install in the engine bay, and deliver heat through the cab air vents, as well as pre-heat the engine to negate cold start.

Interesting. That might be an ideal solution, except that it incurs battery power consumption. Still an interesting option regardless.

I had a Webasto unit in the big truck.  It was mounted under the bunk and had a fuel line to draw diesel from the big tanks.  It also had a temperature setting so you could adjust your comfort level.  I kept mine about 68 in the winter and it cycled on and off just like a home furnace.  You could hear a faint rumbling when it turned on to heat up the plenum air then the fan would kick on and circulate the air and then it would just kick off when the desired temp was reached.  The only battery power you'd use would be the electronic ignition, the thermostat to monitor your interior and the fan when it was blowing warm air.  Mine could work all night long and never drop the voltage in the batteries enough to start the generator.  I had 4 batteries in the truck.  Espar units work the exact same way.  I never worried about cold starts since I added 2 gallons of Lucan oil treatment in the crankcase at every oil change.  Smaller diesel engines would need less Lucas of course.

 

[tx2sturgis]

Yep, these bunk heaters and parking heaters fall into the category of a 'furnace' that use DC.

Again, burning motor fuel for the gas and diesel units. 

I tend to forget who has asked about what sometimes...we have had this topic come up a lot recently.

 

[ZoNiE]

Some people have used RV water heaters to make a hydronic system, but they are propane, some with 110V option. You then only need a small amount of current to run a very small 12V pump. The heat continues to radiate long after the burner turns off. I have an ALDE unit that is made for this, but alas, it is too small for my current Motorhome and I need to spend $$$ to get the controller for it out of Europe, because NOTHING is cheap in Europe. I can run it on "Test" mode without it and may just use a regular old thermostat to do that if I decide to use it to heat the bedroom and bathroom of my Motorhome only...

 

[TMG51]

I wonder how much power these bunk heater fans use compared to the blower in my old Suburban propane furnace I have in the van.

It sounds like this would be a good option for running 24/7, should I choose to stay in the northeast while it's cold. Maybe I should have propane anyway for cooking and more immediate heat output.

 

[tx2sturgis]

 The only battery power you'd use would be the electronic ignition, the thermostat to monitor your interior and the fan when it was blowing warm air.  Mine could work all night long and never drop the voltage in the batteries enough to start the generator.  I had 4 batteries in the truck.  

I wonder how much power these bunk heater fans use compared to the blower in my old Suburban propane furnace I have in the van.

It sounds like this would be a good option for running 24/7, should I choose to stay in the northeast while it's cold. Maybe I should have propane anyway for cooking and more immediate heat output.

I also have about 2 decades of experience with these bunk heaters. They work well, but there are certain things to be aware of.

For a commercial truck, normally after a night of the bunk heater running, the next day the driver will start the truck and probably drive for many hours. This will recharge those 4 batteries.

For someone van-dwelling or boondocking, they need to be able to replace that battery power with either solar or maybe a generator.

On the APU's that we had, we could select automatic APU (generator) start so that if the battery voltage dropped below about 12.2 the APU would start automatically and recharge the batteries. 

In addition to the heater's electronic controls and the blower, there is also a small fuel pump. All of this pulls power all night long, or all day if running it during the day, and that DC power has to be replenished, especially if running the heater for days on end. 

Other issues:

They are expensive, complex, and require time and experience or at least a good mechanical aptitude to install.

Failure rates are not high, but they are not zero either. Sometimes they will quit working due to a failed ignitor, bad fuel pump, or low system voltage. They will quit at 3 am when it's -5 degrees, guaranteed. Now what? You had better have a backup plan. When you wake up shivering in the cold and the display says "ALT fail"...oh great, now what?

Service is hard to find, and the only places that can work on them will ALWAYS give priority to commercial customers. Bet money on it. 

Replacement parts HAVE to be ordered, your local Sears, Autozone, Harbor Freight, Tractor Supply, or Walmart will NOT have parts for them. It could be inoperative for a week or more in the winter. I have had to slip seat (more than once) from one truck to another JUST because of a failed part on a bunk heater. 

Then my main gripe is that you are paying highway motor fuel tax for fuel that is not being used to run a motor on a highway. In commercial trucking we get a tax credit on that, but a private owner and user most likely won't get that tax credit.

This is all intended to convey the 'cons' as well as the 'pros'...Caveat emptor in other words. Just so we are all on the same page. 

As long as the OP has the facts...that's all that matters.

 

[John61CT]

tx2sturgis, excellent summary.

For someone van-dwelling or boondocking, they need to be able to replace that battery power with either solar or maybe a generator.

Best with a lead bank would be both.

These (and the Propex units) are **much** more efficient, both of fuel and electricity, than any US furnaces designed for RV usage.

If you're boondocking in the snow, especially for very long periods, I really can't imagine a better solution, doing that with unvented propane devices is just too dangerous.

Yes it is expensive, but I've lived in S&B homes where the winter oil bill gets over $1500 a month, plus an occasional pipes freezing evemt, so everything is relative.

 

[John61CT]

Here's a relevant currently running thread in a marine forum

http://www.cruisersforum.com/forums/showthread.php?t=195161

Yes these guys often have more money to spend, but it helps to at least see what can be done.

 

[tx2sturgis]

130 ft yachts AND hot water too?



BTW on our truck units with the APU, which is a small diesel engine with an alternator and AC compressor, there was also an engine coolant loop that shared coolant with the main large engine and the smaller APU motor. 

This way, the APU kept the main engine at around 75-100 degrees all night so it would start easier on the coldest of mornings, and the APU motor will always start first thing at night as you shut down, since its been kept at operating temps even out there exposed on the frame, because it has main engine coolant circulating thru it while driving. 

I think if someone could design, manufacture, and market a small APU to supply heat/cool/electric for RV's and an even smaller one for van-dwellers, camper vans, and expeditors, they would make a LOT of money right now. The market is wide open.

 

[Motrukdriver]

I think if someone could design, manufacture, and market a small APU to supply heat/cool/electric for RV's and an even smaller one for van-dwellers, camper vans, and expeditors, they would make a LOT of money right now. The market is wide open.

I've been thinking about that exact thing for years now.  The closest I've seen similar is the auto start boards you connect to your house batteries that sense low voltage and start your generator automatically and stop it when the charge level tops out.  Might could cannibalize and old APU for electronics to build a prototype.  The outfit I was leased on with sells takeoffs for cheap. You'd have to take the generator apart to figure out how to connect an AC compressor to the drive.  I think I'd consider using a propane heating unit since most RV's have a propane source but of course you'd need to carry more propane than you would just for cooking.  A diesel heating unit would be fine but I'd be leery about a gasoline one.  Dunno why but I have this vision of something springing a leak and then a huge fireball and crater where the vehicle once parked.  I've seen it in cartoons...

 

[John61CT]

If you're boondocking in the snow, especially for very long periods, I really can't imagine a better solution, doing that with unvented propane devices is just too dangerous.

Recent tragic example

http://www.ktxs.com/679434246

 

[John61CT]

if someone could design, manufacture, and market a small APU to supply heat/cool/electric for RV's and an even smaller one for van-dwellers, camper vans, and expeditors, they would make a LOT of money right now. The market is wide open.

Maybe. But the % of boondockers out of the wider RV market is pretty tiny, and the market is not well-informed, would rather be bamboozled dreaming of "solar generators" and the like.

A little Honda genny, a high-amp charger and a decent LFP bank will do the job with off-the-shelf parts much more cheaply than prototyping something new.

And even then such a system, if done right, will cost more than many of us have to spend on our whole rig.

A handy DIYer can replace the first two components with a DC charger, high output alt and a small engine, get much higher kW charging so shorter runtimes, but it will likely end up costing about the same, and won't be as quiet.