Diesel Wall Tent Heater

[aragor764]

Originally Posted by CBintheNorth

I definitely am trying to put the unit inside, as the air I'm trying to heat will have a large differential inside vs outside.
I thought about putting it outside and fastening a duct to the inlet and plumbing them both into the tent, but I'd still like to capture that huge amount wasted exhaust heat. This is easier done with the unit inside the tent. So I'm back to inside.

Let us know how you did that, TIA

[slabm7]

Originally Posted by CBintheNorth

I definitely am trying to put the unit inside, as the air I'm trying to heat will have a large differential inside vs outside.
I thought about putting it outside and fastening a duct to the inlet and plumbing them both into the tent, but I'd still like to capture that huge amount wasted exhaust heat. This is easier done with the unit inside the tent. So I'm back to inside.

Inside would be much more efficient and something I might plan to try on our next trip out, I'm thinking of some kind of an extension with eaves trough stuffed with steel wool or hi temp wrap.

[lambski]

They have 2 sizes of Hippy Killers at Home Hardwear...cheap..light and warm! PS get the big one.

[Phil McCracken]

Originally Posted by CBintheNorth

I just bought the exact same one (8kw) and just finished putting it through it's paces.
Tank volume is just under 5 litres (calculated).
When I read that the fuel consumption was under 1/2 litre/hr I was a little skeptical of the output. 8kw is roughly 27,000 BTU's.
Sure enough, this heater uses 1/3 litre/hr (averaged over 9hours), which at 37,500 BTU/ Litre, equals 12,500 BTU of Input.

The heater is far from 100% efficient given that the exhaust is coming out over 220°F.
So if I had to take a random stab at a figure, I would say output is roughly 9-10,000 BTU's.

Power consumption was nearly 12 amps in startup mode with the glow plug on. This lasted for a few minutes.
Once the glow plug shut off the draw was reduced to around 5 amps on highest setting.
On lowest setting the draw dropped to around 2 amps.

My Interstate SRM-31 battery has an amp hour rating of 210, which means I should get roughly 40 hrs of run time on high on a fully charged battery, and about 16 hours on a tank of fuel.

To compare, a Big Buddy inputs roughly 18,000 BTU's and because it exhausts inside, you get basically 100% of those BTU's.

I plan to use a piece of steam hose to extend the exhaust out of the ice tent (Otter), and because rubber is a horrible conductor, it shouldn't melt my tent flap.

Overall, this little heater is awesome. As long as you know its limits.

Hopefully this info helps others.

Thanx for sharing this information. Interesting concept. I have a couple of questions if you don't mind.

1) At hunting camp, we all use Big Buddies to heat the sleeping cabins. They work good. But as most may know, you have to leave a window partially open. If this diesel heater is inside, and I realize the exhaust goes outside, do you still have to leave a window partially opened?

2) Our camp kitchen/meeting room is heated with a wood stove. Most guys bring their wet clothes/boots in there for drying, as propane heat is not as "dry" as wood heat. And often, clothing will still be damp in the morning with the Big Buddies. How are these diesel heaters in that department?

Thanx in advance...

[CBintheNorth]

Originally Posted by Phil McCracken

Thanx for sharing this information. Interesting concept. I have a couple of questions if you don't mind.

1) At hunting camp, we all use Big Buddies to heat the sleeping cabins. They work good. But as most may know, you have to leave a window partially open. If this diesel heater is inside, and I realize the exhaust goes outside, do you still have to leave a window partially opened?

2) Our camp kitchen/meeting room is heated with a wood stove. Most guys bring their wet clothes/boots in there for drying, as propane heat is not as "dry" as wood heat. And often, clothing will still be damp in the morning with the Big Buddies. How are these diesel heaters in that department?

Thanx in advance...

To answer your first question, no, you don't have to.
While it will use some air for combustion, it is not an amount to be concerned with unless you're in an air-tight box for days on end.

As far as drying clothes, nothing beats wood. It literally dries out air.
While the diesel heaters aren't as good at drying out stuff, they are far better than propane heaters that exhaust inside..
Consider it equal to your furnace at home.

[aragor764]

Also the way to go as others have mentioned would be to run the heater inside and vent the exhaust, that would be way more efficient. I saw a guy on FB somewhere running it inside and he ran his exhaust through a double wall 3" pipe and said it works great.

[CBintheNorth]

Originally Posted by CBintheNorth

To answer your first question, no, you don't have to.
While it will use some air for combustion, it is not an amount to be concerned with unless you're in an air-tight box for days on end.

As far as drying clothes, nothing beats wood. It literally dries out air.
While the diesel heaters aren't as good at drying out stuff, they are far better than propane heaters that exhaust inside..
Consider it equal to your furnace at home.

I should clarify, I am only speaking about the Vevor/Webasto style forced air diesel heaters.
I have no experience with the open-drip style heaters like the Prospector or Expedition.

[Big Grey Wolf]

I was sitting in my trappers cabin by large wood heater. I would estimate our larger wood heaters we use in our cabins and tents can put out 200-300,000 BTu's. That is why wood has unlimited warming or drying capability for wet hunting cloths etc in Any weather. Show me a $2.00/liter diesel heater that can compare to that with All the unlimited free wood in the forest. Do I need to say more.

[CBintheNorth]

Originally Posted by Big Grey Wolf

I was sitting in my trappers cabin by large wood heater. I would estimate our larger wood heaters we use in our cabins and tents can put out 200-300,000 BTu's. That is why wood has unlimited warming or drying capability for wet hunting cloths etc in Any weather. Show me a $2.00/liter diesel heater that can compare to that with All the unlimited free wood in the forest. Do I need to say more.

Yes, you mentioned that on the last page.
While I don't think anything will replace wood for the big tents, there is a time and place for these little heaters.
An ice fishing tent is a prime example.

I use a wood stove in my outfitters tent, and I'm pretty sure nothing will ever replace it.
But hauling in things the size of a stove, chimney and wood just for a couple nights on the ice doesn't make a lot of sense.
Nevermind the fact that embers and plastic/nylon tents don't mix well.
But yes, for sheer output and affordability it's pretty tough to beat an air-tight, in most cases.

[Big Grey Wolf]

CB I agree that ice fishing tent has different needs than trapper cabin or outfitter tent.

[Serengeti Charters]

Buddy said we need a battery for diesel heater? Not for deluxe wall tents diesel heater though no? One we purchased

[nimrod]

I just ordered my diesel heater for my cargo trailer , thats what i use, has a flip up bed so my quad fits in the cargo trailer when in the back country, i also have a rechargeable battery in the cargo trailer ,

[CBintheNorth]

Originally Posted by Serengeti Charters

Buddy said we need a battery for diesel heater? Not for deluxe wall tents diesel heater though no? One we purchased

2 totally different heaters, so yes.
The prospector style is just an open drip.
Consider it more like a wood stove that sheds heat through its walls and chimney. It does not require battery power as it doesn't do anything other than burn diesel.
If hauling a car battery is not a option, it is a better choice.

The other style is just like a forced air furnace. It uses a pressure pump to force fuel through an injector and burn it in a chamber, with one fan forcing air around that chamber and out to a duct (inside air), while another fan pulls exhaust from within the the burn chamber and exhausts it to another port which goes outside.
Those fans and pump run off 12v power.
Much more efficient, but you'll need a big battery.

In all honesty, I think the weight difference would be nil on a week-long hunt, as you would likely burn 2 jerry cans of fuel more in the open drip style, due to the inefficiency.
One of the big differences I think you'll notice is smell.
While the newer open-drip style are better than the old, you still wind up with a tent that smells like diesel over time.
With the forced air style, there is zero smell inside, allowing your tent to retain and exude its natural aroma of campfire and farts.
As it should.

[aragor764]

As reference i ran my diesel heater for 2 nights and still had 60% battery left according to my charger, It is a size 24 deep cycle battery so not that big. Also had 1/4 tank left.

[CBintheNorth]

An update on the diesel heater efficiency project...

For a proof of concept I tried running a 1" steel exhaust flex hose through a piece of 3" aluminum flex pipe and drawing intake air through the 3", over the exhaust, in an effort to cool the exhaust while preheating the intake air. This itself, actually worked surprisingly well, but wasn't very compact, and was quite fragile (prone to crushing if stepped on).

I took the same concept and expanded a bit.
I made a copper pipe exchanger which splits from a single 1" copper pipe, to (4) 1/2" copper pipes to further boost efficiency, then back to 1" copper.

A few things to note:

1) The first time I made the exchanger, I soldered the joints. The exhaust of this heater reaches 570°F, and solder typically melts @ 450°F. I didn't realize the exhaust was that hot until I saw a drip of solder hit the bench while I was testing.
A lick of JB Weld Extreme Heat over the first few solder joints seems to be holding up. After the first return bend the exhaust was cool enough that melting solder wasn't an issue.
I definitely didn't want an exhaust leak in the exchanger as the intake air would be passing directly over any leaks.

2) The heater self-regulates diesel consumption based on its burner chamber temperature. According to the built-in digital thermometer, the range it maintains internally appears to be 405°F to 435°F. (Display is in Celsius)
Not really important, and I only mention that because the description in my pictures mentions "High temp @ highest setting". That temp was taken right before the heater cut back the fuel.


When first testing the heater without the exchanger connected, discharge air temperature on highest setting was 270°F, with an intake temperature (ambient) of 73°F, and an exhaust temperature of 570°F.
Again, horribly inefficient.

With the unit again on the highest setting, and the exchanger completed and connected, the results were much, much different.
Intake air temperature (ambient) was 66.7°F
Intake air into the heater after running through the exchanger box had nearly doubled in temperature, and was now at 132.3°F going into the heater. A substantial gain.

Discharge air obviously saw substantial gains as well, and climbed from its original 270°F, to a very balmy 361.8°F.
The best part for me, as I was concerned about fires and melting fabrics, was the exhaust temperature which plummeted to well below 100°F.
Not horribly inefficient anymore...

Out of curiosity, I ran it on the lowest setting to see how much change there would be. Surprisingly, the temperatures didn't change a whole lot, but the blower fan obviously cut way back.

On the lowest setting the inlet air was being preheated to 120.7°F, and discharge air was still up there at 327.4°F.
Unfortunately I did not record the discharge temps on low without the exchanger connected to compare.

I made two modifications to the heater itself:

1) I cut a round section of the housing out of the back so I could slide the 3.5" intake tube over the air inlet snuggly.

2) I mounted some 3/4" square tube to the bottom for stability in transport. These will stay on permanently and I used two corresponding pieces on the exchanger to secure the heater to the exchanger.

Other Things...

This project likely doesn't make financial sense to most people. The copper itself cost me around $120. If I didn't have access to the the tools and materials that I do, this project would have easily cost triple what the heater did.
I wanted this heater and needed something that was going to eliminate the exhaust from becoming a fire hazard, and a way to make the unit more efficient to save fuel, and especially to conserve battery power.
With the new exchanger I think this will be able to run at a much lower setting most of the time and just sip fuel.

This unit might be really handy this spring, as I can see wood stoves being nixed with the dry conditions.
Overnight stays on the ice is where I think it's really going to shine.

Once I do some in-field use I'll post up consumption rates and overall performance.

[CBintheNorth]

More Pics.

[bezzola]

Friend has the diesel heater from deluxe wall tents. It sits inside and exhausts outside and there isn’t a smell of diesel at all