$200 5KW Portable Diesel Air Heater

[Rbertalotto]

Found this....Guy is using a EGR Heat Exchanger from a French Citrion (I had a couple of them back in the 70s!)

Diesel Heater Hot Water

How about this for an idea.......Place an underfloor, hot water radiant heat coil under the mattress and run the hot water through it!

 

[luthj]

An option that was tested on another forum, was to take a small radiator, and duct the heating air through it. Then use a small pump to circulate water. Its fairly efficient with 2 stacked radiators (about 4" thick), so you can heat water quite fast.

 

[Rbertalotto]

Appears anything you can think of, has been done on YouTube!

Copper Pipe on Exhaust Pipe

 

[Rbertalotto]

Well, Well, Well....Lookie here! There is now available one of these Diesel Heaters with a built in hot water heater!

Hot Air AND Hot Water Diesel Heater

 

[Rbertalotto]

An option that was tested on another forum, was to take a small radiator, and duct the heating air through it. Then use a small pump to circulate water. Its fairly efficient with 2 stacked radiators (about 4" thick), so you can heat water quite fast.

I'd have to go look through my engineering books, but I believe itis much more efficient to transfer heat through water rather than air. And it will hold the heat better for transport...?

 

[luthj]

I am sure its less efficient than a dedicated water heater. But its a good option compared to carrying a separate water heater for some.

 

[Rbertalotto]

I bet if he used a bit more copper pipe and insulated it, and used an insulated water jug or a cooler for the water supply, the temp of the water would be so high it might be TOO hot.....

 

[luthj]

Only about 20% of the heaters output goes through the exhuast. You would need a fairly long heat exchanger as well, as the normal stainless pip is not very conductive and has minimal surface area.

 

[john61ct]

I am sure its less efficient than a dedicated water heater. But its a good option compared to carrying a separate water heater for some.

Only in winter

Can't turn off the forced air side.

Better to just go full hydronic if you want integrated HWS,

 

[Rbertalotto]

I already have an On Demand H2O heater in the trailer. I was just thinking a way to use the wasted heat only in the cooler months when the heater would be on anyways. Get the chill out of the water and keep it from freezing in very cold weather. But I still like running warm water under the sleeping pad. That would be great in cold weather.

 

[robepa]

Only about 20% of the heaters output goes through the exhuast. You would need a fairly long heat exchanger as well, as the normal stainless pip is not very conductive and has minimal surface area.

Seams like 20% is a reasonable number, where did you get it from? Standard natural gas furnaces are 80% efficient going up to 95%. Given the compact size I would guess they may be less than 80% efficient.

 

[luthj]

I am quoting from the Espar/webasto literature. They indicate roughly 80% efficient. I am not seeing it in the consumer pamphlet, but if I find the source I will post it.

 

[Rbertalotto]

I think the temperature of the exhaust is the more important number.....no?

 

[luthj]

Heat exchanger rates are determined primarily by delta T and surface area. I would guess you could get maybe 50% of the heat from the exhaust stream. So a 4KW heater on high would have at least 800W exhaust heat. so 400W to heat water. Not particularly large, but if you are running the heater for extended periods, its enough to heat significant amounts of water.

 

[alia176]

Well, Well, Well....Lookie here! There is now available one of these Diesel Heaters with a built in hot water heater!

Hot Air AND Hot Water Diesel Heater

This one is a game changer, IMHO, as it can heat both ait+water. You can opt to not heat up water by not turning on the pump. I have an EcoTemp that I can use for hot shower and faucet but this gizmo can effectively "warm" up the fresh water tank in my Adrenaline camper. Granted it'll take a long time to bring up the temp of a 20g tank to shower temp but having not freezing water to wash your face/hands on a cold morning is muy bueno. I'm using the unit to heat up the air space anyway so why not recirc some cold water through it? I can still use the Ecotemp for actual hot water and it'll use less propane if I'm showering with it due to the less delta T.

Of course, it's wise to insulate your fresh water tank so the water will maintain the temp just a little while longer.

Something to noodle with.......