Getting more heat from diesel heater

[Clouse House]

Had anyone done one of these in their bus yet? He has the typical Chinese Diesel Heater but he attaches an EGR to the exhaust and has the coolant run through a heater core to capture even more heat from the diesel heater.
Pretty cool right? I attached the youtube link below but I was thinking this could be a great way to get heat to a second area that might not get it from the main heater. You could even have it plumbed with your fresh tank instead so that anytime you run the heat in your bus it is heating up your water tank as well.

https://www.youtube.com/watch?v=OtnrBYz3uRE

[Sehnsucht]

Totally feasible. Freightliner OTR semi trucks offer a system like this. The hydronic bunk heater uses diesel fuel to provide idle-free bunk heat while simultaneously circulating engine coolant back to the engine block for a warm start in the morning. I've been parked in freezing temps and cozy in the well-insulatee sleeper then the next morning the engine starts right up with 100 degree temp reading until it begins circulating the warmed water with the cold water from the radiator... But it was as easy to start as a spring day. I don't know if you could boil water with the waste heat using this method but it would certainly be useful to prevent fresh water tanks freezing and warming otherwise cold floors.

The biggest problem we've always had with the diesel burner bunk heaters is they're too good. For the small size of a truck sleeper it'll cook you alive. Sizing up to a bus or RV and it'll be just right to keep the space comfortable. Many also segment their living spaces with doors or curtains so they can control which spaces keep the heat. I think you could offset this a little with shown method but I don't think I would rely on it being the primary heat source for any area of the living area of the RV.

[Booyah45828]

Very interesting. I see no reason that a waste heat capture system couldn't be used, so long as it doesn't create any restriction in the exhaust.

IMO any restriction there would cause soot/fouling issues, and those already seem kind of prevalent in the chinese diesel heaters. I've always wanted to ceramic coat or line the combustion chamber in one of these, as I feel that doing so could allow the chamber to maintain it's heat better and then burn cleaner. If you enable a way to make the combustion not such a sensitive process, It would become more complete and I feel it wouldn't be so sensitive to a device in the exhaust, like a muffler or this egr cooler.

Also, if you're going to do something like this, use a coolant/water that doesn't contain silicates, as the high heat will cause them to precipitate in the cooler much like they would if installed and used on an engine.

[cadillackid]

it works.. I did an experiment with one of my spare diesel heaters in recovering heat from the exhaust... you can drop the temperature of the exhaust pretty significantly without issues, however you dont want to recover so much heat that you create codnensation.. these diesel heaters burn OK clean but not perfectly so if you drop the exhaust temp down too low you will mix carbon with moisture and clog things up... here in the states we dont have near the number of small diesel cars that they do overseas where dinfing an EGR cooler is easy.. it will cost quite a bit to obtain one unless you get lucky and find a V-dub diesel in the junkyard that still has one.. most good EGR coolers get harvested off of junked medium / heavy duty trucks as they are a ver ycommon failure point so shops and fleet owners will keep them..



the EGT on my 16kw heater reaches close to 450 degrees F so you have to be careful using other types of heat exchangers with standard soldered copper as the solder can melt...


EGR coolers are a good fit because they are designed on the exhaust side to take the 500+ degree EGT seen in diesel combustion..

[sawickipedia]

EBay is a great resource to find the smaller EGR coolers salvaged from cars over in the UK/EU. Based on some videos I found on YT - I am going to try an EGR for a PEUGEOT 307 2001-2005 2.0 HDi DIESEL EGR COOLER 9639874380. I love the idea of capturing diesel heater exhaust heat so looking forward to trying this out.

[Bjorkinman]

I allegedly deleted an 06 F250 by welding an EGR shut and replacing the existing one. I kept the used one around for about a year then gave it away not thinking I would use it... This is a really cool idea though and I may look in to trying it.

[AllisonWanderland]

That is way overkill and overcomplicated, you can just route the exhaust through an air-to-air intercooler with 12v fan on it to capture waste heat from exhaust.

Cheaper and less to break.