Why don't Motorhomes use waste heat from Engine to produce a nice hot tank of water ?

[paulhelenwilko]

It has often occurred to me on arrival on site waiting for the hot water to heat up, that we have just been travelling and the engine has generated vast amounts of heat that we then send through
the radiator to cool down. Why can't it be diverted through a heat exchanger to create a tank of hot water ?.

 

[Siimplyloco]

It has often occurred to me on arrival on site waiting for the hot water to heat up, that we have just been travelling and the engine has generated vast amounts of heat that we then send through
the radiator to cool down. Why can't it be diverted through a heat exchanger to create a tank of hot water ?.

Great idea: it happens on boats - mine included - so why not in motorhomes? Cost? Complexity? Lack of demand? Or just a lack of original thinking?
John

 

[maingate]

My engine heats the hab area while driving, through a heat exchanger and a 2 speed fan.

There is also another type of heat exchanger for Burstners that heats the radiators (Alde heating system) and also gives a tank of hot water. Mine is also the Alde system but my type of heat exchanger works fine and it is not worth paying a couple of hundred pounds just for some hot water on arrival.

 

[GRWXJR]

Isn't the van cabin heater a heat exchanger? So..... If a DC circulation pump could be installed into the engine cooling system (maybe with a bypass valve to isolate the engine radiator?) - then you could carry on circulating the warm engine coolant through the heater matrix perhaps?

Not sure if the hassle would be worth it though even if it'd work though!

 

[maingate]

Just tee off the heater hoses to a radiator in the hab area. You could fit a small 12 volt fan to spread the heat a bit.

 

[phillybarbour]

My Burstner works both ways, the engine water heats the Alde heating and the hab hot water, and the Alde heating also heats the engine (great idea when skiing in the Alps), both ways has an on/off switches so only use when needed.

 

[winks]

Calorifier

On my wagon at work we have an insulated heat exchanger which is fed from the engine cooling and sets us up nicely for a brew when we get to site.

From the sound of it these have not been taken up widely in motorhomes and I can only assume its down to cost or space. Great bit of kit though and saves gas by using waste heat from the engine. I found one on eBay a while ago and I think it was about £300.


Harold.

 

[Steve121]

Heat Exchangers

3rd party heat exchangers which plumb into the vehicle's heater hoses are popular on expedition vehicles, particularly Land Rovers and Toyotas. They can be used as an instant 'on demand' heater with a supply of running water, or circulated to heat a tank or bucket of water.
They are available from at least one Australian manufacturer, and I have seen one from a UK supplier. They have both been offered on ebay in the past, but a quick search just now didn't turn anything up.
The Australian one has a double coil of copoper tubing inside a larger copper tube. The UK one I think was a plate type, probably made from aluminium alloy.
With a bit of ingenuity it may be possible to use a central heating heat exchanger, or even make one yourself if you have the necessary skills.

 

[pughed2]

wasting engine heat

my previous motor home, toyota pop top was brilliant..........engine took about 5 minutes to get hot, then when parked all the heat from engine which is below the van heated the cabin for up to 5 hours. my present van fiat tribute takes 15minutes to heat engine, and wastes all heat.......steve

 

[teckguy]

Heat Exchanger

I have an Eberspacher diesel heating and hot water system that uses the engine water to heat the on board water when travelling. It's not powered on when travelling as it uses a heat exchanger system.
Very nice having plenty of hot water on arrival to wash or shower. I would guess the other diesel systems have the same facility.

 

[Robmac]

I've had boats with calorifiers, heat up the water whilst moving, and with a properly lagged tank, would stay hot for up to 12 hours.

 

[Siimplyloco]

my previous motor home, toyota pop top was brilliant..........engine took about 5 minutes to get hot, then when parked all the heat from engine which is below the van heated the cabin for up to 5 hours. my present van fiat tribute takes 15minutes to heat engine, and wastes all heat.......steve

Our Hymer has a Mercedes engine fitted with 'Residual Heating' which uses the heat from the engine to heat the cab for about 30 minutes after switch off. We have yet to try it out. It doesn't heat the water though, which was the point of the original post.
John

 

[Tezza33]

I have an Eberspacher diesel heating and hot water system that uses the engine water to heat the on board water when travelling. It's not powered on when travelling as it uses a heat exchanger system.
Very nice having plenty of hot water on arrival to wash or shower. I would guess the other diesel systems have the same facility.

My previous van was an Autosleeper Palermo with the same system, hot water when you arrive and it preheated the engine in the Winter, it was great to use but I would not pay for it to be retro fitted

 

[Kontiki]

Using the engine to heat the van & water is something I have often thought about, I also wonder why nobody has developed a small solar water heater. There is plentybof room on the roof of the van, a sensor could check if the water is hotter on the roof than in the tank then pump the water until it isn't, this would eventually heat the water.

 

[Rodeo]

If you google heat exchangers you will see somehome made types and some proprietory ones.Theyre easy to make.Im probably going to make something up for mine soon as I get time.
My Transit m/bus had a pair of pipes T'd from the heater pipesand run to a small heater rad with fan in front of it, all mounted in a box about 12 inch cube.It was mounted in the middle of the rear floor(probably under a seat when a m/bus) unfortunately it was in the way for the camper conversion so I pulled it out.It was just an extension of the vans heating system. It was very hot!
You could t off a similar pair of pipes to a home made heat exchanger to heat the sink/shower water.Probably about a days work.

 

[Deleted member 775]

Isn't the van cabin heater a heat exchanger? So..... If a DC circulation pump could be installed into the engine cooling system (maybe with a bypass valve to isolate the engine radiator?) - then you could carry on circulating the warm engine coolant through the heater matrix perhaps?

Not sure if the hassle would be worth it though even if it'd work though!

i had something similar in my old seat Alhambra there was another heater box in the rear ,you could turn it on or off via the heater controls in front or with another set of controls in the rear there was also a diesel heater like an erbaspacher that used to heat up the coolant aswell

 

[tugair]

It has often occurred to me on arrival on site waiting for the hot water to heat up, that we have just been travelling and the engine has generated vast amounts of heat that we then send through
the radiator to cool down. Why can't it be diverted through a heat exchanger to create a tank of hot water ?.

I asked my dealer about this a couple of years ago. Was told that systems were quite expensive to fit, but that particularly for the current Fiat versions, any such fitting immediately invalidated the engine warranty. Now waiting till the warranty on our latest vehicle expires before considering this further.

Totally agree that all that waste heat generated in getting to your destination, could be used to provide hot water or heating, as in our share narrow boat. :nicethread:

 

[nitramarion]

Heat Exchanger

Most modern diesel engines are pretty efficient bits of machinery.
With the quest for more mpg and faster warmup times on engine cooling, the tendancy is to fit smaller volume cooling systems which help to get the engine up to temperature faster.
Many vehicless have esbatcher type fuel heaters to augment engine warming because they generate low frictional and combustive losses. Modern engines like running at a fixed temp where possible and additional thermal losses like additional heaters have to be paid for from some where, usually as a sacrifice to efficiency.
If you need instant hot h2o when you arrive consider a 12v 30amp water heater which will give you nice hot water but 360watts of energy per hour needs to come from somewhere (ie the alternator) which requires 360w plus a bit to power it.
Somebody said energy cannot be created or destroyed - manufacturers would have us think otherwise!

 

[vwalan]

most old water board vans have the ideal thing they have to have hot water for the workers . its not a new idea . easy sorted if you really want to make your own . but a kettle on gas if stopped for days works fine . instantanious water heaters use very little gas to be used for showers etc . good thought but not always practical or useful. shame good thinking though.

 

[iveco4x4]

Search for Calorifiers. I looked at retrofitting one to my truck , they are not as expensive as gas water heating. My problem was fitting one into the available space. If I built from scratch I would include one as we tend to move every day so its a good way of getting hot water and I like it as its a simple system with very little to go wrong.

Rich