[Lee.]

What do you think? Is it possible, are there any engineers that think this could be done? Wondering whether some metal brake pipe could be run the length of the pipe a few times and circulated back into tank or straight out of hose? or maybe wound around the pipe a few times and cased up in insulation. A car exhaust reaches somewhere between 500 - 700 degrees surely that's free waste energy that's got to be tapped into! I would be interested in anybodies opinion.

[dave0123]

Water in the fuel filter? have you checked there

[dave0123]

Sorry ignore that thought u had a problem with water coming out exhaust 

[♠Winp®oClean♠]

What do you think? Is it possible, are there any engineers that think this could be done? Wondering whether some metal brake pipe could be run the length of the pipe a few times and circulated back into tank or straight out of hose? or maybe wound around the pipe a few times and cased up in insulation. A car exhaust reaches somewhere between 500 - 700 degrees surely that's free waste energy that's got to be tapped into! I would be interested in anybodies opinion.

In theory it could be done, pretty much the same as a domestic vented indirect system. However, it wouldn't be effective. The microbore copper pipe which would wrap around the exhaust pipe just isn't sufficient enough in volume to heat a large water tank- it would take forever. On a solid fuel domestic system (stove/wood burner) you are looking at 28mm pipe right through the primary circuit.

[Ian Lancaster]

Some marine engines use water-jacketed exhaust coolers.  The exhaust pipe is encased in a steel container with an inlet and outlet for "raw" water (from the river/sea or whatever) to circulate.  Something similar might work, if you're a competent engineer/welder and there's room under the vehicle.

Probably need to drive around all day, or keep the engine ticking over while you work (illegal unless there's a qualified driver sitting in the vehicle).

"Diminishing Returns" comes to mind

[Ian101]

your theory of using heat from engine is half correct as I thought about this last winter but this then grew into using a marine calorfier http://www.asap-supplies.com/marine/boat-hot-water-heaters

these use the hot water in an engines cooling system to warm the cold water  on a boat via heat exchange however I rekon it can be modified for a vehicle and i have got as far as thinking quite a bit about this ... need a calorfier, an extra pipe teed into the vans coolant hoses, another shurflo on a switch to push water from vans tank thru calorfier and back into tank on a constant loop and an in tank thermometer to check water temp in tank as ian lancaster stated diminishing supply thru day will make water too hot possibly (not done it yey so not sure) ...... maybe someone cleverer than me can think of a more direct hot water to the brush head way of doing it ??

not sure if it would work but u can get very small calorfiers plus no cost to heat it up .......... was gonna try it and then tell the forum how I got on but maybe someone else may like to beat me to it and save me a few hundred quid if its fails  

[Spruce]

http://www.thefreeheater.co.uk/

Watch the videos, especially the 1 on Bournemouth beach car park. Then apply those exact principles to a van setup. The part when Debbie is showering would be you washing windows.

It wouldn't work for us as the van's engine doesn't even get off cold in the winter.

[Spruce]

What do you think? Is it possible, are there any engineers that think this could be done? Wondering whether some metal brake pipe could be run the length of the pipe a few times and circulated back into tank or straight out of hose? or maybe wound around the pipe a few times and cased up in insulation. A car exhaust reaches somewhere between 500 - 700 degrees surely that's free waste energy that's got to be tapped into! I would be interested in anybodies opinion.

There were two guys that used to drive a truck from Johannesburg through to Harare in Zimbabwe. Their lorry had a twin bunk sleeper cab. In the summer it was jolly hot in the cab, especially in the midday heat of the Limpopo river valley at Beit Bridge, the crossing point between South Africa and Zimbabwe.

They devised a header tank fitted to the back of the cab and some copper tube round the exhaust. They left Johannesburg early morning and they always managed to get through the border into Zimbabwe when it closed by 8 in the evening. They had travelled some 600kms and that water was just warm enough for them to have a quick shower each in a layby on the side of the road before retiring to bed.

[Lee.]

Thanks for comments. May try it one day for instant hat water as opposed to circulating it back into the tank.

[Lee.]

Thanks Spruce, the free heater looks great, my fan heater is hot after 5 - 10 mins so It might be worth just going the extra mile to have free heated water. The hot water could be stored in a smaller tank.

[Spruce]

Thanks Spruce, the free heater looks great, my fan heater is hot after 5 - 10 mins so It might be worth just going the extra mile to have free heated water. The hot water could be stored in a smaller tank.

The heat exchanger is linked into the engine coolant circuit. You also need a small 12v pump in the line as well as an on/off switch. The pump circulates water in one direction when on so it must be fitted in the same direction as the water flows around the system when the engine is running. The heat exchanger has 4 connections. If its fitted horizontally then the top 2 will be linked into the engine coolant. The bottom 2 will be coupled into your wfp hose from your pump to your hose reel. The water flow from your wfp pump must flow through the heat exchanger in the opposite direction to the flow through the heat exchanger of the engine coolant. When the engine isn't running, you switch your switch on and it keeps the hot water circulating through the engine and through your heat exchanger.

You also need to have that mixer valve in the wfp circuit as it keeps the water to your brush at the right temperature, taking just enough heat from the engine to warm the water to your requirements.

So the engine block will be your heat source and you will take warm/hot water on demand. You won't need to store it. Forget the Calorifier hype from the manufacturers that it will heat 20 litres of water in 20 minutes from the engine. It won't. The other issue is that you can't pressurise a calorifier to the pressure our pumps will deliver (100psi), so your pump will need to draw warm water through the calorifier first and then pump it to the pole. Our pumps are designed as 'pushers' rather than 'pullers'.

[Spruce]

your theory of using heat from engine is half correct as I thought about this last winter but this then grew into using a marine calorfier http://www.asap-supplies.com/marine/boat-hot-water-heaters

these use the hot water in an engines cooling system to warm the cold water  on a boat via heat exchange however I rekon it can be modified for a vehicle and i have got as far as thinking quite a bit about this ... need a calorfier, an extra pipe teed into the vans coolant hoses, another shurflo on a switch to push water from vans tank thru calorfier and back into tank on a constant loop and an in tank thermometer to check water temp in tank as ian lancaster stated diminishing supply thru day will make water too hot possibly (not done it yey so not sure) ...... maybe someone cleverer than me can think of a more direct hot water to the brush head way of doing it ??

not sure if it would work but u can get very small calorfiers plus no cost to heat it up .......... was gonna try it and then tell the forum how I got on but maybe someone else may like to beat me to it and save me a few hundred quid if its fails  

Hi Ian,
Hurricane heaters do a compact diesel heater that they have adapted for window cleaners. It contains its own diesel burner as a heat source. From what I gather they also incorporate a calorifier type of system in their design. They use the calorifier in reverse as a heat source.

The diesel heater heats all the 20 litres in the calorifier and the water to be heated (our wfp water from the pump to the pole) is past through the heat exchanger within the calorifier which heats the water on demand. Again this water temperature is regulated with a mixer valve.

I contacted each of the calorifier manufacturers a couple of years ago and asked if I could use a Webasto diesel heater to heat the water in the calorifier as a heat source and pump my wfp water through the heat exchanger in the same way as a Hurricane heater. Again, opposite to the way they have designed it. They said that the heat exchanger is simply a length of copper tube (around 6 foot) and won't zap enough heat as the water passes through it too quickly. ( I can't remember the figures but at 2 LPM flowrate the water was only in the heat exchanger (their 6' copper tube) for a few brief moments - 2. something secs I think it was.)

We were in Scotland at the time on holiday staying at a newly built cottage near Fort William. The house was oil heated and they used the oil burner to heat all the water in the hot water tank. The heat exchanger was good enough to heat water for the bath using the 210 litre tank as a heat source. The oil burner got that 210 litre tank hot in about 15 minutes.
The owner of the cottage was quite into this and he got me thinking on these lines.

One of these calorifier manufacturers suggested I buy one and report back to them my findings.

There are some slightly larger units that have 2 heat exchangers. One is for the engine coolant circuit and the other is for another heat source ie a diesel heater. One manufacturer also suggested that linking the 2 of these together won't raise the wfp water temperature enough to use.

[Rob_Mac]

Heating the water in a tank from the exhaust is straightforward.

My Farrow System has two saddle tanks, metal with the exhaust from the compressor running the length of the underside of one of the tanks.

Hot water within twenty minutes, very hot water within half an hour of switching the compressor on.

I will have a look at the exact set up, underneath the one tank in the next couple of days and if anyone wants to see I will get a couple of photos.

Rob

[andi wilson]

Alternatively run the engine coolant through a heat exchanger in the water tank.. Same principle as a Bane Clene truckmount..

[♠Winp®oClean♠]

Alternatively just buy something much cheaper & much more simple!!

[Arnold Palmer]

We tried a heat exchange on the exhaust. Basically a great long coil of copper pipe wrapped around the exhaust, wrapped in insulation, circulated slowly from the tank.

We were only looking to raise the temp a degree or two to keep the frost off. The issue was that to achieve the desired increase in temperature the pump needed to be running so slowly that it was pointless. Any quicker and there was no change in temperature.

The heat was going somewhere as the exhaust was cold after the coil but it just wasn't enough to make any significant difference to a tank of water that size.

[Arnold Palmer]

Alternatively run the engine coolant through a heat exchanger in the water tank..

We have done this too. It works better than the exhaust. The issue here is that it is too efficient and the engine won't get hot.

Again all we wanted was to keep the frost off which it did, but no heat in your engine when it is frosty is problematic.