Water Cooled Radiator for a Generator

[ilovegennys95]

Hello all 👋

I want to add a water cooled radiator to my portable generator leading to an exhaust heat exchanger to produce hot water. What I really need to know is what radiator would be suitable as I am struggling to find one suitable for a portable generator as they are either for computers or 60kw house size generators 😂 I imagine a small car radiator might do the trick? Just need a nodge in the right direction.

The generator is a 17hp Bohmer 9000w. Clearly I would have to do some creative work to fit it to the generator but I am comfortable with that!

Thanks

[E-bmw]

What you want is a heat exchanger (which is the same thing but different) try looking on ebay for exhaust gas heat exchanger or similar.

[ilovegennys95]

I will be putting a heat exchanger on the exhaust. Cool water will run through the radiator to aid cooling of the engine then onto the heat exchanger to be heated then put to use.

[E-bmw]

So is the engine already water cooled?

[Hawkshaw]

So how does this work exactly?

[ilovegennys95]

More back ground info. So, the generator powers a van mounted Carpet cleaning machine. There is a fresh water tank on board with cold water. The idea is that the cold water is pumped to a radiator at the fan of the generator cooling the air pulled in by the fan, the water then carries on to a heat exchanger at the exhaust, the water is then heated by the exchanger and carries on to the Carpet cleaning tools.

I hope that explains things a bit better!

[ruggedscotty]

Worked with CHP's that has mossive heat exchangers in the cooling circuit and also in the exhaust system. so its doable, and can be done in your case but you need to look at how best to do this, and how best to watch your engine temperatrues etc. Its a significant change in operation and your adding a lot of water into the system.

can the pump deal with it and provide enough of a push to circulate the water round the system.

Your exhaust heat exchanger.... number of options here..

https://www.ebay.co.uk/itm/393442330563?var=0&...

https://www.ebay.co.uk/itm/363474099762?mkevt=1&am...

If you take heat out of the engine then you affect how that operates - so you would be looking at that hopefully so that you dont keep running the engine exessively cool, also if that engine isnt loaded then it would make a lot of heat.

You also need to think whats going to be warmer... the exhaust or the engine, id say the exhaust, so you would be looking to pump the water through the engine water to water heat exchanger and then through the exhaust heat exchanger, and use that to provide your heat for the heating your water.

Basically a primary circut being the ngine coolant thats being used to heat an intermediate loop - this loop being two step engine and then exhaust heat to run through your output exchanger that heats your process water.

Does that make sense ?

https://www.ebay.co.uk/itm/254152896655?chn=ps&amp...

[ruggedscotty]

Okay this makes it a little bit more complicated -

engine is aircooled so your only source is going to be the exhaust. You will need to fabricate a fair bit for this, some form of exhaust exchanger right on the exhaust from the engine. I wonder if you could also wrap some small bore copper pipe and use that to capture heat from the engine block itself ?

Talk about a task and a half... Air cooled will be very hard to get decent heat from without a lot of modification of the exhaust.

[finlo]

Pipe the exhaust through an old heater matrix? How much hot water are you expecting?

[gazza285]

How will the water cool the air before the engine? Would not they both be at the same ambient temperature to start with?

I doubt that there is that much thermal energy available from the exhaust of a generator that size, even with an efficient exchanger I wouldn't expect the water to be very warm.

[ruggedscotty]

Okay....

Thinking about this... You have 8kw to play with...

https://www.amazon.co.uk/Instant-Electric-Tankless...

Now to make this work, you would need to have a pump aswell to get water pressure and a storage tank - draw from the storage tank through pump 1 and discharge back to tank. have the pump and a pressure flow switch so that the heater will only be called when the water is flowing. Also a level switch in the tank to cut the system when the water level drops below the low limit...

Im sure this would give you the hot water you seek. without all the trials of extracting heat from the exhaust. You may find that drawing three kilowatt from the generator may give you useful exhaust heat but you would need to look into that. id stick with the instant water heater and pump set up to begin with.