Waste Heat Recovery System

Anyone ever seen a waste heat recovery system applied to an inboard engine on something smaller than a full-sized cargo vessel? I’m thinking anything from a 20-foot launch with a Westerbeke/Perkins 4-107 all the way up to a big ole’ ATB tug boat. I know there are problems with waste heat recovery systems in smaller engines with a lesser BTU output in their exhaust but I’m wondering if it’s ever been done successfully. I feel like anyone who could use the exhaust heat on a Westerbeke/Perkins 4-107 to extract greater thermal efficiency might have something the world might want.

I’m just a deckie so I’m way out of my depth, for which I apologize profusely to engineers on here, but even a broken clock is right twice a day! Just some food for thought…

I have seen them on small engines but mainly for use as wetsuit heaters. Basically just a heat exchanger with exhaust on one side and water on the other.

[QUOTE=gulf_engineer;124287]I have seen them on small engines but mainly for use as wetsuit heaters. Basically just a heat exchanger with exhaust on one side and water on the other.[/QUOTE]

Hahaha well that’s not saving me a whole hell of a lot of fuel is it?

No, but if that is your goal, you should just buy a Prius.

[QUOTE=gulf_engineer;124294]No, but if that is your goal, you should just buy a Prius.[/QUOTE]

It’s all about the $$$$$$$$$$$ :slight_smile:

The 750 series AT/B’s have waste heat recovery on the stacks for each main engine. Granted the engines are 12V32 series Wartsila 8000 HP engines. Also they use thermal oil instead of traditional steam.

I’ve seen some gensets with thermal oil heaters for bunkers. In the past on the smaller high speed engines like EMDs or Alcos, the only waste heat used was jacket water through the evaporator.

Same here, have seen them on cruising sailboats to get warm water for showers, etc.

This does not save fuel, but a warm shower is always a good start !

I suspect that the technical effort is not big enough to offset the savings on smaller engines. It adds complexity, additional maintenance, etc. On big engines even a small improvement in efficiency translates into a lot of saved fuel (=money).

Couple of our older survey launches have that kind of setup for cabin heat. 500 hp Cummins.

Paddy - What do you want to use the waste heat for anyway?

On small boats you a fairly limited to comfort heat. On our 42 with the pair of DD 6-71’s we had a heat exchanger run from the fresh water side of the engine cooling system (that’s the glycol side) to our hot water heater. That would give us 10 gallons of hot water - good for 2 showers. After that we would have to hook into shore power or fire up the generator to power the hot water heater.

On frosty fall days, those Detroits would act as big heat sinks and would keep the salon nice and toasty warm…

[QUOTE=Jetryder223;124367]Paddy - What do you want to use the waste heat for anyway?

On small boats you a fairly limited to comfort heat. On our 42 with the pair of DD 6-71’s we had a heat exchanger run from the fresh water side of the engine cooling system (that’s the glycol side) to our hot water heater. That would give us 10 gallons of hot water - good for 2 showers. After that we would have to hook into shore power or fire up the generator to power the hot water heater.

On frosty fall days, those Detroits would act as big heat sinks and would keep the salon nice and toasty warm…[/QUOTE]

Ah, I was just spit-ballin’ ideas about squeezing a little more efficiency out of diesel engines. I figured if the big boys could have fun with all these cool waste-heat turbines and what not then why can’t little engines too? I’m sure there’s nothing there, I just wanted to hear what the more intelligent, and more sober, people had to say on the matter.

On our little tug we have a radiator style heater w/ a 12volt fan in the wheelhouse to push the air & hot water heater off the me jacket water tank works quite well not sure who makes it I will look into it when I have time.

Google “bus heater”.
Or look in your Boats and Harbors.