Combined Heat and Power System

[diesel guy]

This is a neat setup:

http://www.youtube.com/watch?v=UAZKxYZ3QH0


I was thinking of something simular to it. Its nice to see a working unit to finalize my design.

Diesel Guy

[compig]

That is one of the rigs that finally inspired me to set up my own. I particularly like the exhaust heat exchanger on it.

[Tom]

Aw man, did you see that bilng. He's got a chrome valve cover! And I wonder how he figured 8KW of heat into the exchanger without a load? Isn't he just flowing the water in a loop and measuring the water temp x water flow?

[1958steveflying]

Aw man, did you see that bilng. He's got a chrome valve cover! And I wonder how he figured 8KW of heat into the exchanger without a load? Isn't he just flowing the water in a loop and measuring the water temp x water flow?

He puts 4Kw load on at around the 1 min 50sec point.

[Tom]

That was an electrical load on the generator. I'm questioning the claim of 8kw of heat out put that is showing up on the meter on the side of the exhaust heat exchanger.

[1958steveflying]

Apologies Tom 

[rcavictim]

Look at that baby shake!  I cannot see this being trouble free with all that vibration and shaking.  The machine will try to disassemble itself.  First time I have had a chance to see what Volvox Engineering was building.  IMO there are much, much better small output diesel engines for trailer mounting as a generator plant.  These Lister types need to be married to a large hunk-o-cement.  That means stationary installation.

[ronmar]

Tom
   About 3 minutes into the video when he is going over the temps and flows, on that meter assembly on the ex heatex, he says that the flow is combined with the engine cooling system, and that 8KW is the sum of both systems.  With 4KW of output/load, 8KW out of cooling and exhaust sounds about right to me...  But if I am reading and converting his numbers correctly in the video, 240V@18A is 4320W.  4.93 Liters Per Minute is 1.3GPM or 10.4 Pounds per minute.  His temps convert to 175F and 134F respectively, so he is dropping 10.4 pounds of water 41F each minute.  That is 426.4 BTU/Min or 25,584 BTU per hour being dissipated by the radiator(from combined cooling and exhaust recovery).  My convert program says that ammount of BTU is about 7.5KW.  If his roid is true to form, it is burning about .125 Gallons per KW/hour or a little less, about .54 GPH at that load.  With #2 at around 140,000 BTU/Gallon, he is consuming around 74,000 BTU of fuel and getting 25,584 back as heat. That is about 1/3 of the heat, when the rule of thirds tells me that he should be getting closer to 2/3.  His high temp seems low, which is also hurting his efficiency IMO.   

As for the shaking, that looks like a demo system to me.  I don't think it is intended for use from a trailer, but I may be wrong.

Ron

[jzeeff]

I agree, the figures don't add up but we know it is going somewhere.   A lot of heat will be lost to the air and this isn't accounted for.  A little bit goes out the exhaust as heat and perhaps a little bit of diesel is left unburned.

IMO CHP systems should be inside the building.

[Tom]

Yes that is my thought that a lot of the heat would be lost too. I still like the chrome valve cover thought. Polished aluminum would be nice too.

[mobile_bob]

typically you can figure about 5% heat loss due to radiation, but
it is likely much higher in a listeroid, maybe as high as 10%, maybe even more

there is alot of iron to suck away alot of heat that is evidenced by the low sump temperatures typical
of most listeroids i have heard of.

i applaud his efforts, but am not sure a listeroid is the best prime mover for a cogenerator

however, if it were put into a well insulated building at least in the winter months the radiant losses
could be put to use, i suspect as was stated that this is a demo unit and will find its place on a
block of concrete somewhere.

but then again,, concrete can suck up a lot of heat as well

bob g

[oliver90owner]

concrete can suck up a lot of heat as well

Thermal mass is what we call it.  No real problem as long as the heat is in the same room   It, too, will radiate.

Regards, RAB

[jzeeff]

Interestingly, shiny surfaces don't radiate heat nearly as much as other surfaces.