Real life test values, Diesel to electricity and heat

[Bikerbob]

Finally the first tests done. Nothing theoretical at all, this is real life values!
Testing is knowing 

More tests will be made over the coming weeks (two weeks of christmas vacation  ).

Summary:
Electrical output: 5kW
Thermal output: 3 kW (output temp from het exchanger: 47 degrees C, 120F)

Setup:
JKSON 10/1.
Thermostat 85 degrees C (190F).
STC 7,5 genhead.
Engine speed: Approx 650 rpm.
Thermosiphon heat exchanger.
Techem water energy meter (temp in / out, flow, energy). Typically used when charging for hot water use in apartments.

Ambient temperature at testing: ~5 C (40F).

Electrical load: ~ 5 kW (+ / - 10%)

Cooling water flow in heat exchanger: 77 liter (20 gallons) per hour.

Inlet cooling water temp: 10 C (50F).

Outlet cooling water temp: 47 C (120F)

Thermal energy transferred from the engine to the cooling water (exhanger cooling water): ~3 kW.

Time from startup to "steady state" (readings): Approx 35 minutes.


To be tested next time:
Fuel consumption, precise electrical load, output at various cooling water temps.

Pictures will be posted later.

[Bikerbob]

Water energy meter. Pretty much a common volume meter, but also checking temp in and out.


Heat exchanger.
A car heater element, wrapped in copper.
Works good, since the thermosiphon goes "top" to "botton", and the cooling water "bottom" to "top".
In the picture the exchanger is wrapped in a highly insulating material. A cotton towel...
Note the not-so-permanent fixing to the engine...

[fattywagonman]

Good stuff Bob,
There is likely another 3-4 kW of heat in the exhaust... rule of thumb with heat engines... 1/3 of the fuel is absorbed by the cooling system, 1/3 goes out the exhaust, and 1/3 gets turned into useful energy...

[SHIPCHIEF]

I always try to figure out ways to remove the soot build-up in the exhaust heat collector.
Some way to operate the soot tool without shutting down the engine.
I noticed that a narrow gauge rail operator's steam engine had twisted flat bar in each fire tube, that helped with the heat transfer, but if it could be periodically twisted, would it scrape the soot off and let the exhaust velolcity blow it out the stack?
Scott E

[Bikerbob]

Good stuff Bob,
There is likely another 3-4 kW of heat in the exhaust... rule of thumb with heat engines... 1/3 of the fuel is absorbed by the cooling system, 1/3 goes out the exhaust, and 1/3 gets turned into useful energy...

Exacly what I have heard as well, but now I know...

Also have to figure out the exhaust heat exchanger. Anyhone have an idea about how much surface area I need?

/Bob

[fattywagonman]

Anyhone have an idea about how much surface area I need?

No idea... but it depends on some things like material of the HE and how much heat you are trying to extract... I would think that the HE would need to double in size to go from 70 to 90% efficiency.. a shell in tube HE like this would be my recommendation...

Here's one from Polar Power

http://www.polarpowerinc.com/products/heat_exchanger/heat_exchanger.htm

And one from Bowman

http://www.ejbowman.co.uk/products/ExhaustHeatExchangers.htm

and another

http://www.abco.dk/heatrec.htm

Hopefully these will give you some ideas....