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generator run time
2

generator run time

generator run time

(OP)
I have been asked to provide the estimated run time for our 2 megowatt generator with 2000 gallons of fuel. Any one with suggestions on what information I should collect and a formula to plug them into. Many thanks in advance.

RE: generator run time

Have you tried to look up the product data sheet/catalog of a 2MW generator?

RE: generator run time

0.25 litres per kilowatt hour is a good round figure i use for sizing fuel tanks.

There is about 3.38 litres per (U.S.) gallon, i think.

RE: generator run time

Here's what one 2 MW generator data sheet says.  Check your supplier's information.    


At 25% of full load, gpm:    0.725 gpm (164.7 lph)
At 50% of full load, gpm:    1.25 gpm (283.6 lph)
At 75% of full load, gpm:    1.81 gpm (411.8 lph)
At 100% of full load, gpm:    2.50 gpm (558.5 lph)
 

RE: generator run time

What safety margin do you (your client) want?   

What warmup or "idle" times do you expect when the generator will be unloaded but running before getting to "full load" - and remember that your actual "full load" will be LOWER than the generator nameplate rated load?   

When your generator is called on as an emergency source, will you be able to (automatically or manually) trim low priority loads - what we used to call "rig for reduced electrical" on the submarines - so the actual emergency loads are reduced from your regular operation load?

RE: generator run time

Keep in mind that the rates that rcwilson noted are fuel burn rates, actual consumption.  The unit will pump much more than that, approximately 50% more.  The unspent fuel is returned to the tank and is hot.  Hopefully it will be returned to a large tank where the fuel will mix with cooler fuel.  Some manufacturer's do not recommend running on "hot fuel".  Caterpillar among them. And, they actually may de-reate the units accordingly.  How much differs between manufacturer's.  This is all assuming they are Diesel fired units.

RE: generator run time

Given rcwilson's fuel rates and EEJaime's warning (you don't want to boil your fuel), I'd say you have no more than 10 hours of run time.

RE: generator run time

I use 13 kW hours per US gallon as an estimate. Most modern engines will do a little better.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: generator run time

(OP)
Thank you all for your input. The product data sheet ( that we got from our maintanence vendor )says the generator burns 104 gallons per hour. Thanks for the "hot fuel" tip, also.

RE: generator run time

$5.50 a minute.  Ouch.

Thanks y1a1n1k1s1 for coming back and telling us so we can hone our numbers a bit.

Keith Cress
kcress - http://www.flaminsystems.com

RE: generator run time

y1a1n1k1s1:

You may want to double check that data sheet. The numbers you mention are more likely to be for a 1500kW genset rather than a 2MW. I presume we are all talking about diesel fuel!

RE: generator run time

Most 2000 kW units I have tested use about 125 to 140 gph.  Make sure you check the spec for the referenced fuel density, if you are using ultra low sulphur fuel you'll likley find you'll burn about 2-3% more gallons per hour because the fuel is less dense than the test fuel the spec was derived from.

Fuel temp has two impacts, it is measured at the inlet of the fuel transfer pump, and above 75 to 90 degrees F will affect the fuel consumption rate by volume, at about 125 degrees F on many standby engines it will affect the power output.  At between 135 and 150 degrees F it may affect service life of fuel system components due to low lubricity, low sulphur fuels compound this problem.

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