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Diesel generator -diesel consumption

09/18/2008 1:53 AM

how to calculate the diesel consumption in various generator ..like 62.5,125kva

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Guru
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#1

Re: Diesel generator -diesel consumption

09/18/2008 3:00 AM

Too little information. Look in the user manual.

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Guru
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#2
In reply to #1

Re: Diesel generator -diesel consumption

09/18/2008 4:07 AM

Hello The Prof

from me

Kind Regards....

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#3

Re: Diesel generator -diesel consumption

09/18/2008 4:40 AM

Please address this query in mechanical section. Though I am sure you will get similar answers as above to this question as it lacks basic information and is almost like a class room question. Remember that Diesel engine is a mechanical device the alternator connected to it is an electrical machine called generator.

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#4

Re: Diesel generator -diesel consumption

09/19/2008 12:50 AM

If all you need is a ball park you could chain the component efficiencies.

kva*(Kwh/kva)*Gen eff*Diesel eff*gallon/BTU=gallons/hr

kva*(48/60)*.90*.40*(3412 BTU/1kwh)*(1 gallon/130,000 BTU)=

I get 1.46 gallons /hr for a 62.5kva genset.

Cross checking by estimating hp gives powering a 67 hp engine for one hour. This compares to the smallest 4 cylinder production engines which MIGHT give an hour of power for a gallon and a half. However, don't bet on it. 40% efficiency for a desiel engine is best case. If you can not get a direct read on the projected fuel consumption you could refine the estimate by looking at the gen/alternator set speed and the engine power factor at that speed.

1800 rpm gens are too slow for best engine power and 3600 or higher engine rpms give a smaller engine and better efficiency but potentially shorter service life.

Hope this helps.

Sincerely,

Mr. Gee

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#6
In reply to #4

Re: Diesel generator -diesel consumption

09/19/2008 10:13 AM

GA Mr. Gee for a good back of the envelope estimate. These are usually good enough to get that ROM estimate. I might go lower on the engine efficiency perhaps 30-35% but given the information in the original question, this is all one can expect.

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#7
In reply to #4

Re: Diesel generator -diesel consumption

09/19/2008 11:10 AM

I just looked at a 62.5 KVA gen set and the consumption at full load was 4.3 GPH. Just for your information.

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#5

Re: Diesel generator -diesel consumption

09/19/2008 8:15 AM

The simplest and easiest way is to check the manufacturer's specification sheet. It will be shown there.

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Guru

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#8

Re: Diesel generator -diesel consumption

09/19/2008 4:43 PM

Double check all these posts against 0.335 pounds of diesel per horsepower per hour. You can convert this to commie units! To get hp, take the kVA x .8 if your gen set name plate shows 0.8 PF rating, then x 1.341 to get commie units then / .95 (average generator eff).

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#9

Re: Diesel generator -diesel consumption

09/21/2008 11:12 PM

Consumption of fuel should refer to the output. The other way what we do is to caculate Electrical Units (KWH)/Liters or gallons. we take measurements of Electircal Energy in KWH and diesle consumed for one hour & compare.

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#10
In reply to #9

Re: Diesel generator -diesel consumption

09/22/2008 12:38 AM

I agree. The unstated assumptions in my rough cut answer were full output and near perfect efficiency. Very questionable assumptions. If the user manual data provided by the commoner are correct and I believe they are then that particular units net thermodynamic efficiency is really pretty low.

That is the type of thermodynamic inefficiency that a diesel engine can show when run slowly.

Even so, only hitting 35% of best case is pretty bad. I wonder if I may have made a mistake in my estimation method. If its there I didn't find it. But, it is very hard for me to accept that this system is that bad. That result would give an engine efficiency of only about 15%. I know that running slow can cut the engine efficiency a lot, but cutting it more than half seems unrealistic. If someone has further thoughts on this subject I would be interested to listen.

Thanks in advance,

Mr. Gee

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#11

Re: Diesel generator -diesel consumption

07/23/2010 3:36 AM

we have 500 kva & 370 kva generator we need the diesel consumption for both generators. how to calculate ?

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Anonymous Poster (1); Brave Sir Robin (1); Current Maarey (1); hara143 (1); Mr Gee (2); PetroPower (1); Sparkstation (1); The Commoner (2); The Prof (1)

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