Fuel Consumption by Generator

The principle of Conservation of Energy implies that the greater the load on the generator, the greater the fuel consumption.

As to specific figures for specific loads, the generator manufacturer is in the best position to supply this information, and by a long shot the best way to contact the manufacturer is by telephone. Make the call.

Something makes no sense here, if you need a 82.5 kVA generator diesel-generator set then that means your load is less than that. If you look back on all the postings about DG you would know that loadings below 50% reduces the life of the engine.

If you are simply looking for a generator to attach to your existing engine then the larger generator will be fine (assuming it can be physically connected) and the fuel consumption won't be much different than the smaller generator.

Exactly what is your situation, replacing just the generator, there is load beyond the machine rating, etc, etc. Please clarify my doubts.

It is always safer to put less load on DG than rated. If it is below 80% and your requirement is 82.5 KVA ,there is absolutely no problem. You may conirm with Kirloskar Cummins too.

I think a few things need to be clarified abit relating to running diesel engines at part loads like on gensets.

The very large units in the several hundreds of KVA capacity and up are the most prone to the issues with running at light loads causing early engine wear and the like.

The smaller ones under the few hundred KVA range are far less prone to that issue being the engines themselves are far smaller and can run at higher constant average block temps and the like which solves a lot of the issues related to wet stacking and oil thinning.

The thing is there are millions of small continuous run power plant systems that are used for remote locations that have generator heads of 15 - 20 KVA capacity attached to bigger four and six cylinder industrial engines that should be capable of 5 - 10 times that peak power capacity but they are never loaded to a fraction of that just to get extremely high running life expectancies from them.

For example a buddy of mine had me fix up a old stationary power plant that came from from some remote resort camp some place way up in northern Canada. It had a 5 KVA generator head attached to a large four cylinder Ford industrial diesel engine that was rated for about 75 HP which was about 8 times the size of diesel engine that generator head needed.

The six digit hour meter was broke but well into the 40,000's running hours and the engine ran perfect despite being bone stock and never opened up according to the guys he bought it from who knew its history from day one!!

After I got it up and running he had me switch it over from being a 110/220 50 Hz unit to a 120/240 60 Hz output which mostly involved turning up the RPMS from 1500 to 1800 and adjusting the old voltage stabilizer regulator system to drop the volts down to 120/240 once the RPM's had been turned up.

The point is that engine ran for 10's of thousands of running hours at a very light load and never had a problem with it and there probably a few million more small systems that use the same combination of small generator head and oversized diesel engine that work very well in that type of applications.

The generator will be loaded about 50% (82.5/160) and hence the specific fuel consumption will be more(Fuel required per unit of electricity generated).

Ideally you should go for generator of about 120KVA to get better efficiency.

You can get the specific fuel consumption for various loading condition from the manufacturer. It is not advisable to buy generator with larger capacity since you will end up spending more on fuel in long term, if you are going to use this generator extensively. But if it going to be used once in a while, the efficiency does not matter.

Get the generator specific fuel consumption for the generator of offer at various loads before you buy it.

Get the best efficiency point from manufacturer & load it up to that point.