How to Monitor Diesel Consumption in a Generating Set

You can either find a secure area to lock up the fuel or invest in an inexpensive video monitoring system to catch your thief.

You didn't say what your formula is. It should take into account the manufacturer's expected fuel consumption at various load conditions, which is sometimes available in genset literature.

nice....GA

Does the genset have a kWh meter? If it does, you can use that with engine and alternator efficiency to find the amount of diesel you should have used. Ideally, get manufacturer's data at a range of loads. The kWh figure compared with full-load kW x running time will give you an idea of the (average) % load. If you can only get full-load data it's unlikely to be wildly out, and you can adjust it from that based on the actual load, using a bit of judgement.

Cheers........Codey

Install flow meter to measure actual fuel consumed.

Hook the meter signal to a simple recording device (PLC), which can tell you the total volume of fuel over a given time-frame.

You will know exactly how much fuel the gen-set consumed during the chosen length of time.

Measure the remaining fuel to see if it matches.

Suitable accurate meters are the type used as watermeters people's homes. A good generic phrase for internet search is: "Positive displacement water meters" or just "displacement water meters". There are several manufacturers of these items. You will need one specially fitted for diesel fuel. Since the production rates of such meters is a good deal lower than residential water meters you can expect to pay a higher price.

Here is a link to one source that will educate you on these things.

http://www.omega.com/manuals/manualpdf/M1096.pdf

Because of the general industrial market this supplier (Omega) serves I suspect they can supply one of their small meters with the right materials of construction and calibration for diesel fuel. They provide excellent application engineering help and if they cannot offer you such a model they may be able to direct you to one of the other manufacturers that can provide similar meters for diesel fuel.

This type of meter is very accurate. Meters of similar operating principle are used in liquid fuel sales and are generally suitable for trade use. They can be made quite accurate and calibration test results should be available for an extra cost. This kind of evidence can be very useful in criminal prosecutions.

Installation should be a simple job for a professional plumber or millwright. I would mount it in a secure lockable steel box with the pipe connections inside the box and with access limited to trusted employees, preferably someone from your company financial accounting group. These meters are easy to read as your home water meter and should prove to be no problem for a non-technical employee to read and certify. If your situation is far out of control and there are few you can trust a secure seal can be used in addition to the lock. Tamper proof seals covering all pipe connections and external valves in the fuel line may also be in order if you suspect someone in your maintenance organization of involvement in the fuel loss.

Ed Weldon

If the fuel is in a large reservoir (I suspect) you could install a float level sending unit. you could calculate the volume of fuel depending on the geometry and level of fuel, you would know how much is missing/remaining.

Or perhaps you could install locking caps/hatches, which only you(or the fuel supplier) hold the key.

Keep the reservoir inside a cage.

Maybe employ a large angry dog to live near fuel storage? Or a pack of monkeys perhaps?

I too faced same situation. I used this simple trick. stand in front the of DG set while running and record fuel consumption at different load conditions at different times on sampling basis; now you can arrive at approximate consumption per hour. You can definitely detect major or gross theft;

We use a fuel meter on our Gen-sets to determine daily fuel usage. The meter itself combines engine hour meter, tachometer, flow meter, and daily fuel totalizer. It also has a GPS systems that sends the above data back to my office. If you need the web site info just mail me. The make both english and metric versions.

The simplest way is to put a flowmeter on the fuel outlet from the tank and another at the intake to the engine. Connect both to your security system and set it to record video of the tank area when signal is received from the tank with no signal from the engine. Recorded readings from both sensors will reveal "inventory shrinkage" at times when the engine is running. If the differential is large enough it can also trigger video capture. That will also tell you if there is a hidden leak.

If you are considering installing flow measurement equipment (highly recommended if you can afford it), keep in mind these lines can have pulsing flow. Depending on the size of the installed equipment and the other equipment installed on the fuel distribution piping, this pulsing can be significant and can cause large errors in readings. If you purchase your meter from a mfg offering purpose built devices for measuring diesel flow, they should offer a pulsation damper (also...purpose built meters come with a sensor for supply and return and only indicate fuel consumed which saves a step on the math/logging).

Having tried it the hard way (without the damper), I can tell you it is something to at least consider before installation.

We have used an intrinsically safe ultrasonic level measurement inserted in one of the ports on the top of our tanks. The level is reported back to our main office via SCADA and we calculate the current volume of diesel based on the tank geometry. We then get current level and the rate of change which provides consumption rates during usage. This has worked very well, been cost effective and been very low maintenance.

This is tricky.

A) Install a Power recorder meter (If not already installed by the manufacturer) to record the Amount of kW produced during a period (ex. 1 month). This to cover the load variations.

B) Measure the amount of fuel consumed during that period. This can be done by metering the amount delivered to the fuel tank feeding the GenSet. This exercise should be done at least once with enough security to eliminate a theft during that period.

C) Divide the Litres by the kW and you will have an average L/kw for the GenSet and the loacation/type of load.

D) Verify consumption against this reference for future periods etc.

N.B. You can repeat the B) at random during the year to see if your reference does change. All depends on the accuracy of securing no theft during the test period.

Now, if there is a big variation (upward) from what the reference tells you, then you know that there was a high possibility of theft. Anything above +/- 5% (in my Opinion) can be considered suspicious. Then to catch the perpetrators, you can install discrete Monitoring by Video Cameras where there can be any bypassing of fuel...