I'm trying to find out if there is any correlation between keeping hydraulic, gear, etc oil clean and a reduction in energy consumption. Any help would be appreciated.

ssctim,

One of the consecuences of contaminants in oil is the premature and acelarated oxidation of the oil. Oxidation leads to increase viscosity meaning more energy to desplace the oil.

There has been a study on the correlation between oil contamination and energy costs. In the study, valves that had oil oxidation by-products had significantly higher coefficient of friction values then clean oil. I have also seen an actual field result reporting an 8% reduction in energy requirements.

I think that you raise an excellent question. A subject that deserves more study.

The big payoff for oil cleanliness is longer equipment life and higher reliability.

It is a very clear cut case. In a machine which is run without any oil cleaning system, the wear and tear of components goes on increasing with time reducing the efficiency of the machine and so increasing the energy consumption.Assuming the life span of the machine at 12000 hours, the energy consumption will be something in first 3000 hours, will be more in next 3000 hours and will increase accordingly in future.

But if the oil is kept reasonably clean, almost no wear and tear, hence no reduction in the efficiency of machine and no significant increase in energy consumption. It will be approximately same during last 3000 hours as during first 3000 hours. Moreover there will be increase in the life of the machine itself.

I dont have any technical data, but it is very clear from the common sense itself. If somebody studies the effect of clean oil on some machines through out their life span, it will give solid backing to this thought.

Energy consumption increase depends on many factors like positioning of the filters in the proper places with proper ratings. Second as the oil becomes contaminated either on internal or external factors the differential pressure across the filter increases therby increasing energy consumption.This is in the case of absolute filtration.

In fact a study was made on screw compressors and higher differential pressures across filtersa wasted energy to the tune of 7000 US dollars/year.

In the case of bypass filters a part of the contamination reduces the component life for eg : bearings and a shaft mounted with gear could run with play or slack and increase load on drives.

Hope I am on the right track? and this helps

$7,000 a year?

Well let's say 8,000 hours a year, round number $1 per hour.

Let's say 10 cents per killowatt hour (I assume an industrial facility gets power at least as cheap as I get at my house).

That means $1/hr * (killowatt*hr /$0.10) = 10kw.

Again round numbers 10 kw power input corresponds to roughly 10hp electric motor fully loaded.

How big is the oil pump to begin with? (Some systems don't even have a pump that big).

Did they happen to mention whether they changed/cleaned the filters during this study? I'm sure I could demonstrate a pretty good increase in cost if I stopped taking care of everything.

Didn't really mean to be sarcastic but I would be interested to hear some more details on the basis for this $7,000 per year.

Going to Franky's comment again (not trying to pick on you)

The cost you are talking about is the cost to keep the oil clean I think. If anything, that shows up on the other side of the ledger. (We have to find more than enough savings to justify the money spent on keeping the oil clean).

btw my opinion as above is that reliability is the reason to keep the oil clean. Trying to sell it based on efficiency sounds to me a little bit dubious. Has anyone ever had their gas mileage on their automobile go up after an oil change? Didn't think so.

Maybe not quite a fair comparison since the wear caused by the previous bad oil is not erased. I think if significant wear is occuring to the point that it is significantly affecting machine efficiency, your reliability concern is a lot bigger than your efficiency concern.