Refrigerant Oil, Volume Temperature and Weight

Last week during the during the uncensored @HVACOvertime Overtime show episode 143 (46.51/ 1:23:56) there was an interesting discussion about refrigerant oil by volume or weight and the effects of temperature.
I thought this was a great opportunity to do a little research and make a little experiment.
Inspired from @DaveJohnsonnola @curioushvacguy6876 @HVACRVIDEOS A-Team Adam @HVACRNorth

I tossed un unopened jug of alkylbenzene refrigeration oil in the freezer for a few days. The wife was not thrilled about this. 🤣
We set up a scale and measured in a volume of oil in a small and larger container right out of the freezer.

After letting it sit for a few hours the temperature rose to 95F
The volume also increased slightly but the weight stayed the same.
This proves the fact that fluids do expand with temperature, however the small increase over a large temperature change is negligible for practical application in our small quantities of refrigerant oil. it would be significant for water heaters and boilers which is why they install expansion tanks for this reason. Expansion of liquid is the fundamentals of a mercury (or now alcohol filled) thermometers work.

We also see how the viscosity changes. When the oil was at a lower temperature it had a high viscosity, resisting flow and moving slow. When the oil warmed up the viscosity dropped and the oil had less resistance and flowed more freely.

Next we filled 2 containers to the same volume and temperature. One with alkylbenzene refrigeration oi and the other with Water. The difference was the weight of each. the oil was lighter and the water was heavier. Even water volume at 16.9 FL oz did not equal the same in weight OZ confirming that FL OZ in volume and Weight OZ are a different measurement.

We looked at the specific gravity of Mineral oil, alkylbenzene, POE, POV and PAG oils compared to water and found each of them had a different specific gravity. This means each of the oils had a different weight at the same volume and temperature.

I researching and confirmed with the major compressor manufactures that measuring oil by volume with fluid OZ was the preferred method.
Applying that to the experiment we can see that even though Weight would be technically more accurate, the manufacture would have to list the weight for each of the oil types and listing oil by volume was much simpler. Supply houses also sell refrigerant oil by the volume and not by weight so that further confirmed the reasoning.

This little experiment did not show the difference of measuring by oz weight vs foz (fluid oz or floz). its unknown how much it would be off or the implications if any it would have on operation.

It was a fun little experiment you may or may not like.

Видео Refrigerant Oil, Volume Temperature and Weight канала Love2HVAC with Ty Branaman