Might be "spec" for specification, if the fuel is subject to a standard.

Super low heating value?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

I thought about the Super Lower heating value too, but LHV is not a unit of measure as such, The way I understand it is that LHV and HHV etc. are terms for a type of measurement. the measurement is in BTUs, but
depending on whether or not you take into account the energy needed to evaporate the water within the combustion cycle, the BTUs becomes an LHV or HHV figure.

Specific latent heat of vaporisation?

Standard, not to be confused with actual. Its an assumption rather than a measure.

VE1BLL - Yeah, that's my understanding of it at least. Now, I could be completely wrong about this. I'm still learning.

CWB1 - So you are saying that the LHV and HHV are assumptions, and the S makes it a standard assumption?

I feel like I'm missing something here. xD

No. A "standard" value is an assumption, a book value. It does not take into account variation in temperature, density, pressure, or chemical composition of the fuel in your tank. Its a "perfect world" engineering value. If I dont have any test data and need to run a calc I'm going to plug in a standard value. OTOH once I have actual test data I'm going to use actual, occasionally called the normal or measured value in all calcs. Sometimes you'll see subscripts S or A used, sometimes software, laziness, or personal preference wont allow and you'll see the S or A prior to the thermodynamic shorthand. SLHV = LHV_S. ACFM = CFM_A.

Liquid onroad fuel in the first world is the most chemically consistent fuel worldwide, but it still varies. In the second and third world even onroad fuel varies significantly as they arent regulated to the high standards the rest of us are. Offroad fuels everywhere vary significantly, head out into the US oilpatch or even your local trash dump and you'll see generators burning whatever comes out of the ground. When you get into the gaseous fuel world, composition and LHV vary significantly hence my quoting of "standard" above, book values often being rather optimistic. That variation might not seem important, but when you're developing a large engine burning many thousands of gallons of third world fuel per year it impacts calibration and even hardware decisions as a 1% improvement in fuel economy can be tens of thousands of US$$$/year.

The "S" is "Saturated" I believe. The opposite of "Dry". My source is Google and a few link follows.

Steve

Context, including typical numerical values and units, could be very useful at this point.

Guessing the meaning of an acronym without the surrounding context (of the given instance) has become dangerous in this age where we need 'Disambiguation Pages' listing the surprisingly-numerous possibilities of any acronym.

CWB1 - I just read the literature taking into account your description above, it all makes sense now, Thank you very much for your excellent
explanation.

Dan