difference in enthalpy for r-134a and hfc-134a?

[Cheetos]

Hi, it has been years since I last worked with refrigerant. I was looking up on enthalpy for r-134a. In my text book (Moran and Shapiro 3rd ed), at 40C, hf = 106 kJ/kg, hg = 268 kJ/kg. I came across this DuPont Suva HFC-134a technical information and it has hf = 257 kJ/kg, hg = 420 kJ/kg at 40C. (I have inserted a screen shot of the table from DuPont) I thought r-134a and HFC-134a are the same. I've seen enthalpy diagram and it's pretty close to the DuPont data. I know my text book is not the most updated material, but I didn't think the data would be that much off. Am I missing something?

 

[MintJulep]

Most likely the two sources are using different "zero" reference points.

 

[Cheetos]

Thanks for replying. I'm new at the HVAC business, so is it normal for people to supply data with different reference points? I googled r134a enthalpy and in another site (

https://www.ohio.edu/mechanical/thermo/property_tables/R134a/R134a_PresSat.html),

it corresponds with my textbook data (hf=107.4 kJ/kg and hg=271 kJ/kg for 39.4C). I checked vf and vg and pressure. All the data are about the same. The only differences are enthalpy and entropy. I think both sets of data are right, but I feel like I'm just missing something here.