Enthelpy change in isentropic condition (air-con)

[yecko]

Homework Statement

How to get h2?
(see pic)

Relevant Equations

isentropic
dH = dQ + Vdp = Tds + Vdp
H = U + pV

h and s can be obtained from "Saturated refrigerant-134a—Pressure table"

however, how to get h2? it is not on the curve, and neither p or dV is given in the question. Thank you

 

[BvU]

Ity says P 0.8 MPa on the curve ! You have s,p and can look up T in table A-13

 

[yecko]

This is table A13, which at P=0.8MPa, s=0.94456, h should be somewhere between 286.71 and 296.82.
However, from the solution, h= 275.39kJ, am I looking at the table in a correct way?

 

[BvU]

Yes you are. Turns out the phys props have changed slightly.
I have an older edition (2002) of cengel and there it matches better.

40	273.66	0.9374
50	284.39	0.9711

https://www.egr.msu.edu/classes/me417/somerton/R134a Tables.pdf

I googled "and operates on an ideal vapor-compression refrigeration cyle between 0.14 and 0.8 MPa" and did indeed find other results too.