Yes, it's possible. The properties you get in the data struct are either functions of pressure, or functions of pressure and normalized energy (unorm). You may find the information about the dimensions of each property matrix here:
Now, you'll need a way to find unorm for the given P & T, and then look up u for the given P & unorm. Try this code:
load r134aPropertyTables;
% specified temperature and pressure
T = 60 + 273.15; % K
P = 0.300; % MPa
% build a p-unorm mesh for 2D lookup
[Xv,Yv] = meshgrid(r134aPropertyTables.p,r134aPropertyTables.vapor.unorm);
% look up temperature at each unorm point at the given pressure
Tvec = interp2(Xv,Yv,r134aPropertyTables.vapor.T,P,r134aPropertyTables.vapor.unorm); % K
% look up unorm at the given T
unorm = interp1(Tvec,r134aPropertyTables.vapor.unorm,T);
% look up u at the given P and the looked-up unorm (for given T)
u = interp2(Xv,Yv,r134aPropertyTables.vapor.u,P,unorm) % kJ/kg
This works for vapor. The code for liquid would be very similar. It'll be a good idea to write something to tell if the given P,T is vapor or liquid first. Mixture would be a bit different.
You can first find the saturation properties (unorm=0 and unorm=1) at given pressure, then use the vapor quality to calculate the mixture property.
