I have a question on ASHRAE-Detailed Interior surface convective coeff. (h) calculation. I found that enhanced and reduced equation require to use current step temperature to calculate h. However the output of E+ shows that it is actually use previous step's surface temperature to get h first then solve current surface temperature. I notice there are some difference exist by using previous step surface temp to calculate h and solve h simultaneously by using nonlinear iteration solver.
My impression is previous step approximation will have roughly 10% lower on peak Convection Heat Rate[W/m2] compared with the results solving h simultaneously with surface temp.
The similar problem is interior surface long wave exchange. It is not on the documentation how to solve the LW exchange Boltzmann nonlinear equation (Ti^4 - Tj^4). I am guessing it use previous step surface temperature linearized approximation just like exterior surface LW radiation. Am I right?
Of course, to use previous step approximation we can linearize surface heat balance, thus avoid using iteration method and greatly increase calculation speed.
Is there any paper published to compare the results' difference between of previous step approximation method and simultaneous h solving method?