Difference between "Average gross" and patchAverage
 

Greetings to all,

I am simulating the problem of natural convection in a parallelepiped. I need to calculate the temperature gradient in the heated walls. However, I am getting different values ​​when I analyze data tool patchAverage (OpenFOAM) or average value in Paraview (in integrate variables patch / area). However, when calculating the average gross of OpenFOAM folder corresponding to the simulation time the result is consistent with the experimental.

Eg
Temperature gradient in the heated faces:
Average gross: 47.41 K/m
PatchAverage (OpenFOAM) / Integrate variables (divided by area) (Paraview): 120.93 K/m

Does anyone have any idea what might be happening?