This paper presents several 2D heat flux calculation methods applied to temperature data of one of the most exposed plasma facing components of the JET tokamak. We have two temerature diagnostics: a high time resolution infrared system is used to measure the surface temperature and two embedded thermocouples to measure the temperature in the bulk at 1cm depth from the surface. A direct calculation is possible using the surface temperature but the presence of thin carbon layers disturb the measurements and leads us to make an inverse computation of the heat flux using the thermocouple data.