This article presents a comparative study using two global optimization algorithms, Electromagnetic Field Optimization (EFO) and Heat Transfer Search (HTS). These techniques are efficient alternatives when classical methods find limitations to solve real problems. To verify methods performance, the rectangular microchannel heat sink design was implemented formulating the respective  Inverse Heat Transfer Problem (IHTP). Experimental results were competitively compared with the traditional Levenberg-Marquardt (LM) outcomes. Moreover, global algorithms achieved estimations with errors lower than 5%, and they converged at least three times faster than LM. &nbsp