The present paper is an investigation of the cooling of hot shear thinning fluids flowing through cylindrical pipes. The study is achieved via numerical simulations with the help of the computer code CFX, which is based on the finite volume method to solve the governing equations. The efficiency of two techniques for achieving the cooling process is investigated, namely: the counter flow and the baffling techniques. In the first part and for the first strategy, the hot fluids are cooled by an external turbulent counter flow of a Newtonian liquid. In the second part and in an attempt to enhance the energy efficiency of the heat exchanger system, semi-circular baffles are inserted. We note that two strategies are used in combination in the second part of study. Effects of the flow rates and the pitch ratio of the inserted baffles on the flow and thermal fields are explored. The obtained results show a great enhancement of heat transfer rates when using both strategies in combination.