In this work, heat transfer has been investigated for several Newtonian and non-Newtonian liquids agitated in a rounded bottom vessel equipped with an atypical helical ribbon impeller. Both experimental and numerical approaches were attempted. The measured rates of heat transfer from the wall of the vessel to the agitated liquid allow the comparison of heat transfer performances of this mixing system with those obtained on standard helical ribbon impeller A method was indicated to correlate non-Newtonian results with those established with Newtonian liquids. No temperature gradient was detected in the bulk. Numerical approach allows the local heat transfer coefficient to be obtained, and underlines the difficulty to relate global heat transfer coefficient to the thickness of the thermal boundary layer.