Abstract: In select embodiments of the present invention, a method for optimizing thermal transfer capacity of a fluid employs multi-walled carbon nano-tubes (MWCNTs) and a surfactant such as Gum Arabic (GA), that are mixed into a fluid, such as water, according to a specific protocol and energized via ultrasound until a specified amount of total energy is applied. For select embodiments, the maximum demonstrated enhancement of an aqueous fluid in thermal conductivity is 20% and in convective heat Transfer is 32%. The thermal conductivity enhancement increased considerably at bulk temperatures greater than 24° C. The percentage enhancement in convective heat transfer in a tube increases with axial distance. The resultant optimized fluid is also described.