For the first time, three alternative techniques were used in this research to enhance the thermal performance of a double pipe heat exchanger: the air bubble injection method, the use of a perforated wavy strip turbulator, and the use of Nano fluids as the working fluid. Distinct bubble injection flow rates ranging 2–6 LPM and turbulators with variable hole diameter ratio (D/L) were used in the experiments. Working fluids have included water, air/water, CuO-water, and air/CuO-water with different volume fractions ranging 0.25 % to and 1 %. Based on the findings, the use of Nano fluid, the PWST and bubble injection method increased the heat transfer by 56, 53 and 14.1 %, respectively. Also, the simultaneous employment of these three techniques increases heat transfer and exergy losses up to 2.15 and 1.82 times greater than those of plain pipe, respectively. The double pipe heat exchanger equipped with a perforated wavy strip turbulator with a hole diameter ratio of 6 and bubble injection with m˙a = 6 LPM was chosen as the best-case utilizing net profit per unit transferred heat load (ηp) and thermal performance factor (TEF). In this case, the maximum amount of ηp and TEF are equal to 2.124 × 10−9 and 1.24, respectively.