Various techniques have been utilized to improve the performance of heat exchangers. In this study, multiple passive enhancement techniques have been applied. Triangular fins have been fabricated on the outside surface of the longitudinal helical heat exchanger. The performance of the new heat exchanger has been investigated experimentally and mathematically. In counterflow, hot water flowed inside the helical tube at 60 ᵒC while cold water entered the shell at 30 ᵒC. A triangle copper fin with 1 cm height, 2 cm base length, and 0.3 cm thickness with 4 cm pitch distance was welded at the external surface of the helical Copper coil tube. Along the helically coiled tube, 123 fins have been welded on the outside surface with 25 overall coil turns heat exchangers.
The results showed a good enhancement ratio compared to the unfinned helical heat exchanger. The thermal performance factor showed an improvement of more than 10% compared to plain tube coils with an increase in the effectiveness of 11%. The improvement in the Nusselt number was 16.5%. These results confirmed that the fins addition on the helical coil heat exchanger modified and improved the helical heat exchanger and supported the industrial design with better performance.