The purpose of this study was to experimentally investigate the effect slotted cones within a heat exchanger have on the heat exchange performance by making the thermal boundary layer thickness thinner producing turbulence, and placing slotted conical ring elements in the inner tube of a tube-in-tube heat exchanger in order to increase heat transfer. In experiments, water was used as the heat transfer fluid, and air was used as the fluid to transfer heat to water. During experiments, slotted conical elements were placed in the inner tube of the heat changer at stage 160 mm and 320 mm; at first in an empty tube, and then as both parallel and counter-current flow at Reynolds numbers ranging between 3000 and 10000. In comparison to the values of a heat exchanger without slotted conical element (without turbulator), the friction loss equaling to the average 70% increase in heat transfer for the heat exchanger with slotted conical element (with turbulator), is twice as much. In addition, entropy production was calculated in order to determine how thermodynamically advantageous the improvement technique was; there was an average 22% loss in entropy production.