This work is a phase in augmenting the cooling load of an air cooler, which is considered as a cross flow heat exchanger. Here, an air cooler of in-line semicircular tubes (SCTs) is proposed and tested at a wide range of the airflow and attack angles of their bases (0    90). Their performance is practically compared with that of complete circular tubes (CCTs). In the experiments, cold water is passed through the tubes while hot air is passed across the bundle. The yields state that converting the tubes to pair of SCT augments the cooling rate besides increasing the air pressure decay. In the ranges, 0    60 and 60    90, the heat load and flow pressure loss are increased and decreased with rising the base angle, respectively. Besides, the thermal performance indicator (TPI) is increased by growing the SCT angle in the domain 0    60, while it is damped with widening the angle in the extent 60    90. Furthermore, the results document that the maximum value of TPI is 1.93.