In this work, a non-evaporative cooling system is used with an assisted thermoelectric cooler (TEC) devices module. The system was proposed as an alternative cooling system in the high temperature climate to overcome the high energy consumption of traditional air-conditioning compression cycle. The open source Open FOAM V.9 was used to solve the transient effect of 3D model of indirect non-evaporative cooling system. The primary air temperature was set to 319 . While, the air flow was tested under four different air inlet velocities: 0.75 m/s, 1 m/s, 1.25 m/s, and 1.5 m/s. the validation shows good and acceptable agreement in COP values of the system with both experimental and theoretical works from literature within an error between (12.9 % and 9.5 %). Results show that the temperate difference value on a slice through the length of the air channel starts to decrease as velocity increasing. For example, at the last timesteps of each velocity, the temperature difference reaches about (~10 oK) when velocity is (0.75 m/s) starting from the first quarter of the channel, while the same difference in temperature not reached until the half way of the channel from the channel inlet when velocity is (1.5 m/s). Revealing that even though the percentage increase in the velocity is about 50%, the change in the temperature difference value between the inlet and outlet of the channel is about 1.2%. The local Nusselt number shows that steady state heat transfer reached very quickly as the velocity increased (i.e., at 0.75 m/s at 12s while for 1.5 m/s at 4s). Notwithstanding, as the time processed the ( increases for all cases but becomes lower as the velocity increased. .