The low-temperature seawater is an important renewable source used for direct and indirect seawater air conditioning. In the northern Arabian Gulf, the water depth is insufficient for direct seawater air conditioning. So, for such circumstances, seawater can be utilized as an auxiliary for precooling the returned air from the conditioned space. In this study, a two-dimensional numerical simulation model of crossflow for a 20-tube bank in a staggered arrangement with a /D as 1.5 and 1.25