A theoretical model is formulated for simulating condensation of humid air in the condenser of a seawater greenhouse located in Muscat, Oman. This model is based on a previously developed model but with new assumptions in terms of seawater temperature output and used air mass flow. Application of this model is carried out to validate its theoretical development. Comparisons are made between predictions of the model and the existing experiment, producing compatible results. The effects of relative humidity, dry bulb temperature, seawater temperature, humid air velocity, and solar radiation on condensate values are also discussed.