A marine equipment optimization depends on the determined criteria. Optimal equipment production and its usage instead of the standard one, could increase the investment costs resulting in the increase of the payback period and the important characteristic of the marine equipment should be in accordance with the technical rules of the classification society and the international conventions. In some cases the optimization of marine equipment is possible and desirable. The paper deals with the refrigerating systems in general and especially with the refrigerating compressor, the most expensive part of the system. The optimization criterion is the minimization of the total costs of the refrigerating system. The model should show the way to decrease refrigerating system costs and give an information tool for a quicker selection of refrigerating system elements.