There are several significant design criteria in order for a dry cooler to perform as needed. From the other point of view, the given cooling capacity information without determining some points is not meaningful.

The required data to design and selection of dry cooler that are used in natural cooling system are the dimensions of the unit, ambient intake air, dry and wet thermometer temperature, process water inlet and outlet temperature, water flow rate, water side pressure loss desired value, glycol ratio and desired cooling capacity.

As 100% of water can be used for the cooling water requirement of the system, glycol-water mixture (brine) water must be used in order to prevent the freeze for the systems operating in negative outdoor temperature. For example, a mixture with 20% ethylene-glycol by volume provides protection up to approximately -8°C, and a mixture with 30% ethylene-glycol provides protection up to approximately –16°C.