The heat exchanger is an important element for heat transfer and energy savings. There are many different types of heat exchangers, but due to the diverse design possibilities, ease of manufacturing, and low maintenance costs, crossflow and counterflow heat exchangers are commonly used in the oil industry, petrochemicals, climate technology, food storage, and other sectors. The shell-and-tube heat exchanger is frequently used in the industry as a refrigeration unit to transfer waste heat from the injection molding machine to the cooling water, thereby improving the efficiency of the injection molding machine. The conversion of waste heat from the injection molding machine into cooling water depends on the heat exchange capacity of the heat exchangers. To increase the heat exchange capacity of heat exchangers, an optimization is carried out aimed at determining the best parameter combination for the heat exchangers. Nine models are created based on the Taguchi method in NX 10.00, and the CFX analysis is conducted in ANSYS 14.5. The resulting outcome provides the optimal dimensions of the heat exchanger for a minimal water outlet temperature.