One of the most important and most common processes of engineering applications is the heat transfer between two or more fluids at different temperatures. The devices carrying out this transfer are generally referred to as heat exchangers. They are widely used in several applications such as thermal power plants, chemical industries, heating, ventilation, and air conditioning (HVAC) systems, cars, electronic devices, use of alternative energy sources, and heat storage. Onaysan has an annual production capacity of 600,000 plate heat exchangers for combi boilers.