This paper provides a review based on the theories and complexities related to the design of air preheaters and the heat transfer surfaces used in them. Numerous articles have been conducted to understand how to design air preheaters and the performance parameters associated with them. Air preheaters (APH) are heat exchangers used to preheat air before any other processes take place. APH has widespread applications in power plants, vehicles, and all areas where air heating and fuel savings are required. A comprehensive review of the heating elements or surfaces used in air preheaters for heat transfer between cold and hot fluids is also conducted. Initially, various types of commonly used profiles are identified, followed by research to find ways to experimentally investigate heat transfer plates. Excerpts are also provided regarding the design of experimental setups for the same and the interdependence of various parameters.
