Heat transfer subject is not static as new things happen frequently and better empirical, analytical & numerical solutions data are continuously available to the professional societies in the field of heat transfer. The research literature provides huge amount of information, the students could be overwhelmed if too many nuances of the topic were focused and expanded. The author focused the role of an interpreter of the subject with findings from analysis & equations presented will be very useful for the readers if more extensive works in a sufficient number of instances in the field of heat transfer. The utilization of heat transfer principles to the design of heat transfer equipment to accomplish a certain engineering objective for product development for economic gain. Economics plays a vital role in the selection and design of heat exchanger keeping in mind that the weight and size of it. The design for a particular application will dictate the rules to obtain best design with consideration of economy, size & weight. I limit my discussion to heat exchanger where the primary mode of heat transfer are conduction and convection.
