Innovative approach of determining the overall heat transfer coefficient of heat exchangers - Application to cross-flow water-air types

Heat exchanger analysis is considered difficult because the determination of the overall heat transfer coefficient is accompanied with high uncertainties. The uncertainties are due to various reasons that are mostly related to the geometrical complexity of any heat exchanger. The present work suggests an innovative iterative technique for determining the overall heat transfer coefficients of heat exchangers as a function of the fluids flow rates. The method depends on a single heat exchanger experimental assessment that takes into consideration several ranges of water flow rates. The extracted experimental data lay out the foundation for the innovative iterative method to provide an explicit relation between the overall heat transfer coefficient and the fluids flow rates. The method is validated against experimental results, for cross-flow water-air type heat exchanger, in which an average relative error of less than 5% is observed.