An effective model of simultaneous heat and mass transfer processes is useful to assistin process design, optimization of existing processes and monitoring product quality. Pre-viously, the lumped reaction engineering approach (L-REA) has been shown to model theglobal drying rate of several heat and mass transfer processes very well. Here, the REA(reaction engineering approach) framework is implemented to model the local evapora-tion/condensation rate in drying of non-food materials, baking and water vapor sorption.The REA is combined with a set of equations of conservation of heat and mass transfer toyield the S-REA (spatial reaction engineering approach) to model these processes. For mod-eling each process, the activation energy is generated from one accurate run and evaluatedaccording to environmental temperature and humidity. The relative activation energy imple-mented in the L-REA is implemented in the S-REA by applying local variables. The resultsindicate that the S-REA is accurate to describe baking, drying and water vapor sorption pro-cess which shows the applicability of the REA to model the local evaporation/condensationrate of these processes. The S-REA is readily implemented to assist in process design, evalu-ation of existing processes and maintenance of product quality. In near future, by couplingwith solid mechanics, the REA may be employed to predict material deformation and shapechange during heat and mass transfer processes by coupling with solid mechanics. Thedevelopment of the REA to describe migration of volatiles inside materials undergoing heatand mass transfer processes is also underway.© 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.