Boiling heat transfer on porous surfaces needs further research for augmentation. Analysis of the microfilm evaporation and two-phase flow inside the microstructure was used to develop new microscale heat transfer model for boiling heat transfer on porous surfaces. Simulation results were used to study in detail the effects of fluid parameter and microstructure dimensions on the heat transfer performance during the bubble formation period. For boiling on porous surfaces with such working fluids as R11, R22, R134a and water, optimum microstructure dimensions were determined for the given conditions. The calculated results fit previous experimental data well. An experimental rig was developed to measure the pool boiling heat transfer to test the predictions of the optimization. The experimental data verified the optimization results. (C) 2000 Elsevier Science Ltd. All rights reserved.