Laminar film condensation inside large space occurs during accidents of nuclear power plants. To further improve the reliability of the passive emergency system, diversion panels are designed to enhance this condensation heat transfer. With simple structures facilitating manufacture and assembly, these diversion panels are also theoretically proved to be able to enhance the film condensation significantly. Effects of the three dependent parameters (length ratio between diversion panel and cylinder wall, diversion panel number and inclined angle of diversion panel) on the overall heat transfer performance are also analyzed elaborately and the optimum configuration of the diversion panel can be identified correspondingly. (C) 2017 Elsevier Ltd. All rights reserved.