A novel concentration difference energy accumulator was evaluated. This accumulator was framed by hollow fiber membranes as the water vapor transfer channels. This was the membrane energy accumulator (MEA). A mathematical model was created to simulate the heat and mass transfer in the crystal dissolving process of the energy discharging stage. In addition, the model was experimentally validated. Based on the simulation results, the heat and mass transfer characteristics of the MEA in the crystal dissolving process were analyzed. The results of the simulation and experiments proved the feasibility of the MEA. The energy storage capacity of the MEA was a minimum of 25% greater than that of a traditional concentration difference energy accumulator. The effectiveness of the MEA was confirmed. (C) 2017 Elsevier Ltd. All rights reserved.