An experimental latent-thermal energy storage device (LTESD) with a flat miniature heat pipe array (FMHPA) as a core heat transfer element is designed. Multihole flat pipes are utilized as a heat supply and heat removal loop for the passage of heat transfer fluid (HTF). Experiments are performed at different HTF volume flow rates and inlet temperatures to investigate the performance of the thermal storage unit consisting of FMHPA and vertical fins and to observe the change in the temperature of phase-change materials, such as lauric acid. The effects of heating/cooling section length and thermal resistance are also examined. Results indicate that LTESD works stably and efficiently and the respective storing and releasing power are 1299 and 1120 W under standard" operating conditions of 2 L/min at 70 degrees C and 2 L/min at 15 degrees C. (C) 2017 Elsevier Ltd. All rights reserved.