Experimental research on the performance of ice thermal energy storage device based on micro heat pipe arrays

Abstract

These are many unsolved technical problems in ice thermal energy storage, including low thermal conductivity of water, thermal stratification phenomenon and poor economy, which limit the further development of this technology. Optimizing the structure of ice thermal energy storage device is one of the most economical and reasonable methods to solve these problems. In this study, ice thermal energy storage device using micro heat pipe arrays as the enhanced heat transfer element was developed. The experimental study of the proposed device was carried out to analyze the cold energy storage and release characteristics under various inlet temperatures and volume flow rates of heat transfer fluid. As a result, the proposed device shows excellent heat transfer performance, the maximum temperature difference of micro heat pipe arrays during solidification and melting processes are less than 1.2 °C and 1.5 °C, respectively. The heat exchange area per unit volume of water and energy storage density for the device using micro heat pipe arrays are 199.7 1/m and 113.65 kJ/kg, respectively. Besides, the performance of ice thermal energy storage devices using micro heat pipe arrays and circular heat pipe were compared. The cold energy storage power of single heat pipe of the former is more than 53.0% than the latter, the energy storage density and ice packing factor are still higher than 51.8% and 51.1%, respectively, even if its volume flow rate is less than the latter. This is due to the high thermal conductivity performance of the former and the surface that it is more conducive to adding fins to enhance heat transfer.