Experimental Investigation of Heat Storage for Phase-Change-Material in a Spherical Container

• Main Authors: Chia-wen Kao, 高嘉文
• Other Authors: Chung-jen Tseng
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/59337260825027193640

碩士 === 國立中央大學 === 機械工程研究所 === 99 === This study analyzes one-dimensional spherical phase change material (PCM) heat transfer formula which derives from the concept of thermal resistance. The viability of this formula is validated by experimental data. In the analysis of thermal resistance, the heat which absorb by PCM is assumed equal to the heat which transfer from the heat transfer fluid (HTF). In the system, there are three types of thermal resistance in series connection, including HTF to capsule outside surface, capsule outside surface to inside surface, and capsule inside surface to PCM. Due to the specific heat of capsule is very small, the sensible heat of capsule is neglected. The heat transfer within liquid PCM is considered as two different types – only conduction and only convection. As the results, the parameters which affect the melting time include size and thickness of capsule, and thermal physical properties of capsule, PCM, and HTF. By the parameter analysis, the melting time is reduced as the Nusselt number of HTF is increasing, and the thermal conductivity of capsule is enhanced. To predict the melting time, it has good agreement by using the heat transfer formula with considering convection. To predict the melting surface location, when the melting location coefficient is larger than 0.37, using the heat transfer formula without considering convection has good agreement. But when the melting location coefficient is smaller than 0.37, using the heat transfer formula with considering convection has good agreement.