石蜡相变储热系统的放热效率

相变储热技术是节能的重要技术之一,对相变储热系统的换热系数以及放热效率的研究,有助于提高相变储热系统的放热效率,对相变储热系统的实际应用有着重要意义。该试验研究了叉排石蜡管束储热系统的整体放热性能,测定了该系统的换热系数及放热效率,并分析了管排数,风速等影响因素。研究表明,在小于3m/s的风速下,空气温度变化在20～55℃的范围内,该类储热系统的换热系数与使用现有准则关联式计算得到的理论值基本吻合;放热效率则随着风速的增大而下降,随管排数的增加而有所提高,最大可达83%;另外,延长放热时间,可以提高换热效率,最高可使放热效率提高62%。

Heat release property of paraffin phase change heat storage system

Phase change heat storage is one of the most important energy-saving technologies.The research of heat transfer coefficient and heat release rate is helpful to improve the thermal efficiency and it also play a significant role in applying of phase change heat storage system.Focused on the heat release property of the staggered tube bank with paraffin thermal storage system,we measured the heat transfer coefficient and the heat release rate,and then analyzed influencing factors in terms of the number of tube rows,wind speed and other factors.The results showed that under the conditions that the wind speed was less than 3 m/s,and the temperatures varied from 20℃ to 55℃,the testing results of heat transfer coefficient were in good correspondence with the theoretical values;The heat release rate reduced with higher wind speed,and increased with the rise of the number of tube rows,which could reach up to 83%.The heat efficiency could be improved by 62% at most by prolonging heat exchange time.