相变介质填充床斜温层蓄热罐蓄放热联合循环运行特性实验

Experiments on the Combined Cycle Operational Performance of Thermocline Heat Storage With Phase Change Material Packed-bed

蓄热装置的应用有利于热电联产机组获得更大的调峰裕度,在传统热水单罐中增加相变储热介质可以大幅提升蓄热罐的储能密度。以石蜡作为相变材料,制备成相变球并以填充床的形式布置在蓄热罐内。通过实验研究其循环蓄放热过程中的运行特性,以蓄放热截止温度、蓄放热流量为变量,分析不同运行工况对各循环的所需时间、罐内温度场、容量利用率等参数的影响。实验结果表明:循环蓄放热过程具有稳定的"收敛"特性,蓄放热截止温度对"收敛"速度等参数具有重要影响,而蓄放热流量的增大有利于缩短"收敛"所用时间,但较大的流量会导致蓄放热容量利用率的下降。

The employment of thermal energy storage(TES) system is helpful for the combined heat and power units to enhance the power load regulation capability.The energy storage density of conventional water TES tank will increase substantially when phase change material is involved.Paraffin wax is selected as PCM to fill the capsules and arranged as packed-bed inside the TES tank.The performance of repetitive charging/discharging cycles is investigated experimentally.Working conditions with different switching temperatures and flow rates are discussed to analyze their impact on the charging/discharging duration,temperature distribution and utilization rate.Results indicate that cyclic charging/discharging operation will reach stable and repetitive state after some cycles and such behavior is influenced by the switching temperatures.Increasing flow rate is able to reduce the time spent on reaching stable state while it will also lead to the decline of utilization rate.