电热型管壳式相变蓄热器的设计与性能实验

Design and Performance Experiment of a Shell and Tube Type Phase Change Heat Accumulator with Electric Heating

相变蓄热技术近年来在电力削峰填谷的应用中发挥了重要作用,成为供热领域的新热点。本文设计了以PTC电加热棒为发热源,水为载热介质,纳米共晶水合盐为相变蓄热材料的管壳式相变蓄热器。实验研究了蓄放热过程中装置内部水和相变材料的温度分布情况以及特定温度范围的蓄放热性能及变化规律。结果表明,以圆管正三角阵列+折流板为特征的管壳式换热器结构可以使蓄热器内部温度分布更加均匀;以某测温点水温75~98℃变化区间为蓄放热周期,蓄热周期的实际蓄热量为779796 kJ,有效蓄热系数达到0.91,平均蓄热功率为94.13 kW;在放热周期,放热功率从74.2 kW随水温的下降而逐渐减小至51.8 kW,当水温降至相变温度以下时,放热功率趋于稳定。

Phase change heat storage technology plays an important role in the application of peak load shifting of electricity utilization,and has become a new hotspot in the field of heat supply.A shell and tube phase change regenerator was developed which took PTC heaters as heat source,water as heat transit fluid and nanocrystalline hydrated salt as phase change material(PCM).The temperature distribution of water and PCM,the heat charging and discharging performance and change rule in a specific temperature range were investigated experimentally.Results showed that the temperature distribution of PCM was more uniform by using round tube triangle array and baffles in a shell and tube heat exchanger.Taking the temperature range of 75-98℃ of a temperature measuring point as the charging and discharging period,the actual heat storage capacity was 779796 kJ,the effectiveness factor was 0.91,and the average charging power was 94.13 kW.In the discharging period,the discharging power decreased from 74.2 kW to 51.8 kW with the decrease of water temperature.When the water temperature dropped below the phase transition temperature,the exothermic power tended to be stable.