高温复合相变材料储热电暖器的储热性能

Charging behavior of an electrical storage heater using a high temperature composite phase change material

本文研究了基于高温复合相变材料的相变储热电暖器,对其储热性能、内部流场和温度分布及温度调控机制进行了实验和模拟研究,并与镁砖显热电暖器的储热性能进行对比。结果表明这类相变储热电暖器的储热平均温度高、平均温差小、出风口温度高,整体性能要优于镁砖显热电暖器。相同体积下两种电暖器储热量相当,但相变储热电暖器的重量可减轻1.6倍;在相同储热时间和储热温度下,同等重量的相变储热电暖器较镁砖电暖器可多储热68%。结果也展示了这类储热电暖器温度控制测点选择的重要性,当选取距离加热单元10 mm处的测点作为温度调控点时,电暖器内的平均温度和储热砖体的最高温度均能满足安全要求,而且加热单元电源在谷电8 h储热过程中只需启停两次。

The work reported in this paper concerns the charging behaviour of an electrical storage heater using a high temperature composite phase change material（CPCM）. A mathematical model was developed to study the transient heat transfer behavior of the composite PCM bricks. The model was validated experimentally. The results showed that the CPCM based electrical storage heater offered a better performance that was superior to Mg O-based electrical storage heater. For a given volume, the same power rating, and the same amount of stored heat, the mass of the Mg O based electrical storage heater exceeded 1.6 times that of the CPCM based storage heaters. For the same mass and the same power rating, the heat storage capacity of the CPCM based electrical storage heater was 68% higher than that of Mg O-based unit. The results also indicated the importance of temperature control strategy. It was found that the average temperature and the maximum temperature inside the electrical storage heater could meet the requirements if the control temperature measurement point was selected to be 10 mm away from the heating elements. In such a case, heating elements only had two start-stops over the 8-hour charging period.