关键词: 相变胶囊, 梯级储热, 储放热特性, 余热利用

Abstract:

The medium and high-temperature phase change heat storage and reuse is effectively achieve low-carbon economies and enhance industrial production. This study designs and tests a high-temperature phase change capsule step heat storage system to efficiently harness industrial high-temperature waste heat. The system uses polycarbonate materials with two different phase change temperatures as heat storage media and experimentally investigates the heat storage and release process under different inlet temperatures and inlet flow rates of the heat transfer air. The study mainly focuses on the temperature changes within the heat storage tank, the heat storage capacity, and the completion time of the heat storage and release processes. Experimental results show that the system can achieve a heat storage capacity of 30000 kJ when the inlet temperature is 500 ℃. Furthermore, increasing the inlet flow rate of the system reduces the heat storage time while having less influence on the total heat storage capacity of the system. The influence of the average liquid phase rate of the phase change material within the heat storage tank is analyzed about the total heat storage capacity of the system under different operating conditions. Meanwhile, the study highlights the air preheater installed in the system, which facilitates the heat exchange between high-temperature exhaust gas and the normal-temperature inlet gas, effectively enabling the waste heat utilization from the high-temperature exhaust gas. The results of the phase change experiment provide valuable insights into the influence law and optimization guidelines of the system operation parameters for the practical application of high-temperature phase change heat storage technology, which has a high reference value.

Key words: phase change capsule, stepped heat storage, heat storage and exothermic properties, waste heat utilization