能源桩试验材料热力学参数测试研究

Measurement of Thermodynamic Parameters of Energy Pile Test Materials

提出在传统混凝土能源桩的基础上加入相变材料和钢纤维来提高能源桩的换热效率,通过钢球封装相变材料不仅将相变材料应用于混凝土,而且钢纤维和钢球的高导热特性可以改善相变材料导热性能上的不足,提高相变储能混凝土的导热性,为相变材料在能源桩工程的应用提供参考依据。通过相变钢纤维混凝土材料不同热力学参数测试的具体过程和结果发现纤维增强型混凝土破坏时没有明显的碎块和崩落,是因为钢纤维与裂缝两边混凝土之间的粘结应力起着约束裂缝开展的作用,从而降低混凝土脆性破坏程度;另外钢纤维可以很好的补偿低导热的相变材料所带来的缺陷,使能源桩整体的导热性能得以提高;钢纤维会降低混凝土的比热容,但砂率对混凝土的比热容有明显的影响。此结果会为后续评估和优化能源桩热交换系统提供参数指导。

This paper proposes to add phase change materials and steel fibers to the traditional concrete energy pile to improve the heat transfer efficiency of the energy pile. By encapsulating phase change materials with steel balls,the phase change materials are not only applied to concrete,but also the high thermal conductivity of steel fibers and steel balls can improve the thermal conductivity of phase change materials and improve the thermal conductivity of phase change energy storage concrete.It provides a reference basis for the application of phase change materials in energy pile engineering.Through the specific process and results of different thermodynamic parameters of phase change steel fiber reinforced concrete,it is found that there is no obvious fragment and collapse in the failure of fiber reinforced concrete. Because the bond stress between steel fiber and concrete on both sides of the crack restricts the development of crack,so as to reduce the brittle failure degree of concrete. In addition,the steel fiber can well compensate for the defects caused by low thermal conductivity phase change materials to improve the overall thermal conductivity of the energy pile. The Steel fiber will reduce the specific heat capacity of concrete,but the sand ratio has an obvious effect on the specific heat capacity of concrete. This result will provide parameter guidance for the subsequent evaluation and optimization of the energy pile heat exchange system.