Development of a novel sulphoalumitate cement-based composite combing fine steel fibers and phase change materials for thermal energy storage

• Published in: Energy and buildings 2019-01, Vol.183, p.75-85
• Main Authors: Sang, Guochen, Cao, Yanzhou, Fan, Min, Lu, Geyang, Zhu, Yiyun, Zhao, Qin, Cui, Xiaoling
• Format: Article
• Language: English
• Subjects: Cement; Cement reinforcements; Composite materials; Compressive strength; Energy management; Energy storage; Fiber composites; Fiber volume fraction; Fibers; Fine steel fiber; Flexural strength; Graphite; Heat conductivity; Heat transfer; Low density polyethylenes; Mechanical and thermal properties; Mechanical properties; Mortars (material); Paraffin; Paraffins; Phase change materials; Polyethylene; Shrinkage; Steel; Steel fibers; Steel structures; Sulfoaluminate cement; Sulphoaluminate cement-based composite; Thermal conductivity; Thermal energy; Thermal energy storage; Thermal energy storage/release performance; Thermal properties; Thermodynamic properties; Thermophysical properties
• ISSN: 0378-7788; 1872-6178
• DOI: 10.1016/j.enbuild.2018.10.039

•A novel fine steel fiber reinforced cement-based thermal energy storage composite was developed.•GM-SSPCM was fabricated by heating mixing of paraffin, low density polyethylene and flake graphite.•Mechanical strength of STESC is improved with the reinforcement of steel fibers.•The thermal conductivity of SF-STESC at different temperatures was measured and analyzed.•Heat storage/release performances of STESCs are enhanced with fine steel fibers. To increase the mechanical strength and thermal energy storage/release efficiency, fine steel fibers and graphite-modified shape stabilized phase change materials (GM-SSPCM) were added into sulphoaluminate cement mortar. Paraffin, low density polyethylene and flake graphite were heating mixed to produce GM-SSPCM. Fine steel fibers were used to reinforce sulphoaluminate cement-based thermal energy storage composite (STESC) for improving mechanical strength and thermal conductivity. The thermophysical and microstructure of GM-SSPCM, and the thermal and mechanical properties of steel fiber reinforced sulphoaluminate cement-based thermal energy storage composite (SF-STESC) were investigated. The results indicated that about 50% paraffin could be effectively encapsulated in GM-SSPCM with multi-level space network structure. And, the steel fiber can increase the mechanical and thermal properties of SF-STESC. When a 3.5 vol% steel fiber was added, the 28-day compressive strength and flexural strength of the SF-STESC were increased by 7.3% and 40.6%, also the compressive/flexural strength ratio was decreased by 21.6%. The three-dimensional reinforcement of steel fibers reduced the volume shrinkage of the composites. In addition, the thermal conductivity of SF-STESC increases with the increase in volume fraction of the steel fibers. When the steel fiber volume fraction increases from 0 to 3.5%, the thermal conductivity of SF-STESC is increased by 51.3% while the inner paraffin is in solid state and 84.5% while the inner paraffin is in liquid state. The results of thermal energy storage/release performance tested using a self-designed setup showed that the steel fiber reinforced STESC leads to a high thermal energy storage/release rate.