Tang Zhuo, Lu Dong, Gong Jing, Shi Xianming, Zhong Jing
School of Civil Engineering and Architecture, Wuhan Polytechnic University, Wuhan 430023, China.
Key Lab of Structure Dynamic Behavior and Control (Harbin Institute of Technology), Ministry of Education, Harbin 150090, Heilongjiang, China.
Materials (Basel). 2020 Feb 5;13(3):714. doi: 10.3390/ma13030714.
In cold climate regions, the energy associated with indoor heating constitutes a large portion of energy consumption. Increasing energy utilization efficiency is critically important for both economic and environmental reasons. Directly converting electrical energy to thermal energy using joule heating construction elements can save energy and investment to the water pipelines which have been extensively used for indoor heating in China. The fired brick has been extensively used to make pavements, walls and other masonry. Taking advantage of the high dispersion quality of graphene oxide (GO) in water, as well as the firing process used to make fired bricks, graphene nanocomposite bricks with excellent electrical properties and improved mechanical performance were prepared in China. The compressive strength of the bricks showed a substantial increase from 3.15 MPa to 7.21 MPa when GO concentration was 0.1 wt.%. Through applying 5 volts of electrical field within 5 minutes, the nanocomposites can be heated from room temperature to 60 °C, 110 °C and 160 °C for the nanocomposite bricks with graphene concentration of 3 wt.%, 4 wt.% and 5 wt.%, respectively, due to the extremely low percolation threshold (~0.5 wt.%) and high conductivity (10 Ω·cm at 1 wt.%). The sheets were connected more tightly when the GO content was increased. The thermal efficiency can reach up to 88% based on the applied voltage, measured resistance and temperature rise curves.
在寒冷气候地区，与室内供暖相关的能源占能源消耗的很大一部分。出于经济和环境原因，提高能源利用效率至关重要。使用焦耳热元件将电能直接转化为热能可以节省能源，并减少对在中国广泛用于室内供暖的水管的投资。烧制砖已被广泛用于铺设路面、建造墙壁和其他砖石结构。利用氧化石墨烯（GO）在水中的高分散性以及烧制砖的烧制工艺，中国制备出了具有优异电学性能和改善力学性能的石墨烯纳米复合砖。当GO浓度为0.1 wt.%时，砖的抗压强度从3.15 MPa大幅提高到7.21 MPa。通过在5分钟内施加5伏电场，对于石墨烯浓度分别为3 wt.%、4 wt.%和5 wt.%的纳米复合砖，纳米复合材料可分别从室温加热到60°C、110°C和160°C，这是由于其极低的渗流阈值（约0.5 wt.%）和高电导率（1 wt.%时为10 Ω·cm）。当GO含量增加时，片层连接更紧密。基于施加的电压、测量的电阻和温度上升曲线，热效率可达88%。
