In the underlayment of a floor radiant heating system (FRHS), using gypsum-based self-levelling mortar (GSM) with high fluidity and early strength properties could save labor force and material costs. Combining phase change materials (PCMs) with FRHS is a promising way to improve energy efficiency and provide a comfortable thermal environment. This paper investigates the feasibility of preparing gypsum-based self-levelling energy storage mortar (GSEM) by incorporating fly ash cenospheres/paraffin (FACP) into GSM. The selection of fly ash cenospheres (FAC) particle size, the pre-treatment of FACP, the additional amount of FACP, and the thermal performance of FRHS containing GSEM are investigated. Results show that the selection of FAC should consider the influence of strength, fluidity, thermal property, and possible economic and environmental impacts. FAC 2 with a particle size (D50) of 110.5 µm is considered to be a suitable choice. FACP pre-treated with 52.5 cement could decrease paraffin leakage and increase the mechanical strength and fluidity of GSEM. With the sand replacement ratio () increase, the mechanical strength of GSEM first increases and then decreases. When the is 100%, the compressive strength and flexural strength of GSEM are 18.8 MPa and 4.3Mpa; the thermal conductivity decreases by about 15.8% and the specific heat capacity increases by about 53.5%. For FRHS, the matching between the supply water temperature and the plate thickness should be considered in the design. Compared with the GSM plate, the GSEM plate could reduce about 2.4℃ temperature fluctuation, and the time at a comfortable temperature is extended by 60.8%. This finding indicates that the prepared GSEM could be applied to FRHS and has good potential to provide a comfortable thermal environment for buildings.

中文翻译：

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粉煤灰微珠/石蜡制备用于地板辐射采暖的石膏基自流平储能砂浆

在地板辐射供暖系统（FRHS）的底层中，使用具有高流动性和早强特性的石膏基自流平砂浆（GSM）可以节省劳动力和材料成本。将相变材料 (PCM) 与 FRHS 相结合是提高能源效率和提供舒适热环境的一种有前景的方法。本文研究了将粉煤灰微珠/石蜡（FACP）掺入石膏基自流平储能砂浆（GSEM）的可行性。研究了飞灰微珠（FAC）粒径的选择、FACP的预处理、FACP的添加量以及含有GSEM的FRHS的热性能。结果表明，FAC的选择应考虑强度、流动性、热性能的影响以及可能的经济和环境影响。粒径 (D50) 为 110.5 µm 的 FAC 2 被认为是合适的选择。用52.5水泥预处理的FACP可以减少石蜡泄漏并提高GSEM的机械强度和流动性。随着砂替代率()的增大，GSEM的机械强度先增大后减小。当为100%时，GSEM的抗压强度和抗弯强度分别为18.8 MPa和4.3 Mpa；导热系数降低约15.8%，比热容增加约53.5%。对于FRHS，设计时应考虑供水温度与板厚的匹配。与GSM板相比，GSEM板可减少约2.4℃的温度波动，舒适温度时间延长60.8%。这一发现表明所制备的 GSEM 可以应用于 FRHS，并具有为建筑物提供舒适热环境的良好潜力。