太阳能建筑用石蜡/CNTs相变乳液的制备及光-热性能研究

结合建筑结构在太阳能领域的蓄热控温特点,采用"两步法"制备出适用于太阳能蓄热的新型石蜡/CNTs相变乳液,通过纳米粒度电位仪和布鲁克旋转黏度仪分析了CNTs掺量对相变乳液技术性能的影响,确定最佳CNTs掺量;再采用差示扫描量热仪、导热系数测定仪、自制太阳光-热转换装置及紫外/可见/近红外分光光度计探究相变乳液的热物性能和光-热转换性能。结果表明,随着CNTs掺量的增大,相变液滴的粒径分布和运动黏度发生较为明显的变化,综合考虑相变乳液的稳定性及泵送性,推荐石蜡相变乳液中CNTs的最佳掺量控制为0.6%。由于石蜡具有较高的相变储热性能及CNTs具有较大的导热系数,掺加石蜡/CNTs能够显著增强相变乳液的导热性能和光-热转换能力,完全可用于建筑结构中以达到对太阳光辐射的蓄热与调温作用。

Preparation and photo-thermal properties of paraffin/CNTs phase change emulsion for solar architecture

Combined with the heat storage temperature control performance of building structure in the field of solar energy,the"two-step method"was applied to prepare a new type of paraffin/carbon nanotube(CNTs)solar heat storage phase change emulsion.The nano particle potentiometer and brooke rotating viscometer were used to study the influence of CNTs content on the technical performance of phase transition emulsion,and determined the optimal amount of CNTs.Moreover,differential scanning calorimetry apparatus,coefficient of thermal conductivity meter,selfcontrol sunlight-thermal conversion device and UV-Vis-NIR spectrophotometer were used to explore the phase change thermal performance and light-heat conversion performance of emulsion.The results shown that as the content of CNTs increased,the particle size distribution and kinematics viscosity of phase change droplets changed significantly.Considering the stability and pumping performance of phase change emulsion,it was recommended that the content of CNTs in paraffin phase change emulsion should be controlled at 0.6%.Due to the high phase change heat storage performance of paraffin and the relatively high thermal conductivity of CNTs,the addition of paraffin/CNTs can significantly enhanced the thermal conductivity and light-heat conversion ability of phase change emulsion,which can be fully used in building structures to achieve thermal storage and temperature regulation of solar radiation.