基于磁性纳米流体的中温太阳能吸收与光热转换性能  

Properties of solar energy absorption and photothermal conversion at medium temperature based on magnetic nanofluids

作　　者：刘长青 王德兵[3] 何燕 汪孔祥[3] 于伟 Changqing Liu;Debing Wang;Yan He;Kongxiang Wang;Wei Yu(School of Mechanical and Energy Engineering,Shaoyang University,Shaoyang 422000,China;Key Laboratory of Hunan Province for Efficient Power System and Intelligent Manufacturing,Shaoyang University,Shaoyang 422000,China;School of Environmental and Materials Engineering,College of Engineering,Shanghai Polytechnic University,Shanghai 201209,China;School of Mechanical and Electrical Engineering,Qingdao University of Science and Technology,Qingdao 266061,China)

机构地区：[1]邵阳学院机械与能源工程学院,邵阳422000 [2]邵阳学院,高效动力系统及智能制造湖南省重点实验室,邵阳422000 [3]上海第二工业大学工学部环境与材料工程学院,上海201209 [4]青岛科技大学机电工程学院,青岛266061

出　　处：《科学通报》2019年第28期3041-3048,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(51590902);上海市自然科学基金(17ZR1411000);上海市教育委员会和上海市教育发展基金会基金(15SG52);湖南省自然科学基金(2018JJ3478)资助

摘　　要：纳米流体基直接式吸收器被认为是进一步提高太阳能热利用效率的重要替代方案,但针对具有较高能源品位的中温太阳能吸收与光热转化性能的研究却较少.为促进中温太阳能光热的规模化应用,本文提出一种较为实用的中温磁性纳米流体基直接式吸收器吸收体系的使用方法.首先,通过“两步法”制备一种导热油基Co@NC中温磁性纳米流体,并利用其优异的光学吸收性能,在大功率模拟太阳光照射下获得较高温度的流体;然后,基于磁分离技术将Co@NC纳米颗粒与导热油基液分离,获得具有较高温度的纯基液;再经过换热器热交换过程得到所需要的各种较高温液体,在5个太阳辐射下,纳米流体最高温度可达120.37℃.该方法实现了较高的光热转换效率,同时可有效解决因纳米流体的不稳定性而引发沉降的问题,为促进纳米流体在太阳能中温热利用中的新发展提供了一种方案.As a kind of clean and renewable energy,solar energy has been widely used in photovoltaic power generation,photothermal utilization,photocatalysis and other fields.According to its working temperature range,photothermal utilization can be divided into three areas:Low-temperature heat utilization(<80℃),medium-temperature heat utilization(80-250℃)and high-temperature heat utilization(>250℃).At present,the technologies of low-temperature heat utilization and high-temperature heat utilization have been relatively mature,while the development of mediumtemperature heat utilization technology is relatively slow.Furthermore,the medium-temperature heat utilization is one of the effective technologies to solve the current energy shortage,environmental pollution and other problems.The key problem in solar energy heat utilization is how to improve the efficiency of solar collector.Nanofluids-based direct absorption of solar radiation energy can effectively improve the collection efficiency of solar collectors.However,nanofluids are easy to settle in the long-term cold-hot alternating process,which will deposit on the pipe wall of heat exchanger and even cause blockage,resulting in the increase of thermal resistance and serious heat loss in the process of heat exchange.In this paper,a way of magnetic nanofluid-based direct absorption system for medium-temperature heat utilization is proposed.Firstly,a heat-conducting oil-based nanofluid with magnetic Co@NC is prepared by“two-step”method,and high temperature fluids are obtained under high-power simulated solar irradiation by its excellent optical absorption performance.Secondly,based on magnetic separation technology,Co@NC nanoparticles are separated from the heat conducting oil matrix to obtain pure base liquids with high temperature.Under five solar radiations,the highest temperature of the nanofluids could reach to 120.37℃.Moreover,various liquids with higher temperature can be obtained by the process of heat exchange.Finally,the effects of illumination on the p

关 键 词：太阳能光热利用 磁性纳米流体 磁分离 光热转换 

分 类 号：TB3[一般工业技术—材料科学与工程]