西安建筑科技大学学报(自然科学版)

直接吸收式太阳能集热器是一种经济有效的吸收太阳能的方法.提出了利用流速控制纳米棒流体从而增强其光谱吸收的方案,并对纳米流体实际光学特性进行实验研究.分析了光照强度、流速以及浓度对纳米棒流体光热特性的影响.纳米流体出口温度随光照强度增大而提升,当流速为0.5 mL/min,辐射强度为600 W/m2时,纳米流体出口温度相较400 W/m2的照射下提升18.5%.纳米流体的光学性能在很大程度上取决于其浓度.加入金纳米棒颗粒明显提高了去离子水的吸热性能.0.3 ppm的金纳米棒流体在0.75 mL/min流速控制时,接受800 W/m2的照射,光热转换效率可以达到52.3%,相较无流速控制的效率提升162%.在直接吸收式太阳能集热器中添加纳米棒状颗粒,并进行流速调控,可有效提升集热器集热性能.

Direct absorption solar collector is an economical and effective way to absorb solar energy. In this paper, a scheme of controlling the flow rate of nanorod fluid to enhance its spectral absorption is proposed, and the actual optical properties of nanorod fluids are experimentally studied. The effects of illumination intensity, flow rate and fluid concentration on the photothermal characteristics of nanorod fluid are analyzed. The outlet temperature of the nanofluid increases with the increase of illumination intensity, especially for the 0.5 mL/min flow rate control, 600 W/m2 irradiation, the outlet temperature of the nanofluid is increased by 18.5% compared with that under 400 W/m2 irradiation. The optical properties of nanofluids depend largely on the concentration. The addition of gold nanorods can significantly improve the heat absorption performance of deionized water. When the flow rate of 0.3 ppm gold nanorods is controlled at 0.75 mL/min, the photothermal conversion efficiency reaches to 52.3%, which is 162% higher than that without flow rate control. It is of great significance to add nanometer rod-shaped particles into direct absorption solar collector and control them by flow rate.

引言
1 纳米流体的制备
2 实验测试
3 实验结果与分析
4 结论

图1 所购置纳米流体吸光度光谱<br/>Fig.1 Absorbance spectrum of purchased nanofluids

图1 所购置纳米流体吸光度光谱
Fig.1 Absorbance spectrum of purchased nanofluids

$图2 不同体积分数纳米流体吸光度<br/>Fig.2 Absorbance of nanofluids with different volume fractions$

图2 不同体积分数纳米流体吸光度
Fig.2 Absorbance of nanofluids with different volume fractions

图3 实验装置示意图<br/>Fig.3 Schematic diagram of experimental device

图3 实验装置示意图
Fig.3 Schematic diagram of experimental device

表1 实验设备<br/>Tab.1 Experimental equipment

表1 实验设备
Tab.1 Experimental equipment

图4 纳米流体光学特性测试实验台<br/>Fig.4 Experiment platform for optical properties of nanofluids

图4 纳米流体光学特性测试实验台
Fig.4 Experiment platform for optical properties of nanofluids

图5 纳米流体载液实物图<br/>Fig.5 Physical picture of nanofluid carrying liquid

图5 纳米流体载液实物图
Fig.5 Physical picture of nanofluid carrying liquid

表2 纳米流体光学特性测试实验<br/>Tab.2 Test experiment of optical properties of nanofluids

表2 纳米流体光学特性测试实验
Tab.2 Test experiment of optical properties of nanofluids

图6 纳米流体不同光照强度金纳米棒流体温升曲线<br/>Fig.6 Temperature rise curve of gold nanorods fluid under different light intensity

图6 纳米流体不同光照强度金纳米棒流体温升曲线
Fig.6 Temperature rise curve of gold nanorods fluid under different light intensity

图7 金纳米棒流体不同光照强度吸热量对比<br/>Fig.7 Comparison of heat absorption of gold nanorods under different light intensities

图7 金纳米棒流体不同光照强度吸热量对比
Fig.7 Comparison of heat absorption of gold nanorods under different light intensities

图8 不同流速金纳米棒流体光热转换效率<br/>Fig.8 Photothermal conversion efficiency of gold nanorods at different flow rates

图8 不同流速金纳米棒流体光热转换效率
Fig.8 Photothermal conversion efficiency of gold nanorods at different flow rates

图9 纳米流体不同浓度金纳米棒流体温升曲线<br/>Fig.9 Temperature rise curves of gold nanorods with different concentrations of nanorods

图9 纳米流体不同浓度金纳米棒流体温升曲线
Fig.9 Temperature rise curves of gold nanorods with different concentrations of nanorods

图10 金纳米棒流体不同浓度吸热量对比<br/>Fig.10 Comparison of heat absorption of gold nanorods fluid at different concentrations

图10 金纳米棒流体不同浓度吸热量对比
Fig.10 Comparison of heat absorption of gold nanorods fluid at different concentrations

图11 不同流速金纳米棒流体光热转换效率<br/>Fig.11 Photothermal conversion efficiency of gold nanorods at different flow rates

图11 不同流速金纳米棒流体光热转换效率
Fig.11 Photothermal conversion efficiency of gold nanorods at different flow rates

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备注

引言

1 纳米流体的制备

2 实验测试

3 实验结果与分析

4 结论

期刊信息