Paraffin based composite phase change materials for thermal energy storage: Thermal conductivity enhancement

Abstract

Abstract: Paraffin wax (PW) has been widely used as a phase change material for thermal energy storage due to relatively high thermal energy storage density and other desirable properties. However, it has a low thermal conductivity (TC), leading to a long charging and discharging time. To address the issue, carbon nanotubes (CNTs) were mixed with PW to form PW-CNTs composites. As CNTs are highly thermally conductive, the use of such a material is expected to give a good level of thermal conductivity enhancement. To further enhance the heat transfer process, metal meshes were placed in the interior of the PW-CNTs composites. Experimental results show that the addition of 10% CNTs by mass leads to a thermal conductivity enhancement of 31.4% and 40.2% respectively in the solid and liquid states. The results also show that the use of metal meshes shortens the charging and discharging durations by at least 40.3% and 30.2%, respectively. Heating and cooling cycling tests have also been carried on the PW-CNTs composites and the results show a large decrease in the thermal conductivity after a few cycles due to severe aggregation of CNTs in PW-CNTs composites.

Key words: phase change materials, paraffin wax, carbon nanotubes, metal meshes, thermal conductivity enhancement, charging and discharging time

CLC Number:

TK02

MA Bingqian, LI Jianqiang, PENG Zhijian, DING Yulong. Paraffin based composite phase change materials for thermal energy storage: Thermal conductivity enhancement[J]. Energy Storage Science and Technology, 2012, 1(2): 131-138.

References

[1] 叶锋,曲江兰,仲俊瑜,等. 相变储热材料研究进展[J]. 过程工程学报,2010,10(6):1231-1241.
[2] Atul Sharma,Tyagi V V,Chen C R,et al. Review on thermal energy storage with phase change materials and applications [J]. Renewable and Sustainable Energy Reviews ,2009,13(2):318-345.
[3] Wang Weilong,Yang Xiaoxi,Fang Yutang,et al. Enhanced thermal conductivity and thermal performance of form-stable composite phase change materials by using β-Aluminum nitride [J]. Applied Energy ,2009,86(7-8):1196-1200.
[4] Zeng Julan,Cao Zhong,Yang Daowu,et al. Thermal conductivity enhancement of Ag nanowires on an organic phase change material [J]. Journal of Thermal Analysis and Calorimetry, 2010,101(1):3385-389.
[5] Zeng Julan,Sun Lixian,Xu Fen,et al. Study of a PCM based energy system containing Ag nanoparticles[J]. Journal of thermal analysis and calorimetry ,2007,87(2):369-373.
[6] Wang Jifen,Xie Huaqing,Xin Zhong,et al. Enhancing thermal conductivity of palmitic acid based phase change materials with carbon nanotubes as fillers[J]. Solar Energy ,2010,84(2): 339-344.
[7] Wang Jifen,Xie Huaqing,Xin Zhong,et al. Increasing the thermal conductivity of palmitic acid by addition of carbon nanotubes[J]. Carbon ,2010, 48(14):3979-3986.
[8] Fazel Yavari,Hafez Raeisi Fard,Kamyar Pashayi,et al. Enhanced thermal conductivity in a nanostructured phase change composite due to low concentration graphene additives[J]. The Journal of Physical Chemistry ,2011,115(17):8753-8758.
[9] 朱虹,王继芬,黎阳,等. 石蜡基复合相变储能材料的研究进展[J].上海第二工业大学学报,2009,26(3):188-193.
[10] 张鸿声,汪南,朱冬生,等. 纳米铜粉/石蜡复合相变储能材料的性能研究[J]. 材料导报, 2011,25(1):173-176.
[11] 吴淑英,汪南,朱冬生,等. 纳米铜/石蜡复合相变蓄热材料的导热性能研究[J]. 化工新型材料,2012,40(5):104-106.
[12] 杨硕,汪南,吴淑英,等. 纳米铝粉/石蜡复合相变储能材料的性能研究[J]. 材料导报:研究篇,2009,23(12):20-22.
[13] Jegadheeswaran S,Pohekar S D. Performance enhancement in latent heat thermal storage system:A review[J]. Renewable and Sustainable Energy Reviews ,2009,13(9):2225-2244.
[14] Fan Liwu,Khodadadi J M. Thermal conductivity enhancement of phase change materials for thermal energy storage:A review[J]. Renewable and Sustainable Energy Reviews ,2011,15(1):24-26.
[15] Zhao Changying,Lu Wei,Tian Yuan. Heat transfer enhancement for thermal energy storage using metal foams embedded within phase change materials (PCMs)[J]. Solar Energy ,2010,84(8): 1402-1412.
[16] Wu Shuying,Wang Hezhou,Xiao Song,et al. An investigation of melting /freezing characteristics of nanoparticles-enhanced phase change materials[J]. Journal of Thermal Analysis and Calorimetry ,2011,doi:10.1007/s10973-011-2080-x.
[17] Andrew Mills,Mohammed Farid,Selman J R,et al. Thermal conductivity enhancement of phase change materials using a graphite matrix[J]. Applied Thermal Engineering ,2006,26(14-15):1652-1661.
[18] Sumin Kim,Drzal L T. High latent heat storage and high thermal conductive phase change materials using exfoliated graphite nanoplatelets[J]. Solar Energy Materials & Solar Cells ,2009, 93(1):136-142.
[19] Wang Jifen,Xie Huaqing,Xin Zhong. Thermal properties of paraffin based composites containing multi-wall carbon nanotubes[J]. Thermochimica Acta ,2009,488(1-2):39-42.
[20] Wang Jifen,Xie Huaqing,Xin Zhong. Preparation and thermal properties of grafted CNTs composites[J]. Journal of Materials Science &Technology ,2011,27(3):233-238.
[21] Cui Yanbin,Liu Caihong,Hu Shan,et al. The experimental exploration of carbon nanofiber and carbon nanotube additives on thermal behavior of phase change materials[J]. Solar Energy Materials & Solar Cells ,2011,95(4):1208-1212.