Abstract
Nanoparticle-enhanced phase change materials (i.e., nano-PCM) exhibit improved heat transfer and have been extensively investigated because of their potential application to latent heat thermal energy storage systems. However, the sedimentation of nanoparticles is a concern, as observed from numerous experimental investigations, which limits the application of nano-PCMs in an operation with many repetitive cycles. The studies of sedimentation of nanoparticles have been limited to qualitative observations, and the quantitative studies are primarily limited to the sedimentation of nanoparticles with time in nanofluids, with few studies on the sedimentation in nano-PCM. The different potential techniques to quantify the concentration of nanoparticles after each thermal cycle have been discussed. A novel image analysis technique was used to measure the concentration and non-uniformity in the dispersion of nanoparticles after each thermal cycle. The understanding of effect of different thermophysical properties of PCM and nanoparticles on the stability of the nano-PCM is essential for the development of stable nano-PCM for their practical applications. The present study analyzes the effect of size, density, and concentration of nanoparticles, along with the effect of viscosity, density, and difference in the density in solid and liquid phase of PCM on the stability of nano-PCM. Two different concentrations of copper oxide (<50 nm) and iron oxide (50–100 nm) nanoparticles in Rubitherm35 HC and CuO in coconut oil were studied. The larger density difference in the solid and liquid state of PCM leads to higher sedimentation. The effect of particle size dominated over nanoparticles density on sedimentation process.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- a :
-
Parametric constant
- b :
-
Parametric constant
- c :
-
Parametric constant
- i :
-
Pixel in the horizontal direction
- j :
-
Pixel in the vertical direction
- L :
-
Lightness value
- M :
-
Maximum value of RBG
- m :
-
Minimum value of RGB
- N :
-
Number of thermal cycle
- n :
-
Total number of pixels in the vertical direction
- U :
-
Uncertainty
- φ :
-
Coefficient of variation
- θ :
-
Nanoparticles concentration
- t :
-
Quarter volume at the top
References
Abdullah M, Malik SR, Iqbal MH, Sajid MM, Shad NA, Hussain SZ et al (2018) Sedimentation and stabilization of nano-fluids with dispersant. Colloids Surf A Physicochem Eng Asp 554:86–92
Choi C, Yoo HS, Oh JM (2008) Preparation and heat transfer properties of nanoparticle-in-transformer oil dispersions as advanced energy-efficient coolants. Curr Appl Phys 8(6):710–712
Colla L, Fedele L, Mancin S, Danza L, Manca O (2017) Nano-PCMs for enhanced energy storage and passive cooling applications. Appl Therm Eng 110:584–589
Fan L, Khodadadi JM (2011) Thermal conductivity enhancement of phase change materials for thermal energy storage: a review. Renew Sust Energ Rev 15(1):24–46
He G, Chen R, Lu S, Jiang C, Liu H, Wang C (2015a) Alternative assessment of nano-TiO 2 sedimentation under different conditions based on sedimentation efficiency at quasi-stable state. J Nanoparticle Res 17(11):454
He GA, Chen R, Lu S, Jiang C, Liu H, Wang C (2015b) Dominating role of ionic strength in the sedimentation of nano-TiO 2 in aquatic environments. J Nanomater 16(1):338
Ho CJ, Gao JY (2009) Preparation and thermophysical properties of nanoparticle-in-paraffin emulsion as phase change material. Int Commun Heat Mass Transf 36(5):467–470
Ho CJ, Gao JY (2013) An experimental study on melting heat transfer of paraffin dispersed with Al2O3 nanoparticles in a vertical enclosure. Int J Heat Mass Transf 62:2–8
Hwang YJ, Lee JK, Lee CH, Jung YM, Cheong SI, Lee CG et al (2007) Stability and thermal conductivity characteristics of nanofluids. Thermochim Acta 455(1-2):70–74
Jiang L, Gao L, Sun J (2003) Production of aqueous colloidal dispersions of carbon nanotubes. J Colloid Interface Sci 260(1):89–94
Leong KY, Rahman MRA, Gurunathan BA (2019) Nano-enhanced phase change materials: a review of thermo-physical properties, applications and challenges. J Energy Storage 21:18–31
Nourani M, Hamdami N, Keramat J (2018) Preparation and evaluation of a stable nanoalumina-paraffin composite: melting rate investigation using image analysis. J Dispers Sci Technol 39(10):1385–1393
Rahim MSA, Ismail I, Choi SB, Azmi WH, Aqida SN (2017) Thermal conductivity enhancement and sedimentation reduction of magnetorheological fluids with nano-sized Cu and Al additives. Smart Mater Struc 26(11):115009
Regin AF, Solanki SC, Saini JS (2008) Heat transfer characteristics of thermal energy storage system using PCM capsules: a review. Renew Sust Energ Rev 12(9):2438–2458
Saravanan G, Yamuna G, Nandhini S (2016) Real time implementation of RGB to HSV/HSI/HSL and its reverse color space models. In 2016 International Conference on Communication and Signal Processing (ICCSP) (pp. 0462-0466). IEEE.
Saydam V, Duan X (2019) Dispersing different nanoparticles in paraffin wax as enhanced phase change materials, J Therm Anal Calorim. 135 HC(2):1135 HC–1131144
Venkateshwar K, Ebadi S, Simha H, Mahmud S (2019) Influence of pore density and porosity on the melting process of bio-based nano-phase change materials inside open-cell metal foam. J Therm Sci Eng Appl 11(4):041004
Wu S, Zhu D, Zhang X, Huang J (2010) Preparation and melting/freezing characteristics of Cu/paraffin nanofluid as phase-change material (PCM). Energy Fuel 24(3):1894–1898
Funding
This work is partially supported by Globalink Graduate Fellowship Program of MITACS (Mathematics of Information Technology and Complex Systems) of Canada (funder ID: 10.13039/501100004489) and Discovery Grant from Natural Sciences and Engineering Research Council (NSERC) of Canada (funder ID: 10.13039/501100000038).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors would like to declare that there is no conflict of interest.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Venkateshwar, K., Joshy, N., Simha, H. et al. Quantifying the nanoparticles concentration in nano-PCM. J Nanopart Res 21, 260 (2019). https://doi.org/10.1007/s11051-019-4716-x
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s11051-019-4716-x