Experimental study on the cascaded thermal energy storage system using MWCNT-enhanced phase change materials

  • Lokesh SelvamEmail author
  • Dillibabu Ramalingam
Technical Paper


The proposed work is about the effectiveness of latent heat dispersion on energy storage using phase change materials with modified thermal stratifiers on charging inlet of the tank. A novel flow-governing nozzle with swirl flow injection is designed and fabricated to enhance the steady state of heat flow inside the cascaded thermal energy storage (TES) system. Spherical phase change materials (PCM) capsules with added multiwall carbon nanotubes (MWCNT) particles used as an energy storage material inside the TES tank. Experimentation conducted for the variable process parameters with mass flow rates, temperature, and injection pressure to differentiate the initial stratification of the thermocline system. Results obtained from the analysis clarify that with the increase in swirl number through injection pressure, temperature, and flow rate increases the steady state stratification behavior inside the cascaded TES tank. It is clear that the effective charging rate of 35 min observed from the system at 1 wt% of MWCNT with the increase in injection pressure and flow rate of 4 bar and 3 L/min. It also noted that the swirl effect increases the heat dissipation on the PCM capsules by maintaining a concentric heat transfer with the radial flow over the layers of the PCM capsules. Discharging trials are carried out by the batch-wise process to recover the stored thermal energy. Moreover, the cascaded latent heat thermal energy storage system using MWCNT-filled PCM is best suitable for water heating applications to overcome the intermittency.


Thermal energy storage Stratifiers Phase change material Multiwall carbon nanotubes The swirl flow 

List of symbols

Tf, in

HTF inlet temperature

Tf, out

HTF outlet temperature


Instantaneous heat transfer


Cumulative heat stored


Swirl number



Differential scanning calorimetric


High-density polyethylene


Heat transfer fluid


Latent heat thermal storage


Multiwall carbon nanotube


Organic material


Phase change material


Process identifier


Resistance temperature detector


Scanning electron microscope


Transmission electron microscope


Thermal energy storage



I acknowledge that the present work is conducted under the financial grant offered by the Department of Science and Technology, India—Innovation in Science Pursuit for Inspired Research (INSPIRE) fellowship. Ref. No: DST/INSPIRE/03/2014/000347.


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Copyright information

© The Brazilian Society of Mechanical Sciences and Engineering 2019

Authors and Affiliations

  1. 1.Department of Industrial Engineering, CEG CampusAnna UniversityChennaiIndia

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