Thermal performance assessment of lauric acid and palmitic acid based multi-transformation phase change material and exfoliated graphite composites

ABSTRACT

The large variation in day and night temperature of Thar Desert area provides an opportunity to reduce temperature fluctuations and thermal discomfort inside temporary shelters and buildings using phase change materials. Melting and solidification temperature of lauric and palmitic acid based multitransformation phase change material (MTPCM) are tuned in such a way that it melts during day time and solidifies during night time passively throughout summer season of Desert area. However, the poor thermal conductivity of MTPCM (0.2 W m⁻¹K⁻¹) hampers its complete phase reversal from liquid to solid with natural convection during peak summer night time. Therefore, the natural graphite flakes are exfoliated with ~ 300 times volume expansion and micropores are generated to imbibe MTPCM. The exfoliated graphite – MTPCM composites are prepared using vacuum impregnation technique to enhance thermal conductivity of MTPCM. The effect of exfoliated graphite mass fraction and composite samples density on thermal conductivity, latent heat of fusion, melting temperature, and solidification temperature of MTPCM is investigated. Thermal conductivity of exfoliated graphite-MTPCM composite is increased up to 11.95 Wm⁻¹K⁻¹ at density 1170 kg m⁻³. The Morphology of composite samples is also investigated using scanning electron microscopic analysis. The MTPCM with significant latent heat of fusion, appropriate melting and solidification temperature, and high thermal conductivity make it suitable for passive building cooling applications in Desert area.

KEYWORDS:

• Multi transformation phase change material
• exfoliated graphite
• vacuum impregnation
• thermal conductivity

Highlights

• LA and PA based Multi Transformation PCM (MTPCM) and exfoliated graphite (EG) with 300 times volume expansion was prepared.

• EG-MTPCM composites with different EG mass fraction ratio (1:5 to 1:20) and different density (660 to 1170 kg m⁻¹) were prepared.

• Optimization of trade off latent heat and thermal conductivity of MTPCM carried out and thermal conductivity increased from 0.2 to 11.95 W m⁻¹ K⁻¹ while latent heat decreases from 166.3 to 138.7 kj kg⁻¹.

Acknowledgments

The authors acknowledge Defence Research & Development Organization (DRDO) for providing fund to carry out this work. Authors would also like to acknowledge Dr. Manoj Patra and Dr. Smita Soni, for XRD and SEM measurements of samples.

Additional information

Funding

This work was supported by the Defence Research and Development Organization (DRDO) [vide grant No.- DLJ-330].

Notes on contributors

Anju Nirwan

Anju Nirwan, has received degree Mater of Science (M.Sc.) from University of Rajasthan. Her research interests are phase change materials based composite materials with different types of carbonaceous materials for thermal management applications.

Rohitash Kumar

Rohitash Kumar is working in development of Phase change materials (PCMs) based technologies for thermal management of personnel, buildings and equipments. His major achievements are development of various phase change materials and PCM based products such cool vest & cap, reusable PCM heat packs, PCM based air cooling device, PCM heat withdrawal system and PCM panels for passive temperature moderation of buildings. He has three patents to his credit, published 5 technical papers in international journals including one in Nature scientific reports, 02 book chapters, and 10 conference papers.

Bobin Mondal

Bobin Mondal, has received Bachelor of Engineering in Mechanical Engineering from Regional Engineering College (now NIT) Rourkela, India in 1999 and Master of Technology in Thermal Engineering from Indian Institute of Technology Kharagpur, India in 2008. His research interests are phase change (melting-solidification) heat transfer modeling and simulation, computational fluid dynamics and latent heat storage (PCM) heat exchanger design. His other expertise is accelerated desert environmental testing and heat management of pulsed heat dissipating systems. He has two patents to his credit and published around 10 papers in national/international conferences and also chaired session in symposium/conference. He is also a permanent member of Indian Society for Heat and Mass Transfer (ISHMT).

Jeetendra Kumar

Jeetendra Kumar, has received Bachelor of Engineering in Mechanical Engineering from MBM Engineering collage, Jodhpur

Anuradha Bera

Anuradha Bera is M.Sc. in Chemistry and Ph.D in organic Chemistry, from Indian Institute of Technology (IIT), Delhi. Her doctoral research was in the design and synthesis of supramolecular organic compounds for sensor application. Currently she is working for the development of a number of application oriented materials including radiation sensitive compounds, metal nanoparticles and polymer composites. She has twelve research publications in peer reviewed International and national journals, three patents granted and two patents filed. She has participated in several national and international conferences and has presented more than twenty conference papers.

Ravindra Kumar

Ravindra Kumar, completed his B.Tech in Metallurgical Engineering from Roorkie University and M.Tech from IIT Bombay. His pioneering work in the field of Phase Change Material  based heat management technologies and products He has five patents to his credit, published more than 50 technical reports, 25 national and International publications and has deliberated in several national and international conferences.