Preparation, characterisation and energy storage performance study on 1-Decanol-Expanded graphite composite PCM for air-conditioning cold storage system.

• Energy-efficient 1-Decanol-Expanded graphite composite (CPCM) was prepared. • CPCM has 84.99% of 1-Decanol, and it reduces the chiller operating time by 81.85%. • Thermal conductivity of CPCM is 16.33 times higher than that of 1-Decanol. • CPCM is having high freezing temperature (∼4.1 °C) and zero degree of supercooling. • Utilisation of CPCM paves the way for efficiently storing and recovering cold energy. Performance of a typical ice-based cold thermal energy storage system (CTESS) is immensely affected by its supercooling nature and low freezing temperature (0 °C). In this study, 1-Decanol (PCM) was recognised as a potential replacement for ice as it is cost-effective as well as having zero degree of supercooling, and high freezing temperature (5 °C). High thermal conductivity PCM-Expanded graphite (EG) composite (CPCM) was prepared by incorporating the PCM into the porous structure of EG. The thermal conductivity, specific heat, and thermal cycling stability of CPCM were studied. Further, the charging and discharging characteristics of CPCM were investigated in a 64 mm diameter spherical capsule at -3 °C and 13 °C wall temperatures, respectively. CPCM has an incorporation efficiency of 84.99%, and its thermal conductivity is 16.33 times higher than that of PCM. CPCM and PCM have good thermal reliability for 1000 cycles. The freezing temperature of CPCM is ∼4.1 °C higher than that of ice and its charging time is 81.85% lower than that of PCM, which signifies that the chiller operating time can be reduced by 81.85% to store the specified amount of energy in CPCM. Further, the time-averaged charging and discharging rate of CPCM is 5.51 and 5.97 times higher than that of PCM, respectively. Experimental results concede that CPCM is having high freezing temperature (∼4.1 °C), zero degree of supercooling and enhanced energy storage characteristics, which ensure that the utilisation of CPCM paves the way for efficiently storing and recovering the energy. [ABSTRACT FROM AUTHOR]