Thermal Analysis of the Addition of MgCl2.6H2O to Eggshell Based Calcium Chloride Hexahydrate to Enhance the Properties of Phase Change Materials Vidya E. P. Hilda1, Hafidhoh Tasya1, Alawiyah1, Wardoyo1, P.N.A. Nugroho2 and D.A. Wulandari1,*
1 Department of Mechanical Engineering, Universitas Negeri Jakarta, Jakarta 13220, Indonesia
2 Shipbuilding Engineering Department, Politeknik Perkapalan Negeri Surabaya
Abstract. Increasing energy needs have driven the development of efficient Thermal Energy Storage using calcium chloride hexahydrate (CaCl2.6H2O) as a Phase Change Material. This material has good thermal energy storage capacity, although it faces challenges such as supercooling and phase separation. This study examines the synthesis and characteristics of CaCl2.6H2O from chicken eggshell waste using 5% HCl. Then, 20 wt% MgCl2.6H2O was mixed with the CaCl2.6H2O synthesis to obtain a eutectic mixture by adjusting the phase transition temperature. 1 wt% SrCl2.6H2O was added to suppress the supercooling phenomenon in the eutectic mixture. The combination with 0.5 wt% CMC was used to overcome phase separation. FTIR analysis confirmed the presence of carbonate chemical bond functional groups in the eggshell as well as crystalline water molecules in the synthesized hydrate system. XRD results showed that eggshell powder and CaCl2.6H2O had diffraction patterns with a degree of crystallinity. Based on DSC testing on CaCl2.6H2O - 20wt% MgCl2.6H2O - 1wt% SrCl2.6H2O - 0.5wt% CMC, an enthalpy value of 109.3 J/g was obtained with a melting onset temperature of 21.7 degrees celsius and a melting peak temperature of 26.3 degrees celsius and a melting end temperature of 27.9 degrees celsius was in accordance with human thermal comfort indoors.
Keywords: CaCl2.6H2O, Eggshells, MgCl2.6H2O, Phase Change Material, Thermal Energy Storage
