THE EFFECT OF STATIC ELECTRIC FIELD AND NUCLEATOR AGENTS ON THE SOLIDIFICATION OF SALT HYDRATES (CACL2.6H2O AND CA(NO3)2.4H2O)

• Main Author: Afandi Putri, Risky
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/49924
• Institution: Institut Teknologi Bandung

The development of Thermal Energy Storage (TES) system with Phase Change Material (PCM) is as important as development of new and renewable energy (Sharma dkk., 2009b). It contributes for science and technology to save energy consumption associated with increasingly scarce fossil fuels. This is due to the ability of PCM to store and release the high thermal energy density, in the form of latent heat energy through the solid-liquid phase transition and vice versa. TES using PCM for building applications has been studied since 1980s (Kern and Aldrich, 1979). Salt hydrate is one of the promissing material for building application because of its energy density (400-870 kWh m-3) and the low melting point (<150°C) (Clark dkk., 2020). However, the relatively large degree of supercooling of salt hydrate can inhibit its performance as a TES system. Therefore, it is important to study the characterization of salt hydrate to reduce it. This experiment studies the effect of electric field on the solidification of CaCl2?6H2O, CaCl2.6H2O+BaSO4(0,1 wt%), Ca(NO3)2.4H2O and Ca(NO3)2?4H2O+ Ba(OH)2.8H2O (1 wt%) through the various voltage of the flat end copper electrodes. This is due to electric field is one of the effective way to overcome the obstacle and has been intensively researched for water, salt solution and salt hydrate. Nucleator agent was also used in this experiment, in order to be compared with the pure samples under the internal electric field. The copper electrode was also used in this experiment due to its high nucleation probability and is one of the cheapest and commanly sold electrode material. The electric field was ranged from 0 V/m to 3 × 106 V/m. It was experimentally found that the electric field was effected to reduce the supercooling degree for both of the pure CaCl2?6H2O and CaCl2?6H2O with BaSO4 and also the pure of Ca(NO3)2?4H2O. The higher electric field, the higher temperature of supercooling and effect in a smaller degree of supercooling. Probability of nucleation for CaCl2?6H2O with BaSO4 was higher than the pure of CaCl2?6H2O. Meanwhile, the induction and the crystallization time of pure of CaCl2?6H2O is not revealed a clear trend. However, the greater application electric field on the solidification of CaCl2?6H2O+BaSO4(0,1%) effect in the shortening of the induction time and extend the crystallization time. Meanwhile, the application of electric field on the solidification of Ca(NO3)2?4H2O tends to increases degree of supercooling. Ca(NO3)2?4H2O does not take time to induce. The application of nucleator agent on the solidification of Ca(NO3)2?4H2O under the application of electric field was found experimentally can inhibit the nucleation, that is, the probability is lower than the pure of Ca(NO3)2?4H2O.