Equilibrium temperature and dissociation heat of tetrabutylphosphonium acrylate (TBPAc) ionic semi-clathrate hydrate as a medium for the hydrate-based thermal energy storage system. (May 2020)

• Record Type: Journal Article
• Authors: Koyama, Ryo; Hotta, Atsushi; Ohmura, Ryo
• Is Part Of: Journal of chemical thermodynamics. Volume 144(2020)
• Publication Date: 2020-05
• Subjects: Ionic semi-clathrate hydrate -- Tetrabutylphosphonium acrylate (TBPAc) -- Phase equilibrium temperature -- Dissociation heat -- Phase change material (PCM) -- Thermal energy storage; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2020.106088
• Languages: English
• ISSNs: 0021-9614

Abstract

Highlights: First investigated thermophysical properties of TBPAc hydrate as the thermal energy storage medium. Showed the relationship between the mass fraction and the thermophysical properties of TBPAc hydrate. TBPAc hydrate with the highest equilibrium temperature, 14.4 °C, was suitable for the general or air conditioning systems. The dissociation heat of TBPAc hydrate, 210.4 kJ kg −1, was the greatest in the sustainable and eco-friendly TBP hydrates. Revealed a new significance tendency on the thermophysical properties of TBP + carboxylate hydrates. Abstract: The hydrate-based thermal energy storage system is one of the most effective supplemental technologies to stabilize the energy supply for renewable energies. The system is expected to solve the global energy-management issues related to energy-demand increase and energy supply chain. In fact, this eco-friendly technology requires prospective hydrate candidates for the thermal energy storage media, followed by the extensive investigation of the thermophysical properties of the selected hydrates. In this study, to satisfy these requirements, the equilibrium temperature and the dissociation heat of tetrabutylphosphonium acrylate (TBPAc) ionic semi-clathrate hydrate were studied. It was found that the highest equilibrium temperature was 14.4 °C at the mass fractions from 0.37 to 0.40. It was also found that the largest dissociation heat was (210.4 ± 5.3) kJ kg −1 at the mass fraction 0.39. These values indicate that TBPAc hydrate could be a new promising thermal-storage medium for the general or data-centre air-conditioning systems. The experimental results of this study also revealed an underlying tendency between the thermophysical properties of the tetrabutylphosphonium (TBP) + carboxylate salt hydrates and the molar mass of the guest anion in salt.