Thermophysical property measurements of tetrabutylphosphonium acetate (TBPAce) ionic semiclathrate hydrate as thermal energy storage medium for general air conditioning systems

This paper reports the experimental study on measuring the phase equilibrium temperatures and the dissociation heats of ionic semiclathrate hydrate formed with tetrabutylphosphonium acetate (TBPAce) under atmospheric pressure. The phase equilibrium temperature and the dissociation heat measurements were performed in the range of the mass fraction of TBPAce aqueous solution from 0.10 to 0.42. The highest phase equilibrium temperature was 11.0°C at the mass fraction range from 0.35 to 0.39. The largest dissociation heat of pure TBPAce hydrate was 192.0 kJ kg-1 at the mass fraction 0.36. The obtained results indicate that TBPAce hydrate would be suitable for a new thermal energy storage medium for general air conditioning systems.