Facile approach to fend off the supercooling phenomenon of water in a spherical enclosure for energy-efficient and sustainable cold thermal energy storage system

Abstract

Performance of an ice-based cold thermal energy storage system (CTESS) is immensely affected by its supercooling nature. In this research, it was mitigated entirely using 1-Decanol as a nucleating agent, which has favourable properties such as absence of supercooling, low cost, suitable phase change temperature (5 °C) and reasonable freezing enthalpy (200 J g−1). The optimum concentration of 1-Decanol required to eliminate the supercooling nature of water is found to be 2 wt%. Moreover, charging characteristics of water with 2 wt% 1-Decanol were explored in various diameter spherical capsules (42, 51, 64, 75, 85, and 105 mm) at −3, −6, and −9 °C wall temperatures. The addition of 2 wt% 1-Decanol eliminated the supercooling nature of water in all diameter capsules at all wall temperatures. As a result, complete solidification time is considerably reduced. Based on freezing time and charging rate, the optimum wall temperature is found to be −6 °C. Experimental results concede that 1-Decanol is highly reliable in eliminating supercooling, and its addition only led to 0.79% reduction in energy storage capacity. Mitigation of supercooling significantly reduced the chiller operating time and wall temperature required for charging, which further leads to utilisation of energy efficiently and sustainably.