Cobalt phosphate-based composite with wall care putty as building envelope material for thermal energy storage

Abstract

The four different thermal energy storage composites were synthesized by charging Co3(PO4)2·xH2O with wall care putty (Korean make) in aqueous media. These four different composites are abbreviated as A1, A3, A4 and A5 having composition 0.46 %, 1.00 %,1.63 % and 2.22 % of Co3(PO4)2·xH2O, respectively. Differential Scanning Calorimeter (DSC) was used to measure specific heat capacity (CP) for all above composites. Among all composites, the CP = 1.34 Jg-1K−1 is found maximum for composite A5 at 339 K in N2 atmosphere. The highest heat storage density is also observed, 80.95 ∼ 88.83 kJ kg−1, for composite A5 in temperature range 336 K to 342 K for storing heat up to ∼ 13 min. The optical band gap (Eg) is calculated using Tauc and Menth as well as Kubelka-Munk function for all composites and all found insulator. The calculated crystallite size of composite A3 is ∼ 400 nm.