Bio-based lamb tail fat phase change material with enhanced thermal properties by incorporation of cyclophosphazene additives

Abstract

Among organic phase-change materials (PCM), paraffin is commonly used, but it is not environmentally friendly due to its petrochemical origin. For efficient utilization of solar or thermal energy, new PCM are needed, or it is necessary to improve the thermal properties of existing materials. Therefore, the utilization of renewable alternatives such as lamb's tail fat as a latent heat storage material is of particular importance for the evaluation of bio-based waste oils. In this study, new PCM were developed by using different concentrations of cyclophosphazene derivatives as an additive to the starting lamb tail fat (LTF) material. According to the results, doping the LTF with 1% and 2% hexa(N,N-dibutyl-4-aminophenoxy)cyclotriphosphazene (HBACP) the heat of fusion is significantly improved, while the 1% hexa(2-ethylhexyloxy)cyclotriphosphazene (HEHCP) doping decreased the heat of fusion. In a comparison of various doped PCM, it was found that the tail fat doped with 1% HBACP had a heat of fusion of 166.6 kJ/kg, but a lower specific heat capacity and thermal conductivity than that doped with 2% HBACP. On the other hand, 1% HEHCP had the lowest thermal conductivity but a higher specific heat capacity than 1% HBACP. In addition, it was found that the PCM developed by incorporating HBACP could be operated as a cooling fluid for photovoltaic modules or as a working fluid in concentrated solar energy systems due to the higher heat of fusion value of 1% HBACP and the higher specific heat capacity of 2% HBACP, which consists of lamb's tail fat.