Comparison of thermal characteristics and cooling performance of crude palm oil and mineral oil as electrical insulators

Abstract

Crude Palm Oil (CPO) has the potential to be an environmentally friendly renewable insulator, one of which functions as a coolant. This study evaluated and compared thermal characteristics between Mineral Oil (MO) and CPO, such as specific heat, thermal conductivity, and heat distribution. The data analysis used ANOVA, Response Surface Methodology, and dimensionless analysis. Specific heat was measured by heating CPO, MO, and water to 100 °C, while thermal conductivity was assessed using a two-point observation method under steady-state heating conditions. Forced convection experiments were conducted with varying mass flow rates and air velocity. As a result, CPO had a higher specific heat and thermal conductivity than MO. Moreover, CPO produced a lower cooling temperature on average, but MO produced a lower temperature for all data and lower power. Also, CPO was more sensitive to mass flow rate changes, while MO was more responsive to air velocity. The optimization for CPO was an air velocity of 2.35 m s^-1 and mass flow rate of 0.37 g s^-1, resulting in a temperature of 56.90 °C and power of 6.82 W. Besides, CPO showed a Nusselt number range of 10.5–12.0 and a heat transfer coefficient of 370–410 W/m² °C, indicating relatively high thermal efficiency. The correlation between the predicted heat transfer coefficient and experimental observations was strong (R² = 0.99). The Nusselt number showed a proportional increase with the Prandtl number, with a correlation of R² = 0.95. These results suggest that CPO could be a more effective insulator with better cooling performance than MO.