Thermal performance of oscillating heat pipe with ethanol/methanol for heat recovery application design

As one of the two-phase heat transfer technology, Oscillating Heat Pipe (OHP) gains popularity in heat pipe technology recently. OHP has an excellent performance, simple structure, low production cost and high flexibility for a wide range of applications. OHP is also suitable for applications in the waste heat recovery system. This paper experimentally examines a closed loop OHP design for heat recovery application. Therefore, an OHP was manufactured and tested to find out the thermal characteristics for heat recovery application. OHP was made from a capillary copper tube with 1.6 mm inner diameter based on the critical diameter for ethanol and methanol working fluids. The length of OHP evaporator, adiabatic and condenser were 260, 240 and 260 mm respectively. The total length of the OHP was 13.6 m and had 18 U-turns. The result showed that evaporator temperature for methanol was lower than ethanol at the high heating input. Quasi-sine wave oscillation occurs at methanol OHP (Q=64 Watt). Methanol also had the lowest thermal resistance which was 0.258 °C/W at 79.5 Watt heat input.