An experimental and analytical study of a variable conductance heat pipe: Application to vehicle thermal management

This paper reports on about an analytical and experimental study of a Variable Conductance Heat Pipe (VCHP) applied to vehicle thermal management. The reduction of engine energy consumption after a cold start by controlling heating–cooling cycle of oil is the objective of the present study. A theoretical model based on a nodal method and an experimental test bench was developed to study the performance of a copper/water VCHP, using nitrogen as a non-condensable gas. VCHP operate as a thermal switch, with a start-up temperature of 80 °C. The effect of the inclination angle (i.e., adverse-gravity, horizontal position or gravity-aided) was studied. The results allowed us to identify the effect of the air mass flow rate on the condenser and the effect inclination angle on the performance of the VCHP. Our results show that the VCHP performance improves with a small inclination angle aiding liquid return to the evaporator.

► We model a variable conductance heat pipe. ► We develop an experimental setup to study the VCHP performances. ► We study the influence of the air velocity on the VCHP. ► We study the effect of high power on the VCHP. ► A positive inclination, with the help of gravity, improves VCHP efficiency.