Experimental assessment and numerical study of a pump-assisted loop heat pipe for high capacity thermal systems

In the present work, the results of a study and experimental activities carried out on a pump-assisted heat pipe intended for the use in large-capacity thermal conversion and storage systems are presented. A specific test setup for the experimental assessment of heat pipes operating in a loop configuration was realised. The key feature of the system is the use of a pump for liquids for the transport of the condensate, thus distinguishing it from the vast majority of commercial or research-grade heat pipes, which employ gravity or capillary action for liquid transport. The set-up is equipped with high-accuracy sensors and allows continuous operation. Results of an experimental campaign realised with R600 as working fluid inside the heat pipes are reported, analysing the effect of temperatures at the evaporator and condenser, flow rate of the working fluid and filling ratio and a correlation was derived to predict the experimental outcomes. The examined system was able to transfer up to 3 kW under the selected boundary conditions with an optimal filling ratio of 46%.