Graphene : Enhanced Evaporator for Loop Heat Pipe Applications by Composite Porous Structtures and Functionalization
Enhancing the performances of Loop Heat Pipes by graphene coatings.
October 2014 – 2022
The two main goals of this deliverable were to exploit the thermal and morphological properties of graphene/graphene oxide to enhance the performance (max power / Delta T) of a Loop Heat Pipe and lower its switch-on power. In order to achieve these goals, the main challenges were to produce wicks able to create an increased capillary pressure with respect to the existing configuration and to assure that the thermal performances of the wicks were able to cope with the necessity to activate the heat transfer loop at low start-up power.
Concerning the first challenge, the consortium considered a number of coating procedures for the wicks and selected the most promising ones: i) Chemical Vapor Deposition (CNR – ITALY), ii) Brushing (GRAPHENEA – SPAIN; University of Cambridge – United Kingdom and iii) Wicks Soaking (ULB – Belgium). One of the coated wicks has also been tested in operational configuration and gave promising results. Also, the maximum capillary pressure that the grapheme coated wicks could withstand was up to three times the one of the no-coated samples. It was demonstrated that the properties of graphene oxide could play an important role in lowering the switch on power of the entire heat transfer device. By solving this problem, wider application markets open up for the Loop Heat Pipes, especially in the Space sector.
The loop that is to be designed and built at MRC won’t fly in microgravity. However, it will be tested under hypergravity conditions at the ESTEC centrifuge (ESA, end of 2015).
Increasing of the fluid-dynamics performance of the wicks.
Good operability of the designed system in microgravity.