Electrowave – ELECTROWetting heat pipes for cooling Applications in Electric Vehicles


The Electrowetting Heat Pipe (EHP) is a new cooling technology capable of transporting high heat loads over long distances. The working fluid evaporates in the evaporator (which is in contact with the heat source), thereby removing heat. This vapor then condenses in the condenser (cold region) and the condensate is returned to the evaporator. Conventional heat pipes are limited in their ability to transport high heat loads over long distances.

The EHP solves this issue acting disruptively in two ways: i) using electrowetting-based pumping to move the condensate back to the evaporator, and ii) utilizing electrically enhanced evaporators to enhance heat transfer and prevent dry-out in the evaporator. In this project, the heat transfer enhancement in the evaporator was studied via experiments and numerical analysis.

The project mainly showed that evaporation characteristics can be increased by further enhancing the wetting properties of the evaporator surface (working as the dissipator). The model further provided interesting features on the boiling regime and on the mechanisms explaining such heat transfer enhancement. The results also show that the use of nanofluids offers a potential increase to the boiling heat transfer. However, stability issues limit the concentration of the nanoparticles to be used, thus limiting the enhancement effects. On the other hand, the team at IN+/IST-ID could develop (in collaboration with FEUP) and characterize new sets of stable nanofluids, with potential use in the heat transfer enhancement for several cooling applications. Finally, from the practical side, model and experiments suggest that this heat pipe configuration can be used for cooling purposes in the electric motorizations and in the batteries.

This work is now expected to enable future development of a new class of heat pipes with much higher performance than current heat pipes, with a very low power consumption. This can favourably impact the energy efficiency in many thermal systems. One of the major goals of Electrowave was to evaluate how this disruptive technology could be used in the thermal management of electric vehicles. In fact, efficient thermal management in these vehicles, particularly considering batteries is a real obstacle towards their broader implementation in the mass mobility market, given the current limitations in fast charging. Electrowave showed that such EHP technology is able to cope with the specificthermal management requirements of this important market.


Title ELECTROWetting heat pipes for cooling Applications in Electric Vehicle
Reference UTAP-EXPL/CTE/0064/2017
Scientific Area Nanotechnologies
Funding € 98 475,00 plus matched funding at UT Austin
Leading Institution Associação do Instituto Superior Técnico para a Investigação e o Desenvolvimento (IST-ID)
Participating Institutions The University of Austin at Texas (UT Austin)
Duration 24 months
Begin date December 1, 2018
End date November 30, 2020
Keywords Electrowetting, Heat pipes, Cooling applications, Electric vehicles

Main Highlights

  • Project of new EHP based on an original patent;
  • New nanofluids prepared and characterized, that can be applied in a much broader range of applications, opening a new market opportunity;
  • Work presented at the 16th UK Heat Transfer Conference was selected as a highlight and invited to a full publication (in JBE).


  • 11 Published/accepted papers in peer-reviewed Journals and Conferences. 2 Jointly authored (PT-US);
  • 1 Book chapter published;
  • 3 MSc. students involved in research work;
  • 1 Patent filed (UT Austin research team);
  • 1 Experimental prototype (research team in Portugal);
  • 2 New funding applications deriving from Electrowave project.

Papers and Communications

  • Maia, I., Rocha, C., Pontes, P. Cardoso, V., Miranda, J.M., Moita, A.S., Minas, G., Moreira, A.L.N., Lima, R. (2019) Heat transfer and fluid flow investigations in PDMS microchannel heat sinks fabricated by means of a low-cost 3D printer. In: “Advances in Microfluidic Technologies for Energy and Environmental Applications”, IntechOpen, (In press). https://dx.doi.org/10.5772/intechopen.89735
  • Lima, R., Vega, E.J., Moita, A.S., Miranda, J. M., Pinho, D., Moreira, A.L.N. (2020) Fast, flexible and low-cost multiphase blood analogue for biomedical and energy applications. Experiments in Fluids, 61:231 (11 pages). https://doi.org/10.1007/s00348-020-03066-7
  • Figueiredo, M., Marseglia, G., Moita, A.S., Panão, M.R.O., Ribeiro, A.P.C., Medaglia, C.M. Moreira, A.L.N. (2020) Thermofluid characterization of nanofluid spray cooling combining phase doppler interferometry with high-speed visualization and time-resolved IR thermography. 10.3390/en13225864
  • Pontes, P., Cautela, R., Teodori, E., Moita, A.S., Georgoulas, A., Moreira, A.L.N. (2020) Bubble dynamics and heat transfer on biphilic surfaces: experiments and numerical simulation. Journal of Bionic Engineering, published online on the 25th June 2020. https://doi.org/10.1007/s42235-020-0064-x
  • Pontes, P., Cautela, R. Teodori, E., Moita, A. S., Georgoulas, A., Moreira, A. L. N. (2019) Bubble dynamics and heat transfer on biphilic surfaces. 16th UK Heat Transfer Conference, The University of Nottingham, 8-10 September, Nottingham, UK
  • (Accepted) Pontes, P., Freitas, E., Cautela, R., Moita, A.S., Miranda, J., Lima, R., Ribeiro, A.P.C., Moreira, A.L.N. (2022) Pool boiling of nanofluids on biphilic surfaces. To be presented at the 3rd Int. Conf. on Interfacial Phenomena and Heat-Mass-Transfer, 5-9 July, Marseille, France
  • Bohinikova, A., Maia, I., Smieskova, M., Buganova, A., Moita, A.S., Cimrak, I., Lima, R. (2020) Assessment of computational cell mode benefits for optimization of microfluidic devices. 13th International Joint Conference on Biomedical Engineering Systems and Technologies, Biodevices 2020, 24- 26 February, Valletta, Malta. DOI: 10.5220/0009173202800287
  • (Accepted) Pontes, P., Moita, A. S., Moreira, A.L.N. (2021) Design optimization of microchannel geometry using a genetic algorithm parallel with Openfoam. Accepted to be presented at the 15th Int. Conf. on Heat Transfer, Fluid Mechanics and Thermodynamics, 20-22 July, Amsterdam, Netherlands
  • Ferrão, I., Silva, A., Moita, A. S., Mendes, M., Costa, M. (2020) Single droplet combustion of aluminum nanoparticles added to a biofuel. ILASS- Asia 2020, 23-26 October, Zhenjiang, China (online conference). Lista de publicações · Ana Sofia Oliveira Henriques Moita (ulisboa.pt)
  • Freitas, E., Pontes, P., Cautela, R., Bahadur, V., Miranda, J., Ribeiro, A.P.C., Souza, R.R. Oliveira, J.D., Copetti, J.B., Lima, R., Pereira, J.E., Moreira A.L.N., Moita, A.S. (201) Nanomaterials, Pool boiling of nanofluids on biphilic surfaces: an experimental and numerical study. Nanomaterials, 125(11):1-23. https://doi.org/10.3390/nano11010125 (open Access)
  • Freitas, E., Pontes, P., Cautela, R., Moita, A.S., Bahadur, V., Miranda J., Lima, R., Ribeiro, A.P.C., Moreira, A.L.N. Pool boiling of nanofluids on biphilic surfaces. Eurotherm 2020 – 8th edition of the European Thermal Sciences Conference, Lisbon Portugal (postponed)
  • Master thesis (Concluded) Freitas, Eduardo Jorge Pereira (2020) Pool boiling of nanofluids using biphilic surfaces. University of Minho (Final grade 20/20)



ELECTROWetting heat pipes for cooling Applications in Electric Vehicles

Project Team

Ana Moita

Principal Investigator in Portugal

Vaibhav Bahadur

Principal Investigator in Austin