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Recent overview of research on electrocaloric cooling

A recent literature review presents an overview of research on electrocaloric cooling. The authors addressed the following topics: thermodynamic cycles, electrocaloric materials, experimental devices, numerical studies, energy performances, and perspective cooling applications.

Electrocaloric cooling is a relatively recent field according to a literature review. [1] Over the last decade, it has been the focus of research because of its potential as an environmentally friendly alternative to vapour compression, especially for applications at room temperature. [1] Nevertheless, the authors observed that the number of models developed and numerical studies presented in the literature is still small after 15 years of research.

 

An electrocaloric cooler exploits the electrocaloric effect of a material. An electrocaloric material transmits heat from the cold to the hot environment through the cyclical repetition of four or more processes. The components of an electrocaloric system typically include: a system for generating/removing the electric field, the solid-state electrocaloric material, two heat exchangers, and a heat transfer mechanism.

 

According to the authors, the performance of an electrocaloric cooling system is closely linked to the caloric material used. They found that the most suitable electrocaloric materials should meet the following conditions:

  • Non-toxic and chemically stable.
  • Low economic cost.
  • Resistance to corrosion (by the heat transfer fluid or by contact with other materials).
  • Low electrical conductivity to avoid undesirable heating which could conflict with the cooling phases of the cycle.
  • High thermal conductivity to efficiently manage heat fluxes as fast as possible.
  • Reproducibility and compatibility with large-scale production.
  • The material should show little thermal hysteresis.
  • The material should have a pronounced electrocaloric effect, detectable at room temperature under relatively low electric field intensities.
  • The material should have low specific heat values to enhance adiabatic temperature changes as well as a rapid response, in terms of electrocaloric effect, to variations in the electric field.
  • The material should be able to withstand high electric fields without deterioration.

 

The authors found many promising electrocaloric materials among ceramics that exhibit great electrocaloric effect as well as among polymers and polymer nanocomposites due to their flexibility. Such flexibility could lead to the development of revolutionary prototypes. For instance, in 2020, a team of researchers developed a prototype of a cascade electrocaloric cooling device that increases the temperature change, with enhanced cooling power and cooling efficiency at the same time. The device integrates four cascaded layers of electrocaloric polymer elements and can achieve an estimated COP of 9.0 for a temperature lift of 2.7 K and 10.4 at zero temperature lift. [2]

 

For more details on the thermodynamics of the electrocaloric effect, numerical models or experimental devices, please download the complete article on FRIDOC: https://iifiir.org/en/fridoc/electrocaloric-cooling-a-review-of-the-thermodynamic-cycles-142901

 

 

Sources

[1] Greco, A.; Masselli, C. Electrocaloric Cooling: A Review of the Thermodynamic Cycles, Materials, Models, and Devices. Magnetochemistry 2020, 6, 67. https://doi.org/10.3390/magnetochemistry6040067

[2] Meng, Y., Zhang, Z., Wu, H. et al. A cascade electrocaloric cooling device for large temperature lift. Nat Energy (2020). https://doi.org/10.1038/s41560-020-00715-3