Dresden, August 15, 2024 — As Germany transitions from fossil fuels and works towards climate targets, alternative heating and cooling technologies are becoming essential. Conventional heat pumps, though effective, are noisy, energy-intensive, and use climate-harmful refrigerants. Electrocaloric heat pumps, which use materials that change temperature when an electric field is applied, offer a promising alternative.

The Fraunhofer Institute for Electron Beam and Plasma Technology (FEP) has made significant strides in this area through the ElKaWe lighthouse project. Researchers at Fraunhofer FEP have developed advanced thin films to improve heat transfer in electrocaloric heat pumps. Their findings will be showcased at the PSE 2024 Conference and Exhibition in Erfurt, Germany, from September 2-5, 2024.

Effective heat transfer in these pumps relies on the full wetting of electrocaloric surfaces by working fluids during condensation and evaporation. However, these surfaces are naturally hydrophobic. To address this, Fraunhofer FEP developed superhydrophilic metal oxide thin films using magnetron sputtering. These films enhance surface wettability, promoting faster condensation and evaporation, which accelerates heat transfer.

The coatings, made from materials like titanium dioxide, feature a mesoporous structure that boosts capillary effects, enhancing liquid spread on the surface. This results in faster droplet formation and improved heat transfer performance—up to two orders of magnitude faster than uncoated surfaces.

The thin films’ permanent hydrophilicity makes them ideal for solid-state cooling devices, like electrocaloric heat pumps. Fraunhofer FEP is now focused on scaling this technology for market readiness within 5 to 7 years, aiming to revolutionize energy-efficient cooling and heating solutions.

Find the original press release here.