Lighthouse project ElKaWe

Electrocaloric heat pumps

In the lighthouse project »ElKaWe«, six Fraunhofer Institutes under the direction of Fraunhofer IPM are working on the development of electrocaloric heat pumps for heating and cooling. Today, heat pumps work almost exclusively based on compressor technology. Electrocaloric heat pumps promise significantly higher efficiency and do not require harmful refrigerants. As part of the project, the scientists are developing ceramic and polymer-based electrocaloric materials and are working on an innovative system concept that enables particularly efficient heat dissipation.

Work in the project is intended to demonstrate that electrocaloric heat pumps have the potential to replace compressors in the long term. Heat pumps are an important component of the energy revolution, as they ensure optimized space heating and hot water generation. Powered by electricity generated from renewable sources, they form the missing link between electricity and heat generation. However, the number of heat pumps for air conditioning in buildings is growing slowly because compressor-based heat pumps are economically inefficient. In cooling technology, the gradual ban on refrigerants within the framework of the European »F-gas Regulation«, which aims at reducing fluorinated greenhouse gases, also makes alternative technologies desirable.

How does an electrocaloric heat pump work?

If an electric field is applied to electrocaloric materials, the electric dipole moments in the field are aligned. This additional order is accompanied by heating of the material according to the laws of thermodynamics. The resulting heat is dissipated via a heat sink so that the material cools down again to the initial temperature. If the electric field is removed, the order is reduced and the material cools down to a temperature below the initial temperature  – again in accordance with the laws of thermodynamics. Now it can absorb thermal energy from a heat source. The effect is reversible. In this way, a cycle can be set up that functions as an efficient heat pump for cooling or heating.