Elastocaloric materials & systems

elastocaloric cooling cycle
© Fraunhofer IPM
Elastocaloric material heats up when exposed to a mechanical force field (F). When this heat is released into the environment and the force field is removed, the material supercools and extracts the same amount of heat from the environment again. The effect is reversible. In cyclical operation, the elastocaloric effect can be used to set up a heat pump or cooling machine.

Elastocaloric materials are known as shape memory alloys and have long been used in medical technology on account of their biocompatibility. The best-known shape memory alloy is known by the acronym Nitinol. With these pseudoelastic alloys, a strong shape deformation can be achieved by adding heat; when the heat source is removed, the metal returns to its original shape. This effect is absolutely reversible. The reverse effect, the so-called elastocaloric effect, is also possible: a change in shape results in transformative heat being exchanged with the environment. In our systems, we use this caloric effect through smart system integration. In future, such solid-state heat pumps and cooling systems could provide an environmentally friendly and efficient alternative to compressor technology.

How does an elastocaloric heat pump work?

When an elastocaloric material is exposed to a mechanical field of force, a crystalline phase transformation occurs, which causes the material to heat up. The heat generated is dissipated via a heat sink, so that the material cools down again to the initial temperature. Once the force field is removed, the crystalline order is reduced and the material cools down to a value below the initial temperature. It can now absorb thermal energy from the environment. Through the cyclical loading and unloading of the material and a corresponding heat supply and removal, a cyclical process can be created that can be used for heating as well as cooling.

Central innovation: a novel heat transfer concept

Fraunhofer IPM relies on a patented system concept for the construction of its elastocaloric systems that is based on rapid heat transfer using latent heat within a saturated steam atmosphere (heat pipe condition). By evaporating and condensing a fluid, heat is effectively transferred to the caloric material and then released again. This makes it possible to achieve thermal power densities that are an order of magnitude higher than in alternative system approaches.

In future, this will make it possible to realize cost-effective systems that require less installation space.

In particular, Fraunhofer IPM is working on:

  • Development and construction of measurement setups for direct measurement of the elastocaloric effect, material efficiency as well as fatigue strength
  • Simulation of elastocaloric materials and systems
  • Development, construction and characterization of elastocaloric heating and cooling systems

We support industrial companies in the conceptual design and development of caloric systems – all the way to the construction of finished systems for specific applications. We draw on many years of technological experience, established supplier contacts and the capacity of our highly specialized workshops and laboratories.

Further information

 

Elasto-Cool project

The Elasto-Cool project focused on the development of highly efficient heat pumps for cooling and heating. Their operation is based on the elastocaloric effect – which is why they can work without harmful refrigerants and without a compressor.

SMArtCool project

In the SMArtCool project, we are working with industrial partners to develop mobile elastocaloric systems for use in automobiles.

 

 

Animation

The principle of
refrigerant-free cooling using elastocalorics as an example

From the media

 

Magnetocaloric cooling systems

Fraunhofer IPM develops energy-efficient cooling systems – entirely without any harmful fluids.

 

Elastocaloric cooling
systems

Fraunhofer IPM is working on the cooling technology of the future – with materials and systems that make optimum use of caloric effects.

Editor's Choice 2024

»Highly Efficient Drive System for Elastocaloric Heat Pumps and Cooling Systems«

The editor of the journal »Shape Memory and Superelasticity« selected the scientific publication on the drive system for elastocaloric heat pumps developed at Fraunhofer IPM as Editor's Choice Article 2024.

Comprehensive nature and overall excellence

A special distinction, as only six of all the articles published in this journal each year make it into the Editor's Choice selection! It confirms and recognizes both the paper's comprehensive nature and its overall excellence.

Our publications relating to »Elastocaloric systems«

Jahr
Year
Titel/Autor:in
Title/Author
Publikationstyp
Publication Type
2024 Highly Efficient Drive System for Elastocaloric Heat Pumps and Cooling Systems
Unmüßig, Sabrina; Burghardt, Andreas; Schäfer-Welsen, Olaf; Bartholome, Kilian
Zeitschriftenaufsatz
Journal Article
2024 Steigerung der Systemperformance eines elastokalorischen Kühlsystems
Bachmann, Nora
Dissertation
Doctoral Thesis
2022 Phenomenological model for first-order elastocaloric materials
Bachmann, Nora; Fitger, Andreas; Unmüßig, Sabrina; Bach, David; Schäfer-Welsen, Olaf; Koch, Thomas; Bartholome, Kilian
Zeitschriftenaufsatz
Journal Article
2022 Elastokalorik: Entwicklung hocheffizienter Wärmepumpen ohne schädliche Kältemittel zum Heizen und Kühlen
Fitger, Andreas; Bartholome, Kilian; Bachmann, Nora; Unmüßig, Sabrina; Winkler, Markus; Mahlke, Andreas
Bericht
Report
2022 Long life elastocaloric regenerator operating under compression
Ianniciello, Lucia; Bartholome, Kilian; Fitger, Andreas; Engelbrecht, Kurt
Zeitschriftenaufsatz
Journal Article
2022 Modeling of an Elastocaloric Cooling System for Determining Efficiency
Bachmann, Nora; Schwarz, Daniel; Bach, David; Schäfer-Welsen, Olaf; Koch, Thomas; Bartholome, Kilian
Zeitschriftenaufsatz
Journal Article
2021 Long-term stable compressive elastocaloric cooling system with latent heat transfer
Bachmann, Nora; Fitger, Andreas; Maier, Lena Maria; Mahlke, Andreas; Schäfer-Welsen, Olaf; Koch, Thomas; Bartholome, Kilian
Zeitschriftenaufsatz
Journal Article
2017 New concept for high-efficient cooling systems based on solid-state caloric materials as refrigerant
Bartholome, Kilian; Hess, Tobias; Winkler, Markus; Mahlke, Andreas; König, Jan D.
Konferenzbeitrag
Conference Paper
Diese Liste ist ein Auszug aus der Publikationsplattform Fraunhofer-Publica

This list has been generated from the publication platform Fraunhofer-Publica

Applications »Elastocalorics«

 

Efficient heating and cooling without harmful refrigerants