"Tube-based Ni-Ti porous structures for elastocaloric cooling"

Elastocaloric cooling utilizing latent heat associated with martensitic transformation during the superelasticity of shape-memory alloys shows high potential as an alternative to the vapour-compression refrigeration cycle. Probably the most effective way of utilizing the elastocaloric effect for different practical applications is an active elastocaloric regenerative cycle. It is based on a porous structure made of superelastic shape-memory alloys through which a heat transfer fluid is pumped in order to transfer heat between elastocaloric material and the surroundings. However, one of the main challenges of the elastocaloric technology is limited fatigue life of shape memory alloys in particular for tension loading. On the other hand, in compression loading any cracks and impurities have much less space to grow, which can prolong its fatigue life.
Here, we will show the results of the development of different tube-based porous structures made of Ni-Ti tubes to be loaded in compression that could serve as an elastocaloric regenerator. The elastocaloric effect, mechanical stability during compression and fatigue life of Ni-Ti tubes will be shown and discussed together with the cooling performance of a tube-based elastocaloric regenerator tested in a new experimental set-up.