ECPOR

The cooling applications belong to our daily life for the perishable food conservation, drug conservation (vaccine), for the reliability of the electronic devices as well as for the welfare of people. The most popular technique for cooling down is the cyclical compression and expansion of a gaz. Based on this principle, the widely used machines present several drawbacks: a limited potential for integration, complicated in embedded systems and environmental impact when using harmful volatile materials. Consequently, efforts have been put on the development of alternative technologies in the domain of the solid-state physic. Three effects have been studied in materials to replace the vapor compression of a gas refrigerant. All of them are based on the same principle: a variation of the entropy caused by the reversible transition between an ordered state and a non-ordered state induced by external excitations. In the case of the magnetocaloric effect (MC), an external magnetic field imposes a variation of the magnetization within a magnetic material. In the case of the electrocaloric effect (EC), an external electrical field imposes a variation of the polarization within a dielectric material. In the case of the mechano caloric effect, a distinction is done between the barocaloric effect for which the material is driven by a hydrostatic pressure and the elastocaloric effect for which the material is driven by uniaxial stress. The transition to the ordered state provokes an increase of the temperature whereas the return to the non-ordered state induces a decrease of temperature, which must be exploited to cool down the charge. If the magnetocaloric and electrocaloric effects have been widely studied and if there is already, at least on a laboratory scale, prototypes of refrigeration systems, the elastocaloric effect, while it is just as promising as the two previous ones , has not been so deeply studied. The aim of the ECPOR project is to contribute to this topic by evaluating the efficiency of the elastocaloric effect within polymers for refrigeration applications. A multidisciplinary approach, combining experiences and modeling will be used to better understand the mechanisms which are at the origin of the elastocaloric effect in order to enhance it, to accurately characterize the heat transfer between the polymer surface and its surrounding and to build some laboratory prototypes of thermal machines to gain in experiences on this novel technique. This project is in good agreement with the societal challenge "Clean, Safe and Efficient Energy" and in particular its research axis "Fundamental and. Exploratory Research and breakthrought"