Phenomenological model for first-order elastocaloric materials

Elastocaloric cooling systems may offer a potentially more efficient as well as environmentally friendly alternative to compressor-based cooling technology. These cooling systems use stress-induced phase transformation in elastocaloric materials to pump heat. Thermodynamically consistent material models can be used to design and quantify the efficiency of these cooling systems. In this paper, we present a phenomenological material model that depicts the behavior of first-order materials during stress-induced phase transformation. This model is based on a phenomenological heat capacity equation, from which the parameters adiabatic temperature change and isothermal entropy can be derived. Hysteresis of the materials, which determines it dissipative effects, is also taken into account. Based on this model, these parameters can be calculated as a function of stress and temperature. The performance coefficients derived from the model can be used to evaluate the materials efficiency. Furthermore, the data obtained using this model coincided very closely with experimental data.