Scaling Laws of Elastocaloric Regenerators

Specific cooling power (SCP), a.k.a. cooling power density, measures the cooling power of a unit mass of solid-state refrigerant. Comparing SCP is popular but is only reasonable if SCP is an intensive parameter that does not change with system size. However, to the best of our knowledge, there is no evidence that this fundamental assumption is valid. To address this question, we have derived the scaling laws of SCP and other performance metrics in terms of size and the hydraulic diameter for elastocaloric regenerators. The resulting scaling laws indicate that in many cases the specific cooling power does vary with the system size, subject to specific design constraints. Therefore, there is no engineering significance to compare the SCP among different systems with different sizes unless one maintains the same constraints including pumping power density, efficiency, etc. Although the present scaling laws were developed specifically for elastocaloric regenerators, the methodology can be easily adopted for other caloric cooling technologies.