An alternative cooling method can be achieved with efficient elastocaloric systems

Identifying an alternative cooling process is necessary to address the projected multifold increase in energy use for cooling by the middle of the century. One of the most promising technologies is elastocaloric cooling, in which heat is cyclically absorbed and generated by a material when stressed. Because the necessary stress must be applied properly, Slaughter et al. identified a set of metrics for selecting an actuator for elastocaloric systems.

“As vapor compression nears its limits, next generation cooling technologies are vital for improving energy efficiency and sustainable growth,” said author Julie Slaughter. “Elastocaloric cooling, with its inherently high efficiency and solid-state nature of the working bodies, is one of several promising non-vapor-compression cooling techniques that can meet this need.”

The authors found the interplay between several parameters plays an important role in the effectiveness of an actuator. For example, the stress-strain capabilities of a candidate actuator must be considered in order to maintain a reasonable actuator-to-material volume ratio. Moving coils, piezoelectric materials and linear motors are a few potential candidates, though the group’s case studies indicated a rotary motor and Scotch yoke mechanism provide the best balance between power, torque and size.

“While energy density and power density are good methods for preliminary actuator selection, considering the actuator as part of the whole system is key to developing an energy-efficient, cost-competitive and compact elastocaloric cooling technology,” Slaughter said.

A number of challenges remain to be addressed and optimized before the commercialization of elastocaloric cooling.

“System design for elastocaloric cooling is still in its early stages, and we hope our work is one of the critical first steps in the right direction,” said Slaughter.

Source: “Compact and efficient elastocaloric heat pumps – is there a path forward?,” by Julie Slaughter, Agata Czernuszewicz, Lucas Griffith, and Vitalij Pecharsky, Journal of Applied Physics (2020). The article can be accessed at https://doi.org/10.1063/5.0003275 .