Exploring Barocaloric Solid State Refrigeration: Device-Level Modeling and Device Development

Solid-state refrigeration using caloric materials has emerged as a promising alternative to inefficient vapor compression cooling systems. While electrocaloric, magnetocaloric, and elastocaloric effects have received substantial attention, barocaloric refrigeration, which utilizes hydrostatic pressure, has been less explored. This study addresses the gap in device-level investigations by presenting a thermodynamic and heat transfer model for a barocaloric refrigerator using commercially-available nitrile butadiene rubber (NBR). By integrating NBR properties and high thermally conducting nanofluids along with dynamic transient heat transfer modeling, the performance based on reversed Brayton refrigeration cycle is assessed for the device. Impact from factors such as device geometry, operating frequency, heat transfer coefficient, and applied pressure are analyzed on device performance. Results indicate that the barocaloric refrigerator achieves a COP of up to 8, greatly surpassing traditional vapor compression-based systems, when operating with a 2.3 K temperature span, a 10 mHz cycle frequency, and a 0.1 GPa pressure change. Furthermore, increasing the thermal conductivity of the barocaloric refrigerant from 0.2 W m-1 K-1 to 1 W m-1 K-1 enhances COP by 67%. This study demonstrates the potential of soft barocaloric materials in solid-state cooling devices and provides a framework for quantitative assessment of their performance and device development in near future.