Device for Direct Barocaloric Measurement

Abstract

Direct measurements of adiabatic temperature change (\(\Delta {{\varvec{T}}}_{{\varvec{S}}}\)) to characterize the barocaloric effect (σ_b-CE) were a challenge and a point of interest for many research groups. In this work, we propose a device to measure \(\Delta {{\varvec{T}}}_{{\varvec{S}}}\) in a system with a simplified design and a new method to seal the pressure chamber. This new concept was tested for several materials in solid or liquid states. The methodology involves acquiring a temperature curve as a function of time under desired initial conditions. The results showed that the equipment can measure solid-state materials in powder, flakes, or solid bodies, in the absence or presence of a phase transition. When using coconut oil at high temperatures, for example, the apparatus remained sealed until the end of the experimental run. Promising values of σ_b-CE, ranging from large to colossal, were captured for polymers, composites, first-order-transition materials, coconut oil, paraffin. This concept can inspire new research groups to develop equipment to study the barocaloric effect.