Colossal Barocaloric Effect of Binary Fatty Acid Methyl Esters under Low Pressures near Room Temperature

Abstract

Refrigeration technology based on the caloric effect is one of the more environmentally friendly alternatives to gas compression refrigeration. The barocaloric effect utilizes pressure to induce phase transition and results in a large entropy change. In this work, a colossal barocaloric effect in the liquid−solid transition (L-S-T) of binary fatty acid methyl esters (BFAMEs) was discovered. At 295 K, an isothermal entropy change as high as 591 J kg −1 K −1 and a reversible entropy change of 356 J kg −1 K −1 at a hydrostatic pressure of 80 MPa were obtained by mixing methyl palmitate and methyl stearate with a specific ratio to synthesize a BFAME. The value of the isothermal entropy change of the BFAME is comparable to that of a commercial gas compression refrigerant, R134a. This work will provide a new L-S-T candidate material to replace commercial refrigerants for the potential application of caloric effect refrigeration technology.

Colossal Barocaloric Effect near Ambient Temperature in 1-Dodecanol under a Low Pressure

“…The structural changes of C 12 H 26 O during the solid–liquid process are depicted in Figure c. Combined with the heat flow data obtained in DSC (as shown in Table S2), it can be observed that as the temperature increases, the structure of C 12 H 26 O undergoes a transition from S to L. Rotation of one or more C–C bonds occurs, resulting in a significant increase in configurational entropy, accompanied by characteristic bands at 1060 and 1130 cm –1 showing a significant decrease and broadening in Raman spectroscopy. Additionally, the solid–liquid phase transition is accompanied by scissoring deformations of the CH 2 bonds (1293 cm –1 ) and CH 3 bonds (1440 cm –1 ).…”