On the colossal barocaloric effect in higher n-alkanes

Abstract

In this work we present a combination of experimental, theoretical and computational analysis to demonstrate the colossal barocaloric (BC) effect in long-chain linear n-alkanes (paraffins). Adiabatic compression experiments with eicosane...

Pressure-freezing of dodecane: exploring the crystal structures, formation kinetics and phase diagrams for colossal barocaloric effects in n-alkanes

“…Recently, dodecane have been predicted to exhibit the highest entropy change upon phase transition among the liquid n -alkanes. 96 In order to calculate the entropy change, we have redetermined its phase diagram at high pressure. The results show that the determined melting line is consistent with the literature data 76,80 below 0.30 GPa, but then diverges from the line determined by Nelson (Fig.…”

“…Even if the material remains solid within a given P – T range, pressure alone can activate |Δ T ad | ∼10 K, due to substantial volume reduction. 36,96 Additional entropy contribution to BC effect beyond the phase-transition, Δ S + , associated with the elastic heat, can be calculated as:(assuming that thermal expansion coefficient is pressure-independent 99 ). For instance, in solid n -dodecane, compression to 90% of its initial volume (0.9 GPa) causes the substantial incipient BC effect of 42.5 J kg −1 K −1 (without considering |Δ S | associated to the phase transition).…”

“…Even if the material remains solid within a given P-T range, pressure alone can activate jDT ad j ∼10 K, due to substantial volume reduction. 36,96 Additional entropy contribution to BC effect beyond the phase-transition, DS + , associated with the elastic heat, can be calculated as:…”

Structure and thermal property relationships in the thermomaterial di-n-butylammonium tetrafluoroborate for multipurpose cooling and cold-storage

“…In the recent years, barocaloric materials have been demonstrated to exhibit very large thermal changes, some of them as large as DS $ 100 J K −1 kg −1 (the same order of magnitude as refrigerant gases) under the application of low/ moderate pressures of p = 70-1000 bar (while refrigerant gases normally operate at p # 150 bar). [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] These barocaloric materials belong to many different families of compounds, such as ammonium or phosphate salts, [35][36][37][38][39][40][41][42][43] superionic conductors, 44,45 spin crossover materials, [46][47][48][49][50][51][52] n-alkanes, 53 hybrid organic-inorganic materials, [54][55][56][57][58][59][60][61] organic plastic crystals [62][6...…”

Large barocaloric effects in two novel ferroelectric molecular plastic crystals

“…While in most materials the magnitude of such caloric effects is small, there exist classes of solid materials that exhibit a large elddriven thermal response in the vicinity of a FOPT. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] A solidsolid transition is characterized by a change in the lattice, in the electronic and/or magnetic conguration. If such transition takes place near ambient conditions, the ensuing caloric effect can be more easily exploited in refrigeration devices.…”