Investigation of the Thermal Properties of Diesters from Methanol, 1-Pentanol, and 1-Decanol as Sustainable Phase Change Materials.

Rebecca Ravotti,Oliver Fellmann,Anastasia Stamatiou,Jörg Worlitschek,Ludger J Fischer

doi:10.3390/ma13040810

Abstract

Esters present several advantages when compared to traditional materials used for thermal energy storage, amongst which are better sustainability and greater chemical stability. However, at present, their thermal properties remain mostly unknown or not well documented. In this study, 12 diesters from four dicarboxylic acids (oxalic, succinic, suberic, sebacic) and three alcohols (methanol, 1-pentanol, 1-decanol) have been assessed as bio-based phase change materials for thermal energy storage. All diesters have been synthesized via Fischer esterification to high purities, and their chemical structures, as well as thermal properties, have been fully characterized. The diesters investigated show phase change transitions in a low–mid temperature range between −32 and 46 °C with maximum enthalpies of 172 J/g and show higher degrees of supercooling compared to fatty monoesters. Similarly to other esters classes, some trends correlating the chemical structures to the thermal properties were identified, which would allow for the development of property prediction tools.

Highlights

In view of the 2020 and 2050 European energy goals set by policymakers to allow for a more sustainable future less dependent on fossil fuels, energy storage technologies will play a greater role in the upcoming years [1,2,3,4,5,6,7,8]
DiMeOHOx, a commercially available diester, was both purchased and synthesized in house, and its properties compared in terms of chemical structure and thermal behavior
To confirm the formation of the ester bond and the absence of unreacted alcohol or carboxylic acid in the product obtained, the IR spectras were measured through Attenuated Total Reflectance (ATR) on a diamont tip

Summary

Introduction

In view of the 2020 and 2050 European energy goals set by policymakers to allow for a more sustainable future less dependent on fossil fuels, energy storage technologies will play a greater role in the upcoming years [1,2,3,4,5,6,7,8]. Thermal energy storage (TES) is of key importance in covering for the mismatch between demand and supply, especially in the case of renewable energy sources [9]. Amongst other types of TES, latent heat storage (LHS) with phase change materials (PCM) presents the advantage of allowing achieving more compact solutions. This is of critical importance in the context of urban realities where the available space is limited [10]. Some of the desirable properties are thermal stability, narrow phase change transitions, low supercooling, high heat of fusion, chemical stability, non-toxicity and preferably bio-origin or recyclability [11,12]. The possibility of alternative PCMs is currently being evaluated

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Results

Conclusion