Characterization of Fatty Acids as Biobased Organic Materials for Latent Heat Storage.

Marie Duquesne,Fabien Rouault,Clément Mailhé,Sergio Santos-Moreno,Stefania Doppiu,Guillaume Fleury,Jean-Luc Dauvergne,Elena Palomo Del Barrio,Alexandre Godin

doi:10.3390/ma14164707

Abstract

This work aims to characterize phase change materials (PCM) for thermal energy storage in buildings (thermal comfort). Fatty acids, biobased organic PCM, are attractive candidates for integration into active or passive storage systems for targeted application. Three pure fatty acids (capric, myristic and palmitic acids) and two eutectic mixtures (capric-myristic and capric-palmitic acids) are studied in this paper. Although the main storage properties of pure fatty acids have already been investigated and reported in the literature, the information available on the eutectic mixtures is very limited (only melting temperature and enthalpy). This paper presents a complete experimental characterization of these pure and mixed fatty acids, including measurements of their main thermophysical properties (melting temperature and enthalpy, specific heats and densities in solid and liquid states, thermal conductivity, thermal diffusivity as well as viscosity) and the properties of interest regarding the system integrating the PCM (energy density, volume expansion). The storage performances of the studied mixtures are also compared to those of most commonly used PCM (salt hydrates and paraffins).

Highlights

Latent heat thermal energy storage (LHTES) systems are a viable solution for several applications such as building, food industry, electronics, and transport, due to their ability to store a large amount of heat in quasi-isothermal conditions
This study is focused on the principal thermophysical properties of phase change material (PCM), such as melting temperature and enthalpy, specific heat, thermal conductivity, diffusivity, heat capacity, density and viscosity according to the temperature
The fatty acids-based eutectic mixture of capric and myristic acids constitute a promising biobased alternative to paraffin waxes for latent heat storage at low temperatures to maintain a comfortable temperature in a building

Summary

Introduction

Latent heat thermal energy storage (LHTES) systems are a viable solution for several applications such as building, food industry, electronics, and transport, due to their ability to store a large amount of heat in quasi-isothermal conditions. This work is focused on LHTES systems in which the charge period corresponds to the melting of the phase change material (PCM) and the discharge to its crystallization. The Interreg SUDOE SUDOKET project aims for sustainable urban development, with a final objective to contribute to improving the energy efficiency of existing buildings. In this framework, our work is focused on the thermal regulation of the indoor environment of buildings using a LHTES system as an alternative to conventional heating and air-conditioning systems. Most previously developed LHTES systems [5,6,7] are based on paraffin waxes

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