TY - JOUR

T1 - Reaction of Calcium Chloride and Magnesium Chloride and their Mixed Salts with Ethanol for Thermal Energy Storage

AU - Korhammer, Kathrin

AU - Apel, Christina

AU - Osterland, Thomas

AU - Ruck, Wolfgang K.L.

N1 - The study was part of a European cooperation-project with the Research Centre for Natural Sciences HAS Budapest and funded by the Federal Ministry of Education and Research. Publisher Copyright: © 2016 The Authors.

PY - 2016/6/1

Y1 - 2016/6/1

N2 - The use of thermochemical energy storage systems increasingly gains interest in order to meet the energy targets of the European renewable energy directive. In this study the suitability of calcium chloride, magnesium chloride and mixed salt ethanolates as heat storage materials for practical implementation was determined by investigating specific thermodynamic properties and estimating the materials' lifetime at various operating conditions. It was proven that the reaction of the before mentioned metal salts with ethanol depends on the applied ethanol vapour pressure. The ethanol sorption increased in the following order: MgCl 2 < CaCl 2 < 2CaCl 2∗MgCl 2. The enthalpies followed the same sequence. Over-stoichiometric ethanol uptake, in particular for CaCl 2 and 2CaCl 2∗MgCl 2 with increasing C 2H 5OH vapour pressure, was observed. However, the reaction systems CaCl 2-C 2H 5OH and 2CaCl 2∗MgCl 2 -C 2H 5OH showed the best sorption properties and cycle stability and thus have a great potential for low-grade thermal energy storage as well as cold storage due to their low reaction temperatures in comparison with salt-water-systems. In general, physically mixing of single salts from the same family with different chemical properties leads to superior thermal behaviour with higher heat storage capacities and material stabilities.

AB - The use of thermochemical energy storage systems increasingly gains interest in order to meet the energy targets of the European renewable energy directive. In this study the suitability of calcium chloride, magnesium chloride and mixed salt ethanolates as heat storage materials for practical implementation was determined by investigating specific thermodynamic properties and estimating the materials' lifetime at various operating conditions. It was proven that the reaction of the before mentioned metal salts with ethanol depends on the applied ethanol vapour pressure. The ethanol sorption increased in the following order: MgCl 2 < CaCl 2 < 2CaCl 2∗MgCl 2. The enthalpies followed the same sequence. Over-stoichiometric ethanol uptake, in particular for CaCl 2 and 2CaCl 2∗MgCl 2 with increasing C 2H 5OH vapour pressure, was observed. However, the reaction systems CaCl 2-C 2H 5OH and 2CaCl 2∗MgCl 2 -C 2H 5OH showed the best sorption properties and cycle stability and thus have a great potential for low-grade thermal energy storage as well as cold storage due to their low reaction temperatures in comparison with salt-water-systems. In general, physically mixing of single salts from the same family with different chemical properties leads to superior thermal behaviour with higher heat storage capacities and material stabilities.

KW - Chemistry

KW - calcium chloride

KW - cycle stability

KW - ethanol

KW - magnesium chloride

KW - mixed salts

KW - reaction kinetics sorption; TCM; TGA; Therma

KW - sorption

KW - TCM

KW - TGA

KW - Thermal energy storage

UR - http://www.scopus.com/inward/record.url?scp=85006012965&partnerID=8YFLogxK

U2 - 10.1016/j.egypro.2016.06.194

DO - 10.1016/j.egypro.2016.06.194

M3 - Conference article in journal

VL - 91

SP - 161

EP - 171

JO - Energy Procedia

JF - Energy Procedia

SN - 1876-6102

M1 - 125043

ER -