Experimental devices to investigate the long‐term stability of phase change materials under application conditions
An important prerequisite to select a reliable phase change material (PCM) for thermal energy storage applications is to test it under application conditions. In the case of solid-liquid PCM, a large amount of thermal energy can be stored and released in a small temperature range around the solid-liquid phase transition. Therefore, to test the long‐term stability of solid-liquid PCM, they are subjected to melting and solidification processes taking into account the conditions of the intended application. In this work, 18 experimental devices to investigate the long‐term stability of PCM are presented. The experiments can be divided into thermal cycling stability tests, tests on PCM with stable supercooling, and tests on the stability of phase change slurries (PCS). In addition to these experiments, appropriate methods to investigate a possible degradation of the PCM are introduced. Considering the diversity of the investigated devices and the wide range of experimental parameters, further work toward a standardization of PCM stability testing is recommended. ; This survey has been carried out within the framework of IEA ES Annex 33/SHC Task 58 "Material and Component Development for Compact Thermal Energy Storage", a joint working group of the "Energy Storage" (ES) and the "Solar Heating and Cooling" (SHC) Technology Collaboration Programmes of the International Energy Agency (IEA). The responsibility for the content of this publication is with the authors. The work of ZAE Bayern is part of the project properPCM and was supported by the German Federal Ministry of Economic Affairs and Energy under the project code 03ET1342A. The work of CIEMAT is part of two projects: ACES2030 (S2018/EM-4319) which is supported by Comunidad de Madrid and European Structural Funds through and SFERA III (GA No 823802) which is supported by European Union's Horizon H2020 Research and Innovation Programme. The work of DTU was supported by HM Heizkörper GmbH and the Danish Energy Agency through the EUDP program. The work of EHU is part of the project Sweet-TES (RTI2018-099557-B-C22), funded by the Spanish Ministry of Science, Innovation and Universities. The work of GREiA was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31—MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades—Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (GREiA 2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme. The work of HSLU was partially funded by the Swiss Competence Centre for Energy Research on Heat and Electricity (SCCER HaE). The authors would like to thank the SCCER HaE as well as METTLER TOLEDO AG for the support given. The work of Fraunhofer ISE was part of the projects KOLAN (FKZ 03ESP357B) and KOKAP (FKZ 03ET1463A) which were administrated by the Projektträger Jülich (PtJ) and funded by the German Federal Ministry of Economic Affairs and Energy. The work of LAMTE was supported by Intel Corporation, along with the Natural Sciences and Engineering Research Council of Canada (NSERC) and the Canada Foundation for Innovation. The work of LGCgE is partly funded by the French National Research Agency (ANR) under the project "Hybrid storage and heat exchanger device with PCM—EUROPA". Noé Beaupere's PhD work was funded by the French Alternative Energies and Atomic Energy Commission (CEA) Grenoble. The work of LTTT is part of the project MALATrans and was funded by the German Federal Ministry for Economic Affairs and Energy (BMWi) under the project code 03ESP227B.