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Materials 2018, 11(9), 1752;

Macro-Encapsulation of Inorganic Phase-Change Materials (PCM) in Metal Capsules

Chair of Engineering Thermodynamics and Transport Processes (LTTT), Center of Energy Technology (ZET), University of Bayreuth, Universitätsstraße 30, 95440 Bayreuth, Germany
Author to whom correspondence should be addressed.
Received: 17 July 2018 / Revised: 12 September 2018 / Accepted: 13 September 2018 / Published: 17 September 2018
(This article belongs to the Section Energy Materials)
PDF [1608 KB, uploaded 17 September 2018]


The design of phase-change material (PCM)-based thermal energy storage (TES) systems is challenging since a lot of PCMs have low thermal conductivities and a considerable volume change during phase-change. The low thermal conductivity restricts energy transport due to the increasing thermal resistance of the progressing phase boundary and hence large heat transfer areas or temperature differences are required to achieve sufficient storage power. An additional volume has to be considered in the storage system to compensate for volume change. Macro-encapsulation of the PCM is one method to overcome these drawbacks. When designed as stiff containers with an air cushion, the macro-capsules compensate for volume change of the PCM which facilitates the design of PCM storage systems. The capsule walls provide a large surface for heat transfer and the thermal resistance is reduced due to the limited thickness of the capsules. Although the principles and advantages of macro-encapsulation have been well known for many years, no detailed analysis of the whole encapsulation process has been published yet. Therefore, this research proposes a detailed development strategy for the whole encapsulation process. Various possibilities for corrosion protection, fill and seal strategies and capsule geometries are studied. The proposed workflow is applied for the encapsulation of the salt hydrate magnesiumchloride hexahydrate (MCHH, MgCl 2 · 6 H 2 O) within metal capsules but can also be assigned to other material combinations. View Full-Text
Keywords: phase-change material; macro-encapsulation; thermal energy storage; latent heat storage; salt hydrate; waste heat; corrosion phase-change material; macro-encapsulation; thermal energy storage; latent heat storage; salt hydrate; waste heat; corrosion

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Höhlein, S.; König-Haagen, A.; Brüggemann, D. Macro-Encapsulation of Inorganic Phase-Change Materials (PCM) in Metal Capsules. Materials 2018, 11, 1752.

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