Global Decarbonisation 3050-0230 Caravel Press 10.17184/eac.9501 2025.005 Controllable Supercooling in Phase Change Materials-Advances in Triggering Methods, Lab-Scale Investigations, and Prototype Demonstrations https://orcid.org/0000-0003-0921-3283 JarimiHasila Hasila.Jarimi@nottingham.ac.uk https://orcid.org/0000-0002-5292-7567 AydinDevrim devrim.aydin1@nottingham.ac.uk https://orcid.org/0000-0002-6616-7626 SuYuehong yuehong.su@nottingham.ac.uk https://orcid.org/0000-0002-3911-0851 RiffatSaffa saffa.riffat@nottingham.ac.uk Department of Architecture and Built Environment, The University of Nottingham, NG7 2RD, UK; Solar Energy Research Institute, Universiti Kebangsaan Malaysia, 43600, Bangi Selangor, Malaysia Department of Architecture and Built Environment, University of Nottingham, University Park, Nottingham, NG7 2RD, UK 25072025 1 1 25 25 July 2025 © 2025 The Author(s). Published by Caravel Press. 2025 This is an open access article under the CC BY 4.0 licence.

Supercooled Phase Change Materials (PCMs) offer significant advantages for thermal energy storage by enabling latent heat retention over extended periods with minimal loss. However, controlling crystallization in supercooled states remains a critical challenge for practical applications. This review provides a comprehensive analysis of lab-scale experimental studies on controllable supercooling in PCMs, categorized by triggering methods such as local cooling, mechanical agitation, bubble injection, electric and ultrasonic fields, mechanical shock, and cold crystallisation. Furthermore, the transition of these control techniques into physical prototypes is discussed, highlighting operational challenges and integration issues observed in heat pads, thermal batteries, battery preheating systems, and long-term thermal energy storage units. Despite substantial progress, scaling up supercooled PCM systems introduces new barriers, including premature crystallization, inconsistent triggering, and material degradation. Addressing these challenges through prototype-scale research is critical to achieving reliable, cost-effective thermal energy storage solutions utilising supercooled PCMs as controllable thermal energy storage.

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