Integrated Thermal Management Applications

Phase Change Materials (PCMs)

Phase Change Materials, commonly referred to as PCMs, are products that store and release thermal energy during the processes of melting and freezing. Phase Change Materials release large amounts of energy upon freezing in the form of latent heat but absorb equal amounts of energy from the immediate environment upon melting. This enables thermal energy storage; heat or coolness being stored from one process or period of time and used at a later point in time or transferred to a different location. PCMs can also be used to provide thermal barriers or insulation, particularly useful for industry sectors such as temperature-controlled transport.

Interestingly, the simplest, cheapest and most effective Phase Change Material is water/ice. Unfortunately, its freezing point of 0°C (+32°F) precludes it from the majority of energy storage applications. However, a number of alternative Phase Change Materials have been identified and developed that freeze and melt like water/ice, but at temperatures from the cryogenic range to several hundred degrees centigrade.

• Eutectics- solutions of salts in water or alternatively non-water based solutions with a phase change temperature below 0°C (+32°F)
• Salt Hydrates - specific salts able to incorporate water of crystallisation during the freezing process, normally above 0°C (+32°F)
• Organic Materials - which tend to be polymers composed primarily of carbon and hydrogen. These mostly change phase above 0°C (+32°F) and can be as simple as coconut oil, waxes or fatty acids.
• Solid-Solid - A specialised group of PCMs that undergo a solid/solid phase transition with the associated absorption and release of large amounts of heat. These materials change their crystalline structure from one lattice configuration to another at a fixed and well-defined temperature, and the transformation can involve latent heats comparable to the most effective solid/liquid PCMs.a range of solutionsfrom +25°C (77°F) upto +180°C (356°F).