What is a PCM?

PCM stands for Phase Change Material. In the most basic terms, a PCM is a substance which can store and release large amounts of energy, typically in the form of heat. Although phase changes can occur among any combination of the three phases of a substance - gas, liquid, or solid - the most commercially viable transition is between the liquid and solid phases. When a PCM is in its' solid phase it can absorb heat, providing a cooling effect. When a PCM is in its' liquid phase it can release heat, providing a warming effect.

As the material cycles between the two phases it holds the temperature around its' particular melt point. Phase change materials can be purchased in a wide variety of temperatures ranging from approximately -114°C to +885°C / 173°F to 1625°F. Main Types of PCMs: Examples

  Examples
Key Advantages
Key Disadvantages
Organic
•  Paraffins (Wax)
•  Fatty Acids (Oils)
•  Polyglycols
•   Chemically stable
•   High enthalpy (high heat storage)
•   Safe and non-reactive
•   No loss of effectiveness with cycling
•   Can be microencapsulated
•   Low thermal conductivity
•   Cost
Inorganic
• Salt hydrates
•   Low cost
•   High enthalpy (high heat storage)
•   Very large melt point range
•   Loses effectiveness with thermal cycling
•   Large volume change between phases
•   Large degree of supercooling
•   Corrosive
•   Cannot be microencapsulated
Eutectics
•  Salt-Water Solutions
•   Low cost
•   Limited temperature range
•   Corrosive
•   Cannot be microencapsulated