Hydrocarbons, primarily paraffins (CH) and lipids but also sugar alcohols.
* Advantages
** Freeze without much supercooling
** Ability to melt congruently
** Self nucleating properties
** Compatibility with conventional material of construction
** No segregation
** Chemically stable
** Safe and non-reactive
* Disadvantages
** Low thermal conductivity in their solid state. High heat transfer rates are required during the freezing cycle. Nano composites were found to yield an effective thermal conductivity increase up to 216%.
** Volumetric latent heat storage capacity can be low
** Flammable. This can be partially alleviated by specialised containment.