Many applications in our daily lives require efficient storage and transport of energy in the form of heat. For example, for a solar system to be reliable, the energy available during sunny days should be stored for use during sun deprived periods. Most heat storage systems use sensible heating of a fluid like water to store heat. To store a substantial amount of heat using sensible heating, either the amount or final temperature of the fluid should be increased, both of which increase the insulation cost for storage.
Phase Change Materials (PCMs) have great potential to enhance the efficiency of heat storage by increasing the amount of heat absorbed and released within a narrow temperature range. Phase Change Materials (PCMs) are substances that are capable of absorbing and releasing large amounts of energy (latent heat) within a particular temperature range due to phase change.
Applications
Energy storage is a topic of pressing importance in various aspects of technology. For example, solar energy is a renewable energy resource with great potential to solve growing ecological problems, like global warming, by reducing the dependence on fossil fuels for energy.
Energy in buildings can be stored and transported effectively using PCMs. Heat energy rejected from one part of the building (as in refrigeration systems) can be utilized in heating systems elsewhere in the building.
Classification
1. Gas-liquid PCMs
2. Solid-liquid PCMs
3. Solid-gas PCMs
4. Solid-solid PCMs