Thermal Energy Storage Classification
Thermal energy storage technologies commonly used in the district cooling industry can be classified according to the form of energy stored in the system. Cool energy can be stored either in the form of sensible heat or latent heat.
Sensible Heat Storage
In a sensible heat storage system, the energy is stored as sensible heat associated with the change in temperature of the storage media. The storage media does not undergo a phase change. The amount of energy stored in a sensible heat storage system is dependent on the sensible heat capacity of the media and the degree of temperature change during the charging process. In district cooling systems, the most popular form of sensible heat storage is the chilled water storage system.
Latent Heat Storage
In a latent heat storage system, the energy is stored as latent heat as the storage media undergoes a phase change, transitioning from liquid to solid form. The amount of energy stored in a latent heat storage system is dependent on the latent heat of fusion of the media.
In district cooling systems, the most popular form of latent heat storage is the ice storage system.