Latent heat storage is a thermal energy storage method that uses phase-change materials to absorb and release heat during material transitions between solid and liquid states. Unlike sensible heat storage, latent heat systems store considerably more energy in smaller volumes because the phase transition stores energy without significant temperature change.
Technical Mechanism
Phase-change materials like paraffin wax store 150-300 kJ/kg of latent heat during melting and release it during freezing. The storage density is 5-15 times higher than water-based sensible heat systems. Common PCM materials melt at 16-28°C for building applications and 90-120°C for industrial applications.
HVAC Applications
Latent heat storage systems reduce peak cooling demand by shifting loads to off-peak hours. They integrate into thermal storage tanks, building envelopes, and chilled water systems. This technology particularly benefits facilities with time-of-use electricity rates and limited cooling capacity.
Performance Benefits
Systems achieve 20-40% energy savings in favorable conditions by reducing compressor runtime during peak demand periods. Equipment costs range from 15-40% premium over conventional systems but recover through utility bill reductions and demand charge avoidance over 5-10 years.