Phase change materials (PCMs) effectively store thermal energy in urban areas by leveraging high latent heat capacity during phase transitions. The most effective options depend on temperature requirements, stability, and thermal conductivity, with these being top candidates:
Common PCMs by Temperature Range
- Low-temperature applications (e.g., building insulation, cooling systems):
- Water/ice: Simplest and cheapest PCM, but limited to 0°C (32°F).
- Paraffin waxes: Organic PCMs with melting points between 20–60°C, ideal for passive thermal regulation in buildings.
- Fatty acids: Biodegradable options like capric acid (melting point ~30°C), suitable for moderate climates.
- Medium-temperature systems (e.g., solar thermal storage, HVAC):
- Salt hydrates (e.g., sodium sulfate decahydrate): Inorganic PCMs with high energy density and melting points of 30–90°C.
- Polyethylene glycol (PEG): Polymeric PCM adjustable to specific temperatures; used in textiles and thermal buffering.
Advanced Materials for Urban Energy Storage
- Carbon-enhanced composites: Paraffin or salt hydrates combined with graphene, carbon nanotubes, or porous carbon improve thermal conductivity and stability while retaining high energy density. These address PCMs’ low heat transfer rates.
- Microencapsulated PCMs: Paraffin or fatty acids encapsulated in polymer shells prevent leakage and degradation during repeated phase cycles, making them safer for integration into building materials.
- Metal-organic frameworks (MOFs): Emerging materials with tunable phase transitions and high thermal storage density, though still in experimental stages.
Key Considerations for Urban Use
- Thermal conductivity: PCMs inherently have low conductivity, requiring additives like carbon nanomaterials for efficient heat transfer.
- Long-term stability: Encapsulation and hybrid formulations prevent phase separation and material degradation over cycles.
- Cost-effectiveness: Water/ice and paraffin are economical, while advanced composites trade higher costs for enhanced performance.
For urban settings, paraffin-based composites and salt hydrates are currently the most practical due to their balance of cost, scalability, and efficiency in applications like smart windows, thermal batteries, and district heating systems.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-most-effective-phase-change-materials-for-thermal-energy-storage-in-urban-areas/
