Phase Change Materials (PCM) and thermal energy storage & cooling technologies: principles, applications, and advantages

I. Overview of Phase Change Materials (PCM)

Definition

Phase change materials are a class of functional materials that absorb or release large amounts of latent heat to store or release energy through changes in physical state (such as solid-liquid, liquid-gas, and solid-solid phase transitions). Their core principle relies on the characteristic of constant temperature but significant energy variation during phase transitions, enabling efficient storage and release of thermal energy.

Working principle

When the ambient temperature rises, phase change materials melt from a solid state into a liquid state (or undergo other phase transitions), absorbing heat and storing it; when the temperature drops, the materials solidify from a liquid state back into a solid state, releasing the stored heat. Throughout this process, the material temperature remains near the phase transition point, achieving constant-temperature control.

II. Core Advantages of Phase Change Materials in Thermal Energy Storage

• High energy storage density:The heat storage capacity per unit volume is much higher than that of water or air, thus saving space.

• Constant temperature characteristics:The temperature remains stable during phase transitions, making them suitable for precise temperature control scenarios (such as cold chains and electronic device cooling).

• Bidirectional energy utilization:They can store cold energy during off-peak electricity periods at night and release it for cooling during the day, balancing grid load and reducing energy costs.

III. Typical Application Scenarios

1. Building air conditioning and heating

Embedding phase change materials into walls, floors, or ceilings allows them to absorb excess indoor heat (such as solar radiation) during the day and release it for cooling at night, thereby reducing the load on air conditioning systems.

Application cases:Paraffin-based phase change material wall panels are used in buildings across multiple European countries, capable of reducing indoor temperature fluctuations by 3~5℃ and achieving 15%~30% energy savings.

2. Food cold chain and medical transportation

Replaces traditional ice packs for maintaining a constant low temperature during the transportation of vaccines and fresh products. Phase change materials have a higher cooling capacity and can sustain low temperatures for longer periods (e.g., -20°C phase change materials can keep items below 0°C for over 48 hours).

Core advantages:Eliminates the moisture issues caused by the melting of traditional ice cubes, and is reusable.

3. Data centers and electronic cooling

Integrates phase change materials into server cabinets or chip cooling modules to absorb peak heat and release it slowly, preventing local overheating.

Application cases:Google's data centers use organic phase change material cooling systems to reduce air conditioning energy consumption by approximately 40%.

4. Renewable energy peaking

When combined with solar and wind power, phase change materials store cold (or heat) during peak power generation periods and release it during off-peak periods to balance energy supply and demand.

Case study:The ice thermal storage system produces ice to store cold energy during off-peak nighttime electricity periods and uses it for cooling during the day.