储能技术简介（英文）_24页

Thermal Energy Storage Summary

Core Content

Thermal Energy Storage (TES) is a technology that stores thermal energy in various forms—sensible heat, latent heat, and thermo-chemical energy—to be used later for heating, cooling, or power generation. It plays a crucial role in balancing energy demand and supply, especially in the context of renewable energy integration, and is widely applied in buildings and industrial processes. TES systems can help reduce peak demand, $\mathrm{CO}_2$ emissions, energy costs, and increase overall system efficiency.

Main Types of TES Systems

There are three primary types of TES systems:

1. Sensible Heat Storage: Stores energy by heating or cooling a medium (e.g., water, sand, molten salts). It is the most commercially available and cost-effective type, with storage capacities ranging from 10–50 kWh/t and efficiencies between 50–90%. Water is the most common and cheapest medium, though it requires large volumes due to its low energy density.

2. Latent Heat Storage (PCM): Uses phase change materials to store energy during phase transitions (e.g., solid to liquid). It offers higher storage capacities and more stable discharging temperatures. Storage capacities can reach up to 150 kWh/t, with efficiencies of 75–90%. Costs range from €10–50 per kWh.

3. Thermo-Chemical Storage (TCS): Relies on chemical reactions to store and release thermal energy, offering the highest storage capacities (up to 250 kWh/t) and efficiencies (up to nearly 100%). However, it is still in development and demonstration stages. Costs range from €8–100 per kWh.

Key Features of TES Systems

• Capacity: Depends on the storage medium and system size.
• Power: Refers to the rate at which energy can be discharged or charged.
• Efficiency: Measures the ratio of energy delivered to the energy input, affected by losses during storage and cycles.
• Storage Period: Can range from hours to months, depending on the application.
• Cost: Influenced by the type of system, materials, and technologies used.

Applications

• Building Sector: TES is used for domestic hot water, space heating, and air-conditioning. It can also be integrated into building walls using PCM, such as micro-encapsulated paraffin wax, to improve thermal mass and enable passive cooling.
• Industrial Sector: TES systems are used for process heat and cold, especially in energy-intensive industries like cement, steel, and glass manufacturing. They help improve energy efficiency and reduce waste heat losses.
• Renewable Energy Integration: TES is particularly important for concentrating solar power (CSP) plants, where solar heat is stored for later electricity generation. It also supports the integration of renewable electricity into heating and cooling systems, such as in compressed air energy storage (CAES) and cold storage systems.

Economic Viability

• Sensible Heat Storage: Economically viable for most applications due to its lower cost (€0.1–10/kWh), but requires large volumes.
• PCM Storage: More expensive (€10–50/kWh) but offers higher efficiency and storage capacity.
• TCS Storage: Most expensive (€8–100/kWh) but has the highest potential for energy storage and efficiency. It is often used in industrial and long-term applications.

Potential and Barriers

• Potential: TES can significantly reduce $\mathrm{CO}_2$ emissions and fossil fuel dependence. In Europe, it is estimated that 1.4 million GWh per year could be saved and 400 million tonnes of $\mathrm{CO}_2$ emissions could be avoided.
• Barriers: High costs, especially for PCM and TCS systems, and the need for improved stability and performance. For TCS, material properties and heat/mass transfer technologies are key challenges. In mature economies, low construction rates of new buildings limit TES deployment, whereas emerging economies have greater potential.

Key Technologies and Materials

• Sensible Heat Storage: Commonly uses water, oil, molten salts, and rocks. Underground storage is also used for large-scale applications.
• PCM Storage: Includes materials like ice, paraffin, and sodium acetate trihydrate. These materials have varying melting temperatures, enthalpies, and densities.
• TCS Storage: Utilizes chemical reactions such as adsorption, dehydration, and dissociation. Materials under investigation include zeolites, metal hydroxides, and salts like calcium chloride.

Cost Analysis

• Sensible Heat Systems: Cost ranges from €0.1–10/kWh, depending on the size, application, and insulation.
• PCM Systems: Cost is between €10–50/kWh, with micro-encapsulated PCMs being more expensive due to advanced materials.
• TCS Systems: Cost is between €8–100/kWh, with the highest costs associated with advanced chemical storage technologies and heat/mass transfer equipment.

Summary of TES Technologies

Conclusion

Thermal energy storage is a versatile and essential technology for improving energy efficiency, reducing emissions, and supporting the integration of renewable energy sources. While sensible heat storage is currently the most mature and cost-effective option, PCM and TCS systems offer higher performance and potential for future applications. Continued R&D and supportive policies are necessary to enhance the commercial viability and widespread adoption of all TES technologies.