Understanding Thermal Energy Storage (TES)
Thermal Energy Storage (TES) has gained significant attention in recent years for its role in enhancing energy efficiency and sustainability. The most common question people ask about TES is simple: What exactly is it, and how does it work?
TES is the process of storing thermal energy for later use. This stored energy can be utilised for heating, cooling, or power generation. The main goal of TES is to balance energy supply and demand. It stores excess energy during periods of low demand and releases it when demand peaks. This ensures a stable energy supply and improves the overall efficiency of energy systems. Imagine always having energy exactly when needed—TES helps bring us closer to that reality.
How Does Thermal Energy Storage Work?
TES operates using three main methods: sensible heat storage, latent heat storage, and thermochemical storage.
**Sensible Heat Storage (SHS):** This is the simplest method, where thermal energy is stored by heating or cooling a storage medium, like water or sand. The energy stored depends on the medium’s heat capacity and temperature change. For example, hot water tanks store energy by heating water, which can later be used for heating when required.
**Latent Heat Storage (LHS):** This method uses phase change materials (PCMs) to store and release energy during transitions between solid, liquid, or gas states. PCMs absorb or release a large amount of heat at a nearly constant temperature. For instance, in building cooling, PCMs absorb heat during the day and release it at night as they solidify, stabilising indoor temperatures.
**Thermochemical Storage (TCS):** TCS stores energy through reversible chemical reactions, offering higher energy density compared to SHS and LHS. Energy drives an endothermic reaction during storage, and the reverse exothermic reaction releases energy when needed. An example is using metal hydrides, which store and release energy through hydrogen absorption and desorption.
Applications of Thermal Energy Storage
TES has broad applications across many sectors. In renewable energy, TES stores excess energy from sources like solar and wind during high production periods, ensuring consistent power when generation is low.
In urban areas, TES supports district heating and cooling systems by providing stable thermal energy to multiple buildings, especially when demand fluctuates. Industries that require large amounts of heat, such as manufacturing and food processing, use TES to improve energy efficiency by reusing waste heat, reducing energy costs.
For homes and businesses, TES lowers heating and cooling expenses. Technologies like ice storage for air conditioning and solar thermal storage for hot water are increasingly popular in residential and commercial buildings.
Benefits of Thermal Energy Storage
TES is gaining traction for its many benefits. By storing and reusing thermal energy, TES improves energy efficiency and minimises waste. It helps reduce energy costs by shifting consumption from peak to off-peak hours, when energy prices are lower. TES also stabilises the grid by balancing supply and demand, helping to prevent overloads and blackouts.
Furthermore, by supporting the use of renewable energy and boosting energy efficiency, TES reduces greenhouse gas emissions and lessens environmental impacts. Its ability to provide sustainable, cost-effective energy solutions makes TES a critical technology for the future.
