How Does Thermal Energy Storage Help in Daily Life and Exams?
When we talk about thermal energy, we refer to the heat energy that is produced when there is a rise in temperature. This rise in temperature causes the atoms and molecules in a material to vibrate at a high frequency. It will eventually collide with each other. As a result, energy is dissipated from them, which is called thermal energy. Now that we know what is thermal energy let's take a look at the thermal energy definition.
Thermal energy is defined as when any atoms or molecules of an element start vibrating due to the rise in temperature; it produces energy which is called thermal energy. In other words, thermal energy definition can be the movement of atoms and molecules. These atoms and molecules will keep moving faster as the temperature rises. Therefore, we can say that the kinetic energy of the particles and their thermal energy is the same. Now that you are familiar with what is thermal energy and the thermal energy definition, we will see the different sources of thermal energy.
Sources of Thermal Energy
Chemical energy: We can convert chemical energy to thermal energy. Some good thermal energy examples are the burning of wood and coal.
Solar energy: Solar energy comes under the best sources of thermal energy. It is the cleanest and readily available source of energy.
Mechanical energy: We can convert mechanical energy to thermal energy. An excellent thermal energy example is the energy released due to friction.
Fossil fuels: Fossil fuels are burnt to produce thermal energy.
Geothermal energy: We can convert geothermal energy to thermal energy. A good thermal energy example is the energy released due to volcanoes, hot springs, and geysers.
Thermal Energy Storage
It is crucial to understand exactly what is thermal energy storage. Energy storages are designed to store energy, and when the demand for power increases, it can maintain a constant supply. It helps to keep the supply and demand for energy, use renewable sources of energy, and increase the efficiency of the use of energy. Thermal energy storage is a technology that stores up thermal energy. It is obtained by continuously heating and cooling the storage system. The energy stored can be utilised in the future when the need arises. By using energy storage, we can reduce the time and rate mismatch between the supply and demand for energy.
Take solar energy for an example. Solar energy can only be produced during the day when the temperature of the environment increases. But the same energy is utilised day and night. Therefore, storing energy becomes essential. By storing the thermal energy during the day, we can use it at night.
Working of Thermal Storage Energy
To properly understand the working of the thermal energy storage system, we will look at an example relating to an air-conditioning system.
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The image shows the various steps in the working of thermal energy storage.
In the first step, during night time, we take a mixture of water and 25% of propylene glycol or ethylene. This mixture is then cooled with the help of a chiller. In our example, we are using an ice storage cooling system. The next step is to circulate this mixture in the ice bank, which acts as a heat exchanger. In the tank, we can freeze 95% of the water. Then ice is uniformly created inside the container with the help of the heat exchanger.
Now, during the day time, the glycol from the mixture can freely move between the ice. This glycol is then used to deliver the stored energy into a room of a building. A fan is used to blow off the cold atmosphere into the room.
There are two main types of thermal energy storage. The first type of thermal energy storage is sensible heat storage. In this type, heat energy is stored in either liquid material or solid material. The second type of thermal energy storage is latent heat storage. In this type, heat energy is either stored in Solid-Solid material, Solid-Liquid material, or Liquid-Gas materials.
Different Types of Thermal Energy Storage
Thermal Energy Storage Applications
Thermal energy is a good source of energy. Let’s look at some of the good uses of thermal energy.
We use thermal energy in solar power plants to provide energy during the night time.
Thermal energy is used in cooking, baking, water heating, and heating.
It is also used in thermal processing of non-metals.
It has applications in automobiles.
They are used as incinerators to burn down waste.
It has applications in thermal power plants.
FAQs on Thermal Energy Storage Explained: Principles, Types & Uses
1. What is thermal energy storage and why is it important in physics?
Thermal energy storage (TES) is the technology used to temporarily hold thermal energy—either as heat or cold—for later use. It works by heating, melting, or causing a chemical reaction in a storage medium. Its importance lies in its ability to bridge the gap between energy availability and energy demand. This improves the efficiency of energy systems and is crucial for making intermittent renewable sources, like solar energy, more reliable.
2. What are the main types of thermal energy storage systems?
Thermal energy storage systems are primarily categorized into three main types based on the physical or chemical process used:
- Sensible Heat Storage: This involves storing energy by raising the temperature of a solid or liquid medium, such as water, rocks, or molten salts, without changing its phase.
- Latent Heat Storage: This method utilizes materials known as Phase Change Materials (PCMs). Energy is stored or released when the material changes its phase, for example, from solid to liquid (melting) or liquid to solid (freezing).
- Thermochemical Heat Storage: This advanced method uses the heat absorbed or released during reversible chemical reactions to store energy.
3. Can you provide a simple example of thermal energy storage we use in daily life?
A very common example of thermal energy storage is a hot water geyser or a thermos flask. The geyser uses electricity to heat water and stores this hot water in an insulated tank for later use (a form of sensible heat storage). Similarly, a thermos flask keeps a beverage hot by using a vacuum layer to minimise heat loss, effectively storing the liquid's thermal energy for several hours.
4. What are some key applications of thermal energy storage technology?
Thermal energy storage technology has several important applications across different sectors:
- Concentrated Solar Power (CSP) Plants: Storing solar heat in molten salts to generate electricity even after sunset.
- Building Heating and Cooling: Storing heat or 'cold' during off-peak hours (when electricity is cheaper) and releasing it during peak hours to regulate building temperature.
- Industrial Waste Heat Recovery: Capturing excess heat from industrial processes and reusing it, which improves overall energy efficiency.
- District Heating Systems: Large-scale storage of heat for distribution to multiple buildings in a community.
5. How does latent heat storage differ from sensible heat storage?
The primary difference between latent and sensible heat storage lies in how energy is stored. Sensible heat storage involves a change in the temperature of the storage material. In contrast, latent heat storage occurs at a nearly constant temperature during a phase transition (e.g., solid to liquid). Because of the large amount of energy involved in phase changes, latent heat systems can store significantly more energy in a smaller volume compared to sensible heat systems, a property known as higher energy density.
6. Why are Phase Change Materials (PCMs) considered so effective for thermal energy storage?
Phase Change Materials (PCMs) are effective because they can absorb and release a large quantity of thermal energy, known as latent heat, at a specific, constant temperature. This high energy storage capacity allows for the design of compact and efficient TES systems. It makes them ideal for applications where temperature stability and a small physical footprint are critical, such as in electronics cooling, building materials, and smart textiles.
7. What is the role of thermal energy storage in making renewable energy more viable?
Renewable energy sources like solar and wind are intermittent—they are not available 24/7. Thermal energy storage solves this problem by capturing excess energy when it is abundant (e.g., during a sunny day) and storing it. This stored energy can then be released to generate power or provide heating when the source is unavailable (e.g., at night or on a calm day). This ensures a stable and continuous energy supply, making renewables a more reliable and practical alternative to fossil fuels.
8. What are the main advantages and disadvantages of using thermal energy storage systems?
Thermal energy storage systems offer significant benefits but also have some drawbacks.
- Advantages: They improve overall energy system efficiency, reduce energy costs by shifting consumption to off-peak hours, decrease reliance on fossil fuels, and provide a stable energy supply from intermittent renewable sources.
- Disadvantages: Key challenges include unavoidable heat loss over time, the high initial capital cost of installation, potential degradation of storage materials over many cycles, and the complexity of system design and integration.
