Phase Change Materials: The New Age Energy Conservation Technique

20 May 2022

A phase change material (PCM) is a material that releases or absorbs enough energy during a phase transition to produce heat or cooling. Most of the time, the changeover will be between one of the first two significant states of matter, solid and liquid. 

The phase transition can also exist between non-classical states of matter, such as crystal conformance, when the material transforms from one crystalline structure to another with a different energy level.

The introduction of PCMs proved to be useful for solar energy, building and construction, textiles, and other applications and is projected to support its overall market growth. 

A growing emphasis on reducing greenhouse gas (GHG) emissions are predicted to generate significant market demand for PCMs. Market trends also indicate that higher knowledge of PCMs is required, which may be achieved through several marketing awareness activities.

According to BIS Research, the phase change materials market was valued at $1.52 billion in 2020 and is expected to reach $8.95 billion by 2031, growing at a CAGR of 17.54% between 2021 and 2031. 

During the phase transition, many materials may absorb a significant quantity of heat energy. When a material freezes and solidifies, the heat acquired while melting is released. Various materials melt and solidify at different temperatures and absorb different quantities of heat energy.

Since phase transition materials melt and solidify at exact temperatures, they can be utilized to control the temperature in various applications. 

Materials that melt to absorb heat are significantly more effective in absorbing heat energy than sensible heat energy materials. 

This means that storing heat energy in a phase change material requires far less material than storing heat energy in a non-phase change substance.

Let's learn some key concepts used in phase change material systems.

What is sensible heat capacity?

The ability of a substance to absorb heat energy as its temperature increases (warms up) is referred to as its sensible heat capacity.

Internal temperature rises when a material is heated without changing its phase. A glass of sun-heated water is an example of this. When light falls on the water, it receives energy, the water molecules become more active, and the temperature of the water rises. This is referred to as "sensible heat."

What is latent heat capacity?

When a container of ice cubes is exposed to direct sunlight, the ice gradually begins to warm up. The ice begins to melt when it reaches the phase transition temperature of 0°C.

If you take the temperature of the melting ice, you'll observe that it remains at 0°C until all of it has melted. This is because when a PCM, such as ice, changes phase, the temperature remains constant until all of the substance has melted. This is known as latent heat.

Latent heat capacity refers to a material's ability to absorb or release heat energy when it melts or freezes without increasing its temperature. 

Importance of Phase Change Materials:

The following applications explain the importance of phase change materials:
•    Solar Energy Applications: Solar thermal energy is a technique of generating heat by utilizing solar energy. 

The Earth absorbs the Sun's energy and disperses it at different speeds depending on the composition of the ground and the amount of water present. 

The temperature of the Earth remains constant, and solar energy may be transferred from the Earth's surface to space for heating and cooling. 

Passive systems based on PCMs have been proved to be possible alternatives for thermal energy storage since the 1980s. 

The bottoms of the water heaters were first supported by filling them with PCMs, which was a first step in storing energy in heating systems. 

The limited heat conductivity of the PCM, on the other hand, restricted the quantity of accessible energy in the storage system. 

Because of this, the growth of thermal storage systems and breakthroughs in the use of solar-powered PCMs have been researched extensively. 
•    Building Applications: Temperature control, high-density heat or cold storage, and thermal comfort in buildings with a limited temperature range are all possible with PCMs. 

As a result, if solar energy is stored efficiently, it may be utilized to fight the cold at night. The use of PCMs allows for the fulfillment of heating needs. It helps to store energy generated during the day and keep the building at a reasonable temperature.
•    Vehicle Applications: The magnitude of research on PCM's potential across vehicle applications is growing. 

PCMs are being studied in the context of refrigerated trucks, which are meant to transport perishable goods at particular temperatures.

Refrigerated vehicles are regulated by small refrigeration units placed outside the vehicle to maintain a constant temperature and relative humidity within the trailer. They function on gas; thus, temperature changes in the trailer have a considerable influence on transportation costs.

•    Textiles: Phase change materials (PCMs) in textiles get adapted to the thermal regulating functional performance of PCM clothing by modifying their state of aggregation within a given temperature range.

Phase change textiles are used in apparel, blankets, medical clothing, insulation, protective garments, and various other applications. 

When phase change materials interact with the microclimate (climate of a small area) that surrounds the human body, they adjust to temperature swings caused by changes in activity levels and the external environment. 

PCM microcapsule-treated fabrics might enhance surgical gear, patient bedding materials, bandages, and goods used to regulate patient temperatures in intensive care units.

To summarize, the market for phase change materials is expanding and evolving and shifting toward more thermally efficient and high-energy storage capacity PCMs, influencing individual choices and demands substantially.


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