In new era, human society is endeavored to protect our environment. One of the important tasks is to save energy so that we can reduce consumption of precious natural resources. While we are dedicated to searching for new renewable energy sources, lot of energy we generated is wasted because of lack of efficient storage. Heating supply as an example is usually greater than the demand, so results in latent heat wasted. In decades, researchers have conducted intensive studies for new methods of latent heat storage. One of the significant outcomes is the PCMs, namely phase change materials. After a decade of development, PCMs have found applications in latent heat storage, solar heating systems, building energy management and HVAC systems. The solar energy is the richest renewable energy available to us almost everywhere. The development of solar energy use has been decades. Solar energy can be used to serve our needs in two forms. The first one is to directly convert the solar energy to electricity by solar panels. The second way is to convert the solar radiation to thermal energy for heating needs. While solar farms for power generation are prosperous everywhere, solar thermal conversion has seen much less breakthroughs due to limitation in technology and materials. No matter which form of energy output of the solar energy source, energy storage is necessary because of the intermittent nature and temporal variation of solar energy source.
Thermal-Energy-Storage – Berkeley Lab researchers by Jenny NussIn SHS (Sensible Heat Storage), the thermal energy is stored by transferring the energy to the medium resulting in a much-elevated temperature. An example is to use molten salt contained in an insulated tank that is considered as a thermal battery. This type of thermal storage shows big drawbacks, such as limited volume due to cost and large temperature variations.
Phase change materials have gain interest as it’s capable of absorbing large amount of energy without large temperature change, which is a huge advantage over SHS (Sensible Heat Storage) technology. Therefore, PCMs (phase change materials) used in latent heat storage (LHS) is much more advantageous because PCMs adsorb thermal energy by the phase change of the medium, for example, from solid to liquid or liquid to gas, with very small change of temperature. PCMs absorb thermal energy when they melt and release the energy when they turn solid again. PCMs bring us many benefits including greater energy density, which enable us to easily scale up the energy storage system to suit applications of various scales.
Mature applications of PCMs in building thermal management and HVAC have shown the potential of reducing the demand of heaters and coolers thus significantly reducing greenhouse gas emissions in long term. In such applications, the PCMs are used because of low temperature variations thus much more effective insulation resulting less compressor load for heating and cooling requirement for maintain the target temperature settings. The ultimate goal of decreasing the carbon emission is one of the most important driving factors for PCMs demand.
A recent report by Research and Markets shows a big increase in worldwide sale of PCMs from about $477 million in 2021 to $1004 million by 2026. Because of emerging of advanced PCMs (phase change materials), thermal energy is gaining more importance in the process of conversion of renewable energy to end-use sources, such as heating and electricity. With efficient PCMs, thermal energy can be more efficiently stored and reused in a variety of domestic and industrial applications to yield more system reliability, higher efficiency of conversion and greater cost saving. As the cost and technology for manufacturing PCMs are improved further, new applications will continue to emerge.
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