Page 61 - IJAMD-1-3

International Journal of AI for
Materials and Design
Phase change materials and digital twin technology in thermal energy

Figure 4. Different categories of phase change materials

– approximately twice that of organic compounds with the PCM must have a high latent heat of fusion relative
64
a high fusion temperature. Salt hydrates also have a to its volume to achieve adequate energy storage density.
59
thermal conductivity of about 0.5 W/m-K, are non- Finally, the phase transition must occur uniformly to
combustible, readily available, inexpensive, and have ensure that the process is repeatable, stable, and durable
15
minimal environmental impact. Most importantly, they over time. The selection criteria and key properties of
60
can be recycled. PCM materials are illustrated in Figure 5.
A newer type of PCM, called eutectic, consists of a In terms of physical properties, the vapor pressure
combination of elements that form crystals as they melt and at operating temperatures must be limited, and the
freeze. Eutectic alloys contain both organic and inorganic material should undergo minimal volume change during
elements, with the most common being inorganic salt the phase transition. The material’s density is also an
hydrates. These materials exhibit homogeneous melting important factor to consider. Given that different
64
and freezing properties, avoiding phase segregation. The temperatures are required for melting and solidifying,
61
advantages and disadvantages of organic and inorganic an insufficient nucleation rate can lead to super-cooling
PCMs are summarized in Table 1. in the liquid state, which significantly alters the kinetics
of the charging and discharging cycles. Therefore, both
3.2. Selection criteria of PCM high nucleation rates and enhanced crystal formation
Materials can only be used as PCMs if they meet specific are necessary for optimal performance. In addition,
65
requirements related to thermal, physical, chemical, the material must be able to withstand repeated freezing
and mechanical properties. Ecological and economic and melting cycles without deterioration. It must also
66
considerations also play a crucial role in the selection be environmentally safe when used. From a financial
process for thermal storage applications. From a thermal perspective, PCMs should be inexpensive, abundant, and
perspective, the phase transition temperature of a PCM readily available.
must fall within the target operating temperature range
to ensure efficient heat absorption and release during 3.3. Practical applications of PCMs in TES for
operation. Another essential property for effective TES buildings
63
is high thermal conductivity, which facilitates the efficient PCMs have a wide range of potential applications, including
absorption and release of thermal energy. In addition, heating, cooling, and hybrid systems. The principle behind

Volume 1 Issue 3 (2024) 55 doi: 10.36922/ijamd.4696