Shashwat phase change
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Presentation onPhase Change Materials
(PCM)
By :-Shashwat MishraR.No - 201410102110068B.Tech – ME
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What is a PCM ?
• A phase-change material (PCM) is a substance presenting a high heat of fusion, and capable of storing and releasing large amounts of energy.
• Heat energy is absorbed or released when the material changes from solid to liquid phase and vice versa, thus, being classified as latent heat storage (LHS) units.
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PCM physical principle and behaviour
• Latent heat
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Classification of PCM
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Example :Water as a PCM
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Heat (energy)
is transferred into the ice.
The heat is used to
break the bonds
between molecules,
not to increase the
average kinetic
energy of the
molecules.
Since the bonds among the ice molecules have been broken,
water is formed. The water
molecules, at this moment, have the
same average kinetic energy as
they did when they were ice.
Since the ice and water
molecules both have the same average kinetic
energy, they are at the
same Kelvin temperature
.
• Changing levels
Water as a PCM
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PCM general applications
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Application : Heating in building
Heating:• PCM mats are used on the roof and walls of the building.• It absorbs the heat during sunshine hours and melts.• The liquid PCM freezes during night and releases the heat
in the building.
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• Costly• Coating reduces the air
permeability and moisture transmission etc.
• Only perform for short intervals • Does not absorb all the heat • Reduces the dimensional
stability
Limitations
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Conclusions
• PCM provide solutions requiring much less volume than existing classic systems
• PCM materials present great advantages in buildings.
• It suitable for use in any region with climates with high demands in cooling and heating
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