Transcript PCM Incorporation - CivilDigital.com

Guide
Asst. Prof Ashraf
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1.Introduction
2.Principle
3.Working
4.PCM incorporation
5.Building application
6.Bio PCM
7.GlassX
8.Thermal core
9.Selection criteria
10.Case study
11.conclusion
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• Modern architecture is Attractive, flexible and light weight
• Leads to less thermal storage capacity and more solar
heat gains
• PCM - Interior finishing alternatives
• Stores much larger amount of thermal energy per unit
mass than conventional building materials
• Requires less amount of energy for production
• This presentation involves microencapsulated PCM use,
its applications, etc.
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• When heat is applied to any substance, heat transfers in
two ways
Sensible heat
Latent heat
• PCMs works on the principle of latent heat
• Latent heat enables PCMs to control room temperature
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• PCMs used in construction change from solid to liquid at
23ºC - 26ºC
• They melt, absorb heat from room and room temperature is
kept constant until the change of state is complete
• PCM then returned to solid state by night time ventilation /
mechanical means
• The phase change cycle repeats
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• There are many types of PCM but not all are suitable for
use in buildings
• The two main types of PCM used in construction are
inorganic salt hydrates and organic paraffin or fatty acids
• both materials have a set of advantages and disadvantages
that must be taken into consideration.
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Inorganic salt hydrates
• Salt hydrates are a low-cost, readily available PCM.
• They have a high latent heat storage capacity and high
thermal conductivity
• They are also non-flammable.
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• Paraffin’s and fatty acids do not expand as they melt, and
freeze without much super cooling,
• They are chemically stable, compatible with conventional
construction materials and recyclable.
• Paraffin’s are hydrophobic, which means they are waterrepellant.
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• Paraffin’s are hydrophobic, which means they are waterrepellant.
• As a result, their phase-change points are reliable.
• Pure paraffin’s are also highly durable, and do not degrade
in contact with oxygen.
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• Impregnated into building materials by 2 ways :
Either directly or as pellets
(Paraffin wax – most promising material used)
Microencapsulation
• Microencapsulation most preferred always.
• Night cooling considered as the main difficulty
• Mechanical ventilation provided
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• A process by which individual particles of solid/ liquid
material are coated with a continuous film of polymeric
material to produce capsules called microcapsules.
• Microcapsules – small sphere with uniform wall round it
• Micrometer to millimeter range
• Appearance of beads, powder
• Polymer sphere shaped
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Structure of a microcapsule :
• Material inside is called core.
• Wall is called shell or coating.
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Morphology :
• Depends on core material and the deposition process of
the shell
• Basically 3 types :
 Mononuclear
Poly nuclear
Matrix encapsulation
• Also mononuclear with multiple shells, or clusters of
microcapsules.
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Building Applications:
• Used as ceiling material
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• BioPCM:
A rolled mat that contains PCM
Integrated into new construction or retrofitted into existing
Mat is installed between insulation and drywall layers and
located in walls and ceiling.
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GlassX
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An insulated glazing unit that can be used as full glass walls
and windows.
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It has an outer pane of glass that reflects high-angle sun
and allows low-angle sunlight to pass.
•
Sunlight transmitted through this outer pane of glass passes
through inner polycarbonate channels that are embedded
with salt-hydrate PCMs.
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•
These PCMs store the heat from the sunlight, release the
heat to the interior of the building as the temperature cools.
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ThermalCORE
• Made by National Gypsum/BASF Corporation.
• A drywall panel embedded with paraffin PCM.
• The microscopic paraffin capsules absorb and distribute heat
as the wax melts and solidifies with temperature fluctuations.
•
ThermalCORE is not currently commercially available for
purchase and is still undergoing testing.
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• A melting temperature range
in construction is 23°C or
26°C.
• A high latent heat of fusion per unit volume minimizes the
area of PCM tiles that are needed.
• High thermal conductivity.
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Minimal changes in volume
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Congruent melting
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• A completely reversible freezing/melting cycle.
• Durability over a large number of cycles.
• Non-corrosiveness to construction materials.
• Non-flammability.
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• Three
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semi transparent domes of 18.5,20,24m
diameter
Building has been built in one of the city harbor of
Rotterdam
Climate is managed in different way in different room
Exhibition hall temperature is kept about 15 ˚C
Conference hall temp is maintained about 21˚C
Temperature is varied with the help of PCM
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CONCLUSION
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Improves thermal comfort levels and obviate or reduce the
need for air-conditioning.
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Reduction in peak temperatures is possible.
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Used in Residential buildings too.
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Significant advantages for both commercial and residential
buildings.
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Night ventilation- an integral part.
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Likely to become a valuable tool for improving thermal
comfort in domestic buildings.
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REFFERENCES
• http://www.basf.com sighted on 10/2/2014
• http://www.apartmenttherapy.com sighted on 10/2/2014
• Zubillaga (2007), “Use of microencapsulated PCM inconcrete
walls for energy savings. Energy and Buildings “, Vol. 39 pp.113119.
•
I.O. Salyer, A.K. Sircar, R.P. Chartoff, D.E. Miller.
1995.Advanced phase-change materials for passive solar storage
applications. In: Proceedings of the 20th Intersociety Energy
Conversion Engineering Conference. Warrendale, Pennsylvania,
USA: 699-709.
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THANK YOU
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