Development of Heat Insulating Paint Using Rice Husks and Kaolin
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
The global warming scenario increased demands for the heat insulator material,
especially in the construction sector. The present day popular roofing materials are
asbestos and metal sheets. These have poor shield to outside temperature, thus have
relatively high indoor temperatures compared to clay tile roofs. This study focuses
on development of a roofing paint with heat insulating properties to reduce indoor
temperature. Here primers paint was modified adding different percentage of kaolin
and rice husks. Percentage of kaolin and rice husks added in to primers paint was
5% (w/w) for each. In both cases, particle size of kaolin and rice husk was 150 Rm.
A small metal piece coated by the paint that has additives were tested for heat
insulating properties with the consistence of silica according to the Fourier law. The
loading paint content on a piece of metal square was varied according to the number
of coatings applied. The thickness of the paint coat and weight of the paint per
square centimeter were recorded for each sample. Each sample was prepared in
triplicate for analysis. The temperature difference between top and bottom of the
metal sheet was evaluated using a custom made apparatus using thermocouples
under insulating conditions from the surroundings. The heat transfer rate was
calculated using the Fourier law assuming the thermal conductivity of the metal
sheet has the value of steel due to the fact that very thin coating was applied. The
results reveal that the average heat transfer rate decreased with the increasing
number of coatings applied and relatively faster decay of heat transfer rate was
observed for kaolin and rice husk containing paints than primers paint only.
However, the greater temperature difference between top and bottom of the metal
piece was observed for primer paint with 5% kaolin loading. The average
temperature difference of paint with kaolin is 9.67 with 12 number of coatings. This
results conclude that addition of rice husk or kaolin to a primer paint can enhance
the heat insulating properties.
Keywords: Insulating paint, Fourier law, Heat transfer rate, Kaolin, Rice husk
Description
Keywords
Materials Sciences, Mineral Sciences