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Coconut oil melts at 24 deg C (76 deg F). This makes it the perfect material for
filling cavity walls, to provide a brief respite from the heat during the peak of a
heatwave.
[link]
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So most of the time, the coconut oil will be a near-solid, with a fairly high U value - thus reducing the tendency of heat to enter or leave the building. |
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Presuming the inside temperature never exceeds 23 C and it's hotter inside than outside, all well and good - apart from the fact that your walls are filled with a flammable wax-like solid with a low melting point. |
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But when the outside temperature rises above 24 C, the solid starts to soften, and eventually liquifies, allowing convection to transfer heat from the hotter outside to the cooler inside. |
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So unless your system has some subtle way of reversing the Second Law of Thermodynamics, it doesn't seem a very good way of keeping a building cool ... |
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I think the theory was that the wall filling would absorb latent heat at 24°C. |
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That is correct. However, since coconut oil seems to be a eutectic mixture of short-chain lipids with a poorly-defined melting point, and a specific heat capacity a lot less than water, the benefits are not obvious - unless you have an overwhelming compulsion to have your home smell like the inside of a coconut. |
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Perhaps [Wrongfellow] has made a heavy but ill-judged investment in the Asian Coconut Oil Lake, and is seeking ways to recoup his losses. |
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The obvious answer would be to fill the wall cavities with a non-flammable insulation such as rockwool or fibreglass, and use the coconut oil as the fuel in a small diesel engine directly coupled to an air conditioning compressor. |
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If it's warm enough to require the arcon, then some of the oil will be fluid, and waste heat from the engine can be used to melt the rest in the feed tank. |
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Latent heat of fusion for coconut oil is 249 J/g.
Specific heat for water is 4.2 J/g/deg C. So the heat
storage over the small melting range of coconut oil could
only be provided by the same mass of water if the water
temperature changed by 59 deg C. The melting point of
coconut oil may be poorly defined, but it's a good bet
you'll store a heck of a lot more heat in coconut oil
between 20 and 28 deg C than you would with water. |
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That being said, you don't want to fill the walls. You
want to thermally couple the coconut oil to the interior
of a well insulated house |
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Of course when I googled "latent heat of fusion of
coconut oil" the first link was to research on using
coconut oil for this very purpose. |
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Great to see that it's in the oven! |
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Why are people comparing coconut oil to water? I don't see how water is relevant. Filling your cavity walls with water sounds like a recipe for disaster. |
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//Filling your cavity walls with water sounds like a recipe
for disaster// |
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Yes, but that's not much of a choice - being grilled, deep fried, or poached ... |
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