New Drywall Helps Save Energy, Therefore Isn't Boring

Wouldn't you think drywall loaded with paraffin would be highly combustible? Seems like a bad idea to me.

Good point. On the other hand, they did not say how the paraffin was encapsulated. If the capsules can withstand the temperatures in a fire, then no paraffin would be exposed to oxygen, so no combustion.

Speaking of boring, when you drill or otherwise cut this material, I presume it would expose some paraffin to the atmosphere. Also lubricate your cutting tools!?

I suspect (and hope) that different formulations of paraffin or similar substances could provide somewhat different temperature ranges. Personally, I consider only the lower third of that temperature range (68-86°F) as comfortable for working, and only the lower quarter as marginally comfortable for sleeping. I prefer to sleep with an ambient well down into the 60's.

Oh, by the way, the drywall they tested was only 1.5 inches (3.81 cm) thick.

I suppose if you didn't want a brick wall as a heat sink, selected use of this material might make some sense. I noticed that they were very selective in not providing any real data with this article. There was a comparison to a brick wall in terms of heat storage and vague claims of not needing air conditioning for some unspecified building in Spain. Typical fluff journalism with nothing to say.

Only 1.5" thick? Here in California, the last time I looked, standard drywall is only 0.5 (0ne half) inch thick. The interior walls in my house (1962 vintage) are made with one "two by four" stud, which is actually 3.5-3.75" wide, and two layers of 0.5" drywall, so the entire wall is 4.5-4.75" thick. I believe that is still standard, although I think I have seen 0.625" drywall somewhere. I have never seen anything thicker than 0.625", but then I have not observed construction in the northern states or elsewhere.

And in reality, a brick wall is not all that impressive in terms of R factor.

The R factor that I'm familiar with is a measure of the ability of a layer of material to reduce heat flow into or out of a specific volume. That is quite different from the ability of a material to absorb heat energy when the temperature is high and store that energy for return when the temperature is low, as this material does. A phase change is clearly desirable for the energy storage. I know practically nothing about the heats of fusion for materials that melt around room temperature, like coconut oil and apparently some paraffins.

What would be really neat would be if someone could develop a material that acted as a thermal diode, allowing heat to pass through in one direction, but not the other.

Now if they could make that a switchable thermal triac, so it would be possible to control the direction of heat flow, that would be really really neat (and valuable).

I actually have a concept for a thermal diode of sort. Sadly, entropy dictates it only works for one season (no violation of the second law of thermodynamics!) and realistically it would be prohibitively expensive to integrate into a building structure. I may make a small prototype just for kicks to test the idea this winter but mostly out of curiosity. Who knows, maybe I can convince a bunch of people with too much money to give me money, err, uh, I mean invest in this radical new technology, but I have given up on my dreams of saving the world:)