As a result, the material is really bad at absorbing sunlight, and thus it doesn't capture the heat in the same way regular wood does.
But it gets better. The sugars in cellulose are effective emitters of infrared radiation, and they do so in two areas of the spectrum where none of our atmospheric gasses is able to reabsorb it. The end result is that, if the treated wood absorbs some of the heat of a structure, wood can radiate it away so that it leaves the planet entirely. And the wood is able to do so even while it's being blasted by direct sunlight; the researchers confirmed this by putting a small heater inside a box made of the treated wood and then sticking it in the sunlight in Arizona.
In the heat of the day, a square meter of the wood could radiate away about 16W of power. At night, that figure shot up to 63W, for a 24-hour average of 53 Watts per square meter. At mid-day, if there was no source of heat in the box, its ambient temperature was over 4°C lower than the surrounding air. This is all the result of the fact that the treated wood emits energy in the infrared more efficiently than it absorbs energy in thee visible wavelengths.
https://arstechnica.com/science/2019/05/chemically-treated-wood-could-send-excess-heat-to-space/
But it gets better. The sugars in cellulose are effective emitters of infrared radiation, and they do so in two areas of the spectrum where none of our atmospheric gasses is able to reabsorb it. The end result is that, if the treated wood absorbs some of the heat of a structure, wood can radiate it away so that it leaves the planet entirely. And the wood is able to do so even while it's being blasted by direct sunlight; the researchers confirmed this by putting a small heater inside a box made of the treated wood and then sticking it in the sunlight in Arizona.
In the heat of the day, a square meter of the wood could radiate away about 16W of power. At night, that figure shot up to 63W, for a 24-hour average of 53 Watts per square meter. At mid-day, if there was no source of heat in the box, its ambient temperature was over 4°C lower than the surrounding air. This is all the result of the fact that the treated wood emits energy in the infrared more efficiently than it absorbs energy in thee visible wavelengths.
https://arstechnica.com/science/2019/05/chemically-treated-wood-could-send-excess-heat-to-space/