Material scientists from Lawrence Berkeley National Laboratory have developed a new kind of roof coating material that can keep your house cool or hot depending on the outdoor air temperature.
We all are familiar with commercial roof coatings or “cool roof” systems. So, how is it different from these commercial ones?
The cool roof systems that we currently have a reflective color coating to reflect the sunlight and keep the house cool during hot summer. The issue is that the coating also reflects sunlight in winter, making you spend more on better heating solutions in winter.
This is where the smart-roof coating comes in. The developers of the tech are calling it temperature-adaptive radiative coating or TARC.
According to ScienceDaily, TARC uses an interesting property of vanadium dioxide. This compound has a phase-changing property. Vanadium dioxide changes state once it reaches 67°C (153°F) and stops absorbing thermal infrared light. This wasn’t feasible so they implemented the “doping” technique and replace 1.5% of the vanadium dioxide with tungsten. Now, the compound changes state at 25°C (77°F) and becomes suitable for maintaining room temperature.
TARC reflects around 75% of sunlight year-round, but its thermal emittance is high (about 90%) when the ambient temperature is warm (above 25 degrees Celsius 77 degrees Fahrenheit), promoting heat loss to the sky. In cooler weather, TARC’s thermal emittance automatically switches to low (about 20%), helping to retain heat from solar absorption and indoor heating, Levinson said.
The scientist team is very excited as “With TARC installed, the average household in the U.S. could save up to 10% electricity.”
Certainly, this piece of technology is a boon to us all humanity as we can dramatically reduce our energy consumption and start green living.
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