World’s 1st artificially-made pigment Egyptian blue, can help produce solar energy
Egyptian blue has also been found to have a cooling potential for buildings.
The colour developed by Egyptians thousands of years ago, Egyptian blue, has a modern-day application as well — as reported by Berkeley Lab.
The pigment can boost energy efficiency by cooling rooftops and walls, and could also enable solar generation of electricity via windows.
- Egyptian blue, derived from calcium copper silicate, was routinely used on ancient depictions of gods and royalty
- The colour held utmost importance for them; they associated it with the sky and the river Nile
- Previous studies have shown that when Egyptian blue absorbs visible light, it then emits light in the near-infrared range
Now, the study, conducted by Berkeley Lab researchers and published in the Journal of Applied Physics, confirms that the pigment’s fluorescence can be 10 times stronger than previously thought.
How this potential of the pigment was found
Measuring the temperature of surfaces coated in Egyptian blue and related compounds while they are exposed to sunlight, Berkeley Lab researchers found the fluorescent blues can emit nearly 100 percent as many photons as they absorb.
The energy efficiency of the emission process of Egyptian blue is up to 70 per cent (the infrared photons carry less energy than visible photons).
Is Egyptian blue most effective for cooling rooftops?
- The finding adds to insights about which colours are most effective for cooling rooftops and facades in sunny climates
Though white is the most conventional and effective choice for keeping a building cool by reflecting sunlight and reducing energy use for air conditioning, building owners often require non-white colours for aesthetic reasons.
- For example, bright-white asphalt shingles are almost never used on sloping residential roofs
Researchers have already shown that fluorescent ruby red pigments can be an effective alternative to white; this insight on Egyptian blue adds to the menu of cooling colour choices.
- Further, they found that fluorescent green and black colours can be produced with yellow and orange co-pigments
How Egyptian blue can help produce solar energy
- In addition to its cooling potential for buildings, Egyptian blue’s fluorescence could also be useful in producing solar energy
Used on windows tinted with the Egyptian blue, photovoltaic cells on the edges can convert the fluoresced near-infrared energy to electricity.
Why reflecting sunlight is essential
- Reflective roofs and walls can cool buildings and cars
- This reduces the need for air conditioning and mitigates the urban heat island effect
By reflecting the sun’s rays back to space, these cool materials also release less heat into the atmosphere, thus cooling the planet and offsetting the warming effects of substantial amounts of greenhouse gas emissions.