Study on a kind of high heat radiation cooling bamboo

"I would rather eat without meat than live without bamboo" is a widely circulated saying by the great poet Su Dongpo
.

Bamboo is one of the favorite plants of the Chinese

In developed countries, more than 40% of energy is consumed by building systems, and about half of that energy is consumed by heating, ventilation and air conditioning systems
.

Therefore, reducing building energy consumption has become one of the most effective and practical solutions for energy conservation

Figure 1 shows the production process and working principle of this radiant cooling energy-saving bamboo
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After removing the lignin from the bamboo and filling it with epoxy resin, the silver nanowires evenly dispersed in ethanol were covered on one side of the sample by spin coating, and a low-emissivity coating was provided (Figure 1a)

Figure 1.
High-radiation cooling bamboo manufacturing process, schematic diagram of working principle, and XRD, FTIR, and composition analysis of delignified bamboo

At the same time, through scanning electron microscope (SEM), the author analyzed the microstructure of the bamboo before and after the delignification and epoxy filling (Figure 2)
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Since the epoxy resin fills the porous structure of the bamboo, the light scattering caused by this is minimized, making the bamboo transparent

Figure 2.
The structure of bamboo before and after delignification and epoxy filling and electron micrograph of silver nanowire coating

In order to find out the relationship between the thickness of the silver nanowire coating, optical properties and emissivity, 0 to 18 layers of silver nanowires were respectively covered on the surface of the high-radiation cooling bamboo
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As shown in Figure 3, when more silver nanowire coatings are covered, the transmittance decreases accordingly

　　Then the author analyzed the relationship between the thickness of the silver nanowire coating and the emissivity
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At first, only slight differences were observed between the silver nanowire coated surface and the epoxy surface (Figure 3)

　　In addition, in order to understand the potential of high-heat radiation cooling bamboo in window applications, its annual energy-saving performance has been simulated in Singapore and compared with commercial low-e glass with similar solar transmittance and traditional 3 mm silicon-based glass (Picture 3)
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In Singapore, the annual energy-saving performance of high-heat radiation cooling bamboo surpasses that of commercial low-e glass

　　

　　Figure 3.