The summer nights of 2022 were not calm in the People’s Republic of China after the country was exposed to the worst heat wave it had witnessed since 1961, which led to a significant increase in electricity consumption rates for air conditioning buildings, as temperatures reached about 40 degrees Celsius.
The hot nights and long hours of power outages may have been due to the doubling of consumption to cope with the sudden rise in temperatures. This is a reason for researchers at the City University of Hong Kong to be busy developing the “white ceramic” compound, which the study conducted by researchers has proven to be able to break records in cooling buildings without the need for huge amounts of energy.
and delivery the study Recently published in the “Science” magazine, the development of cellular ceramics can achieve highly efficient light scattering. It is composed of a material known as passive radiative cooling (PRC), and can reach a near-perfect solar reflectivity rate of up to 99.6%, which is a record. for this type of material. In addition, it is easy to make, relatively cheap, durable, and can be placed on the roof and walls of the building to keep it cool on its own.
Energy saving
The high temperature during the peak of the summer of 2022 in China caused electricity consumption to increase by 6.3% on an annual basis, as residential consumption jumped by 26.8%, according to the Chinese National Energy Administration.
According to the study, white color, weather resistance and mechanical durability are the main features that ensure the durable and versatile nature of cooling ceramics, thus facilitating its marketing in various applications, especially building construction.
The team behind the development of the cooling ceramic says in a press release that the material is capable of removing more than 130 watts of thermal energy per square meter when the sun is at its highest, amounting to a significant cooling effect.
According to the study, white ceramic material can overcome some of the problems with current options in the People’s Republic of China, such as poor weather resistance, and “it can withstand temperatures higher than 1,000 degrees Celsius (1,832 degrees Fahrenheit), and according to the researchers, it “has the ability to work in buildings.” In all weather conditions and in all climates.
It also reduces the need to run air conditioners all day long. Simply by choosing the right materials for building surfaces, we can significantly reduce energy use and indoor heat.
“The white ceramic material has a high ability to return sunlight and allow heat to escape, both of which contribute to passive cooling,” says mechanical engineer Tsu Shi Yan, leader of the research team from the City University of Hong Kong.
Ceramic uses a nanostructure that contains pores similar in size to different wavelengths of sunlight, which means that almost all of it is reflected back rather than absorbed. Ceramic achieves a high mid-infrared thermal emissivity of 96.5%, which means that all the heat emitted from The building can almost leak into the atmosphere.
In his interview with Al Jazeera Net via email, Johnny Lin, researcher in the study and professor of energy and environment at City University of Hong Kong, said: “The manufacturing of cooling ceramics includes two main steps, the phase separation process and the sintering process.”
Phase separation is a chemical process used in the manufacture of synthetic membranes by removing the solvent from a liquid polymer solution, leaving a solid, porous membrane.
As for the sintering process, it is the process of forming a solid mass of material through pressure or heat, and it is the method used in the manufacture of ceramics, metals, and plastics.
Easy to manufacture
Lin added, “The cooling ceramic manufacturing process presented in this work is straightforward, as both the phase reversal process and the sintering process can be performed using industry-standard equipment without the need for special processing.” In addition, the manufacturing process does not require precise equipment or materials. They are expensive, which makes scalable manufacturing of cooling ceramics very possible.
Lin explained that cooling ceramics can serve as “energy-saving alternatives to commercial tiles, as cooling ceramics can be pre-manufactured in the factory and then transported to the construction site.”
Regarding the difficulties that may be encountered in fully implementing the use of white ceramic practically, Lin said, “The optical properties of cooling ceramics are improved for effective cooling, and this makes them very effective in reducing the demand for space cooling, especially in hot climates. However, the demand for cooling varies due to… Geographic and seasonal climatic differences.
He explained that cooling ceramics may face challenges in providing benefits in cold regions, however, “Our research team is also developing passive radiative cooling materials capable of adapting their cooling power based on local temperatures, as this innovative approach holds great promise to be A solution for areas with dynamic cooling and heating requirements.
