New technology! Solve the big base pain point problem in the Shaggy Wilderness!

Desert photovoltaic is beneficial to the country and the people, but has a fatal flaw
China's desertification area has reached 2.62 million square kilometers, accounting for 27% of the country's land area, and it is expanding. Take China's largest desert - Taklamakan Desert for example, its area is about 330,000 square kilometers, where the bare desert seems worthless, but if the entire desert is covered with solar modules, the total installed capacity can reach 9,900 GW, and the annual power generation is astonishingly 13.86 trillion degrees! It is understood that the total electricity consumption of the whole Chinese society in 2020 is only about 7.5 trillion kilowatts, and the power generation of the above-mentioned desert photovoltaic power plant is equivalent to 1.8 of the electricity consumption of the whole Chinese society.

It is understood that to establish a photovoltaic power plant in the desert, a series of inherent bottlenecks must be overcome. In addition to the well-known sandstorm, high temperature is also a major bottleneck to build a desert photovoltaic power plant!

According to meteorological data, desert climate extremes exist, the night temperature can be as low as 0 ℃, while the daytime temperature can be as high as 50 ℃ or more. And photovoltaic modules in the work because the energy can not be fully converted into electricity, so there will inevitably be part of the energy into heat. Therefore, during daytime operation, the surface temperature of PV modules can be even higher!

Actual research cases show that the output power of crystalline silicon solar cells is about 20% higher at a temperature of about 20 degrees than at about 70 degrees. This means that even with average light conditions, areas with lower average annual temperatures are more favorable for PV solar power plants, with much higher power production than areas with too much light and too high temperatures. In addition to affecting power generation efficiency, high temperatures may also induce hot spot effects and affect module life!

Therefore, to build PV plants in desert areas, you need to overcome a huge problem - how to cool down the PV modules!

New technology! Let the PV panel "sweat to cool down"

The current mainstream cooling methods for PV modules are air-cooling (blowing wind to keep it cool) and water-cooling (pouring water over it to cool it down). Unfortunately, using traditional techniques to cool PV modules in desert areas often consumes valuable water resources.

Inspired by a research team from King Abdullah University of Science and Technology and Hong Kong Polytechnic University, a research team from Nanjing University recently wanted to achieve efficient cooling of PV modules through a hydrogel.

This gel contains a common water-absorbing material, calcium chloride salt, which can absorb water vapor from the air, while the gel-like structure condenses the water into liquid water and wraps it, and when it is heated, the water inside will be released again.

Based on this, this gel can be adhered to the back of the PV module. At night when the temperature is low and the humidity is relatively high, the gel can adsorb water vapor from the air, and when the temperature rises during the day, this gel will absorb heat from the solar panel to release water vapor, and the evaporated water will cool the PV module, just like the sweat evaporating from the skin will cool the human body.

If a device is set up to collect and recondense the water, the released vapor will be trapped and condensed into liquid water that flows into a storage container, the researchers said: This water can be used to clean the dust that accumulates on the photovoltaic modules, or can be stored for drinking, addressing the urgent needs of drought-stricken areas.

But the technology currently exists only in the laboratory stage, there are many details have not been perfected. For example, rainwater can dissolve the calcium chloride salts in the gel, weakening its water-absorbing properties; in addition, the preparation of hydrogels requires expensive materials such as carbon nanotubes, which is costly.

Nanjing University researchers said: Our goal is to reduce the production cost of hydrogel, improve the stability of its work, and strive for early industrial production, to help the desert more emergence of photovoltaic "blue ocean".