Saudi Research Tests New Energy-Efficient Cooling System

KAUST's new cooling system
KAUST's new cooling system
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Saudi Research Tests New Energy-Efficient Cooling System

KAUST's new cooling system
KAUST's new cooling system

The King Abdullah University of Science and Technology (KAUST) has conducted observational experiments in the houses located inside the campus to create a new cooling system that consumes energy less than the currently used systems.

These experiments aim at testing the efficiency of the new system under different weather conditions in Saudi Arabia.

Air conditioning systems in use today typically achieve only 35–40 percent of the cooling possible for the amount of electricity they consume. As well as their principal task of cooling air, they remove moisture from the air by lowering its temperature to the level at which the water in it condenses. But this double step wastes a lot of energy.

A team led by Kim Choon Ng, professor of Environmental Science and Engineering at KAUST, has now devised a way to reduce the amount of energy consumed by decoupling the two processes.

Instead of dehumidifying air by cooling it, the system uses a more efficient process called adsorption. This binds the water in the air to the surface of a specially developed nanomaterial. Made of calcium chloride salt embedded in a silica gel lattice, this material can adsorb up to 20 times as much water as conventional silica gel in proportion to its weight.

Ng is now testing prototypes, and findings to date show an improvement in efficiency of 30–60 percent over conventional air conditioners. “This new type of air conditioner could offer a much-needed mean to slow down the increasing contribution of cooling systems to climate change,” says Kim Choon Ng.

In this new system, the proprietary adsorbent coats the coils of a mechanical vapor compressor, which cools the air the adsorbent has dehumidified in the manner of a conventional AC system. Air flow through the system is reversed and then reversed again in a period cycle to regenerate the saturated adsorbent.

Global consumption of air conditioning electricity, mainly generated from burning fossil fuels, has risen from 600 TWh in 1990 to 2,200 TWh in 2020, and based on current trends, could reach 6,300 TWh in 2050. By then, half of all electricity used by the world’s hottest countries, including Saudi Arabia, would be used just for keeping people cool.



Climate Change Causing More Change in Rainfall, Fiercer Typhoons, Scientists Say 

People and vehicles wade through the water along a street that was flooded by Typhoon Gaemi in Kaohsiung on July 25, 2024. (AFP)
People and vehicles wade through the water along a street that was flooded by Typhoon Gaemi in Kaohsiung on July 25, 2024. (AFP)
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Climate Change Causing More Change in Rainfall, Fiercer Typhoons, Scientists Say 

People and vehicles wade through the water along a street that was flooded by Typhoon Gaemi in Kaohsiung on July 25, 2024. (AFP)
People and vehicles wade through the water along a street that was flooded by Typhoon Gaemi in Kaohsiung on July 25, 2024. (AFP)

Climate change is driving changes in rainfall patterns across the world, scientists said in a paper published on Friday, which could also be intensifying typhoons and other tropical storms.

Taiwan, the Philippines and then China were lashed by the year's most powerful typhoon this week, with schools, businesses and financial markets shut as wind speeds surged up to 227 kph (141 mph). On China's eastern coast, hundreds of thousands of people were evacuated ahead of landfall on Thursday.

Stronger tropical storms are part of a wider phenomenon of weather extremes driven by higher temperatures, scientists say.

Researchers led by Zhang Wenxia at the China Academy of Sciences studied historical meteorological data and found about 75% of the world's land area had seen a rise in "precipitation variability" or wider swings between wet and dry weather.

Warming temperatures have enhanced the ability of the atmosphere to hold moisture, which is causing wider fluctuations in rainfall, the researchers said in a paper published by the Science journal.

"(Variability) has increased in most places, including Australia, which means rainier rain periods and drier dry periods," said Steven Sherwood, a scientist at the Climate Change Research Center at the University of New South Wales, who was not involved in the study.

"This is going to increase as global warming continues, enhancing the chances of droughts and/or floods."

FEWER, BUT MORE INTENSE, STORMS

Scientists believe that climate change is also reshaping the behavior of tropical storms, including typhoons, making them less frequent but more powerful.

"I believe higher water vapor in the atmosphere is the ultimate cause of all of these tendencies toward more extreme hydrologic phenomena," Sherwood told Reuters.

Typhoon Gaemi, which first made landfall in Taiwan on Wednesday, was the strongest to hit the island in eight years.

While it is difficult to attribute individual weather events to climate change, models predict that global warming makes typhoons stronger, said Sachie Kanada, a researcher at Japan's Nagoya University.

"In general, warmer sea surface temperature is a favorable condition for tropical cyclone development," she said.

In its "blue paper" on climate change published this month, China said the number of typhoons in the Northwest Pacific and South China Sea had declined significantly since the 1990s, but they were getting stronger.

Taiwan also said in its climate change report published in May that climate change was likely to reduce the overall number of typhoons in the region while making each one more intense.

The decrease in the number of typhoons is due to the uneven pattern of ocean warming, with temperatures rising faster in the western Pacific than the east, said Feng Xiangbo, a tropical cyclone research scientist at the University of Reading.

Water vapor capacity in the lower atmosphere is expected to rise by 7% for each 1 degree Celsius increase in temperatures, with tropical cyclone rainfall in the United States surging by as much as 40% for each single degree rise, he said.