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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.

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Varieties

Greece's 'Instagram Island' Santorini nears Saturation Point

Tourists queue as they wait to take a picture from one of the balconies. Aris Oikonomou / AFP
Tourists queue as they wait to take a picture from one of the balconies. Aris Oikonomou / AFP
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Greece's 'Instagram Island' Santorini nears Saturation Point

Tourists queue as they wait to take a picture from one of the balconies. Aris Oikonomou / AFP
Tourists queue as they wait to take a picture from one of the balconies. Aris Oikonomou / AFP

One of the most enduring images of Greece's summer travel brand is the world-famous sunset on Santorini Island, framed by sea-blue church domes on a jagged cliff high above a volcanic caldera.
This scene has inspired millions of fridge magnets, posters, and souvenirs -- and now the queue to reach the viewing spot in the clifftop village of Oia can take more than 20 minutes, said AFP.
Santorini is a key stopover of the Greek cruise experience. But with parts of the island nearing saturation, officials are considering restrictions.
Of the record 32.7 million people who visited Greece last year, around 3.4 million, or one in 10, went to the island of just 15,500 residents.
"We need to set limits if we don't want to sink under overtourism," Santorini mayor Nikos Zorzos told AFP.
"There must not be a single extra bed... whether in the large hotels or Airbnb rentals."
As the sun set behind the horizon in Oia, thousands raised their phones to the sky to capture the moment, followed by scattered applause.
For canny entrepreneurs, the Cycladic island's famous sunset can be a cash cow.
One company advertised more than 50 "flying dresses", which have long flowing trains, for up to 370 euros ($401), on posters around Oia for anyone who wishes to "feel like a Greek goddess" or spruce up selfies.
'Respect Oia'
But elsewhere in Oia's narrow streets, residents have put up signs urging visitors to respect their home.
"RESPECT... It's your holiday... but it's our home," read a purple sign from the Save Oia group.
Shaped by a volcanic eruption 3,600 years ago, Santorini's landscape is "unique", the mayor said, and "should not be harmed by new infrastructure".
Around a fifth of the island is currently occupied by buildings.
At the edge of the cliff, a myriad of swimming pools and jacuzzis highlight Santorini is also a pricey destination.
In 2023, 800 cruise ships brought some 1.3 million passengers, according to the Hellenic Ports Association.
Cruise ships "do a lot of harm to the island", said Chantal Metakides, a Belgian resident of Santorini for 26 years.
"When there are eight or nine ships pumping out smoke, you can see the layer of pollution in the caldera," she said.
Cruise ship limits
In June, Prime Minister Kyriakos Mitsotakis floated the possibility of capping cruise ship arrivals to Greece's most popular islands.
"I think we'll do it next year," he told Bloomberg, noting that Santorini and tourist magnet Mykonos "are clearly suffering".
"There are people spending a lot of money to be on Santorini and they don’t want the island to be swamped," said the pro-business conservative leader, who was re-elected to a second four-year term last year.
In an AFP interview, Tourism Minister Olga Kefalogianni echoed this sentiment and said: "We must set quotas because it's impossible for an island such as Santorini... to have five cruise ships arriving at the same time."
Local officials have set a limit of 8,000 cruise boat passengers per day from next year.
But not all local operators agree.
Antonis Pagonis, head of Santorini's hoteliers association, believes better visitor flow management is part of the solution.
"It is not possible to have (on) a Monday, for example, 20 to 25,000 guests from the cruise ships, and the next day zero," he said.
Pagonis also argued that most of the congestion only affects parts of the island like the capital, Fira.
In the south of the island, the volcanic sand beaches are less crowded, even though it is high season in July.
'I'm in Türkiye
The modern tourism industry has also changed visitor behavior.
"I listened (to) people making a FaceTime call with the family, saying 'I'm in Türkiye," smiled tourist guide Kostas Sakavaras.
"They think that the church over there is a mosque because yesterday they were in Türkiye."
The veteran guide said the average tourist coming to the island has changed.
"Instagram has defined the way people choose the places to visit," he said, explaining everybody wants the perfect Instagram photo to confirm their expectations.