The science behind an air-conditioned World Cup: Dr Cool, Ford Mondeos and airplane wings - The Athletic

Like many parts of Qatar’s World Cup bid, the concept of air conditioning an entire football stadium was met with, to say the least, plenty of scepticism when they were awarded the tournament in 2010.

It was added to the pile of objections, somewhere between the relatively minor (is it weird to have a World Cup in a country that has never qualified for one before?) to the not so minor (worker deaths and human rights abuses). The very idea of it seemed to serve as a reason not to host the tournament in Qatar: if you have to air condition the stadiums, should the World Cup even be there? PVC Flexible Duct

The science behind an air-conditioned World Cup: Dr Cool, Ford Mondeos and airplane wings - The Athletic

Most of all though, it just sounded weird and implausible. Air conditioning, as most of us know it, is an indoor thing. Trying to apply it to an outdoor stadium surely wouldn’t work. It definitely wouldn’t work. They couldn’t do it. Could they?

For better or worse, it seems they have.

Assuming everything goes to plan, the World Cup will be played in stadiums cooled just so — by a network of air conditioning systems that are simultaneously complex and remarkably simple.

But how does it work? How do you actually air condition an open-air football stadium?

In the most basic terms, this in-stadium air conditioning works via a series of nozzles around the edge of the pitch that shoot out cold air at different angles and at different speeds to cover as much of the playing area as possible. It’s a similar principle to how water sprinklers work on grass, ensuring maximum coverage from a central location. In the stands, more nozzles beneath the seats will cool the air for spectators.

That’s the simple bit. The tricky part is how to keep all that cooled air inside a stadium that has an open roof, to ensure it doesn’t escape through the hole and render the whole operation pointless. The answer is via carefully designed airflows, dictated by the shape and orientation of each stadium.

Chris Lee, from architects Populous who were involved in the design of the Lusail Stadium, the venue for the December 18 final, explains: “If you think of a stadium roof as a little bit like an airplane wing, you can direct the prevailing wind quite a lot by how you orientate the stadium and how you tip or dip the leading edge of the roof. So if you think of how an airplane wing tips up and the air rushes up and effectively jumps up on a different trajectory, that’s more or less how it’s done.

“The whole principle works in a very simple, thermodynamic way: cool air is heavier and sinks to the bottom, and hot air rises, as we all know. So you put the cool air in, it sits on a lower level, then you design the roof and the orientation so the hot air doesn’t ingress into the opening and down to the pitch.”

When you put it like that, it all seems pretty simple. But, of course, it isn’t quite as easy as all that. The complexities in making those theories a reality are extensive: controlling the in-stadium climate in every part of that stadium; ensuring it is all done in the most efficient way possible; tailoring each cooling system to each stadium and a host of other issues.

Solving those problems cannot just be the work of a single person, but talk to anyone about the air conditioning in these World Cup stadiums and they will point you to one man.

Allow us to introduce you to Dr Cool.

Sadly, this isn’t the world’s most greatest example of nominative determinism: his real name is Dr Saud Abdul-Aziz Abdul-Ghani, But he picked up that nickname because he is the brains behind this whole thing. He is Mister Air Conditioning, and has been working on delivering a cooling system to these Qatari stadiums for 13 years.

Dr Saud’s day job is as a professor at Qatar University, but his formative years were spent in England.

He did his PhD at Nottingham University, which involved working on the air conditioning system for Ford Mondeo cars in the early 1990s, then went on to do a post-doctoral fellowship in Manchester.

The Qatari bid promised this air conditioning system before they knew whether they could deliver it, so when the bid was won they went to their national university in search of expertise.

“People knew the heat would be an issue, so they came to the university because it’s the hub of knowledge,” says Dr Saud.

He put his hand up, and figuring it all out has essentially been his life since that day.

It all started with an extensive series of computer simulations: Dr Saud and his team simulated the weather in Doha, Qatar’s capital city, over the last 30 years (30 years!) to figure out the amount of cooling required, and which parts of a stadium would most need to be cooled. They then made 3D printed models of each stadium and put them in a wind tunnel, to simulate different directions and speeds of gusts.

“It’s the first time stadiums like this have been led by science,” says Dr Saud. “I had some influence in what colour the stadiums should be, what height the stadiums should be. The architect chose the shape, but I had to make that shape work in this environment, to do things like minimise wind infiltration and optimise the cooling package.”

That point is key, because the design of each stadium is the first line of defence against heat, cooling the interior before the actual air conditioning is even switched on. The stadiums have all been positioned with consideration to the path of the sun to ensure maximum natural shade is provided both for those on the pitch and in the stands.

Additionally, the exterior colours of the stadiums were chosen so they absorb as little heat as possible.

For example, the outside of the Al Bayt Stadium, which will host nine matches including yesterday’s opener between Qatar and Ecuador, England vs the United States on Friday and a semi-final, was initially going to be a sort of black/dark brown, but was changed to what Dr Saud describes as a ‘cafe au lait’ colour.

“I found in my experiments,” he says, “that if we changed the colour from a darker to a lighter brown, we can reduce the temperature by five degrees, just by the reflection of solar rays.”

But back to the air conditioning.

The basic system is not dissimilar to how air conditioning works in your average building: the air is cooled by chilled water in large machines called absorption chillers, which are located deep in the bowels of the stadium.

The cooled water is pumped through pipes, which cool the air. The cooled air is pumped out through the pitch-side nozzles using solar-powered fans and through grilles beneath the seats in the stands. The air is then sucked back in through vents, filtered, cleaned, re-cooled and pumped back out.

“You’re never really taking super-hot, 40C air in (from the outside) and cooling it,” says Chris Lee. “Once it’s pre-cooled, it’s filtered and re-used through the life of the game.”

The idea is to keep the temperature in all stadiums at around the 21C (69F) mark: not too cold, not too hot, just right. The baby bear’s porridge of atmospheric conditions.

When you put it like that, you wonder why it has taken so long to implement, but the clever bits lie in the detail.

Like, for example, how only parts of the stadium are cooled, as opposed to the system in your office or apartment building which just blasts out cool air indiscriminately.

“I don’t want to cool the whole volume (of the stadium),” says Dr Saud, “because nobody is going to be standing on a bridge in the middle of the oculus (the open section at the top of the roof) watching the game — although it would be a very nice view.”

A series of sensors (between 200 and 300, depending on the size of the venue) are placed around the stadium to measure the conditions in different zones. These allow the central control system to alter the temperature in different areas. So if, for example, the sun is shining on one section of the stadium, that part can be cooled more than a section that’s in the shade.

It’s a similar idea in the stands. Only an area of about two metres (6ft 5in) above the spectators in their seats is cooled. Theoretically, if you’re Peter Crouch and stand on your seat, you might have a warm head and cool ankles, but in the normal course of things, the cooling system will keep the areas where people sit at a constant temperature.

And actually, ‘temperature’ isn’t quite the right word to use.

“My number one task is to make a safe environment for the players,” says Dr Saud. “These players don’t measure temperature, because it’s not a true reflection of the heat stresses.

“Players cool themselves with sweat, but if the weather is muggy or humid, it’s very difficult for that film of sweat to evaporate. So my task is to give the players a climate which is not very dry, but not very wet, in a controlled environment. We have something called WBGT (Wet Bulb Globe Temperature), which is a measure of 70 per cent humidity and 30 per cent dry temperature.”

One of the other challenges is ensuring coverage is the same across the full pitch, to avoid having, say, the touchlines freezing and the centre circle sizzling, and also to ensure that air velocity isn’t impacting the ball’s flight.

“We have nozzles — like cannons — which have a throw angle,” says Dr Saud. “The air is fired nine or 10 metres up to the touchline, then it dies away. The nozzles were carefully designed to give enough air to right up to the touchline, and create a bubble (of cooled air over the pitch).

“I get a uniform distribution, plus or minus one or two per cent, on temperature, humidity, air velocity and turbulence as well.”

“They use these ‘eyeball’ nozzles which project the air a certain distance,” adds Lee. “They’re effectively a bit like a hose: you arc the air up, and it will go forwards and then sit (over the pitch).”

Again, this is monitored by sensors — 32 of them, some of which are in the turf itself, some are on the walls at the side of the pitch — which enable the computer system to alter conditions accordingly.

All of this is impressive, but to paraphrase Dr Ian Malcolm from acclaimed 1992 wildlife documentary Jurassic Park, did the Qatari World Cup scientists spend so long thinking about whether they could, they forgot to think whether they should?

The elephant in the baking-hot room is how environmentally friendly all this artificial cooling is.

Keeping eight new/renovated stadiums at an agreeable temperature in the middle of a desert for a month is, on the face of things, not ideal from a carbon footprint point of view.

“It’s a valid concern,” says Dr Saud. “All engineers should have sustainability and looking after the environment as their first priority.”

He says the power for these stadiums is coming from a colossal solar energy farm just outside Doha. He also points out that waste is reduced by the many sensors that allow staff to cool only the areas that need cooling, plus their chillers don’t actually work during the day, for the most part.

“Most of the time, in most of the stadiums, we generate enough chilled water at night. The weather is more merciful, so they will store the chilled water for use during the day. That also minimises the carbon footprint.”

Others though, are more sceptical, particularly when placed in the context of the World Cup as a whole.

“Using air conditioning in an open stadium doesn’t strike me as the most efficient use of energy,” says Gilles Dufrasne, from Carbon Market Watch.

Even the people involved in the project have been sceptical. In 2011, John Barrow, then a director at Populous (he has since retired), commented that the plans were “not good from a long-term sustainability point of view”, and that he was doing his best to persuade the organisers to abandon any air conditioning notions.

There’s also the question of whether, after all of this, air conditioning is actually needed for this World Cup, given that it has been switched to November and December when temperatures in Qatar are actually more manageable.

Sure, you’re still looking at high 20s to low 30s C (80s to low 90s F), which is warmer than ideal for a couple of hours of top-class sport, but for the most part it’s perfectly safe and feasible to play football in those sorts of conditions. Indeed, clubs did so in England at the start of this Premier League season.

However, the argument is that a relatively neutral temperature will be better for both players and fans, although the broader view includes what happens after the tournament ends with the final on Sunday, December 18.

“Even after it was moved from summer to winter,” explains Dr Saud, “our executive management said, ‘Look, we don’t want any white elephants, we want these stadiums to be used all the time’. We need to use them in the Qatar Super League (this season’s QSL was able to start in August, a month earlier than usual and when the average temperature is 40C, thanks to the air conditioning), we want to have concerts, we want them to be community and civic centres. We need air-conditioned stadiums that people can use, not just spend all that money and just use them for the tournament.”

With usage in mind, to an extent, everything you’ve read so far has been the theory of how it should work.

In the real world, the air conditioning has been used at QSL games, but on nowhere near the scale of the looming World Cup fixtures. At a test event in September, fans reported sweltering temperatures and some areas of the stadium where the air conditioning didn’t appear to work.

The argument would be that this is the point of having test events — to identify the problems and iron them out, but it caused some concern.

As Elliot Arthur-Worsop, founder of Football For Future, a charity geared towards sustainability in the game, says, the whole thing feels reasonably dystopian.

Why is all of this necessary? On a basic level, is this a symbol of the sterilisation of football, where those in charge are now controlling the weather? If we need air conditioning to hold football matches in a certain place, should football be held there at all?

But as the impact of climate change increases and global temperatures rise, this sort of technology is going to become more prevalent.

Chris Lee and Populous have already been working on other projects that will implement similar ideas, while Dr Saud and his ideas are already in demand elsewhere.

“We have approaches from neighbouring countries to look at their stadiums and put together schematic designs of their new and existing stadiums,” Dr Saud says. “The good thing with this technology is we’re open, we want others to learn from it.”

Twelve years ago, people weren’t necessarily wrong to be sceptical about an air-conditioned football stadium. But assuming it all works well at this World Cup, prepare yourselves for it to become ubiquitous.

Every World Cup question you’ve been too afraid to ask

(Top photo: Christopher Pike/Bloomberg via Getty Images)

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The science behind an air-conditioned World Cup: Dr Cool, Ford Mondeos and airplane wings - The Athletic

Negative Duct Nick Miller is a football writer for the Athletic and the Totally Football Show. He previously worked as a freelancer for the Guardian, ESPN and Eurosport, plus anyone else who would have him.