Tag Archives: air conditioning

Climate-friendly air conditioning could cut years’ worth of emissions

Up 460 billion tons of greenhouse gas emissions (or about eight years’ worth at the current rate) could be avoided over the next four decades if we paid more attention to our air conditioning. Establishing tougher standards on air conditioning and cooling appliances could make a world of a difference a new report claims, with researchers calling for ways to improve the energy efficiency of the cooling industry.

Credit Wikipedia Commons

The Cooling Emissions and Policy Synthesis Report from the United Nations Environment Programme (UNEP) and the International Energy Agency (IEA) has a clear message: they want to make air conditioning more efficient. In the report, the authors argue that by improving the efficiency of refrigerants, we could “freeze” global warming in place for time, offsetting emissions equivalent to 4-8 years of the planet’s emissions.

“By improving cooling efficiency, governments can reduce the need for new power plants, cut emissions and save consumers money. This new report gives policymakers valuable insights to help them address the global cooling challenge,” said in a press release Dr. Fatih Birol, IEA Executive Director.”

Worldwide, an estimated 3.6 billion cooling appliances are already in use. That figure is expected to skyrocket by 400% by 2050 as the planet becomes hotter and the world becomes more affluent. Cheap devices require a lot of electricity and if that electricity comes from coal or gas-fired power plants, we’re just creating a feedback loop that leads to more global warming, and the cycle repeats.

But it’s not a single issue when it comes to the greenhouse gases produced by cooling systems. Many such devices still use hydrofluorocarbons (or HFCs) — a group of potent but short-lived greenhouse gas. Eliminating them is one of the most straightforward ways to tackle climate change, potentially avoiding as much as 0.4 degrees Celsius of warming by the end of the century.

In 2016, countries agreed to a binding treaty known as the Kigali Amendment to eliminate HFCs. However, major polluters such as the US, China, and India haven’t ratified it yet. Even some countries and regions that accepted the treaty are having major difficulties in tackling illegal refrigerants smuggling. Europe’s flourishing illegal HCF trade of hydrofluorocarbons highlights just how challenging this issue is.

“As nations invest in COVID-19 recovery, they have an opportunity to use their resources wisely to reduce climate change, protect nature and reduce risks of further pandemics. Efficient, climate-friendly cooling can help to achieve all of these goals,” said Inger Andersen, UNEP Executive Director, in a press release.

The report estimates that doubling the energy efficiency of air conditioning by 2050 would reduce the need for 1,300 gigawatts of additional electricity generation capacity to meet peak demand — the equivalent of all the coal-fired power generation capacity in China and India in 2018.

This would also save a lot of money, the report notes. Making air conditioning two times more effective could save the world up to $2.9 trillion by 2050 in reduced electricity generation, transmission and distribution costs alone. Doing so would bring many other benefits, such as increased access to life-saving cooling, improved air quality and reduced food loss and waste, the report says.

But it won’t be easy.

To achieve such goals, the EIA and UNEP recommend a set of policy actions such as implementing energy efficiency labels on cooling equipment, updating building requirements and expanding sustainable cold chains. This involves the transportation of temperature-sensitive products along a supply chain in a way that could prevent food loss and emissions. At the same time, demand for cooling is rising, and supply chains are under immense stress from the coronavirus. It’s a great challenge, but the results will be worth it.

In a warming world, air conditioning only makes things worse

As climate change pushes the summer temperatures higher and higher, more and more people are using air conditioning — and that’s making the problem even worse.

In a special edition of the journal Public Library of Science (PLOSMedicine dedicated to climate change, a team of researchers from the University of Wisconsin-Madison makes some dire predictions. They forecast that air conditioning used to cool our buildings will further add to air pollution, causing as many as a thousand additional deaths annually in the Eastern United States alone.

“What we found is that air pollution will get worse,” explains David Abel, the lead author of the new report and a UW-Madison graduate student in the Nelson Institute for Environmental Studies’ Center for Sustainability and the Global Environment. “There are consequences for adapting to future climate change.”

It’s a good example of a feedback loop: greenhouse gas emissions cause summer temperatures to get hotter and hotter. People want to cool themselves, so they turn on the AC, which uses more energy and causes more emissions. In principle, things are fairly straightforward, but understanding the specifics of this process is no easy feat.

Abel and his colleagues used projections from five different models to forecast increased summer energy use in a warmer world. Jonathan Patz, a senior author of the study and a UW-Madison professor of environmental studies and population health sciences, says that unless we make the switch to renewable energy, ACs won’t solve our problem — they’ll simply offset it.

“We’re trading problems,” says Patz, an expert on climate change and human health. “Heat waves are increasing and increasing in intensity. We will have more cooling demand requiring more electricity. But if our nation continues to rely on coal-fired power plants for some of our electricity, each time we turn on the air conditioning we’ll be fouling the air, causing more sickness and even deaths.”

The study also highlights a larger-scale problem: we need to adapt to climate change, but many of the things we do to adapt end up making things even worse in the long run. It’s only natural for individuals to want to cool themselves during hot days, but at a societal level, this can be a significant problem.

The solution, researchers emphasize, is shifting away from a carbon-based economy and start switching to renewables. If we use clean energy, then we may get away (at least to some extent) with using energy for relatively frivolous things such as air conditioning.

“The answer is clean energy,” concludes Abel. “That is something we can control that will help both climate change and future air pollution. If we change nothing, both are going to get worse.”


New eco-friendly AC uses only water to cool down air, saves on the energy bill to boot

A new type of air conditioning is waiting to make its cool debut on the market. Suitable for both indoor and outdoor use, the system is much more energy efficient than traditional units, uses plain water instead of chemicals refrigerants, and produces drinking water to boot.


The team and their novel AC system.
Image credits NUS.

With the winter holidays coming to a close, it’s time to plan for the future. The hot, sweaty, sticky near-future of summer. There is solid ground to assume that this year will be a scorching one, which should still feel like small fry compared to those in the future.

All this heat will not be doing anyone any favors. According to researchers from the Natural Resources Defense Council, future summers won’t be only about ice-cream and beach holidays — they will be very deadly seasons, claiming tens of thousands of lives all across the US. The EU is on the hook too, and there’s no reason to believe people in other areas of the world will fare much cooler than, essentially, the world’s technological and economic powerhouses.

Too hot for comfort

It’s not an overstatement, then, to say that proper temperature control, in the form of air conditioning, will become a matter of life or death in the future. However, our current approach to the issue leaves us in a spot of hot water.

For one, air conditioning isn’t so much about ‘destroying’ heat as it is about taking it somewhere else — specifically, out of the room. Comfy on the inside, but the reverse of the coin is that the ‘outside’, especially if you live in a big city, gets much warmer very fast. Le Chatelier’s principle on equilibrium tells us that this will make it progressively more difficult for air conditioning units to actually push all that heat outside: it’s more laborious to create a big imbalance (pumping heat from a cold room to a hot outside) than a small one (say, between two bodies at closer temperatures). It’s like pushing water uphill. Which segues us into issue Mk.2:

The harder our ACs have to work, the more energy they need. Ironically, this makes everything hotter, as that energy degrades into heat. It’ll also put a large dent in many a family’s finances, and many people will have to contend with an unenviable choice: go into overdraft, or gamble that nobody’s going to get heatstroke. Zooming back even further, it will put a huge strain on often aging and already-overtaxed power grids — and we definitely don’t want these to pop when everybody’s hugging the AC for dear life.

Lastly, our current systems employ chemical refrigerants such as chlorofluorocarbons and hydrochlorofluorocarbons for cooling, which are quite nasty for the environment. More directly important to you, however, is that these compounds are quite expensive to manufacture and very deadly if leaks occur indoors.

So we need a better alternative. Luckily for us, that’s exactly what one team of researchers from the National University of Singapore (NUS) has been working on, with support from the Building and Construction Authority and National Research Foundation Singapore. The device they came up with could potentially address the limitations of the century-old AC principle in use today.

The water-based AC system can cool air down to 18° Celsius (64.4° F) without using the energy-intensive compressors or the chemical refrigerants the most common ACs today use. Suitable both for indoor and outdoor use, the device is fully portable and can be customized to work in all weather conditions, says the team led by Associate Professor Ernest Chua from the university’s Faculty of Engineering.

Cooler cooling

Because it relies on water in lieu of chemical refrigerants, the device is also cheaper to manufacture than traditional AC systems, is more sustainable, more eco-friendly, and potential leaks will be a nuisance at their worst. Running costs should also be much lower, as the team reports their cooler uses roughly 40% less electricity than traditional systems — good for your bill and the planet, too.

A final feature you’ll enjoy on a scorching noon is that the system also generates potable water as it cools your room.

“For buildings located in the tropics, more than 40 per cent of the building’s energy consumption is attributed to air-conditioning,” Chua says. “We expect this rate to increase dramatically, adding an extra punch to global warming.”

“Our novel membrane and water-based cooling technology is very eco-friendly — it can provide cool and dry air without using a compressor and chemical refrigerants. This is a new starting point for the next generation of air-conditioners, and our technology has immense potential to disrupt how air-conditioning has traditionally been provided.”

Instead of dehumidifying and cooling the air at the same time, as conventional designs do, the team from NUS decided to handle them separately. Finer control over each process allowed the team to increase their energy efficiency.

The first step in the process is to pass air through a paper-like membrane which removes moisture. Then, the dry air is passed through a dew-point cooking system. In broad lines, this is a system that uses part of the dry air produced in the first step to force evaporation on metallic plates inside the AC. Since water needs energy to turn into a gas (and heat is energy), this process cools the plates which, in turn, cool the air flowing through them. Out the end comes a stream of cooled, drier air than compared to the environment, and about 12 to 15 liters (12.68 to 15.85 quarts) of potable water per day.

According to the team, the device can easily be adapted to work in all types of weather and climate, used for individual homes or scaled up to service clusters of buildings. The team says it’s particularly well-suited for confined areas that need reliable humidity control, such as bomb shelters, wine cellars, or hospitals. “Armoured personnel carriers, and operation decks of navy ships as well as aircrafts,” are also good candidates, Chua adds.

The team is currently refining its design to further improve user-friendliness. They plan to incorporate features including pre-programmed thermal settings, based on human occupancy, and real-time tracking of its energy efficiency. The team hopes to work with industry partners to commercialize the technology.

Credit: Flickr user Texas Furniture.

Who invented air conditioning?

Credit: Flickr user Texas Furniture.

Credit: Flickr 

People have been trying to outsmart heat waves for thousands of years but it wasn’t until 1902 that modern air conditioning appeared. You have an American engineered called Willis Carrier to thank for this invention that forever changed the world.

Ancient attempts at air conditioning

Persian wind catchers are still employed to this day. Credit: Flickr User Pilar Torres.

Persian wind catchers are still employed to this day. Credit: Flickr User Pilar Torres.

One of the first people to try to cool their homes were unsurprisingly the Egyptians, who had to deal with scorching temperatures most of the year. The ancient Egyptians would hang wet mats over the doorways. Once the water starts to evaporate, heat gets sucked out. This primitive, but ingenious method had the added benefit of raising the moisture in the air, which was very desirable in dry climates.

Later on, in the Roman Empire, a more advanced air conditioning was introduced. Using their famous aqueducts, some wealthy Romans circulated cold, fresh water from upstream through pipes fitted inside their villas. During the ‘dies canicula’, a Roman term for the hot period of weather between July and mid-August, Romans who couldn’t afford cooled-pipes would congregate at the public baths. Here, they would find the frigidarium, a large cold pool.

The White Horse Temple in China, built during the Han Dynasty (202 BC220 AD), had a Cool Hall. Inside, rotary fans powered party by water, party by human hands, chilled the elite during the hot summer days.

In the Middle East, Persians built wind towers known as ‘wind catchers’ which were fitted with windows through the prevailing winds would sweep. With the help of interior vanes, the cooler air was introduced into homes and the warm air was sucked out.

Experimental refrigeration

In 1778, renowned inventor and statesmen Benjamin Franklin, along with his friend John Hadley, a professor at Cambridge University, started to experiment with the refrigerating effects of certain substances. Their studies suggests that the faster a liquid evaporates, the colder the surrounding air would get. Using ether, the two showed it was possible to cool a mercury thermometer below the freezing point. Franklin would later remark in his journal that ‘it’s possible to freeze to death even on a warm summer’s day.’

Later, in 1820, Michael Faraday learned that by compressing ammonia, the gas becomes a liquid. As it evaporated, the ammonia cooled the air inside his lab.

The first thing that resembled an air conditioner was patented in 1851 by a Florida physician named John Gorrie. His device compressed air and water to create an open cooling system meant to keep yellow fever patients cool. It was aptly called the ‘cold air machine’.

The modern air conditioning

William Carrier. Photo: Public Domain.

William Carrier. Photo: Public Domain.

The modern air conditioner didn’t surface, however, until the early 20th century. Luckily, Willis Carrier came into the picture and the world would never be the same. His invention, however, was intended for a far less grander purpose.

Carrier had been born in 1876 to an old New England family, which as an interesting trivia tidbit included an ancestor who was hung as a witch in Salem. After finishing his studies at Cornell University, Carrier became employed at a company that owned a printing press. He proved himself with various technical upgrades that saved the company a lot of money and was promoted as the head of a new department of experimental engineering. One of his first tasks was to design a system that would reduce moisture in the printing room so pages wouldn’t get wrinkled.

Carrier realized he could dry air by passing it through water to create fog. Within a year, he create a machine fitted with chilled coils that could control humidity, maintaining it at a constant 55 percent inside the Sackett-Wilhelms printing house. That’s the equivalent of using 108,000 pounds of ice daily to cool the plant.

The term ‘air conditioner’, however, was coined by Stuart Crame who invented a similar device.

While working at Sackett-Wilhelms, Carrier partnered with one Irvine Lyle, at the time a salesman at the printing house, and started Carrier Corp., a company that sold air conditioners to Americans and would become very successful in the 1950s. It took a while before normal, working-class Americans could afford this invention. The first home air conditioner was installed in 1914 in the mansion of millionaire Charles Gates who hired Carrier for the job. This machine was the size of a whole room, bulky, and extremely noisy.

Though adoption was slow, the 1950s and 1960s came with a boom in sales. Nowadays, 90 percent of American homes use air conditioning, making summer days more manageable at home and more productive at work.

Not everything is cool about air conditioning, though. Up until the early 1990s, refrigerators, and ACs used refrigerants like CFC and HCFC which plug holes in the ozone and cause global warming. Though they’ve been banned and replaced with more benign refrigerants, these chemicals still heat the planet. Ammonia is toxic and can destroy wildlife if it is improperly disposed of. The biggest environmental concern with modern air conditioning, however, is energy use — energy which nowadays is still largely derived from fossil fuels.  Almost 20 percent of electricity consumption in U.S. homes goes to AC or nearly as much as the whole continent of Africa uses for all purposes.


How air conditioning is making your city hotter

As temperatures continue to rise around the world (sorry “climate change deniers“), the demand for air conditioning increases – but ironically, that’s causing cities to become more and more hot.

Air conditioners soak up a lot of energy, which in turn means more emissions, which in turn means more warming. But that’s the long term effect – a new study has concluded that turning on your AC unit actually sends the mercury skyward on a short time scale as well, making it hotter in the short run.

“General AC systems absorb heat (cooling the indoor air) from the interior of the buildings and release heat into the surrounding outdoor environment,” write researchers from Arizona State University in the Journal of Geophysical Research: Atmospheres. An individual unit obviously doesn’t produce all that much ambient heat, but when you combine all the cooling in cities where it’s hot enough to cook dinner on the pavement, you can make a real difference.

What they did is modeled a system using both building energy schemes and climate inputs, simulating a “10 day extreme heat situation”, something which is already quite common in the city of Phoenix. They found that during the day, the negative contributions of ACs was not significant, but during the night, it was. When a building’s floor area was fully air conditioned, that raised the nearby temperatures by as much as 1.5 degrees Celsius (2.7ºF) during nighttime hours. When they added more parameters to compensate for realistic conditions, they still wound up with 1 degree Celsius. When you take a heavily urbanized area such as Phoenix, where virtually all the buildings have air conditioning, that 1 degree rise is sent throughout almost the entire city.

To make things even worse, the extra warmth piles up over the urban heat island effect, and if scientists’ calculations are correct, then an average city of 1 million inhabitants can be 3 degrees Celsius hotter than its surroundings – and ACs play a significant role. Ironically, they cool off buildings, but make the environment hotter, so there’s more need for cooling off buildings.