Global Cooling with Air Conditioners and Reducing their Carbon Footprint
Air conditioners do more good than most people realise. Unfortunately, they also do much harm.
Air-conditioning has become universal in many countries. It turned them into an engine of prosperity. It even reshaped their politics by luring migrants to regions that had once been desolate with heat and humidity.
The stifling summer of 2018 in the northern hemisphere has been a banner season for air conditioners. It was a reminder of how they have changed the world. Sales in France in the first three weeks of July were 192% higher than in the same period of 2017. In Japan, the government has been putting them into prisons. At current growth rates, according to the International Energy Agency (IEA), which advises national governments, 1bn air conditioners will be installed globally in the next ten years. That would increase the world’s stock (1.6bn in 2016) by two-thirds. If you include refrigerators and systems that cool food, vaccines and data, the stock could be 6bn units in a decade.
The growth in cooling will save lives, improve education and create wealth in the world’s hottest countries.
But it brings huge environmental risks, warming the plant even as it cools people. Lee Kuan Yew, the first prime minister of Singapore, took the view that air conditioning changed the nature of civilisation by making development possible in the tropics. The first thing he did upon becoming prime minister was to install air conditioners in buildings where the civil service worked. This was key to public efficiency. Air conditioning literally makes people healthier, wealthier and wiser. A study by the Australian National University found that, in south-east Asia, people without cooling could not work during 15-20% of working hours. A study by the University of California calculated that, in the Caribbean and Central America, GDP falls by 1% for each degree above 26°C.
In 1990 a few Chinese households had air conditioning.
Twenty years later, the country had just under one unit per household. It now accounts for 35% of the world’s stock, compared with 23% for the USA. India and Indonesia are seeing rates of increase similar to China’s in the 1990s. The population of the 800km long southern coast of the Arabian Gulf increased from 500,000 in 1950 to 20m now, thanks to air-conditioned skyscrapers. At current rates, Saudi Arabia will be using more energy to run air conditioners in 2030 than it now exports as oil.
At the moment, only 8% of the 3bn people in the tropics have air conditioning compared with over 90% of households in America and Japan.
But eventually, it will be near universal because so many trends are converging behind its spread:
- ageing, since old people are more vulnerable to heat stroke;
- urbanisation, since you cannot air-condition fields, be you have to do it to offices and factories;
- and economic growth, since, after mobile phones, the middle class in emerging markets want fans or air conditioners next.
Environmental designers in the construction industry fret about this.
Air conditioners produce greenhouse gases in two ways.
- First, they are responsible for a share of the CO2 generated in the power stations that produce the electricity they run on. At the moment, according to the IEA, it takes about 2000 TWhs (tera-watt hours) of electricity to run all the world’s cooling machines for a year. This produces 4bn tons of CO2, 12% of the total. Without drastic improvements in air conditioners efficiency, the IEA reckons, they will be burning up 6000 TWHs by 2050.
- Second, air conditioners use so-called F-gases as refrigerants. When the machines leak (common) in use or on disposal, these gases escape, doing vast damage. HFCs trap between 1000 and 9000 times as much CO2, meaning they are much more potent causes of global warming.
In 2017, calculations were made at Berkley to show carbon emissions reductions if air conditioners were more efficient.
If HFCs were phased out and all units were as efficient as the best ones, the world could be spared around 1000 average sized (500MW capacity) power stations by 2030. There would be many more air conditioning units. However, each would use less energy.
In India, this would save three times as much in carbon emissions as the prime ministers’ much-vaunted plan to install 100 gigawatts of solar capacity by 2022.
In China, it would save as much as eight Three Gorges dams (the largest dam in the world). Such gains will not be easy to achieve.
A Common way to improve energy efficiency is to impose minimum energy standards or energy codes for buildings.
Still, these vary from country to country. Unfortunately, the poorest and hottest countries do not even have them. This needs to come from central governments. In addition, the call to centralise energy production (no local fossil fuel burning in the building itself through systems such as boilers) will provide the opportunity to gradually reduce fossil and nuclear energy production with a view to switching to renewables and net zero carbon systems.
In general, the way forward needs to be promoted by building professionals, designers and constructors with support through.
Read more: Reducing Carbon Emissions in Construction