The global warming problem is driving a global cooling addiction that threatens to further accelerate climate change and challenge the reliability of electricity supply. The rising trajectory of air conditioning (AC) sales in both economically developed and developing nations has become a major concern for environmentalists and grid operators alike. Buildings, again, sit at the center of the environmental debate but as populations grow and develop, and global temperatures rise, cooling technology could simultaneously be our best friend and our worst enemy.
Today, AC adoption is concentrated in a smaller number of affluent countries that experience extended periods of hot weather every year. Over 90% of households in Japan and the US are equipped with AC units, followed closely by South Korea with 86%, according to IEA 2018 figures. Saudi Arabia and China, with 63% and 60% respectively, round out a top five that stand head and shoulders above the rest. Mexico and Brazil share 6th place in the IEA table, but only with 16% of their households equipped with an AC.
The problem is not just that more buildings with ACs will require more electricity, but that all ACs are generally used at the same time — when it’s hot! This places significant seasonal strain on power generation and grid infrastructure, meaning energy systems are built inefficiently with huge capacities to meet that peak summer demand for cooling (and everything else). As economies develop, more buildings are built, more companies grow, more offices are cooled, and more people can afford ACs in their homes. More cooling comes hand-in-hand with economic development.
In many hot countries around the world, having an AC is a symbol of success and a key goal of personal economic growth. However, cooling is even more significant for commercial buildings, where it is linked to the health, wellbeing, and productivity of workers, as well as the comfort of clients and customers, or the protection of assets. The world is getting warmer and many of the warmest parts are developing the fastest — but this shouldn’t be a choice between staying cool or saving the planet, it should be a discussion about the urgent need for more energy-efficient cooling systems.
“The problem is, today's consumers are not buying the most efficient ACs. The average efficiency of air conditioners sold today is less than half of what is typically available on the shelves – and one-third of the best available technology,” states the IEA Future Cooling Report. “Investing in more efficient ACs could cut future energy demand in half. Our Efficient Cooling Scenario shows that effective policies can double average AC efficiency and reduce cooling energy demand by 45%”.
Active solar panels have doubled their efficiencies to reach parity with fossil fuels and support climate change. Batteries have undergone a revolution to trigger a wave of energy storage technology that includes electric vehicles. The energy and cost efficiency of lighting was transformed by the LED, which utilized established supply chains to reduce energy consumption around the world. The ‘cooling industry’ now needs that kind of revolutionary innovation to reduce its contribution to climate change while supporting economic development.
“The fact that window AC use continues to increase while the product largely looks and works the same as it has for decades speaks for itself,” says Vince Romanin, chief executive of San Francisco–based Treau, a stealth cooling startup developing a novel type of heat pump. “I think a lot of folks are excited for something new here, but there has only been incremental progress.”
One new innovation comes from Transaera, a company co-founded by MIT energy professor Mircea Dincă. AC units dedicate huge amounts of energy to deal with the heat retention of humid air entering the system, which then requires lower temperatures to liquefy the vapor. “It’s just incredibly inefficient. It’s a lot of energy, and it’s unnecessary” Dincă says. His company, Transaera, is attempting to tackle the problem with a class of highly porous materials known as metal-organic frameworks that can be customized to capture and cling to the water vapor. The AC attachment promises to improve overall energy efficiency by more than 25%.
Meanwhile, in Mountain View, California, SkyCool Systems is harnessing a natural phenomenon known as ‘radiative cooling’ through a system of high-tech mirrors that can cast heat away from buildings. Designed to emit radiation in a narrow band of the light spectrum that can bypass water molecules and other atmospheric compounds to send that heat out of the earth’s atmosphere. The company is completing its fourth commercial rooftop installation and estimates that the technology can reduce the energy used to cool buildings by 10% to 70%, depending on the configuration and climate.
Other startups are promoting geothermal heat pumps to avoid the need for refrigerant gases, evaporative cooling to reduce air temperatures with water-soaked pads, and more innovative early-stage technologies are emerging. Investment in HVAC is up too, increasing from $40 million in 2015 to $350 million in 2019 according to CB Insights. However, these figures are insignificant when compared to other energy and technology sectors, or when put into the context of the environmental impact of inactivity. The evolution of the cooling market towards energy-efficient solutions is not moving fast enough to avoid the rapidly accelerating energy-for-cooling problem.
“Air conditioning represents one of the most insidious challenges of climate change and one of the most difficult technological problems to fix. The more the world warms, the more we’ll need cooling — not merely for comfort, but for health and survival in large parts of the world,” warns James Temple, senior editor for energy at MIT Technology Review. “Without major improvements, energy demand from cooling will also triple, reaching 6,200 terawatt-hours by 2050 — or nearly a quarter of the world’s total electricity consumption today.”