Air Conditioning: Reinventing Cool Technology to Reduce Climate Change
Air conditioning (AC) units have become an essential part of modern life, but this simple refrigeration technology has remained relatively unchanged since the 1940s. As climate change effects like rising temperatures and heat waves encourage more AC use, the increase in energy needed to cool us down could easily accelerate climate change.
Air cooling technology needs a fundamental rethink to avoid this destructive climate feedback loop. That might seem small fry next to total industrial greenhouse gas emissions, but the International Energy Agency estimates that 4.5 billion units will be installed by 2050, using around 13 percent of all electricity worldwide.
Buildings need to be part of the solution. Tighter regulations will stop construction companies from relying on AC alone and concentrate on sealing air leaks, adding insulation, and applying reflective colors to rooftops. Retrofitting 80 percent of the 28 billion square feet of US commercial building roof area with cooling, reflective white would save $735 million in energy costs annually.
Nine out of ten domestic households now have AC units. Redesigning those units could be a major way we tackle climate change. New air conditioners use roughly 50 percent less energy than they did in 1990, but what if each unit captured carbon dioxide from the air and converted it into renewable hydrocarbon fuels.
Research published under the title of ‘Crowd oil not crude oil’ suggests just that. Chemical engineer Roland Dittmeyer says the system will take carbon dioxide and water from air, extract hydrogen and then turn it into liquid synthetic oil. Wells of oil then provide individual buildings or neighborhoods with crowd-sourced carbon-free energy.
Meanwhile, the World Economic Forum suggests that increasing energy efficiency and improving AC performance will massively reduce emissions. Manufacturers are creating hybrid technologies that transfer heat between semiconductors or use magnetic fields, which perform four or five times better.
In hotter developing countries the need for improvements is stark. More than 22,000 Indians died from heat exposure between 1992 and 2016, and 75 percent of the population face dangerous heat and humidity levels by 2100. So the Global Cooling Prize was launched, attracting more than 1,600 engineering teams with a prize worth at least $1 million to the winner.
Finalists have come up with solutions that reduce or remove entirely harmful hydrofluorocarbon (HFC) refrigerants from air conditioners. Alternatives include using low-cost solid-state non-toxic ‘plastic crystals’ and a moisture storage battery assembly that dries the air first, making it easier to cool.
Another improves compressor and heat exchanger performance and has an in-built solar panel to power it. The reality is that older units will not cut it and programs to reduce HFC are aiming to shrink their use by 80 percent by 2050, reducing emissions equivalent to 140-290 billion tons of CO2.
Alternative cooling technologies such as ground source and dual-source heat pumps that draw on ground and air temperature exchange to cool buildings are also increasing in popularity. In winter they warm buildings using ground heat and in summer they pump heat out of buildings into the ground and surrounding air.
Cleaner and smarter electricity grid technologies will add to the steady reduction of emissions as more solar, wind, and other renewable sources, like hydrogen, come online. Better control systems and sensors will minimize the energy needed to cool buildings.
And there is always space for true futuristic innovation, such as Penn State University’s thermoacoustic chiller, which uses soundwaves and helium to lower temperatures. Or mirrors that simply bounce heat radiation out into the cold reaches of space, reducing the energy needed to cool structures by up to 70 percent.
Methods may vary, but engineers agree that avoiding the coming ‘cold crunch’ by reducing the energy sucked up by AC will be essential to tackling climate change.