The Search For More Efficient Air Conditioning Technology (With Video)

As the world heats up, the demand for air conditioning will skyrocket. According to a report by the International Energy Agency, demand from air conditioners is expected to triple by 2050. The amount of electricity required to operate them will equal the combined electricity capacity of the United States, the EU, and Japan as of 2018. The global stock of air conditioners in buildings will grow to 5.6 billion by 2050, up from 1.6 billion today — that’s 10 new air conditioners sold every second for the next 30 years.

Using air conditioners and electric fans to stay cool already accounts for about a fifth of the total electricity used in buildings around the world — equal to 10% of all global electricity consumption today. But as incomes and living standards improve in many developing countries, the growth in AC demand in hotter regions is set to soar. AC use is expected to be the second largest source of global electricity demand growth after the industrial sector by 2050, according to the IEA.

During a heat wave, millions of people come home between 4 pm and 9 pm and turn on an air conditioner (or two). When that happens, air conditioning can account for a whopping 60 to 70% of electricity demand, according to the Washington Post.

Air Conditioners & Efficiency

There are two primary considerations at work here. One is energy efficiency. The other is the use of refrigerants that harm the environment. Efficiency is one of the key reasons to drive an electric car. A typical gasoline engine is somewhere between 20 and 25% efficient. That means only a quarter of the gasoline you pay for at the pump is used to move you down the road. The rest is wasted as friction, heat, or noise.

By contrast, an electric motor is 85 to 90% efficient, which means the vast majority of the electricity you use to charge your electric car gets converted into forward motion instead of going to waste. Many drivers complain about high gas prices, but never stop to consider they are being cheated out of most of the energy they pay for at the pump.

A conventional air conditioner works by using a special liquid that turns into a gas when it is exposed to heat, such as in a room that has been warmed by the sun. That heat causes the refrigerant to evaporate, which cools the air. A compressor then turns the refrigerant back into a liquid and the process repeats itself.

But the standard process is not very energy efficient and gets less so as the temperature outside rises. During heat waves, conventional air conditioners have to work harder, which requires them to use more electricity.

Some newer air conditioning units use different refrigerants, such as R-32. It has less of a greenhouse gas effect and uses less energy to compress, which lowers the amount of electricity needed. Other units use variable speed compressors that can run faster in the hottest weather but slower when outside temperatures are lower. That allows the unit to run on different settings. Using less electricity to cool a living space saves people money on their utility bills and reduces stress on the electrical grid.

More good news is just around the corner, the Washington Post says. RMI, formerly known as the Rocky Mountain Institute, created a Global Cooling Prize recently to produce affordable air conditioning prototypes that would be at least five times better for the climate than existing models. Two companies shared the prize — Gree Electric Appliances and Daikin Industries. Both used traditional gas compression technology, but with improved refrigerants and designs that could change settings in response to outdoor temperatures.

Air Conditioning & The Environment

In the early days, air conditioning units used chlorofluorocarbons, or CFCs. They worked wonderfully well but had a serious side effect — they created a hole in the Earth’s ozone layer. CFCs were phased out by the 1987 Montreal Protocol, an international treaty to counteract ozone hole depletion, and replaced by hydrofluorocarbons, or HFCs.

But HFCs have their own problems. They are are still greenhouse gases that are thousands of times more potent than carbon dioxide. An amendment to the Montreal Protocol requires HFCs to be phased out almost entirely by 2045, but in the meantime they are still contributing to global warming. Discarded air conditioners eventually leak most of their refrigerant into the atmosphere, with predictable consequences for the environment.

Other researchers are investigating whether they can eliminate gas compression technology altogether. Blue Frontier uses a liquid that extracts moisture from the air and stores it in a tank to control the temperature. According to the company, this approach could save up to 60% of the electricity required to run an AC unit year round. Blue Frontier has also won the Bloomberg New Energy Finance Pioneers Award and secured a $20 million investment from Breakthrough Energy Ventures.

Researchers at Harvard have developed an air conditioning prototype called coldSNAP — (SNAP stands for “superhydrophobic nano-architecture process”). The prototype doesn’t use a refrigerant, but rather a special coating on a ceramic frame that evaporates water to cool the indoor space without adding moisture to the air, according to Fast Company. “Because we don’t have the vapor compression system and the energy of trying to release and compress the refrigerants, the energy consumption of these systems is far, far lower,” said Jonathan Grinham, one of the researchers on the project.

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Heat Pumps & The IRA

Heat pumps are more energy efficient that traditional window air conditioners, although they still use a refrigerant that may not be climate friendly. Look to see if the equipment you are considering uses an HFC gas or R-32. Newer heat pumps are now able to supply heat even when outside temperatures drop to -20º F. In general, a heat pump uses about half as much electricity as a traditional AC unit.

The Inflation Reduction Act provides significant rebates and other incentives for the purchase and installation of heat pumps. It even can help consumers pay for upgrades to the electrical panel in their homes if adding heat pumps or other efficient electric appliances makes that necessary.

The Air Conditioning Conundrum

Ankit Kalanki, a manager at Third Derivative, a climate tech accelerator co-founded by the energy think tank RMI, tells the Washington Post that most consumers just shop for an air conditioner based on price, without considering the cost of the electricity that will be need to operate it for many years. He recommends shoppers consider not only the price but also the type of refrigerant used, the efficiency rating (higher is better), and whether it has a variable speed compressor.

“There are technologies that are two to three times more efficient than the most common ACs on the market today,” he says. The issue is the same as it is for electric cars. EVs tend to cost more than conventional cars, but have lower operating costs. It takes an educated consumer to look beyond the allure of a low price and see the beauty of lower lifetime costs and appreciate a new technology.

Kalanki believes governments need to set stricter performance standards for air conditioners so that all the units on the market — not just higher-end ones — are efficient and safe for the planet. “There are regulations in place to set the floor for air conditioners but that floor is a bit too low,” he says.

The Takeaway

Electric cars are not going to break the grid, but old style, inefficient air conditioning units might. There are only about two people left alive who don’t know the Earth is getting hotter — much hotter in some cases — and that the demand for cooling is going to increase dramatically in the next few years. That is much more of a threat to the grid than EVs will ever be. EVs can be charged any time, but the highest demand for air conditioning is right when the supply of electricity is stretched to the limit in the afternoon.

Often, the best part of the stories printed by mainstream media is found in the comments. The Washington Post article got this response from someone with the screen name of Dignity and Truth. What was written is worthy of sharing with our CleanTechnica readers.

“After my mid-60s ranch house got an insulation makeover, courtesy of MassSave, our energy use declined by two thirds. Mostly that was heating energy for the winter, which was measurable. In the summer, however, we had far less heat radiating from the attic, down through ceilings. Stunning difference.

“Certainly we need fresh tech to improve necessary cooling. At the same time there is a lot of low tech opportunity. In our case, MassSave funded 80% of the cost of the insulation and draft sealing, which was done by a licensed contractor in one day. Massachusetts is a leader in energy with that program, and other programs that foster clean, renewable energy sources.

“We also replaced old appliances, old water heater, and old furnace. MassSave had rebates for most replacements. They also offered a zero percent loan to fund all the work — about $15K in our case. The program is funded by a tiny surcharge on all energy bills.

“We definitely need refreshed, high tech solutions. We also need to massively up our game with the low tech stuff that amounts to low hanging fruit.”

We couldn’t have said it any better than that.


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