Air conditioners in vicious cycle

Rising demand for air conditioners will worsen global warming if steps aren’t taken to change the cooling technology we currently use, says a new study from the Berkeley National Laboratory.

In the last two years, alone, numerous locations around the globe have seen higher temperatures than ever before recorded. Cambodia, Tonga, Botswana, and India all set new all-time record high temperatures in 2016.

As a result, air conditioner sales in many emerging high population economies such as Brazil, India, and Indonesia are growing at a rate of 10 to 15 percent per year,which means the world’s supply of A/C units could increase from about 900 million today to roughly 1.6 billion by 2030.

Hydrofluorocarbons emitted from the refrigerants used in such devices are now the fastest growing greenhouse gases in the atmosphere, with the potential to increase global warming thousands of times more so than carbon dioxide.

Increasing air conditioners’ efficiency will also help to ensure they use less power, which in most developing countries is still produced by burning fossil fuels.

Researchers at MIT found that mass amounts of cooling units release heat back into the environment, which is particularly problematic in urban areas, where it enhances the heat island effect present in most major cities.

“The more cooling you have, the more heat air-conditioning systems release into the urban environment, which then elevates the ambient temperature and further increases the cooling demand. It’s a vicious cycle,” Afshin Afshari, a professor of practice of engineering systems and management and a member of  the MIT research team.

The study was conducted in the national capital of the of the United Arab Emirates, Abu Dhabi. Results found that the city’s heat island effect is responsible for up to 15 percent of the nation’s yearly cooling load.

Since most of the country’s air-conditioners run on electricity generated by natural gas-fired power plants that emit heat-trapping greenhouse gases into the atmosphere, reducing Abu Dhabi’s cooling load would decrease the country’s carbon footprint.

The Berkeley National Laboratory study found that transitioning to less harmful refrigerant materials and improving the energy efficiency in air conditioning units together roughly doubles the benefit of pursuing either strategy separately.

By the study’s estimates, shifting the world’s 2030 world stock of room air conditioners to high-efficiency units using refrigerants with low global warming potential would save between 340-790 gigawatts of peak load globally. China’s portion alone would equal savings of more than eight times the current power production of the Three Gorges dams.

This has led to proposals from Africa, Europe, India,Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer to phase down high refrigerants with this global warming potential.

1 Comment

  1. Soundmind

    I am at war….with the whole world. At least it sometimes seems that way. Knowledge, experience, judgment, against a world of ingnoramuses, tyros, incompetents, parrot salesmen, blundering fools, and crooks. It’s an unfair fight. Me against all of them. They don’t stand a chance.

    In one of the toughest engineering schools I know of, I got a solid C in thermodynamics. Before you laugh, know most other guys got Ds and Fs. I’ve learned a lot more about it since those days.

    Let’s not mix apples and oranges. ChloroFlouroCarbons or CFCs commonly known as Freon used as refrigerant in air conditioners react with ozone in the upper atmosphere. This was discovered decades ago when holes appeared at both the north and south poles. Ozone in the stratosphere protects us against harmful ultraviolet rays from the sun. By international treaty other refrigerants have been developed, you can’t deliberately vent Freon into the atmosphere and other Freons are being developed. It’s working, the holes are closing. CO2 evolved from power plants used to generate electricity and methane are the greenhouse gases claimed to be the source of global warming. They are not a threat to the ozone layer.

    Sometimes it seems I spend half my time fighting with mechanical engineers or correcting their mistakes and the other half doing the same with electrical engineers. When I worked at Bellcore my boss would ask me to interview mechanical engineers. What could I ask them that would tell me if they knew their onions? Then one day working on a project I came across a problem myself that would show me if they knew how refrigeration works. The problem can be scaled up or down to any size and any variant so I simplified it so that even a tyro can understand it. You buy a one ton window air conditioner. It removes 12,000 BTUs of heat an hour from a room. A 3500 watt electric heater produces about 12,000 BTUs an hour of heat. One watt produces 3.412 BTUs per hour. But the air conditioner nameplate shows it draws only 1400 watts or less. How does a 1400 watt machine remove 3500 watts of heat, nearly three times what it consumes? Later I thought of another question. When my air conditioner froze up, the repair technician said I was low on Freon. But if Freon makes air conditioners cold, how can less Freon make them so cold that they freeze water to the evaporator coils instead of just condensing it out of the air as liquid water letting it drip to where it is pumped away or for a window air conditioner drain out of a weep hole. So far not one mechanical engineer I tested including my best ones got the right answer and these are not trick questions. They go to the heart of how mechanical refrigeration works.

    Back to HVAC efficiency and my war with ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) and others such as “The Green Grid” backed by many famous names like IBM, Hewlett Packard, and the US government Department of Energy. There is only one valid scientific method for judging the efficiency of an air conditioner or engine and that is to compare it to the efficiency of a Carnot Cycle engine. There is no other valid way. However, these crooked Hillbillies have invented a new way to evaluate data center energy efficiency called PUE and its inverse DCiE. PUE stands for Power Utilization Effectiveness. This is the total power consumed by a data center divided by the power used for just the IT equipment. Notice they didn’t use the word efficiency. They reserved that word to sneak it into its inverse, Data Center infrastucture efficiency. Typical designs in the old days had PUEs designed at 2.0, and even more. Today there are people promising designs of 1.2 or better. A lot of it depends on air conditioning as cooling can consume a lot of power. If you are located at the end of a fjord in Helsinki Finland, all you need do is stick a pipe in nearly frozen water and pump it to your facility through pipes and then blow air over it. You’ll get all the cold air or water you want for practically nothing. It’s cheap and minimizes power utilization. By contrast if you are in the Amazon Jungle or Sahara Desert, you will be using mechanical refrigeration all the time. The only way to get around it is to raise the temperature of your thrermostat and deliver less cooling to the equipment. You can also turn off your humidifiers that prevent static electricity from building up and potentially damaging electronic equipment. This decreases PUE, increases DCiE but only increases the efficiency of money, not of air conditioning. Remember, only a Carnot cycle can be used to evaluate the relative efficiency of a real air conditioner. You trade saving cost of power for reduced reliability when equipment in racks goes well over 100 degrees and there are times when people have to work in there, often under pressure when something is wrong. We’ve always known the valid ways to improve efficiency such as free cooling and heat recovery chillers but the way they’re going about it to get the most impressive numbers isn’t it.

    When mechanical engineers told IT personnel they didn’t need to keep their data centers at 65 degrees F the engineers were brushed aside. When the accountants told them the same thing, they had no choice. The snake oil in the energy saving industry makes the amount in the high end audio industry look like chump change. There are new valid solutions that work. These include in rack and in row cooling which solves otherwise impossible problems and CFD (computational fluid dynamics analysis) which mathematically models heat distribution and Air conditioning effectiveness, allows the designs to be optimized, and simulates failures to assure adequate cooling if there is a fault somewhere in the system. Other schemes like installing VFDs on CRACs (computer room air conditioners) are of questionable value. Others such as operating cooling towers and central chiller plants at very low levels risk making the towers ineffective by reducing spray efficiency and damaging chiller tube bundles by allowing them to get clogged due to low flow rate.

    Okay, ask your best mechanical engineers my two quiz questions. See if they dance around them talking about things like the characteristics of Freon which have nothing to do with it and is the wrong answer. Brass figleaf and bronze oakleaf cluster to someone who gets it right. Do they really know or are they just guessing. BTW, calculating a design from a cookbook formula is not knowledge, knowing how it actually works is. That’s a difference between a designer and a real engineer.


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