Air conditioners consume vast amounts of electricity and the warmer the world gets the more energy will be required to keep cool. Energy use is directly related to both costs and emissions that cause climate change. While heating and transportation are commonly acknowledged for their power demands, air conditioning (AC)is another important piece of of responsible energy management.
The data is clear, the world is getting hotter. In a growing number of places staying cool is not only a matter of comfort it is increasingly a matter of survival. As the heat associated with climate change intensifies life will become impossible without some form of cooling. In places like the Persian Gulf temperatures have already exceeded 160 Fahrenheit.
The combination of warming temperatures, increasing standards of living and electrification (either through a grid or as part of a local distributed energy system) in some of the warmest places in the world mean that cooling will gobble up even more energy going forward. Heat waves are already killing thousands each year and the toll is expected to continue to mount. The energy requirements associated with cooling will be taxing both in terms of fiscal costs and carbon budgets.
Efforts to cool buildings have been around for thousands of years. Ancient Romans circulated water between the walls to keep their homes cool and large hand powered fans were invented in 2nd-century China. Modern air conditioning was developed by a Florida physician by the name of John Gorrie. He suspending basins of ice from the ceiling and 1851 he patented a cooling machine that used steam engines to force air through a tank of chilled brine.
A half century later an engineer by the name of Willis Haviland Carrier developed a system that pumped air over coils chilled with ammonia and then expelled it with a fan. In 1925, the first commercially available Carrier system was installed at the Rivoli Theater in Times Square. Six years later H.H. Schultz and J.Q. Sherman invented the first window units. However many decades would pass before AC was a staple in American households. Today more than 85 percent of American homes and buildings have AC accounting for 5 percent of the nation's energy demand.
President Obama's 2009 stimulus package invested in building retrofits that provided better insulation making them more energy efficient and helping them to keep out both the cold and the heat. This minimizes the need for heating and cooling. This is particularly important as we are seeing a consistent trend of warmer summers with temperatures exceeding 120 degrees F. in parts of the continental US.
In the developing world the energy demand associated with AC is expected to see the most growth. There is already tremendous demand in China and distributed energy is bringing electricity to rural villages throughout India. The demand is urgent as in places like India thousands die each year due to heat exposure. As a nation of one and a quarter billion Indian energy requirements for cooling will be very substantial.
As reported by the Washington Post, a report from the Lawrence Berkeley National Laboratory suggests that only 5 percent of Indian buildings have air conditioning. However, sales of air conditioners are growing in India, Indonesia and Brazil by between 10 and 15 percent per year. In Mexico, only 13 percent of households currently have AC, by the end of the century more 80 percent of Mexican homes are expected to have AC.
The growth of AC is expected to be astronomical. The Berkeley report states that there are going to be 700 million air conditioners by 2030, and 1.6 billion of them by 2050. If these new units are powered by fossil fuels it will spell disaster for our climate which is already teetering on the brink of tipping points.
In addition to powering cooling units with renewable sources of energy, these air conditioners can be made much more energy efficient and less dependent on greenhouse gas refrigerants like hydrofluorocarbons (HFCs). More efficient cooling units could prevent billions of tons of emissions from being pumped into the atmosphere. The Berkley report suggest that this could amount to as much as almost 100 billion tons of averted CO2 emissions by 2050.
The US Department of Energy's (DOE) new efficiency standards includes AC and it was introduced in December 2015. These new efficiency standards offer the most energy and pollution savings of any DOE energy-saving rule. They will reduce commercial rooftop air conditioner energy use by about 30 percent and save a typical building owner between $3,500 and $16,500 over the life of a single commercial rooftop air conditioner. Altogether over the life of these units (three decades) the standards will save businesses between up to $50 billion, reduce CO2 by more than 885 million metric tons, decrease electricity consumption by 1.3 trillion kilowatt-hours or 15 quadrillion BTUs (quads) of energy. This amounts to energy savings enough energy savings equivalent to the carbon emissions from more than 120 million US homes for a year.
As explained by tne NRDC:
"The outstanding accomplishments of the energy efficiency standards program proves that it's not only possible for industry and advocates to work together toward a common goal, but that collaboration can produce better results for everyone involved."
As explored in Energy Manager Today, a report by Transparency Market Research said that portable air conditions will have the highest compound annual growth rate (CAGR) of the category by 2024.
The NRDC’s Lauren Urbanek estimates that commercial customers will save almost $300 per unit in electrical costs over the life of a unit following the DoE’s rules. These savings increase commensurate with the size of the air conditioner.
There are steps that can be taken to reduce the amount of energy we use from running air conditioners. Passive cooling strategies like natural ventilation can reduce the need for AC. Fans including blade-less fans and solar-fans are the most obvious energy efficient alternatives to AC. Other inexpensive alternatives to AC include installing solar blinds and window films that improve insulation. Using LED lighting can also help to keep a building cool because it generates less heat.
As reviewed in a Grist, the environmental think-tank Rocky Mountain Institute’s new Innovation Center in Basalt, Colorado uses a technique called "night flushing," in which windows automatically open at night when the temperatures drops. This releases heat from inside the building. Then, when it’s hot out during the day, the windows are automatically closed and covered to keep out sunlight. This futuristic green building also has super-insulated walls, an atrium filled with plants, and fans everywhere.