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Cooling in a warming world

Building design is key to reducing demand for energy guzzling air conditioning

Energy demand for cooling indoor spaces to temperatures fit for man and machine is rising fast. It does not have to. Better air conditioning equipment, its correct installation and enforcement of tougher standards for both would rapidly reduce energy use. For that to happen, political action on rules and regulations is urgently needed before cooling becomes a significant accelerator of global warming

Wake up call:
The market for keeping buildings cool is exploding and flooding the world with substandard energy hungry solutions Smell the coffee:
Energy efficiency improvements through the introduction of mandatory norms for cooling equipment could halve energy growth from air conditioning Bring back shade:
Better designed buildings, more space between them, sun protection for roofs and introduction of urban greenery all reduce energy use Key quote:
This is a performance standards issue.”
As the world warms, the need for cooling will escalate as people struggle to avoid heat stress, keep vital medicines at stable temperatures and create cool ambient operating conditions for machines and data centres. The International Energy Agency (IEA) predicts ten air conditioning units will be sold every second for the next 30 years, placing extra load on electricity systems and driving up emissions. More efficient use of electricity, enforcement of standards, standardisation of air conditioning unit design, architecture apt for creating cooler buildings and urban greenery for shade could help reduce demand. Use of energy for cooling buildings is increasing and IEA figures tracking the trend make for sober reading. Since 2000, energy for cooling has doubled in buildings worldwide from 3.6 exajoules (EJ) to seven EJ. Air conditioners and electric fans now account for nearly 20% of total electricity consumption in buildings. While 90% of households in the US and 60% in China have air conditioning (AC), this figure falls to 8% in the hottest parts of the world. As temperatures rise and disposable incomes increase, the number of AC units in use is predicted to rise from today’s 1.6 billion to 5.6 billion in 2050, requiring the equivalent of the current combined electricity capacity of the EU, the US and Japan, says the IEA. Global year end AC sales for 2017 were worth $102 billion, says BRISA, a UK-based building services and research organisation. China, the US and Japan topped the sales charts, with the Asia Pacific region accounting for the largest share of AC units with 58% of global value. Growth in the coming years will be led by Indonesia, India and the Middle East, forecasts the IEA.

Blind spot

In an attempt to draw policy makers’ attention to the subject, the agency’s executive director Fatih Birol has described growing electricity demand for air conditioning as one of the most critical blindspots” in the global energy debate. If the current trajectory is not altered, space cooling will account for 37% of electricity demand growth to 2050, compared to 12.4% for heating. In China, peak electricity consumption will rise by 36% with each degree Celsius of warming due to escalating demand for air conditioning, predict Chinese and US researchers. Lucas Davis, professor at the Haas School of Business, University of Berkeley, US, who has researched AC use in Mexico agrees. I think it is a global blind spot. There is little recognition of the impact air conditioning can have, both economic and environmental. It is just an enormous consumer of electricity.” A typical window AC unit, installed in place of a window and intended to cool a single room, draws 20 times as much electricity as a standard 30-40 watt fan, says Davis. In many parts of the world, putting in a window AC unit will double household electricity consumption.”

Efficiency variations

Efficiency levels of units vary considerably, says the IEA. The best of those available in the EU and Japan are some 25% more efficient that those in the US and China. And householders are not buying the most efficient units available. In Australia, Canada, China, Europe, Indonesia and Japan, people are installing units roughly half as efficient as the best available. And in Mexico, the Philippines South Africa, Thailand and the US, average market efficiency is even lower. No minimum energy performance standards exist for AC units in Algeria and Morocco, says the World Bank. Between 2000 and 2013, the number of units in these countries, plus Tunisia, increased by a factor of 160 or 48% a year from a base of approximately 9.7 million units, it adds. The task of dealing with this issue sounds extremely challenging, but some simple measures such as improving AC efficiency, could considerably slash the energy use of cooling. Forecasting by the IEA shows that efficiency improvements through the introduction of mandatory norms could halve energy growth from AC. This is a performance standards issue,” says the IEAs John Dulac. The agency is conducting research aimed at providing comprehensive resilient cooling technology profiles, well-documented case studies and success stories, and recommendations for the integration of resilient cooling in legislation and standards. Davis says: Typically, international organisations [like the World Trade Organization] have not got involved in energy efficiency standards. Instead what happens around the world is that independent countries adopt the standards of the US.” Standards that are far from being best in class. Barton James, CEO of Air Conditioning Contractors’ America, which represents AC installers, takes a different line of argument. He believes calls for higher efficiency systems are misguided. AC energy efficiency standards in the US are probably higher than what they need to be,” says James. In his opinion, the problem lies in poor installation standards, which can reduce the energy efficiency of a system by 40%. He bemoans the poor standards of AC installation across the US. Only 17 of our 50 states have a licence requirement to be a contractor. It is the wild west out there.” US tax incentives have been towards the purchase of the equipment not the installation”. He hopes that as cooling takes off in other countries they do not make the same mistakes”.

Electricity prices

As a whole, the cooling sector in the US is paying lip service” to the need for energy efficiency in response to the report published in 2018 by the Intergovernmental Climate Change Panel on the impacts of global warming of 1.5°C above pre-industrial levels, James says. He questions the interest of US electricity utilities in energy efficiency. Their biggest concern is meeting peak demand. If that uses a tonne more energy, they don’t care,” he suggests. In Davis’s opinion electricity prices will play a major role in making cooling more energy efficient. He contends that in large parts of the world, where electricity is highly subsidised, it is just too cheap”. He says: If I was only paying $0.2 an hour I’d buy the cheapest most inefficient air conditioner. That is bad for society. Electricity in those cases needs to be more expensive.” The surge in AC and refrigeration demand has a climate impact beyond its high electricity demand due to the escalating use of hydrofluorocarbons (HFCs). Used as substitutes for ozone-depleting substances, HFCs are themselves extremely potent greenhouse gases, up to 4000 times more so than carbon dioxide. The Kigali Amendment of the Montreal Protocol on Substances that Deplete the Ozone Layer, which came into force on 1 January 2019, aims to tackle this problem. Under the amendment, all countries will gradually phase down HFCs by more than 80% over the next 30 years and replace them with more climate-friendly alternatives. Developed countries are expected to start reducing their production and importation of HFCs immediately, while most developing countries will start their phase down in 2024. Altogether this could save around 80 billion tonnes of CO2 equivalent by 2050 and avoid global warming of as much as 0.4°C by the end of the century. As a comparison, global annual carbon emissions reached 37.1 billion tonnes in 2018. Encouraging innovation in air conditioning technology and efficiency is the aim of the Global Cooling Prize launched by a coalition of government and research leaders in November 2018. They are on a mission to incentivise the development of a residential cooling solution with five times less climate impact than today’s standard. Only 14% of maximum theoretical efficiency has been reached by today’s most advanced AC technology (most ACs attain less than 8%), they say.
India plans to keep everybody cool
The energy, environmental and health crises posed by the escalating demand for cooling looms large in India with its growing middle class and increasingly hot climate. Publications from high level energy efficiency advocates and government point to the gravity of the situation for this country of over one billion citizens where temperatures reached nearly 50°C in recent summers.India’s energy demand from cooling will more than double and tonnes of refrigeration used triple between 2017 and 2027 under a business-as-usual scenario, says a report by the country’s Alliance for an Energy Efficient Economy (AEEE), an industry led not-for-profit organisation. The country has one of the lowest levels of access to cooling in the world. Per capita levels of energy consumption for space cooling are around 69 kilowatt hours (kWh) compared to a global average of 272 kWh. This figure rises to 1878 kWh a person in the US. It is the first time the impact of cooling and refrigeration has been done at pan-India level in terms of both energy and greenhouse gas emissions,” says Satish Kumar, president of the AEEE.The publication influenced the government’s draft Cooling Action Plan released in September 2018 and expected to be finalised soon. The plan estimates India’s total cooling requirement will increase by eight in the next 20 years with room air conditioners consuming more than half of the total energy required for space cooling by 2037/38.The idea in the draft of not allowing air conditioning in commercial buildings to be set colder than 24-25°C has incited much discussion in the country. Increasing the temperature of an air-conditioner by just 1°C can save about 6% of electricity consumption, suggests the government’s bureau of energy efficiency.The draft plan was criticised by India’s Centre for Science and Environment (CSE), a civil society organisation, for being too focused on the personal air conditioner market and for ignoring those unable to afford such equipment. Cooling is a much an equity as a sustainability issue, says the organisation. About 60% of current space cooling energy consumption is by the top 10% of the population,” it states, demanding thermal comfort for all without an over-dependence on active cooling.The Indian government is a supporter of the Global Cooling Prize launched in November 2018 by the Rocky Mountain Institute, a US clean energy non-profit, which aims to develop an innovative, climate-friendly residential cooling solution for everyone.Meanwhile, India’s Ministry of Power has published a new energy conservation code for residential buildings that promotes energy efficiency in the design and construction of homes, apartments and townships. Implementation of the code has the potential for energy savings of around 125 billion units of electricity a year by 2030, equivalent to about 100 million tonnes of carbon dioxide emissions, says the ministry.

Building design

Another extremely important, and frequently ignored, means of reducing the demand for AC is through building design and construction. Architectural standards need to change,” says Dulac. We need to teach architects to do things differently.” The desire to have European style buildings in hot climates is not necessarily good for energy efficiency and use, he says, yet we now see the same buildings everywhere”. He adds: Making new constructions out of steel and glass gives relatively poor performance. We need to move towards more traditional means with external shading. This would drastically reduce the need for AC.” Other measures include coating single-pane windows in order to reduce heat gain by 70-90%. This is only standard practice in the US,” says Dulac. We do not see this happening in Asia, where it needs to be created at market scale.” In a similar vein, the Kigali Cooling Efficiency Programme (K-CEP), set up to support the Kigali Amendment, has launched a $2 million challenge aimed at scaling up the deployment of solar-reflective cool roofs in developing countries. By painting roofs with innovative coating materials, indoor temperatures can be reduced by 2-3°C, helping to decrease demand for air conditioning in households that can afford it and providing a passive cooling solution for the billions who cannot. In addition, local ambient air temperatures can be reduced when all the roofs in a whole neighbourhood are treated, says K-CEP.

Urban planning

Urban planning is also vital to reduce the escalation in AC. Creating urban areas which have irregular layouts could help significantly reduce urban heat island effect, concludes research from the Massachusetts Institute of Technology, US, published in 2018. Analysis of layouts of various cities found that those built on regular grid patterns, such as New York and Chicago, had a far greater build up of heat than those which follow a more chaotic pattern, such as Boston and London. And international research over the last 15 years gives clear pointers to urban planners to ensure as much greenery as possible. Trees and vegetation cool down cities regardless of whether they are growing in parks, streets or green roofs. Medellin, Colombia, is one city trying to put this advice in to practice, aiming to reduce the urban heat island effect via 30 green corridors. Addis Ababa, Ethiopia, is focusing on expanding green areas and restoring polluted rivers to cool the local environment. And in Singapore, green space and shading is being incentivised in new building developments. All three cities are shortlisted for the first ever Cooling for People award run by the Ashden Award, a UK non-profit which supports and promotes sustainable energy enterprises from around the world.

Writer: Iva Pocock


This article is part of a series examining how to decarbonise heating and cooling systems