In this piece we focus on the post-millennial present and explore air-conditioning in relation to two major forces – intensified globalization of the past few decades and anthropogenic climate change.

An interior view of google's data center at council bluffs, iowa.

An interior view of google's data center at council bluffs, iowa.

The past few decades of intensified globalization has many architectural and urban implications. Let us look at two of these implications that is closely related to mechanical cooling. For the sake of simplicity, let us differentiate them into the “less visible” and “more visible” climatic architecture of globalization. The less visible, if not invisible, climatic architecture of globalization refers to the infrastructural backbone that enables the current digital age and globalization. An example of that is the data centers that enable the internet and all related activities of cloud computing to function properly. On the screen are images of Google data centers that allow Google to, among other things, crawl and index 60 trillion web pages, handle 3.5 billion searches a day, and support 900 million Gmail users. Mostly located in remote rule sites, these data centers contain hundreds of thousands of servers that produce tremendous amount of heat. Traditionally, these are cooled with giant computer room air-conditioners supported by energy-guzzling chillers. Google’s data centers are the most energy-efficient around. The servers in them are designed and configured in such a way that no air-conditioning is required. Instead they are cooled using a much less energy-intensive water cooling system. In the past few years, Google has been sharing its best practices with other internet corporations. Despite that, all the data centers globally still consume 1.5 per cent of the world’s electricity (Levy 2012).

urban renewal #6, apartment complex, jiangiunAo Hong kong, 2004.

urban renewal #6, apartment complex, jiangiunAo Hong kong, 2004.

The more visible climatic architecture of globalization is closely connected to another much discussed recent phenomenon – the urban century. From 2008 onward, more than half of the world’s population live in cities. The process of relentless urbanization is especially in the developing countries. Out of the 34 megacities with more than 10 million in population globally, only eight are from the developed countries. With 6 megacities of more than 10 million, and more than 100 cities with more than 1 million in population, China is one of the countries where rapid urbanization is most pronounced. The urban population of China has expanded by 500 million in the past three decades. Together with great economic growth, increasing affluence and lifestyle changes, rapid urbanization in China has also led to the skyrocketing of in air-conditioning adoption rates and, concomitantly, the amount of electricity consumption. In 1990, there was less than 1 air-conditioner per 100 households in China. But by 2007, there were 95 air-conditioners in 100 households. In 2010, it was recorded that 50 million units of air-conditioner were sold in China and the sales of air-conditioners in China during 2013 was eight times that of the United States. China is projected to be on its way to surpass the United States as the world’s largest user of electricity for air-conditioning by 2020 (Cox 2012).

The widespread usage of air-conditioning led to inevitably to increased peak load in electricity consumption. As a result, China is estimated to face a shortfall of 20-40 gigawatts between peak load and maximum generating capacity. That resulted in energy rationing but it also led to the building of more power plants, especially coal-fired power plants. In 2014 alone, China added 33 gigawatts of coal-fired capacity. During its peak between 2005 and 2011, China added about two 600 megawatts coal plants a week (2015a). Although China has slowed down its rate of building new coal plants and the Chinese government has promised that there will be no newly constructed coal plant from 2030, the carbon emission and air pollution caused by the existing coal plants are significant (Ottery 2013). China has overtaken the United States as the world’s largest carbon emitter in 2007 although one should also note that China’s carbon emission per capita is still significantly lower than most developed countries. Cities in China also have some of the most polluted air in the world, with the PM2.5 levels of major cities in Yangtze River Delta, Pearl River Delta, and Beijing-Tianjin-Hebei region having over 100 smoggy days a year, when the PM2.5 concentration is two to four times above the World Health Organization guidelines (Berkeley Earth 2015). Air pollution in the cities also meant that urban inhabitants in these cities are more like to shut themselves indoor and rely on air-conditioning for not just keeping themselves thermally comfortable but also for filtering and keeping the polluted air out. As such, greater air-conditioning adoption, increased energy demand, the building of power plants and air pollution come together to create a vicious cycle that increased the air-conditioning dependency of Chinese urban inhabitants.

mapping of the annual average pm2.5 concentration in china by Berkeley earth, 2015.

mapping of the annual average pm2.5 concentration in china by Berkeley earth, 2015.

Rapid urbanization in China led to urban sprawls in many Chinese metropolitan areas. The amount of land classified as urban has doubled since 2000 and new mega-urban conglomerations, such as the supercity of Jing-Jin-Ji, combining Beijing, Tianjin and parts of Hebei Province, were formed (Johnson 2015, 2015b). As rapid urbanization led to the large-scale transformation of rural land into densely built-up urban district, urban sprawls in many Chinese metropolitan areas further magnified the scale of urban heat island effect (Zhou et al. 2015). Temperature differences of up to more than four degrees Celsius were recorded between many Chinese cities and their surrounding rural areas. The urban heat island effect was also exacerbated by waste heat produced by air-conditioners. Together with more frequent extreme weather events, such as heat waves, brought about by anthropogenic climate change, urban heat island effect and urban sprawl form another negative feedback loop that create even greater growth and dependency on air-conditioning in Chinese cities.

As the world’s largest carbon emitter, China has been taking steps to reduce its carbon emission. The recent agreements between the Chinese and the US Governments to cut carbon emission is the latest indication of that. Since the early 2000s, the Chinese government has been actively promoting green buildings and even eco-cities. One of the more prominent green buildings completed in China in the past few years is the Vanke Center by U.S. starchitect Steven Holl. Completed in 2009 as the corporate headquarter (with additional residential, office and hotel components) for Vanke, one of the largest real estate developers in China, the building was one of the first LEED platinum rated buildings in Southern China.  Sensitively conceived as a horizontal skyscraper floating above public gardens, the building incorporated many exemplary sustainable design strategies, making the building, among other things, a “striking example of energy efficiency.”

For the purpose of this article, we’ll focus on the technologies of cooling and ventilation. The building relies on mixed-mode cooling and ventilation, combining both active and passive strategies. The building envelope is optimized for energy efficiency: some facades are shaded by sensor-controlled louvers while others have large operable windows to allow for natural ventilation for up to 60% of the year, during the cooler months between November and March. Photovoltaics panels were installed on the roof to provide 26.8% of the building’s total electricity needs from solar power, furthering reducing the carbon emission of the building.

Does the Vanke Center address the aforementioned problems of air-conditioning in the urban century and the Anthropocene epoch? Does it herald a new norm of more energy-efficient and sustainable use of air-conditioning in China and globally?

view of the public space below the floating horizontal skyscraper.

view of the public space below the floating horizontal skyscraper.

Let us try to answer the earlier questions by looking at two tendencies. First, let us look at the emerging tendency of having more buildings with mixed-mode cooling, which according to its advocates is not only more energy-efficient but also creates greater satisfaction among the occupants (Brager, Ring, and Powell 2000). To facilitate the implementation of mixed mode cooling, the American Society of Heating, Refrigerating and Air-conditioning engineers (ASHRAE) has modified its thermal comfort model in 2004 from one based on the laboratory-based Predicted Mean Vote model by Fanger to one based on adaptive thermal comfort model. The adaptive thermal comfort model is based on field studies conducted in a large number of buildings located at various climatic zones. The studies found that occupants in naturally ventilated buildings felt comfortable in a much wider indoor temperature range than that predicted by the old thermal model based on laboratory-based findings. Furthermore, the studies found that the indoor thermal comfort range was not unexpectedly closely linked to outdoor temperature since they are naturally ventilated (de Dear and Brager 2002, Nicol, Humphreys, and Roaf 2012). Unlike earlier air-conditioned buildings, buildings that rely on mixed-mode cooling are no longer hermetically sealed and disconnected from the local climatic conditions. Not only are these buildings less energy-profligate and have lower carbon emission than traditional air-conditioned buildings, they also invalidate the opposition between rooted culture and universal technique that Frampton and the theorists of critical regionalism put forward.

photovoltaics panels on Arooftop

photovoltaics panels on Arooftop

Next, let us look at a proposed project by Transsolar, the international climate engineering firm that was involved in the Vanke Center discussed earlier. Transsolar, a very innovative firm of German origins, has been working on providing relatively low-energy engineering solutions to the problems surrounding outdoor thermal comfort in the dessert climate of Arabian Gulf states like United Arab Emirate and Qatar. One of their most challenging projects must be that of providing outdoor thermal comfort for both soccer players and spectators for the World Cup that will be held in Qatar in 2022. Their solution involved an innovative hybrid approach that combines passive design solution, radiant cooling and “soft conditioning.” While the engineering solution is undoubtedly clever, the starting point of the project is questionable even if, for a moment, we ignore the accusations of corruption surrounding how the world soccer governing body FIFA awarded the rights to host the World Cup and the subsequent controversies on high death rates of the migrant workers working on Qatar World Cup stadia. The summer daytime temperature in Qatar reaches more than 50 °C, making it not just incredibly uncomfortable for the spectators but, more importantly, even hazardous for the health of the soccer players. Rather than focusing on how technologies can solve certain environmental problems, it is perhaps important to ask why should such extreme environmental problems be posed in the first place? In this case, why disregard climatic constraints and host a physically demanding sporting competition during the hottest time of a year at one of the hottest places on earth? Doesn’t an engineering solution like the one proposed for cooling the World Cup stadia of Qatar represent the tendency of technological-fix that ignores natural and climatic limits? Isn’t this just a small step to the dangerous technological optimism behind the faith in climate control at the mega-scale, i.e. geo-engineering that can purportedly limit the adverse effects of climate change?

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