Facade Design in Hot-Humid Climates
This year’s fellowship goes back to the basics of sustainability and building science. Building envelopes, from the humble brick wall to dynamic, fully-integrated façades, can have huge impacts on occupant comfort, health, environmental impact and energy performance. Building on the work of previous EDR fellows, this research explores how to make affordable envelopes that provide daylight and views while controlling glare. Also, how can the building envelopes of historic structures be upgraded for better performance without moisture drive endangering the very buildings we’re trying to save? And finally, how do we track the carbon impact of building envelope choices as part of the design process?
In New Orleans, we see the impact of climate change first hand – storms are becoming stronger and more frequent as the summers seem to be getting longer and longer. In addition to ample rain, we also struggle with high ambient humidity and relentless solar irradiation. Similarly, a large portion of the globe occupies hot-humid regions, similar to what we see in New Orleans. Here, “hot-humid” climates (shown below) are delineated by Equatorial (Af, Am, Aw) and Subtropical (Cfa, Csa, Csb) in the Koppen-Geiger Climate Classification. These climates have relatively constant temperatures from month to month, typically exceeding 64F (18C) year round, with small diurnal temperature changes that are often greater than the temperature change between seasons (Kottek et al. 2006).
Koppen-Geiger Climate Classification - Summary of Hot-Humid Climates
Many of the world’s most rapidly urbanizing economies reside within hot-humid regions. China and India will contribute more than one third of the global urban population increase between 2014 and 2050 (United Nations 2015). However, Building trends and technologies have developed in primarily cold and temperate regions of the northern hemisphere, where the highly developed can be found. In fact, a quick Google Scholar search for “building envelope hot climate” returns only 43,000 results while the same search in cold climates returns 69,000 results – a 40% difference!
In addition, many developing regions have neither the environmental regulations in place nor the resources, materials or technologies to promote sustainable production and consumption patterns. In fact, developing municipal governments seldom focus on sustainable development and natural resource protection when faced with rapid growth – instead, priority is given to housing, transportation, jobs and economic growth.
Historically, civilizations have established vocabularies of vernacular styles based on cultural antecedents and bioclimatic conditions, including orientation, shading, and natural ventilation. In exchange, these strategies have created unique building styles around the world. However, many architects and developers have abandoned their local aesthetic for the sake of sealed glass towers, emblematic of the heroic structures found in the West, which rely entirely on mechanical conditioning and artificial lighting. In fact, advances in mechanical technologies and air conditioning market penetration have allowed for global trends toward glazing-dominated, sealed buildings regardless of climate, culture or local identity.
With this new style came the desire for thin building enclosure systems, and consequentially, the invention of the curtain wall. Quickly erected and modern in appearance, this thin membrane quickly became the symbol of economic growth and prosperity in the West, changing skylines around the world. Almost immediately, air conditioning became fundamental to commercial building design around the world, even in climates with abundant passive conditioning opportunities.
Home Insurance Building (left). Chicago, 1885. Photo by the Chicago Architectural Photographing Company
Milam Building (right). San Antonio, 1928. Photo from the San Antonio Business Journal
One of the first office buildings, Chicago’s Home Insurance Building (above, left) was built in in 1885. It used operable windows for ventilation, lighting and passive solar gains. Buildings of this generation were typically 20-40% glazed, as compared to the 50-75% glazed facades of the modern buildings. Only 43 years later, the first air conditioned office building was completed in San Antonio, Texas (above, right). From that point on, air conditioning became an expectation of the modern workplace. Just as certain building materials and methods became associate with confidence and power, there became an association between climate control and social status, symbolic of mankind’s victory over nature (Brager and de Dear 2008). Moving from open, naturally ventilated interior spaces to completely sealed environments has narrowed our range of acceptable thermal conditions, in turn affecting the human perception of the outdoor world.
The history of the built environment is quite extensive and building typologies have typically evolved slowly over time. However,
the universal adoption of air conditioning, tall buildings and curtain wall technology, all within the span of a single generation, has created incredible impacts on the urban skyline as well as global energy consumption.
In no place is this phenomenon more evident or environmentally harmful than in the developing tropics. While the focus of this fellowship is innovative façade design in New Orleans and the greater American South, its application must extend well beyond that.
References:
Brager, Gail S., and Richard J. de Dear. 2008. “Historical and Cultural Influences on Comfort Expectations.” In Buildings, Culture and Environment: Informing Local and Global Practices. John Wiley & Sons.
Kottek, Markus, Jürgen Grieser, Christoph Beck, Bruno Rudolf, and Franz Rubel. 2006. “World Map of the Köppen-Geiger Climate Classification Updated.” Meteorologische Zeitschrift 15 (3): 259–63. doi:10.1127/0941-2948/2006/0130.
United Nations. 2015. “World Urbanization Prospects, The 2014 Edition.” New York: Department of Economic and Social Affairs, Population Division.