Environmentally Performative Design for High-Rise Buildings in North America
Due to current rise of environmental concerns, and interest in high-performance and energy-efficient buildings, the question of “what is sustainable high-rise building” has been raised. Increase of the number of tall buildings worldwide and relatively high energy consumption in building operation create a significant impact of high-rise buildings on overall targets set by the environmental agenda.
The growth of cities increases. It is estimated that by the year 2050 almost 70 % of world’s population will live in urban areas and cities. Buildings are responsible for 40 % of energy consumption, and 33 % of global CO2 emissions. In the United States, from that 40 % energy consumption, 46 % of energy and around 35.4 % of electricity generation go into commercial buildings (Fig. 7.1).
However, the real problem is not the energy consumption of the buildings but the nonrenewable energy consumption and the emission of CO2 as by-products. Therefore, the challenge is to reduce the energy consumption while the renewable energies are integrated into the building.
By definition, high-rise buildings are not mainly sustainable. Most of the high-rise buildings follow a standard plan form without considering the context and environmental relationship to the places where they are located.
The arguments are also related to high-energy operation and its impact on the environment and infrastructure. The problems of tall buildings with large quantities of glazing experience heat losses in the winter and overheat of excess solar gain in the summer. Therefore, the idea of high-performance high-rise buildings has been created by measures on integrating water, light, and passive energies and further to relate those to local climate. There are wide differences in the areas of energy consumption due to climatic regions. Though the majority of energy consumption in
Fig. 7.1 Energy consumption in three sectors with associated CO2 emissions
building operation goes into internal environmental control systems and artificial lighting, the key to improve the energy performance also lies under the use of strategies to take those loads off the building’s portfolio.
I t must be noted that the design of environmentally performative high-rise buildings required deep understanding of climatic context potential and constraints. The year 1990 marked the beginning of more environmentally performative high-rise buildings (Fig. 7.2).
Due to many environmental concerns related to high-rise buildings, the sustainable high-rise includes architectural, engineering, and contextual issues related to
Fig. 7.2 2009 Building energy data book US Department of Energy, http://buildingsdatabook. eere.energy.gov/doct/xls_pdf/314.pdf
building and environmental performance. In regard to the impacts on the performance, the basic strategies are to reduce the demands for energy and water considering the context of the building.
Mainly the lessons learned from vernacular architecture such as daylighting, increasing of thermal mass, and using natural ventilation can be translated easily into smaller-scale buildings, while integration of those strategies into larger-scale buildings are more complex. Due to higher wind velocity in tall buildings, opening windows for natural ventilation on the top levels can be complicated and not doable. That is why mostly larger buildings rely on mechanical ventilation equipment.
The designer of the Galleria Vittorio Emanuele II (1877) Giuseppe Mengoni, developed a labyrinth, which was pulling the air into underground chambers to be cooled by the earth and returned through vents in the floor as needed. This idea has been more developed and used in current buildings such as Manitoba Hydro. As Yeang mentioned, “passive design is essentially low-energy design achieved by the building’s particular morphological organization” (Yeang 1999). In addition, integration of advanced fa?ade technology with HVAC systems results in optimizing energy efficiency and thermal comfort of the occupants. Many high-rise buildings also use mechanical environmental systems to achieve thermal comfort for the occupants. Incorporating sustainability can mean integration of passive systems into design of those systems. So the idea is to maximize the Passive strategies for heating and cooling. This is the best way to reduce energy consumption.
The interest in being sustainable has created several misinterpretations around the design of *high-rises resulted in adverse impact on environmental performance. The use of green labels cannot justify the vagueness of actual performance. A distinctive example of this is incorporating highly glazed fa?ades with no appropriate shadings that create overheating and discomfort while increasing the cooling loads. The use of green labels should be demonstrated by the actual performance of the building rather than just implementation of the strategies and no data to support the claims.
The performative building should operate toward zero CO2 emissions. A comprehensive study done by NREL on a large number of building models from 2003 CBECS (Commercial Building Energy Consumption Surveys) found out 62 % of buildings can reach net zero energy by integration of current technologies.
The definition of Net Zero energy building is to use renewable energy sources to provide the amount of energy the building consumes, or to use off-site renewable energy resources that are transported to the site. As discussed above, high-rise buildings always consumed more energy that they can generate on the site, due to limited amount of their roof and site area. The exposure of high-rise buildings to sun and wind provides the possibility of catching solar radiation or harvest winds and as the case studies have shown, these strategies can be effective. Though as a result of many possible combinations of technological solution, there is no formula to determine the final design; however, the guidelines of strategies can provide a platform for architects to make better decisions to explore the potentials and environmental compositions.
Being viewed as a major energy consumer, high-rise buildings are integrating new technologies to be more energy efficient. In this chapter, the technological system and design strategies of two US environmentally sensitive buildings are examined. These buildings are responsive to their climate and using cutting-edge environmental systems while introducing renewable energy generation coupled with passive solutions. The buildings strategies are introduced in four steps of reduction, integration, reclamation, and production.
-  Solar Power: The Evolution of Sustainable Architecture, Behling Sophia and Stefan, 2000.