Asia is experiencing an influx of skyscraper developments, many of which claim to incorporate smart, green design features and innovations, looking to a sustainable future in tall building construction.
But can high-rise buildings ever be sustainable? It’s a simple question that has both a simple and a complicated answer. The traditional view of tall buildings is that they are a fundamentally unsustainable form of development. Critics point to decades of social and environmental evidence as justification ranging from poor life expectancy and energy inefficiency to physical anonymity, economic segregation and social polarisation.
With a plethora of high-rise projects on the horizon, Lai Wan Sing and Dr Stellios Plainiotis of NEAPOLI were invited to present at the Petronas Green Building Forum 2017 on the topic of sustainability in high-rise construction. They discussed innovative design standards and addressed the challenges of applying sustainability principles to high-rise buildings. They proposed solutions based on three of NEAPOLI’s major high-rise projects within Kuala Lumpur’s City Centre: the CitiTower at Lot185 (picture above) targeted for GBI Gold and LEED Platinum, the GBI-Gold targeted Complex Dayabumi Phase 3 and the triple GBI/LEED/GreenRE Platinum Menara PNB118.
Without careful consideration and planning, high-rise developments are more energy-intensive than equivalent low/mid-rise. This is because many of the aspects that affect energy are directly related to height, such as the use of lifts or pumping water. Tall buildings tend to have higher demand for heating and cooling, mainly due to the extensive use of glass as opposed to opaque walls, since solar heat gain and heat transfer are greater through glass. They are also more exposed to solar radiation and are less likely to be overshadowed by trees or other buildings.
However as Lai Wan Sing reasoned, applying sustainability principles to high-rise buildings has great importance since they have a bigger amount of environmental charge due to their scale and the intense human population during the phases of construction, operation and deconstruction. Advancements in construction technologies – such as selective coatings for glazing, efficient HVAC systems, composite materials and renewable energy– have recently allowed high-rise developments perform well in green building rating tools like GBI and LEED. Modern Computational Design tools such as CFD, Dynamic Building Energy, Wind Driven Rain, Daylighting and Solar Reflectance simulations – and their better integration to the design process through BIM – have led to better, more informed decision making at all design stages.
Recent progress in vertical transportation systems has greatly increased the efficiency of elevators, especially with the development of regenerative motors, composite material lightweight rope and rope-free technology. The energy strategies at the three presented case studies will result in comulative energy savings of over 120 million kWh per year and reduction of annual CO2e emissions by nearly 90,000 metric tons. This is equivalent to annual emissions from nearly 10,000 low-rise homes or 350 million km driven by passenger cars. Stellios Plainiotis stressed that sustainability performance should not be measured in isolation but in the overall context of the geography of the area, activity systems of the area including urban form and transport, energy and water grid of the area, food supply. Increased density is undoubtedly compatible with the goals of sustainability and fosters a liveable city with residences, goods, and services concentrated onto a smaller land area. He recommended that the future prototype should be mixed-use, respond to the growing needs of the economy, and achieve the highest possible energy & environmental performance. Future research directions were also been pinpointed; while it’s clear that today’s green buildings solve the energy issues high-rise buildings faced in the past, there’s still a lot of work to be done.