Reduce global emissions by 45 percent within 12 years or else. That’s the warning the United Nations’ Intergovernmental Panel on Climate Change issued in 2018, and those scientists meant business. Should society fail to meet the deadline, the cataclysmic damage to the Earth’s climate could be irreversible.
“We are the last generation that can prevent irreparable damage to our planet,” U.N. General Assembly President María Fernanda Espinosa Garcés warned in March 2019 before challenging leaders to make 2020 the last year that carbon emissions increase due to human activities.
Is it even possible to reduce emissions enough to meet the deadline? It’s not a feat governments can achieve on their own. Builders and property owners also must take action and make moves toward zero net energy. It’s unlikely that most buildings will be able to produce as much energy as they consume, but increased sustainability is a good first step.
New York City has taken the lead in the quest for sustainability with the passage of the Climate Mobilization Act, a collection of regulations targeted toward improved energy consumption in the city’s buildings. After all, the city produces 50 million metric tons of carbon emissions each year, and almost 70 percent of that comes from commercial and multi-family buildings.
Can Supertall Buildings be Sustainable?
The Climate Mobilization Act impacts about 50,000 NYC buildings, and one thing everyone knows about buildings in the Big Apple is they tend to be vertical. Tall buildings present unique challenges in terms of sustainability. After all, renewable energy methods such as geothermal heating and cooling just don’t make sense in very tall buildings. Likewise, the tallest structures require multiple systems to properly heat and cool each story.
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Architects and engineers are up to the challenge, though. When designing China’s 121-story Shanghai Tower, Gensler opted to parcel the skyscraper into zones and employ a hybrid cooling system as opposed to a single, rooftop unit.
By utilizing two chiller plants – one in a sub-basement and the other between the 82nd and 83rd floors – and designating nine zones of 12-15 floors each with their own ventilation system, the designers more efficiently maintained building temperatures and reduced its electrical load.
Air pressure also impacts the energy consumption of HVAC systems in supertall buildings. When cold outside air enters the building on the ground floor, it is heated by the building’s HVAC system before the hot air rises throughout the building by way of elevator shafts, stairwells and other open structures.
This rising warm air creates pressure differences between stories and an uneven demand for heat. When hot air enters a cooler building, the reverse occurs as the cool air falls lower in the building. Design firms are tackling this issue by including air pressure-preserving features, such as vestibules at every stairwell and elevator lobby. Reducing this stack effect will cut the energy consumption of the building’s HVAC system.
Green Construction Technology
Of course, energy consumption isn’t the only way to improve a skyscrapers’ sustainability. When British firm Foster + Partners designed Philadelphia’s Comcast Technology Center, the 1,118 feet-tall building was constructed with recycled materials and sustainably-sourced wood. The building also features water monitoring systems and waterless urinals, so it uses 41 percent less water than a typical office building.
Yes, the skyscraper’s climate is maintained by an ultra-efficient HVAC system. But the need for electrical lighting is also minimized through an automated blind system that maximizes the benefits of natural light.
Similar green construction technology can make other skyscrapers more energy efficient and sustainable, reducing the property’s carbon footprint. Instead of relying on the energy usage of HVAC systems and other equipment, green construction technology involves every aspect of a building, from its site and design to construction materials, its systems and operations.
Green building technology doesn’t end with a building’s design and construction, however. Since up to 40 percent of commercial buildings are typically unoccupied at any given time, sensors like motion detectors, RFID scanners and access card readers can be implemented to monitor areas of the building for occupancy.
If an area is unoccupied, the green technology automatically turns off the lights and adjusts the thermostat, reducing energy consumption by as much as 30 percent.
Other forms of green building technology that can be utilized in the tallest buildings include:
- Solar power
- Biodegradable construction materials
- Green insulation made with recycled materials
- Smart appliances
- Cool roofs that reflect heat and sunlight
- Smart thermostats
- Energy-efficient lighting
- Rooftop gardens
Of course, if these methods can improve sustainability of skyscrapers, then they certainly can be deployed in multi-family or commercial properties, hastening the process of going green.
