The iconic Empire State Building is one of the 20th century’s engineering marvels. The industry has come a long way in terms of development for sustainability and energy efficiency. This article looks at the changes made in the Empire State Building to bring in the new age of sustainability while maintaining the legendary framework.
Historical Prowess
The construction of the Empire State Building began on March 17, 1930, marking the start of an ambitious project and race to create the world’s first 100+ story building. Located on Fifth Avenue, this architectural marvel was designed by Shreve, Lamb & Harmon Associates and built by Starrett Bros. & Eken. Designed in the Art Deco style, the building was meant to resemble a pencil. The framework rose at an impressive rate of 4 ½ stories per week. Even more impressive, the Empire State Building was completed in 1931, taking just 1 year and 45 days. The total construction cost was $40,948,900, which is equivalent to over $800 million today. The Empire State Building occupies an entire city block and has its own zip code: 10118. In 1950, a 222-foot-tall antenna was added, pushing the spire height to 1,472 feet. It boasts a total floor area of 2,768,591 square feet and an approximate weight of 370,000 tons.
This 102-story skyscraper soon became a popular tourist attraction, offering breathtaking skyline views for just 10 cents. The Empire State Building has been a significant part of popular culture. On March 2, 1933, it was famously featured in the movie “King Kong.” By 1955, the American Society of Civil Engineers recognized it as one of the seven greatest engineering achievements in American history. In 2019, the Empire State Building unveiled a comprehensive renovation of its 102nd and 80th floor exhibition spaces. Visitors can now immerse themselves in the building’s rich history, pop culture significance, and New York City culture.
Commitment to Energy Efficiency
Since the Empire State Building was built in the early 20th century, many upgrades were needed to align with new sustainability developments. In 2009, former President Bill Clinton, Mayor Michael Bloomberg, and Anthony E. Malkin announced a groundbreaking energy efficiency program for the Empire State Building. This multi-year, $65 million program introduced new elevators, climate systems, and other technology upgrades. The building switched to no or low use of VOC materials and eliminating use of Red List materials. These are chemicals or materials that are considered harmful when exposed to humans, living organisms, and the environment. The building now places renewed emphasis on sustainability by maintaining regular indoor environmental quality (IEQ) testing.
One of the most challenging aspects of the Empire State Building retrofit was the replacement of 6,514 windows. Instead of installing entirely new windows, engineers chose to re-engineer the existing glass. This involved adding a special low-emissivity (low-e) coating and inserting an inert gas between the panes to quadruple their energy performance. This approach minimized waste and maintained the building’s historical integrity, while improving thermal performance to reduce energy consumption. Engineers also had to account for the significant wind loads that high-rise buildings face, ensuring that the new windows could withstand pressure and maintain air-tightness at such altitudes. This window replacement was the largest window replacement ever authorized by the Landmarks Preservation Commission.
An innovative feature of the retrofit was the modernization of the elevator system. Engineers replaced the motors with regenerative drives that captured energy usually lost as heat during braking and converted it into usable power for the building’s grid. This energy recapture system is particularly effective in high-traffic buildings like the Empire State Building, where frequent elevator use provides a significant opportunity for energy savings. The technical challenge was ensuring that the new system integrated seamlessly with the older infrastructure, requiring advanced software controls and careful load balancing to prevent system failures.
The Empire State Building’s HVAC retrofit focused on increasing energy efficiency while preserving occupant comfort. Engineers upgraded the system with MERV 13 filters to improve indoor air quality and installed advanced digital thermostats to give tenants greater control over their environments. The building’s pre-existing steam heating system posed a challenge due to its age, requiring the integration of modern controls to regulate temperature more precisely. Engineers installed variable air volume (VAV) systems that dynamically adjusted airflow based on real-time occupancy, reducing unnecessary energy use in unoccupied spaces.
To address heat loss from the building’s aging radiators, engineers installed reflective barriers behind each unit. These barriers reflected heat back into the occupied spaces, reducing the amount of energy needed to maintain comfortable temperatures. This low-tech but highly effective solution resulted in significant energy savings without altering the building’s historical features. The installation process required meticulous attention to detail, as the retrofit had to avoid damaging the original masonry and interior walls.
Engineers installed adaptive dimming systems that adjust indoor lighting based on the amount of natural daylight. The retrofit involved integrating daylight sensors and occupancy sensors to dynamically dim or brighten lights based on real-time conditions. The system not only reduced energy consumption but also enhanced tenant comfort by minimizing glare. One technical challenge was ensuring compatibility between the new dimming system and the building’s existing electrical infrastructure, requiring the development of customized software controls.
The Empire State Building’s energy retrofit project demonstrated a payback period of 3 years for a guaranteed energy reduction of 38%. As shown in the image, the sum of the small percentages of reduced consumption in each category create the annual reduction. This energy conservation has been consistently exceeded since its 2010 implementation. It has earned ENERGY STAR certification every year since 2010, a certification only given to buildings who meet strict energy performance standards set by the Environmental Protection Agency (EPA). By 2011, the building received the Green Power Leadership Award from the U.S. EPA and earned its Leadership in Energy and Environmental Design (LEED) Gold certification, an award given to buildings that have excelled in sustainable design and operation. The Empire State Rebuilding program was a testament to its modernization efforts. Since its construction, the Empire State Building has symbolized technology, imagination, and ambition. Today, it leads in sustainability, proving the economic viability of investing in energy efficiency. Despite being nearly 100 years old, it ranks in the top 20% of all Class A commercial assets in the nation. The Empire State Building continues to be a beacon of innovation, sustainability, and architectural excellence, inspiring generations to come.
Retrofit Sustainability
In an American society where disposing of the old to make way for the new can be seen as a simple solution, The Empire State Building leads the way for retrofit projects that can modify existing infrastructure to energy efficient staples. This transformation can save buildings large return on investment in the form of energy saving. As seen in the diagram, the initial investment in retrofit changes had a positive return on investment at the end of the second year for the Empire State Building. As we make advancements toward a more sustainable and energy-efficient future, we must build upon the infrastructure that has been laid in the past. The potential for future retrofit projects can enhance the scope of the engineering industry as we work towards solutions to our increasing climate variability.
How can you use retrofit projects to better suit your building’s sustainability? Instead of reinventing the wheel, we can stand on the shoulders of giants.
By Aquinas Engineering
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