Auditing an Office Park for Site, Architecture, and Energy Improvements
Searching for Greener Solutions in Existing Buildings
According to the think tank Architecture 2030, approximately two-thirds of the global building area that exists today will still exist in 2040, and, without widespread decarbonization of existing buildings, meeting the Paris Agreement’s target of limiting warming to 1.5°C will be challenging.
Existing buildings retrofitted appropriately also inherently have the advantage of avoiding carbon emissions related to new construction. The exodus of occupants from nonresidential buildings when the COVID-19 pandemic hit in early 2020 is causing us to radically rethink the role of existing buildings in a post-pandemic world with a changing climate.
Atlanta Property Group (APG) doubled down on carbon reduction efforts in its 639,000 sf Palisades Office Park campus in Atlanta to help retain existing tenants and attract new clients with Environmental, Social, and Governance (ESG) priorities.
With the help of Lord Aeck Sargent and TLC Engineering Solutions, what started as an energy audit to quantify and improve operational energy and carbon emissions grew into a more holistic effort to encompass site and architectural features of the office park.
The baseline audit, which involved site walkthroughs and APG staff interviews, revealed that the project already had laudable goals and initiatives for the four buildings on campus:
- The campus was all electric, with no combustion for space or water heating end uses.
- A high Energy Star score of 83-93 between the four buildings, based on ongoing operational efficiency.
- Low Energy Use Intensity (EUI) of 43-46 kBtu/ft²/year.
- An existing LEED Gold certification under the O&M category.
- Onsite renewable energy production on its way to reaching 1 MW solar, meeting up to 17% of the campus’ energy needs.
- Proactive building maintenance and upkeep.
We were able to quantify the campus’ carbon emissions avoidance because of building reuse and sequestration opportunities from its site landscape. The avoided embodied carbon emissions from reusing the Palisades Office Park buildings, of 23,746,040 kgCO2e, are equivalent to the greenhouse gas emissions from driving an average car nearly 60 million miles, or the annual electricity use of over 4,000 homes, or the annual carbon sequestration of nearly 30,000 acres of U.S. forest.
The proposed site improvements would have a net impact of sequestering an additional 1,390,949 kgCO2e over a 50-year lifespan and would be climate positive 11 years after completion. This is achieved through a robust landscape that sequesters carbon through series of natural systems. The proposed site improvements of adding densely planted trees, adding living walls or green roofs, replacing turfgrass with native vegetation, and replacing non-native plants will create the natural systems needed to remove carbon from the atmosphere. This new landscape also has other significant benefits including creating habitat for native animals and insects as well as improving biodiversity and creating a more livable environment.
Architectural and other site improvement recommendations included lighting pollution reduction, tenant programs, improved canopies, enhanced circulation spaces, repainted facades, applied film on glazing to improve bird friendliness, softened façade, highlighted entrances, as well as more prominent plaque placements for LEED and Energy Star achievements.
As a part of an ASHRAE level 2 energy audit, a calibrated energy model was developed to define an accurate baseline and apply energy efficiency measures (EEMs) on top of the baseline to explore their energy reduction and cost effectiveness potential. The range of measures considered was based on APG’s preliminary vetting. Such EEMs include HVAC controls upgrades, large fans in AHUs replaced by fan walls, lighting upgrades, new wind turbines, etc.
As of early 2022, APG is in the process of implementing cost effective and strategic measures to enhance the quality of Palisades Office Park’s indoor and outdoor environment while lowering its operational carbon footprint.