Energy-Efficient Empire State Building Serves as a Model
When the Empire State Building was completed during the depths of the Great Depression, it quickly became an icon of progress and the indomitable spirit of America. Now, some 78 years later, as the country and the world again faces economic crisis as well as a new environmental challenge, the Empire State Building is again pointing the way to progress.
In April, owner Anthony Malkin of Empire State Building Co. announced a program to reduce energy use and carbon emissions at the 2.8 million-square-foot building by up to 38 percent over the next four years, saving the building $4.4 million in annual energy costs. More than half the savings-about $2.4 million a year-will result from a $20 million first phase that will be done by the end of 2010, with the rest completed by 2013.
The retrofit will reduce carbon emissions from an annual volume of about 24,000 metric tons down to 15,000 tons once the work is complete, for a total reduction of more than 105,000 tons over the next 15 years. That is roughly equivalent to taking 17,500 cars off the road for a year.
When the retrofit is complete, the team expects to achieve an Energy Star score of 90, placing the Empire State Building among the top 10 percent of energy efficient buildings of its size-an incredible feat for an octogenarian building. The building is pursuing gold certification under the Leaders in Energy and Environmental Design (LEED) for Existing Buildings: Operations & Maintenance (EBOM) program.
The goal is to show it can be financially feasible to retrofit an old building for a high level of energy efficiency. If the Empire State Building can be a highly efficient building, so can any other building.
Those involved in the retrofit started by establishing the building’s theoretical minimum energy use and identifying more than 60 potential energy efficiency strategies. Each strategy was evaluated in terms of its cost and the amount greenhouse gases it would avoid, to determine the dollar cost of one ton of reduced emissions. In various scenarios, the team looked at ways to maximize business value on one hand and greenhouse gas reduction on the other hand.
Using the theoretical minimum energy use as a baseline, the scenario that maximized profitability from the retrofit would have captured just over half of the reduction opportunity. Malkin may have sacrificed up to 30 percent of profits from the retrofit to get a much larger CO2 reduction. Scenarios that maximized conservation would have been prohibitively expensive. The team focused on solutions that best balanced CO2 reduction and financial returns.
Ultimately, 17 strategies were identified, grouped into eight projects that would provide the greatest environmental benefit and the strongest return on investment. The analysis showed that implementing additional strategies would produce a diminishing return, a much higher cost per ton of reduced emissions. Projects to take include:
• Refurbishment of approximately 6,500 thermopane glass windows, using existing glass and sashes to create triple-glazed insulated panels with new components that dramatically reduce both summer heat load and winter heat loss. This work will be done on-site to avoid costs and emissions associated with transportation, and original window glass will be used to avoid building material waste.
• Added insulation behind radiators to reduce heat loss and more efficiently heat the building perimeter.
• Improved lighting designs, daylighting controls, and plug load occupancy sensors in common areas and tenant spaces to reduce electricity costs and cooling loads.
• Replacement of air handling units with variable frequency drive fans to allow increased energy efficiency in operation while improving comfort for individual tenants.
• Reuse of existing chiller shells while removing and replacing “guts” to improve chiller efficiency and controllability, including the introduction of variable frequency drives.
• Upgrade of existing building control system to optimize HVAC operation as well as provide more detailed sub-metering information.
• Installation of demand control ventilation in occupied spaces to improve air quality and reduce energy required to condition outside air.
• Introduction of individualized, web-based power usage systems for each tenant to allow more efficient management of power usage.
Malkin’s vision for energy conservation goes far beyond the Empire State Building. “We have to reduce the energy consumption of existing buildings,” he said. “Without a replicable cost outlay payback modeling and analysis process, we cannot motivate people to make investments.”
A high level of transparency is being put into the process. Documentation and other information is continually being posted on a Web site, for owners of commercial buildings and other interested parties to review and download at no cost.
“This is the first time that such an extensive analysis of an existing building energy retrofit has been made publicly available for other owners to use as a replicable model,” Malkin said. “I hope the establishment of this new replicable process we have created will inform lawmakers, property owners and lenders on actions to take, laws and codes to write, and new financing programs to support, ultimately yielding reduced energy consumption, reduced carbon output, higher quality workspaces and green local jobs.”
Ray Quartararo, Northeast Regional Manager at Jones Lang LaSalle, is program manager for the Empire State Building’s retrofit. Other partners include Rocky Mountain Institute, Johnson Controls and the Clinton Climate Initiative.
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