Long-term capital and retrofit planning enable "right steps in right order" as the "big Aha!"
Immediately following the news release of the Empire State Building retrofit project by the project team, Consulting-Specifying Engineer ’s editor-in-chief, Michael Ivanovich, conducted a 15-min. telephone interview with Clay Nesler, vice president of global energy and sustainability, Johnson Controls, soon after the announcement of the energy retrofit program for the Empire State Building . Here are notes from the interview.
CSE: What is the benchmark energy use per sq foot for the ESB, and what is the ESB’s starting Energy Star rating ?
Nesler: The ESB is using energy at 84 kbtu/sq ft per year in electricity and steam. The steam is pulled from utility steam lines; not made by an onsite boiler. The initial Energy Star rating is 59, so going from 59 to 90 will be quite an achievement.
CSE: The ESBsustainability.com Website, which was developed to
Nesler: Half the energy savings will come from common areas and half from tenant spaces. We’ve developed software to help tenants select energy efficient designs, with options that include occupancy-based ventilation and even individual comfort control. There are some pre-built tenant spaces so prospective tenants can see what can be done and how much energy can be saved. One new tenant (Skanska USA) is coming in will be going for LEED Platinum for LEED for commercial interiors. (Editors note: More information about Skanska’s green initiative and move into the Empire State Building online at the company’s website .)
CSE: How can the ESB project long-term energy savings if so much of the energy will be based on what tenants select?
Nesler: A lot of tenant space savings includes the glazing and radiator measures, and energy savings from the AHUs. These are not optional savings.
CSE: How were the chillers upgraded?
Nesler: We upgraded motors and installed VSDs. Some chillers are electric; others are steam-driven. These are York chillers. York has been in the Empire State Building since the 1950’s. (Editors note: Johnson Controls acquired York International in 2005).
CSE: Tell me about the controls upgrade.
Nesler: We’re installing DDCs and upgrading to manage the chillers and the AHUs supporting tenant space. We’re also installing an IT-based middleware system to interface with energy meters on a floor by floor basis. The goal is to provide information to tenants, most/many of which are floor-level tenants. Customizable dashboards will allow tenants to set energy-use goals and track consumption against the goals as often as they wish. They’ll also be able to look at trends and to access links to tips for reducing energy use.
CSE: I made quick visit to the online information at www.esbsustainability.com . I commend the openness of this project. Who put the Web site together and who will maintain it?
Nesler: Rocky Mountain Institute (RMI)is running the Website, but the whole project team contributed.
CSE: What else did RMI do for the project?
Nesler: RMI brought the whole-building design expertise, and used creative; charettes (project meetings) involving Johnson Controls and other partners. They identified the minimum energy use benchmark for the building and worked collaboratively with the team to get us to where we ended up getting to. They were often the provocateur, challenging us to save more.
CSE: What’s the one thing about the project that you think consulting-engineers should know about?
Nesler: The big AHA was to link retrofit designs to capital plans. This enables saving energy more cost-effectively over the long term. For example, insulating windows to drop cooling loads so can upgrade chillers rather than add new ones. Taking the “right steps in the right order” helps in an environment where owners or tenants are changing. This isn’t often done on commercial buildings.
Note: Following the interview, I found that of the $20 million investment, $13.2 million was incremental cost over infrastructure upgrades that needed to happen anyway. The project team estimates that the payback based on $4.4 million investment will be 3.1 years.
Also, a fact sheet provided after the interview had these building and energy facts:
– Building Gross Square Footage = 2,575,565 sq. ft.
-Current Building Energy Cost (excluding broadcasting) = $11.4 million ($4.42/sq. ft.)
– Current Building Annual Energy Use = 84 kBtu/sq. ft./yr (includes electricity & steam)
– Current Building Peak kW = 9,949 kW (3.86 W/sq. ft.); typically occurs in July or August
– Current Building Peak Cooling = 4,770 tons (540 sq. ft./ton); typically occurs in July or August
