Commercial Architecture February 2018 - 41
urally, we kept looking for more places to apply drives."
M&R Affiliates' Rice explained the astounding elec-
trict. The Challenge commits the U.S. Steel Tower to reducing energy usage 50% by 2030.
tricity savings are derived from the physics of "affinity
"Thanks to Danfoss VLT drives, we've already cut en-
laws," which state that reducing the speed of a pump or
ergy usage by 20%," Sechler says enthusiastically. "Jim
fan motor reduces power consumption exponentially. For
Rice and SSI Inc., Cranberry Twp., PA (ssiinc.org), the
example, applying a VLT drive that can reduce pump
local Danfoss service center, has worked closely with us
speed by 20% results in potential energy savings of as
year after year to phase in the installation flawlessly. Com-
much as 50%.
bine the energy savings, robust quality, and rebates that
In 2011, Sechler embarked on Phase Two of the retrofit
reduce paybacks under one year, I couldn't be happier.
project. Once again, the VLT drives were applied to pump
Additionally, the tenants are happy, and the building
motors-but this time for the chilled water and pre-heat
owners are delighted." CA
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"These pump motors are considerably smaller than
those used for the domestic water pumps," said Sechler,
"but there are more of them." For this project, VLT drives
were applied to 40 pump motors ranging from 50 hp to
200 hp. And once again, the savings were astounding:
annual electric costs were reduced another $138,000.
In 2012, a Phase Three project added 16 drives for
250-hp motors. Phase Four in 2013 applied about 40 VLT
drives to smaller 7.5- to 60-hp pump and fan motors. After each phase, the electric savings amounted to $317,000
and $152,000 a year respectively.
"In 2009, our electric consumption averaged 65 million kilowatt hours," said Sechler. "Now it's down to 53
million kilowatts. Our peak demand was 16 to 17 megawatts; now it's 12 megawatts. This is a huge savings that
goes right to the bottom line. Altogether, nearly 150 Danfoss VLT drives are producing $1,142,000 in documented
annual energy savings. Plus, improved energy efficiency
makes the property more attractive to tenants. We've
been up to 98% occupancy, which is really great in today's commercial real estate market."
To manage the installation, each drive incorporates
Apogee FLN as a software-selectable communications
protocol that connects with the building automation system (BAS). The pump drives are controlled using an inhouse Direct Digital Control (DDC), which measures
pressure differential across the pump to regulate drive
speed. The BAS logs drive performance data and energy
consumption, including drive condition. Sechler's inhouse engineering team is also able to track operational
status-and they are delighted that there has been practically no drive downtime since the first one was installed
nearly 15 years ago.
He also notes that the energy savings from the VLT
drives is helping give the building a greener reputation.
UPMC recently qualified 17 of the floors it occupies for
Keep operating costs
from going through
Our thermally broken roof hatch lowers
building operating costs by minimizing
heat transfer between interior and
exterior metal surfaces, thereby resisting
harmful condensation and providing
superior energy efficiency under
Silver LEED certification and six for Gold LEED certifi-
Roof Hatch Features:
Patented thermally broken design
Engineered cover gasket system
Lab tested & certified for
cation through the services of evolveEA, Pittsburgh
(evolveea.com), a sustainable architecture and consulting
firm. In addition, Winthrop Management recently
signed the U.S. Steel Tower onto the Green Building Al-
liance, Pittsburgh, (usgbc.org/organizations/green-building-alliance) 2030 District Challenge-a public-private
partnership for the downtown Pittsburgh building disCIRCLE 214