The McKinney Office Building, a green project in McKinney, Texas,
near Dallas, is attempting to reach new heights in sustainable
design. In fact, developers and designers hope it will become the
first privately developed Leadership in Energy and Environmental
Design (LEED) Platinum-rated building in the country.
Only about 15 platinum-rated buildings exist in the world today.
The half-dozen in this country are operated by public entities, such
as the Audubon Society, that traditionally are focused on the environment.
The thought of using alternative energy sources to power office space
has remained, for the most part, just a thought.
Alternative energy sources account for less than 10 percent of the
total energy consumed in the country, according to the Department
of Energy’s Office of Energy Efficiency and Renewable Energy.
Much of the reluctance is because of high startup costs. Still, proponents
see promise in the numbers. Although the amount of energy produced
by alternative sources is small compared with conventional electricity
usage, facility executives and others are adopting the new power
technologies at an increasing rate, reports an August 2005 article
in Building Operating Management magazine. The magazine also reports
that the Department of Energy’s Solar Energy Technology program,
for example, sees the use of solar power growing at a rate of 20
percent annually, while industry watchers say that 25-percent annual
growth is possible.
That growth is happening for good reason. Organizations that use
alternative energy sources to power their facilities achieve greater
energy independence, reduce monthly energy expenses and earn appreciation
from their customers for placing importance on sustainable facility
practices. Sustainable, high-performance buildings cost less to operate
and maintain, are healthier for occupants, and are less damaging
to the environment. Potential benefits, of course, include lower
operating costs, higher productivity or reduced absenteeism because
of healthier indoor air quality (IAQ), conserved natural resources
and reduced waste.
Possible intangible benefits are a commendable
community perception and increased building value.
WestWorld Management, Inc., a developer based in Europe, is well-acquainted
with the high costs of energy in Europe, and pursues long-range efficiencies
for its properties. As owner of the McKinney property, it expects
to gain more than the 52 LEED points required for this high-efficiency
Platinum rating, through a combination of mechanical engineering,
electrical engineering, rainwater recovery and sustainable design
elements. Working along with HDR, a leader in the green building
industry, the design/developer team made creative use of an energy-efficient
ground-source heat-pump system, a separate roof-mounted solar hot-water
system, rainwater harvesting and two separate humidity controls per
floor in the McKinney Building.
The McKinney Building is part of the LEED Core and Shell Pilot program,
and has recently gained Platinum LEED pre-certification under this
program. When the 61,000-square-foot, three-story facility is completed
next March, it is projected to reduce energy use by 67 percent, and
cut water usage 30 percent compared with a similar, conventional
office building. Mechanical system costs are greater than a conventional
system, but as energy costs continue to increase, the payback time
will decrease.
Energy and Atmosphere Innovation
The McKinney Building diverges from standard sustainable projects in its concentrated
focus on the USGBC’s Energy and Atmosphere category under LEED; it seeks
to achieve all 10 points in this area. Because of the building’s location
in the south, the first consideration toward energy savings is lowering the cooling
load required of the chiller. The project will achieve this through increasing
use of insulation; use of a “cool roof,” which is a white roof with
a high reflectivity factor; high-efficiency glazing; and sunshade devices.
Contributing to mechanical efficiencies in heating and cooling systems is an
energy-efficient water-to-water heat pump system, which is connected to geothermal
wells. The water-to-water heat pump can be used for both chilling and heating
water. Further refining the mechanical system, an under-floor air-distribution
system supplies the air at the floor level, providing better IAQ and flexibility
for tenants. The under-floor air system will provide each occupant with the ability
to control the airflow and temperature into their space. The building also will
employ a roof-mounted heat-recovery unit for the outside air (incoming 105-degree
air is reduced to a temperature of 79 degrees with very minimal energy input).
Lighting design conserves energy in several ways. First, a smart-lighting system
will be placed throughout tenant spaces to match lighting levels appropriately
for tasks. Networked controls allow users to adjust lights according to their
individual needs directly from their desktops. Second, daylight and occupancy
sensors will activate general lighting on an as-needed basis. Further reducing
power requirements, the building’s daylight-enhancing façade allows
in natural light. In addition, windows include exterior shading devices that
serve a dual purpose: a bottom overhang blocks sunlight from flooding the space,
but also deflects onto the ceiling for increased natural light.
Additionally, the design team will develop a “green tenant guideline” to
encourage tenants to incorporate sustainable design into their respective spaces.
A renewable energy source to reduce pollution associated with non-renewable energy
production is important in any green facility. Originally, owners had requested
a 100-percent-off-the-electrical-grid system, but this was deemed too costly.
Instead, a 45-kilowatt photovoltaic panel system will generate 10 percent of
the building’s annual energy consumption, with expansion capabilities for
the photovoltaic system to generate up to 20 percent of the building’s
energy usage. The remainder of the building’s power will come from a green
energy provider.
The design also incorporates the capability to capture and clean site stormwater
runoff to improve water quality and minimize the negative impacts of pollution
related to stormwater management. In addition, steel cisterns in the corners
of the building will harvest roof rainwater, which will be used for site irrigation,
reducing potable water use. In fact, no city water will be used for irrigation,
whereas typically in the south, more than 50 percent of municipal water used
during the summer months is used for irrigation purposes.
Because efficiency is based on performance, a huge part of LEED certification
is contingent on measurement and verification. Hence, McKinney planners have
gone to great lengths to monitor every mechanical and electrical component in
the building to disclose what works and what doesn’t. Each electrical branch
circuit in the building can be monitored precisely, which informs tenants of
exactly how much energy they consume, and will allow the building management
to charge them accordingly.
Lean, Green Machine
While a fraction of buildings use alternative sources of energy and other renewable
resources, many are on the brink of incorporating some, if not many, of those
practices. WestWorld owns numerous buildings, and if this project proves successful,
it may pave the way to many green projects. HDR has worked on green buildings
of all types throughout the country, from hospitals and laboratories to government
buildings and commercial office buildings.
Going green is not an altruistic strategy reserved for environmentalists, but
is a smart practice of cost-conscious, profit-driven businesses. Taking green
to the next level not only will reach new heights in sustainable design, but
also will explore new possibilities in high performance, productivity and profitability.
David Hale is a mechanical engineer, and can be reached at
david.hale@ hdrinc.com.
Robin Hyman is an electrical designer, and can be reached at robin.hyman@hdrinc.com.
Michaella Wright can be reached at michaella. wright@hdrinc.com. Curt Parde can
be reached at curt.parde@hdrinc.com. All are team members at HDR, an architecture,
engineering and consulting firm based in Omaha, Neb. |
