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Active Façade for Lab Buildings: Quantifying
Energy and Qualitative Benefits
Syed Faruq Ahmed, P.
Richard Rittelmann, and Jayesh X. Hariyani,
Burt Hill Kosar Rittelmann Associates
The façade in a lab building is an extremely important design
element, not only for energy and building functionality, but also
for the building aesthetics. Most lab buildings have used either
opaque façade with windows or large glass areas. Both approaches
have their own special considerations.
The use of "active façade" opens new opportunities
for the lab designs where large glass areas can be utilized in a
controlled manner. This results in not only the energy saving but
also in enhancing the quality of the lab space near the façade.
Active facades have been successfully used in many European buildings.
This approach has been applied to a lab building located in the
Finger Lakes region of New York State. The laboratory building is
located on a site between three buildings such that the only significant
façade is the west side. Therefore, the aesthetics of the
building dictates the use of high quality façade. The west
side presents unique challenges for the sun control, glare control
and aesthetics (when the users are allowed to control the shades
in their own spaces).
The building utilizes an "active façade" where
the lab wall consists of a double glass assembly with Low-E coated
argon filled glass. Outside this window is a 2.5 feet wide cavity
which is covered with single glass. The cavity contains a movable
shading device which allows controlled amount of light into the
lab. A small part of the incident solar energy (referred to as Solar
Admittance) is allowed to enter the lab, another part is reflected
out of the cavity from the shading devices, and some part gets absorbed
in the cavity where it is removed as heat by natural ventilation
of the cavity. This approach provides a means for controlling the
west sun, the heat gain, the glare, and also presents a uniform
building view from the outside. The shades are configured to move
together so that the building face looks uniform everywhere. On
cloudy days the shades can be opened to allow more light in the
labs.
In order to quantify the usefulness of the active façade
for this application, a large number of studies were conducted on
a "shoe-box" model of the lab modules. This allowed the
various parameters and arrangement of the glass in the façade
to be studied in a manner relative to a base strategy. After the
initial screening of strategies, the most beneficial strategy is
selected.
An approach for the evaluation of active façade strategies
for a lab building has been developed. Several strategies are defined.
As an example, the following seven strategies were defined for the
building that has been studied:
CASE 1: Low-E double glass on the lab window, no cavity wall (on
the outside), translucent shade inside the lab.
CASE 2: Low-E double glass on the lab window, no cavity wall (on
the outside), specular reflective shade inside the lab.
CASE 3: Low-E double glass on the lab window, no cavity wall (on
the outside), specular reflective shade outside the lab window.
CASE 4: Cavity wall on the outside, Low-E double glass on the
outside of the cavity, single glass on the lab window, shading device
in the cavity.
CASE 5: Cavity wall on the outside, single glass on the outside
of the cavity, Low-E double glass on the lab window, shading device
in the cavity.
CASE 6: Cavity wall on the outside, single glass on the outside
of the cavity, regular double glass on the lab window, shading device
in the cavity.
CASE 7: Low-E double glass on the lab wall, no cavity, no shades
– REFERENCE CASE.
The shading device is the active element and can be adjusted automatically
to allow a certain amount of solar energy in the space. The active
façade provides continuous control of the solar input into
the laboratory.
The seven cases for the "shoe-box" building, consisting
of two lab modules totaling 968 sqare feet were studied by using
TRNSYS hour-by-hour simulation. The results of the simulation show
that with respect to the base case (CASE 7) and 30 percent solar
admittance in the labs, the heating and cooling energy is reduced
by 16.1 percent for CASE 1 to 25.1 percent for CASE 5. All other
cases are in between. While the strategy in CASE 5 saves 25 percent
of the energy with respect to the base case (CASE 7), using the
energy costs for this project, the yearly savings translate to $1,101.
Based on a 15-year life and 5 percent discount rate, the maximum
allowable incremental cost comes out to be $11,433. This cost is
based on energy savings only.
In addition to the energy savings, there are quantitative benefits
of using the lab area next to the window more effectively. This
amount, conservatively, translates to $22,000 benefit in building
cost. Added to this benefit are the personnel productivity improvements
which amount to $2.96 per sqaure feet per year, resulting in the
15-year discounted savings of $29,552 for the "shoe-box"
model. The total of all the savings discussed above is $63,169 in
15 years which translates to $64.80 per square feet of the shoe-box
module. The active façade cost must not exceed this cost
which is achievable.
The presentation will provide the details about the building project
where active façade is used. The results of the simulations
for the whole building using DOE-2.1E will be presented. The details
for the estimation of the qualitative benefits will be presented.
Also presented will be the performance of the active façade
on the south, west, and east side of the lab buildings in several
climate types in the United States.
The information from the presentation will provide valuable insight
for the building design professionals to use "active façade"
as an innovative strategy which not only saves energy but also provides
high quality lab spaces where personnel productivity can be maximized.
Labs21 Connection:
The active façade system being discussed in the submission
fits into several strategies of Labs21 Approach. The unique and
noteworthy aspect of the submission is that the use of "active
façade" allows the space to be "higher quality"
where users have more control over the environments and, at the
same time, saving energy. For the lab buildings, providing high
quality space, saving energy, and at the same time maintaining the
space functionality, is extremely important.
The Life Cycle Cost Decision Making strategy of Labs21
approach is used to design high quality building façades.
Often decisions are based on initial cost only. When operating costs
for the building are considered for 15 to 25 years, the "annual
cost of operating the building" is minimized. Thus, the initial
cost and operating costs need to be taken together. The use of the
active façade is one example where the value derived from
energy savings and the conservation savings from the qualitative
benefit are used to provide high quality space.
Employ a Broad Range of Sustainable Energy and Water Efficiency
Strategies Daylighting is known to be one of the most cost effective
strategies for building design. Many studies done by organizations
such as Lawrence Berkeley Labs have made that determination. The
use of "Active Façade" allows just the right amount
of daylighting in the space, depending on the outdoor weather conditions.
The daylighting can be coupled with daylighting sensors for light,
which not only reduces energy consumption for lights, but also saves
on cooling energy costs. The submission addresses this strategy.
Another strategy that the "Active Façade" submission
would fit in is, "Assess Opportunities for a 'Whole Building'
Approach." The active façade has implications which
go beyond the obvious – the energy savings. It has implications
for the building footprint, building occupants perception of the
space, and, of course, the health and well being of the building
occupants.
Biographies:
Faruq Ahmed is a Principal with the architecture,
engineering, interiors, and applied research firm, Burt Hill Kosar
Rittelmann Associates in Butler, Pennsylvania. Faruq is a registered
professional engineer with over 36 years of engineering experience.
He holds a Masters degree in Engineering from Colorado State University.
His involvement in various engineering disciplines include: Alternative
energy systems, including power generation technologies, information
systems technology, communications systems, solar and renewable
energy systems, energy conservation, and electric power quality
and reliability. Faruq has been working on energy related projects,
including renewable energy, since 1967. He is an active participant
in various forums for Research Applied to Buildings and Systems.
Faruq is the organization representative for the EPA Cooling Heating
and Power (CHP) Partnership and for EDUCAUSE – the organization
of technology professionals for higher education institutions. He
has been a regular speaker at various Strategic Research Institute
Conferences. He is also a frequent speaker at various conferences
such as Tradelines, EPA Labs for the 21st Century, EDUCAUSE, SCUP,
APPA, ERAPPA, SRAPPA and many others.
Dick Rittelmann is
the Chairman of Burt Hill Kosar Rittelmann Associates, an architecture,
engineering, interiors, and applied research firm in Butler, Pennsylvania.
He is a graduate of Rensselaer Polytechnic Institute. Dick is a
Fellow of American Institute of Architects. His involvement with
Power Systems using Alternative Energy systems, dates back to the
1970's. During that time he was actively involved with various DOE
activities for large-scale PV Systems and other Solar Energy projects.
He has participated in the International Energy Agency (IEA) activities
as U.S. representative for several tasks. He also participates on
the Research Advisory Boards for many National Labs which include
Lawrence Berkeley Lab and Oakridge National Lab. Dick is a highly
sought speaker by various professional organizations such as Strategic
Research Institute, Tradelines, AIA, ASHRAE, CIC, EPA Labs for the
21st Century, EDUCAUSE, APPA, ERAPPA, SCUP, AEC Systems, various
Hospital Technology organizations, etc. He has been involved in
presenting papers and seminars for over 40 years. His expertise,
in addition to architecture for Mission-Critical Buildings, includes
Information Systems, High Technology Medical Systems, Research Labs
and Communication Facilities.
Jayesh Hariyani is
an Associate and a lead architect in Burt Hill's high tech market
sector. His artistic ability coupled with his technical capabilities
creates a new dimension to visual presentations. He quickly and
easily transforms design concepts into three-dimensional renderings.
From his international experience, he is sensitive to the multi-cultural
influences. He was the lead architect on the project being presented
in this submission. Jayesh has been involved in many projects for
residential development projects focusing on both research and design
of community development and the sociological impact. He is Burt
Hill's lead architect on the University of Texas Institute of Molecular
Medicine Building in Houston and the Physical Sciences Building
at Cornell University.
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