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Modern UFAD
systems have long been used in Europe and are rapidly gaining
acceptance in the United States. In principal, UFAD systems can
reduce or even eliminate overhead plenum spaces and sheet metal
ducts that make up conventional ceiling air distribution systems.
This resulted in claims of reduced construction costs and
shortened required deck-to-deck heights in high-rise buildings. A
number of design issues associated with UFAD systems have not been
fully investigated. These include, but are not limited to:
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Maintaining
constant air temperature and controlling humidity in large under
floor plenums
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Attaining
evenly distributed airflow in large under floor plenums
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Achieving
proper air mixing in occupied spaces served by under floor plenums
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Preventing
the propagation of sound in under-floor plenums that can result in
a deterioration of speech privacy in occupied spaces.
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This task
compares the performance and cost-effectiveness of UFAD and
conventional air distribution (CAD) systems. Information is being
developed to determine under what circumstances UFAD systems
should be specified. The actual applications of UFAD systems in
commercial buildings are being assessed and analytical tools for
evaluation and quantification of UFAD performance are being
developed. A test protocol is being developed and implemented in
the UNLV Center for Mechanical & Environmental Systems Technology
(CMEST) laboratory test room, known as the Throw Room, to test
performance of UFAD systems compared to CAD systems.
The goals of
this project are to:
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Investigate
HVAC design, comfort and energy issues related to UFAD systems
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Conduct a
series of interactive seminars in conjunction with ASHRAE chapters
to collect current information on level of knowledge in the design
community related to UFAD
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Collect data on
existing UFAD systems in commercial buildings to characterize
installed UFAD systems, identify areas that may require additional
laboratory research and develop information that is necessary to
develop protocols for future field testing of UFAD systems
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Modify and
upgrade the current Throw Room to obtain laboratory data related
to energy, performance and comfort issues associated with UFAD
systems
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Conduct
laboratory tests to obtain data and answer questions associated
with energy, performance and comfort issues related to UFAD
systems and develop test protocols that can be used in future
field tests in commercial buildings with UFAD systems
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Three different
organizations are executing this project:
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The Building
Diagnostics Research Institute conducted the series of interactive
seminars in conjunction with ASHRAE chapters. The principal
investigator/presenter was James Woods, Ph.D., P.E. This subtask
is complete and a final report (NCEMBT-040815) was published and
can be downloaded.
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GARD Analytics
collected data on existing UFAD systems in commercial buildings.
The principal investigator was Roger Hedrick. A final report will
be published shortly.
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The University
of Nevada Las Vegas (UNLV) is performing the laboratory phase of
this task. The principal investigator is Liangcai (Tom) Tan,
Ph.D.
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This project is
scheduled to be completed by July of 2005.
The results of
this task form the basis for Task 12 where the performance of installed CAD and UFAD will be measured and
compared. |
