Paper Conference
Proceedings of SimBuild Conference 2012: 5th conference of IBPSA USA
 
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Influence of Design and Operating Conditions on Underfloor Air Distribution (UFAD) System Performance
Tom Webster, Tyler Hoyt, Edwin Lee, Allan Daly, Dove Feng, Fred Bauman, Stefano Schiavon, Kwang Ho Lee, Wilmer Pasut, Dan FisherCenter for the Built Environment (CBE), University of California, Berkeley, CA Center for the Built Environment (CBE), University of California, Berkeley, CA Taylor Engineering, Alameda, CA Department of Architectural Engineering, Hanbat National University, Daejeon, South Korea
Abstract: Various methods are used to design and operate
underfloor air distribution (UFAD) systems. There
are a number of factors that affect UFAD
performance: air distribution strategies in the supply
plenum, system configuration and diffuser types, slab
insulation, air handler supply temperature setpoints,
operation of blinds at peak conditions, impact of
occupant control, and the effect of climate
differences. Generally, these factors influence
performance indicators, such as plenum “thermal
decay” (supply air temperature gains) and room air
temperature stratification, which in turn affect system
energy use and comfort conditions. Previously, the
impact of design and operating strategies has been
difficult to evaluate analytically due to the lack of
simulation tools that accurately model the complex
heat transfer processes involved with thermal decay
and stratification. The development of EnergyPlus
along with the recent addition of the UFAD module
has progressed to the point that a systematic
comparison of these strategies is now possible.
In this paper, we take a detailed look at the impact of
a number of design and operating variations for a
medium office building prototype in Sacramento CA.
A comparison to a baseline conventional VAV
overhead (OH) system is included to understand
better the potential energy and comfort differences
between the two technologies. Pages: 676 - 683 Paper:simbuild2012_10b_4_Webster