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How the Number and Placement of Sensors Controlling Room Air Distribution Systems Affect Energy Use and Comfort
Abstract
This study assesses the impact of sensor
number and placement on the energy needed to
condition a typical office using several likely variants
of an underfloor air distribution system (UFAD).
The study uses an empirical-based room stratification
model developed from full-scale tests of UFAD
systems. Annual energy consumption is calculated
for an interior zone using outside air temperature bin
data. The comfort criteria are taken from ASHRAE
standard 55-92. The simulations indicate that there
are benefits derived from using more than one
temperature sensor to control conditions in the
occupied zone of a room. Among these are: 1. By
adjusting both supply air temperature and volume to
maintain the maximum allowable thermal gradient in
the occupied (lower) part of the room, an optimal
supply air condition can reduce energy use (relative
to the best arrangement of a single sensor) while
maintaining comfort; 2. Discomfort caused by
stratification can be detected by having one of the
sensors located at foot level; 3. For the simulated
UFAD interior zone of a typical office building in
Sacramento, an overall energy saving of 8%/24%
(VAV/CAV respectively) can be achieved when two
sensors as opposed to one are used to control room
conditions.
Citation
Wang, D.; Arens, E.; Webster, T.; Shi, M. (2002). How the Number and Placement of Sensors Controlling Room Air Distribution Systems Affect Energy Use and Comfort. Energy Systems Laboratory (http://esl.tamu.edu); Texas A&M University (http://www.tamu.edu). Available electronically from https : / /hdl .handle .net /1969 .1 /5187.