Fault Detection and Diagnostics for Rooftop Air Conditioners

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charge faults for TXV RTU systems. Three Trane RTUs (a 2.5-ton split system, a 5-ton
packaged system and a 7.5-Ton split system) were tested under four operation conditions
(see Table 2-3) with various charge levels.
Table 2-3 Environmental conditions.
Test
Condition
T outdoor ,
°C
T indoor ,
°C
T dew point ,
°C
A 35.00 26.67 15.77
B 27.78 26.67 15.77
C 27.78 26.67 < 3.06
HT 48.89 26.67 15.77
2.3 Field Test Facilities
All the field-sites in California are small commercial buildings that utilize
packaged air conditioning and heating equipment. The criteria used for selecting the
field-sites included: 1) building occupancy type and size; 2) HVAC system installed, and
3) climate region. The types of building include smaller retail stores, restaurants and
modular schoolrooms. The HVAC systems installed include different rooftop and wall
mounted units with different capacities and manufactured by York, Trane and Bard. The
climates include two different macroclimate types: coastal and inland. Table 2-4
summarizes information about all sites (refer to Deliverables 2.1.1a & 2.1.1b for details).
The Purdue field setup is meant to mimic field setups in California in order to aid
in the identification of installation and operational problems locally. In addition, this
setup allows us to test alternative sensors and to artificially introduce faults, both of
which would be logistically difficult to perform in California (refer to Deliverables 2.1.1a
& 2.1.1b).