Fault Detection and Diagnostics for Rooftop Air Conditioners

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LIST OF FIGURES
Figure 1-1 System after being incorporated with a normal operation model....................14
Figure 1-2 2-dimensional residual distribution when system is running in a fault mode ..14
Figure 1-3 Fault detection classifier scheme for a 2-dimensional case .............................18
Figure 1-4 Fault detection and diagnosis boundaries ........................................................22
Figure 1-5 Taxonomy of Rooftop Faults ...........................................................................30
Figure 1-6 Interactions of Rooftop Unit System................................................................33
Figure 1-7 Compressor Valve Leakage Decoupling Scheme ............................................35
Figure 1-8 Condenser Fouling and Non-Condensable Gas Faults Decoupling Scheme ...42
Figure 1-9 Liquid-line restriction illustration ....................................................................43
Figure 1-10 Vapor Compression Cycle Illustration...........................................................44
Figure 1-11 Liquid-Line Restriction Decoupling Scheme.................................................45
Figure 1-12 Evaporator Fouling Decoupling Scheme .......................................................46
Figure 1-13 Ideal Decoupling Scheme of Component-Level Faults with Refrigerant mass
flow measurement......................................................................................................47
Figure 1-14 Actual Decoupling Scheme of Component-Level Faults without Refrigerant
Mass Flow Measurement ...........................................................................................49
Figure 1-15 The Decoupling Scheme for System Level Faults.........................................50
Figure 1-16 ∆ with different refrigerant charge levels .............................................51
Tsh
− sc
Figure 1-17 The Decoupling Scheme of All Rooftop System Faults ................................52
Figure 2-1 Decoupling compressor valve leakage fault using estimated compressor power
measurement and estimated refrigerant mass flow rate.............................................54
Figure 2-2 Decoupling condenser fouling fault using measured refrigerant mass flow rate
....................................................................................................................................55
Figure 2-3 Decoupling condenser fouling fault using estimated refrigerant mass flow rate
....................................................................................................................................56
Figure 2-4 Decoupling evaporator fouling fault using measured evaporator air mass flow
rate..............................................................................................................................57
Figure 2-5 Decoupling evaporator fouling fault using measured refrigerant mass flow rate
....................................................................................................................................58
Figure 2-6 Decoupling evaporator fouling fault using estimated refrigerant mass flow rate
....................................................................................................................................58
Figure 2-7 Decoupling liquid-line restriction using measured pressure drop....................59
Figure 2-8 Decoupling liquid-line restriction using estimated pressure P
up
and measured
3
P ...............................................................................................................................59
Figure 2-9 Decoupling liquid-line restriction using estimated pressure drop....................60
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