Fault Detection and Diagnostics for Rooftop Air Conditioners

More documents

Recommendations

Info

9 NOMENCLATURE AHU α α β c = Air handling unit = Thermal resistance portion = False alarm threshold = Fault diagnosis threshold = Distance from fault point to axes χ 2 ( n) = Chi-square distribution 2 d i = Normalized distance square d max = Maximum normalized distance ∆ T ca = Condenser air temperature difference ∆ T ea = Evaporator air temperature difference EER = Equipment efficiency ratio η v = Compressor volumetric efficiency FDD = Fault detection and diagnosis F i = Fault points f i = Frequency GRNN = General regression neural network h o = Heat transfer coefficient between sensor and ambient air HVAC = Heating, Ventilating, and Air-Conditioning IA = Independence Assumption λ i = Eigenvalue of Σ Λ = Eigenvalue matrix M = Mean vector of residuals M = Mean vector for normal operation normal M current = Mean vector for current operation MCS = Monte-Carlo Simulation m& r = Refrigerant mass flow rate µ = Mean µ normal = Mean value for normal operation M X = Mean vector for sample X M = Mean vector for sample Y Y 9
10 N = Number of generated sample points N X = Normal distribution for sample X Ω X = Area for probability evaluation P dis = Discharge pressure Φ = Eigenvector matrix P i = Data points P Ω = Probability within area Ω X φ ra = Relative humidity of return air P = Discharge pressure dis P suc = Suction pressure Q & cap = Cooling capacity ratio dist = Distance ratio SRB = Statistical rule-based RTU = Rooftop unit σ = Standard deviation σ normal = σ for normal operation Σ = Covariance matrix Σ = Σ with independence assumption assumption Σ current = Σ for current operation Σ normal = Σ for normal operation Σ X = Covariance matrix for X T amb = Ambient temperature T cond = Condensing temperature T = Discharge line temperature dis T = Evaporating temperature evap T ll = Liquid line temperature T ma = Mixed air temperature T oa = Outdoor air temperature T ra = Return air temperature T sc = Sub-cooling T sh = Superheat T wb = Wet bulb temperature VAV = Variable air volume v 1 = Specific volume of compressor inlet refrigerant X = Sample point in original space Y i i = Sample point in transformed space 10
Page 1 and 2:
CALIFORNIA ENERGY COMMISSION Final
Page 3 and 4:
Acknowledgements Jim Braun and Haor
Page 5 and 6:
Abstract Project 2.1, Fault Detecti
Page 7 and 8:
TABLE OF CONTENTS LIST OF TABLES LI
Page 9 and 10:
LIST OF FIGURES Page 1 - Field Test
Page 11 and 12:
The report “Description of Labora
Page 13 and 14:
mounted heat pumps for heating and
Page 15 and 16:
The retail stores are in Southern C
Page 17 and 18:
Figure 1 - Field Test Sites Data Co
Page 19 and 20:
Gibson School (Cont’d) Woodland S
Page 21 and 22:
Table 1 - Data List for Modular Sch
Page 23 and 24:
BUILDING TYPE: Modular School Rooms
Page 25 and 26:
HEATING / AIR CONDITIONING EQUIPMEN
Page 27 and 28:
Sacramento Area McDonalds PlayPlace
Page 29 and 30:
Bradshaw Road (Sacramento Area) McD
Page 31 and 32:
TEST INSTRUMENTATION: Tables 2 and
Page 33 and 34:
Table 2 - Data List for Inland Rest
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
Castro Valley (San Francisco Bay Ar
Page 41 and 42:
Castro Valley McDonalds PlayPlace P
Page 43 and 44:
more or less custom design, publish
Page 45 and 46:
BUILDING TYPE: Retail Store ADDRESS
Page 47 and 48:
TEST INSTRUMENTATION: Similar test
Page 49 and 50:
• Temperature and humidity levels
Page 51 and 52:
November 2001 - December/January 20
Page 53 and 54:
Table of Contents 1. Introduction..
Page 55 and 56:
1. Introduction All the thermodynam
Page 57 and 58:
Table 1.1 Comparisons of Three Mode
Page 59 and 60:
solution procedure involves the non
Page 61 and 62:
independent of the moisture content
Page 63 and 64:
function, f ( X , y) , if it can be
Page 65 and 66:
Figure 2.1 Neural-Network Implement
Page 67 and 68:
prototype was developed by using th
Page 69 and 70:
3. Comparison of black-box modeling
Page 71 and 72:
which is more accurate than the exp
Page 73 and 74:
Similar to GRNN, RBF has very good
Page 75 and 76:
Table 3.2 RMS error (Polynomial,GRN
Page 77 and 78:
Table 3.4 Contrast of Black-box mod
Page 79 and 80:
Polynomial plus GRNN Training Desir
Page 81 and 82:
interpolation(poly+GRNN) extrapolat
Page 83 and 84:
used to build the steady-state mode
Page 85 and 86:
α , ρ, τ I t t s h o A t a Figur
Page 87 and 88:
Temperature (F) 82 79 76 73 Condens
Page 89 and 90:
0.050 0.045 Pressure = 101.3 [kPa]
Page 91 and 92:
T T − T − T W = W −W −W m =
Page 93 and 94:
Figure 4.8 Output of three steady-s
Page 95 and 96:
will be calculated to represent the
Page 97 and 98:
180 175 RMS error = 0.3984 (F) Pred
Page 99 and 100:
180 175 RMS error =1.1472 (F) Predi
Page 101 and 102:
51 50 RMS error=0.3860 (F) Predicte
Page 103 and 104:
4.4 California field site results S
Page 105 and 106:
105 100 RMS error =0.5982 (F) Predi
Page 107 and 108:
Since air conditioners always cycle
Page 109 and 110:
6. Conclusions and future work So f
Page 111 and 112:
Lee, W., House, J.M. and Shin, D.R.
Page 113 and 114:
Table of Contents 1 Introduction...
Page 115 and 116:
AHU α β 2 d i EER ∆ ∆ η v T
Page 117 and 118:
$ !! !! )
Page 119 and 120:
Paper statistics in HVAC FDD Number
Page 121 and 122:
011>" - , ?" 8?"
Page 123 and 124:
+ : 6336" ,
Page 125 and 126:
+ :: !!- :: !!
Page 127 and 128:
6 24 122 7) 6 3++, ) . !! /011
Page 129 and 130:
)
Page 131 and 132:
336 F / s $ S
Page 133 and 134:
N $ V v1
Page 135 and 136:
Figure 3-4 2-dimensional residual d
Page 137 and 138:
10 5 Normal and current operation p
Page 139 and 140:
7 N Ω f N N Ω = Ω X ,
Page 141 and 142:
0 + α 6 d χ ( )
Page 143 and 144:
Normal operation region Residual-2
Page 145 and 146:
Table 3-2 Refrigerant Leak at 20% l
Page 147 and 148:
ratio dist = P F 1 P F 1 2 1 9.0
Page 149 and 150: $ , " - (
Page 151 and 152: )(( 0( 04 ) 6330" /
Page 153: Table 4-2 Polynomial plus GRNN mode
Page 157 and 158: 4.2 m r,predict (kg/min) 4 3.8 3.6
Page 159 and 160: 6 1)( ( ( 6 1)( ) , ( )
Page 161 and 162: - )
Page 163 and 164: ? "J> *"J060 #"J083 *$"J670 #"J08<
Page 165 and 166: Table 4-17 Detected (normal, fault)
Page 167 and 168: c=1 c=10 c=20 1 0.8 Distance ratio
Page 169 and 170: $ /) $ 0111" .. !!
Page 171 and 172: Chen, Bin and Braun, J.E, 2000. Sim
Page 173 and 174: Ventilating, Air-Conditioning and R
Page 175 and 176: 1.T amb 2.T ra 3.RH ra Plant Prepro
Page 177 and 178: F) $
Page 179 and 180: +: + $ 5
Page 181 and 182: .44(' * 5 09( ( 0( F N ( M , Σ)
Page 183 and 184: Load 20% 40% 60% 80% 100% 3 4 Fault
Page 185 and 186: Load 20% 40% 60% 80% 100% 3 4 Fault
Page 187 and 188: 3 4 0 0 0 0 0.4173 0 0.0010 0 0.000
Page 189 and 190: .44(' $ () ) ) - $
Page 191 and 192: ∆P Restrictio n Level=100%* ∆P
Page 193 and 194: 2 TABLE OF CONTENTS TABLE OF CONTEN
Page 195 and 196: 4 A1.2.3 Valve Position Expression
Page 197 and 198: 6 Figure 2-10 Decoupling refrigeran
Page 199: 8 LIST OF TABLES Table 1-1 Fault di
Page 203 and 204: 12 with a fixed-orifice as the expa
Page 205 and 206: 14 (residuals) should have a zero m
Page 207 and 208: 16 expected distribution of the res
Page 209 and 210: 18 operation. Another advantage is
Page 211 and 212: 20 1.1.2.1 Original SRB Fault Diagn
Page 213 and 214: 22 Corresponding to the SRB fault d
Page 215 and 216: 24 integration of the probability d
Page 217 and 218: 26 1. Simplifies fault detection fr
Page 219 and 220: 28 Step i Do FDD on fault i . After
Page 221 and 222: 30 ROOFTOP UNIT FAULTS COMPONENT-LE
Page 223 and 224: 32 has two possible causes: refrige
Page 225 and 226: 34 1.2.3 Decoupling of Component Fa
Page 227 and 228: 36 1.2.3.2 Condenser-Related Faults
Page 229 and 230: 38 mixture, χ ref is known as the
Page 231 and 232: 40 Table 1-3 also lists the refrige
Page 233 and 234: 42 Refrigerant Property T cond, pre
Page 235 and 236: 44 as an independent feature only f
Page 237 and 238: 46 evaporator air flow rate reducti
Page 239 and 240: 48 5. 2 Pll ∆ deviates drasticall
Page 241 and 242: 50 System-Level Faults RefUnder Ref
Page 243 and 244: 52 1.2.5 Summary of Decoupling Sche
Page 245 and 246: 54 noise, system disturbances and m
Page 247 and 248: 56 compressor data. When there is a
Page 249 and 250: 58 Figure 2-5 Decoupling evaporator
Page 251 and 252:
60 Total Pressure Drop of Liquid- L
Page 253 and 254:
62 Figure 2-11 Illustration of Demo
Page 255 and 256:
64 bypass the compressor. At this t
Page 257 and 258:
66 for T dis because there is no ov
Page 259 and 260:
68 Figure 2-14 Outputs of the FDD d
Page 261 and 262:
70 the system requires more refrige
Page 263 and 264:
72 recommended that: the system req
Page 265 and 266:
74 Figure 2-20 Outputs of the FDD d
Page 267 and 268:
76 Figure 2-21 Histogram bar plot o
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
82 2.3.2 Summarized Results for Oth
Page 275 and 276:
84 3 CONCLUSIONS AND RECOMMENDATION
Page 277 and 278:
86 Breuker, M.S. and Braun, J. E.,
Page 279 and 280:
88 Lee, W., House, J.M. and Shin, D
Page 281 and 282:
90 APPENDIX 1 PHYSICAL MODELS OF EX
Page 283 and 284:
92 A1.1.2 Short-Tube Models Many re
Page 285 and 286:
94 m& = CA ρ P up − P ) (A1-5) (
Page 287 and 288:
96 The abrupt change of CA for the
Page 289 and 290:
98 These equations can be combined
Page 291 and 292:
100 H h T sh , max opening T sh , s
Page 293 and 294:
102 A1.2.5 Parameter Estimation Met
Page 295 and 296:
104 T (2 T sh, ratingopening , sh,m
Page 297 and 298:
106 Harms’Result Harms plotted al
Page 299 and 300:
108 Mass flow rate Local linearizat
Page 301 and 302:
110 temperature on the RTD is unifo
Page 303 and 304:
112 in cold water application, it i
Page 305 and 306:
1 ACKNOWLEDGEMENTS The research tha
Page 307 and 308:
3 2.2.3 Todd Harms’ Data ........
Page 309 and 310:
5 LIST OF FIGURES Figure E-1. FDD d
Page 311 and 312:
7 LIST OF TABLES Table E-1 FDD resu
Page 313 and 314:
9 IA = Independence Assumption λ i
Page 315 and 316:
11 EXECUTIVE SUMMARY Packaged air c
Page 317 and 318:
13 current values of the fault indi
Page 319 and 320:
15 Figure E-4 Histogram of the EER
Page 321 and 322:
17 2. Operational cost savings, whi
Page 323 and 324:
19 Table E-5 Conservative Lifetime
Page 325 and 326:
21 constraints. Economic constraint
Page 327 and 328:
23 Paper statistics in HVAC FDD 35
Page 329 and 330:
25 on directional changes to identi
Page 331 and 332:
27 fault levels at different operat
Page 333 and 334:
29 was concluded that the method wa
Page 335 and 336:
31 However, several improvements ar
Page 337 and 338:
33 point sensor placement is genera
Page 339 and 340:
35 2 DATA SOURCES USED FOR EVALUATI
Page 341 and 342:
37 The fives types of faults are re
Page 343 and 344:
39 Occupation Type Climate Location
Page 345 and 346:
41 The SRB FDD method determines wh
Page 347 and 348:
43 The following sections describe
Page 349 and 350:
45 points rather than on a distribu
Page 351 and 352:
47 current operation point P 1, P F
Page 353 and 354:
49 4 A DECOUPLING-BASED FDD TECHNIQ
Page 355 and 356:
51 This approach overcomes the draw
Page 357 and 358:
53 ⎡ ∆T ⎢ ⎢ ∆T 2 ⎢ ∆
Page 359 and 360:
55 improving the compressor model p
Page 361 and 362:
57 Condenser Air Mass Flow Rate (lb
Page 363 and 364:
59 Evaporator Air Mass Flow Rate (l
Page 365 and 366:
61 Liquid-Line Pressure Drop (PSI)
Page 367 and 368:
63 4.2.2 Purdue Field Emulation Sit
Page 369 and 370:
65 1. Evacuated the system, and the
Page 371 and 372:
67 normal _ value − current _ val
Page 373 and 374:
69 Figure 4-16 shows one frame afte
Page 375 and 376:
71 Figure 4-18 shows one frame afte
Page 377 and 378:
73 valve position can be seen from
Page 379 and 380:
Figure 4-22 Outputs of the FDD demo
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
83 4.2.3.2 Summarized Results for O
Page 389 and 390:
85 5 ECONOMIC ASSESSMENTS Since the
Page 391 and 392:
87 inspection savings would be $2,0
Page 393 and 394:
89 Q & Cap = W & × EER (5-2) The e
Page 395 and 396:
91 4. electricity costs ( C e ). Ut
Page 397 and 398:
93 Table 5-3 lists estimates of equ
Page 399 and 400:
95 5.4 Smart Service Schedule Savin
Page 401 and 402:
97 7. A 6-ton RTU having a cost of
Page 403 and 404:
99 Location North California South
Page 405 and 406:
101 5. Three case studies were inve
Page 407 and 408:
103 REFERENCES Aaron, D. A., and P.
Page 409 and 410:
105 Davis, Coby. 1993. Comparison o
Page 411:
107 Rossi, T.M., 1995. Detection, D
show all

Fault Detection and Diagnostics for Rooftop Air Conditioners

Create successful ePaper yourself

Delete template?

Save as template?