Featuring HFC134a Refrigerant
HITACHI CENTRIFUGAL CHILLER HC-F-GSG Series, 1,407 – 4,395 kW (400 – 1,250 USRT) HC-F-GXG Series, 1,407 – 4,395 kW (400 – 1,250 USRT)
TECHINICAL INFORMATION
1
Contents 1. Features and Scope of Supply 1.1 Features 1.2 Scope of Supply 2. Standard Specifications 2.1 Standard Efficiency Type Specifications Table 2.2 High Efficiency Type Specifications Table 2.3 Standard Type Outline Drawing 2.4 Standard Type Foundation Drawing 3. Model Selection Table 3.1 How to use the table (HC-F- GSG/GXG type) 4. Characteristics Information 4.1 Control Characteristics 4.1.1 Capacity control characteristics (a) Part load characteristics 4.1.2 Temperature control characteristics (a) Temperature control characteristics (b) Temperature characteristics at startup 4.2 Motor characteristics 4.2.1 Starting current characteristics 4.3 Noise 4.4 Vibration 5. Instrumentation and Control 5.1 Operation Control System 5.2 Safety Control Equipment 5.3 Sequential Operation with Pump and Cooling Tower Fan 5.4 control panel Indication 5.4.1 Display items 5.4.2 control panel display 5.5 External Signal Tie-in 6. Start-up Panel (Starter) 7. Main Equipment Configuration and Main Options 7.1 Cycle Drawing 7.2 Compressor Unit 2
7.3 Heat Exchanger Unit 7.4 Main Options 7.4.1 Marine-type water chamber case (option) 7.4.2 Hot gas by-pass valve control 7.4.3 Outdoor cover 8. Inspection 8.1 Inspection Items and Points 9. Facility Design Considerations 9.1 Machinery Room and Maintenance Facilities 9.2 Notes for Operating the Chiller 9.2.1 Operation in winter period 9.2.2 Standard range of operation 9.2.3 Other notes 9.3 Low Load Operation 9.3.1 Hot gas by-pass valve control 9.4 Vibration and Earthquake Proofing 9.4.1 Effect of vibration proofing 9.4.2 Earthquake proofing 9.5 Variable Flow Control (optional) 9.5.1 Cooling water variable flow control 9.5.2 Chilled water variable flow control 9.6 Controlling Number of Units 10. Constructional Considerations 10.1 Rigging Work 10.2 Installation Work 10.3 Water Piping Facily Work 10.4 Electrical Work 10.5 Cold Insulation Work 11. Reference 11.1 Properties of refrigerant 11.2 Lubricating Oil 11.3 Maintenance Item List 11.4 Water Quality Control 11.5 Laws and Regulations 3
Preface
Laying the greatest emphasis on environmental protection of the earth, Hitachi has manufactured and offers you a centrifugal chiller featuring HFC-134a refrigerant which has no effects on destroying the ozone layer. Combining our expertise cultivated by a delivery record of about 6,300 chillers with our new technologies required for use of HFC- 134a refrigerant (such as fluid performance improved by the optimum impeller shape, heat transfer performance improved by a high-performance tube, and lubrication performance improved by a new lubricant), Hitachi provides high efficiency, performance and reliability. Please use the Hitachi centrifugal chiller featuring HFC-134a, as a future heat source for air conditioning or a cooling water manufacturing facility. This manual introduces the Standard-Efficiency type (HC-F400GSG to HC-F1250GSG ) and High-Efficiency type (HC-F400GXG to HC-F1250GXG). For more information, please contact your nearest dealer.
4
1. Features and Scope of Supply 1.1 Features
1
This chiller uses HFC134a refrigerant which has an ozone depletion potential of "zero" in terms of protecting the ozone layer.
Using high-pressure refrigerant HFC134a always keeps the internal pressure of equipment
2
higher than the atmospheric pressure at the startup/stop, thus requiring no purge unit and emitting less refrigerant to the air.
3
4
The ues of an economizer cycle, as compared with the conventional HC-F models, provides high efficiency and energy saving.
The microcomputer packaged on the equipment provides highly functional operation control, and no purge unit is required for easy maintenance.
1.2 Scope of supply Item
Delivered equipment or services
1. Chiller main unit
Compressor, main motor, lubricator, heat exchanger
2. Auxiliary equipment
Safety devices, control panel, starter (indoor, not explosion-proof), accessories, spares
3. Testing
Factory performance testing (when multiple chillers are ordered, only one is tested)
4. Painting 5. Transportation
Main unit : Rust-proof painting. Control panel and starter cubicle : Finished with Flat Munsell 5Y7/1 color paint. Shipped on truck or trailer to the port in Japan without any transferring
Out of scope of supply : Unloading FOB port, installation, cold insulation work, primary and secondary electrical wiring, foundation work, commissioning, piping
5
2. Standard Specifications 2.1 Standard Efficiency Type Specifications Table（HC-F400GSG to HC-F1250GSG） Specifications
( ARI temperature condition )
Chilled water inlet temperature 12.3℃, outlet temperature 6.7℃; Cooling water inlet temperature 29.4℃, outlet temperature 34.8℃ Type [HC-F_GSG]
F400GSG
F500GSG
F600GSG
F800GSG
F900GSG
F1250GSG
USRT
416
520
624
832
936
1,300
kW
1,463
1,828
2,194
2,926
3,291
4,571
Flow Rate
3
m /h
226
283
340
453
509
708
Pressure Drop (Approx.)
kPa
68
68
68
75
77
78
DN
200
200
250
250
300
300
－
2
2
2
2
2
2
Cooling Capacity
Chilled Water
Connection Pipe Nominal Size Number of Passes Flow Rate
m /h
3
284
355
427
564
634
889
Pressure Drop (Approx.)
kPa
64
64
64
74
75
76
DN
200
250
250
300
300
350
－
2
2
2
2
2
2
Expected motor Input
kW
279
322
386
494
571
795
Expected COP
－
5.24
5.68
5.68
5.92
5.76
5.75
Length (A)
mm
3,620
3,620
3,620
4,040
4,100
4,640
Width (B)
mm
2,090
2,090
2,200
2,480
2,620
3,060
Height (C)
mm
2,250
2,250
2,370
2,530
2,600
3,040
Length for Pulling Tubes
mm
3,000
3,000
3,000
3,500
3,500
3,500
Operating Mass(Approx.)
ton
10.3
10.5
12.6
16.3
17.4
26.5
Carrying Mass (Approx.)
ton
8.8
9
10.9
14.2
15
20.3
35
40
43
Cooling Water
Connection Pipe Nominal Size Number of Passes
Installation Dimensions
Mass
Refrigerant
－
Insulating Area
m
2
HFC-134a 26
26
29
Notes: 1. This table is applicable to chillers manufactured for normal water. 2. Capacity control range is 100 to approx. 20%. 2
3. Fouling factor is assumed to be 0.000086m ·℃/W for both chilled and cooling water. Other fouling factors may be met upon request. 4. Standard main power sources: 400V AC, 50 Hz, 3-phase
HC-F400GSG to F1250GSG.
5. Capacities: HC-F400GSG to F1250GSG: 4.5kVA. 6. Maximum working pressure if 0.7 Mpa for both chilled and cooling water. If higher maximum working pressure if requiest. Please specify during inquiry. (it is possible to produce it up to 1.6 MPa) 7.For water piping connections, see the dimensional outline drawing. 8. COP values fo not include auxiliary power. 9.Specifications are subject to change without notice for technical improvement.
6
Specifications
( JIS temperature condition )
Chilled water inlet temperature 12℃, outlet temperature 7℃; Cooling water inlet temperature 32℃, outlet temperature 37℃ Type [HC-F_GSG]
F400GSG
F500GSG
F600GSG
F800GSG
F900GSG
F1250GSG
USRT
400
500
600
800
900
1,250
kW
1,407
1,758
2,110
2,813
3, 165
4,395
Flow Rate
3
m /h
242
302
363
484
544
756
Pressure Drop (Approx.)
kPa
78
78
78
86
88
89
DN
200
200
250
250
300
300
－
2
2
2
2
2
2
Cooling Capacity
Chilled Water
Connection Pipe Nominal Size Number of Passes Flow Rate
m /h
3
298
372
446
581
653
915
Pressure Drop (Approx.)
kPa
70
70
70
79
80
81
DN
200
250
250
300
300
350
－
2
2
2
2
2
2
Expected motor Input
kW
279
322
386
494
571
795
Expected COP
－
5.05
5.46
5.47
5.69
5.54
5.53
Length (A)
mm
3,620
3,620
3,620
4,040
4,100
4,640
Width (B)
mm
2,090
2,090
2,200
2,480
2,620
3,060
Height (C)
mm
2,250
2,250
2,370
2,530
2,600
3,040
Length for Pulling Tubes
mm
3,000
3,000
3,000
3,500
3,500
3,500
Operating Mass(Approx.)
ton
10.3
10.5
12.6
16.3
17.4
26.5
Carrying Mass (Approx.)
ton
8.8
9
10.9
14.2
15
20.3
35
40
43
Cooling Water
Connection Pipe Nominal Size Number of Passes
Installation Dimensions
Mass
Refrigerant
－
Insulating Area
m
2
HFC-134a 26
26
29
Notes: 1. This table is applicable to chillers manufactured for normal water. 2. Capacity control range is 100 to approx. 20%. 2
3. Fouling factor is assumed to be 0.000086m ·℃/W for both chilled and cooling water. Other fouling factors may be met upon request. 4. Standard main power sources: 400V AC, 50 Hz, 3-phase
HC-F400GSG to F1250GSG.
5. Capacities: HC-F400GSG to F1250GSG: 4.5kVA. 6. Maximum working pressure if 0.7 Mpa for both chilled and cooling water. If higher maximum working pressure if requiest. Please specify during inquiry. (it is possible to produce it up to 1.6 MPa) 7.For water piping connections, see the dimensional outline drawing. 8. COP values fo not include auxiliary power. 9.Specifications are subject to change without notice for technical improvement.
7
2.2
High Efficiency Type Specifications Table（HC-F400GXG to HC-F1250GXG）
Specifications
( ARI temperature condition )
Chilled water inlet temperature 12.3℃, outlet temperature 6.7℃; Cooling water inlet temperature 29.4℃, outlet temperature 34.7℃ Type [HC-F_GXG]
F400GXG
F500GXG
F630GXG
F800GXG
F1000GXG
F1250GXG
USRT
416
520
655
832
1,040
1,300
kW
1,463
1,828
2,303
2,926
3,657
4,571
Flow Rate
3
m /h
226
283
357
453
566
708
Pressure Drop (Approx.)
kPa
84
44
43
53
43
53
DN
200
200
250
250
300
300
－
3
2
2
2
2
2
Cooling Capacity
Chilled Water
Connection Pipe Nominal Size Number of Passes Flow Rate
m /h
3
285
355
448
569
711
889
Pressure Drop (Approx.)
kPa
46
63
48
71
50
73
DN
200
250
250
300
300
350
－
2
2
2
2
2
2
Expected motor Input
kW
253
305
379
463
578
726
Expected COP
－
5.78
5.99
6.08
6.32
6.33
6.30
Length (A)
mm
4,260
4,100
4,600
4,600
5,300
5,300
Width (B)
mm
2,200
2,200
2,650
2,650
3,350
3,350
Height (C)
mm
2,350
2,350
2,600
2,600
3,150
3,150
Length for Pulling Tubes
mm
3,500
3,500
4,000
4,000
4,000
4,000
Operating Mass(Approx.)
ton
13.6
13.6
19.2
19.2
30
30
Carrying Mass (Approx.)
ton
11.7
11.7
16.5
16.5
23.5
23.5
45
52
52
Cooling Water
Connection Pipe Nominal Size Number of Passes
Installation Dimensions
Mass
Refrigerant
－
Insulating Area
m
2
HFC-134a 33
33
45
Notes: 1. This table is applicable to chillers manufactured for normal water. 2. Capacity control range is 100 to approx. 20%. 2
3. Fouling factor is assumed to be 0.000086m ·℃/W for both chilled and cooling water. Other fouling factors may be met upon request. 4. Standard main power sources: 400V AC, 50 Hz, 3-phase
HC-F400GXG to F1250GXG.
5. Capacities: HC-F400GXG to F1250GXG: 4.5kVA. 6. Maximum working pressure if 0.7 Mpa for both chilled and cooling water. If higher maximum working pressure if requiest. Please specify during inquiry. (it is possible to produce it up to 1.6 MPa) 7.For water piping connections, see the dimensional outline drawing. 8. COP values fo not include auxiliary power. 9.Specifications are subject to change without notice for technical improvement.
8
Specifications
( JIS temperature condition )
Chilled water inlet temperature 12℃, outlet temperature 7℃; Cooling water inlet temperature 32℃, outlet temperature 37℃ Type [HC-F_GXG]
F400GXG
F500GXG
F630GXG
F800GXG
F1000GXG
F1250GXG
USRT
400
500
630
800
1,000
1,250
kW
1,407
1,758
2,215
2,813
3,516
4,395
Flow Rate
3
m /h
242
302
381
484
605
756
Pressure Drop (Approx.)
kPa
96
50
49
60
49
61
DN
200
200
250
250
300
300
－
3
2
2
2
2
2
Cooling Capacity
Chilled Water
Connection Pipe Nominal Size Number of Passes Flow Rate
m /h
3
293
366
457
581
726
907
Pressure Drop (Approx.)
kPa
49
67
50
74
52
76
DN
200
250
250
300
300
350
－
2
2
2
2
2
2
Expected motor Input
kW
253
305
379
463
578
726
Expected COP
－
5.56
5.76
5.85
6.08
6.08
6.05
Length (A)
mm
4,260
4,100
4,600
4,600
5,300
5,300
Width (B)
mm
2,200
2,200
2,650
2,650
3,350
3,350
Height (C)
mm
2,350
2,350
2,600
2,600
3,350
3,350
Length for Pulling Tubes
mm
3,500
3,500
4,000
4,000
4,000
4,000
Operating Mass(Approx.)
ton
13.6
13.6
19.2
19.2
30
30
Carrying Mass (Approx.)
ton
11.7
11.7
16.5
16.5
23.5
23.5
45
52
52
Cooling Water
Connection Pipe Nominal Size Number of Passes
Installation Dimensions
Mass
Refrigerant
－
Insulating Area
m
2
HFC-134a 33
33
45
Notes: 1. This table is applicable to chillers manufactured for normal water. 2. Capacity control range is 100 to approx. 20%. 2
3. Fouling factor is assumed to be 0.000086m ·℃/W for both chilled and cooling water. Other fouling factors may be met upon request. 4. Standard main power sources: 400V AC, 50 Hz, 3-phase
HC-F400GXG to F1250GXG.
5. Capacities: HC-F400GXG to F1250GXG: 4.5kVA. 6. Maximum working pressure if 0.7 Mpa for both chilled and cooling water. If higher maximum working pressure if requiest. Please specify during inquiry. (it is possible to produce it up to 1.6 MPa) 7.For water piping connections, see the dimensional outline drawing. 8. COP values fo not include auxiliary power. 9.Specifications are subject to change without notice for technical improvement.
9
2.3 Standard Type Outline Drawing Table1. Standard Efficiency Type（HC-F400GSG to HC-F1250GSG） Model Outline Drawing Figure Number
Table2.
400V
F400GSG
F500GSG
F600GSG
F800GSG
F900GSG
F1250GSG
Figure 2.3.1
Figure 2.3.1
Figure 2.3.2
Figure 2.3.3
Figure 2.3.4
Figure 2.3.5
High Efficiency Type（HC-F400GXG to HC-F1000GXG）
Model Outline Drawing Figure Number
400V
F400GXG
F500GXG
F630GXG
F800GXG
F1000GXG
Figure 2.3.6
Figure 2.3.7
Figure 2.3.8
Figure 2.3.9
Figure 2.3.10
2.4 Standard Type Foundation Drawing Table1. Standard Efficiency Type（HC-F400GSG to HC-F1250GSG） Model Foundation Drawing Figure Number
Talbe2.
400V
F400GSG
F500GSG
F600GSG
F800GSG
F900GXG
F1250GSG
Figure 2.4.1
Figure 2.4.1
Figure 2.4.2
Figure 2.4.3
Figure 2.4.4
Figure 2.4.5
High Efficiency Type（HC-F400GXG to HC-F1000GXG）
Model Foundation Drawing Figure Number
400V
F400GXG
F500GXG
F630GXG
F800GXG
F1000GXG
Figure 2.4.6
Figure 2.4.6
Figure 2.4.7
Figure 2.4.7
Figure 2.4.8
10
Figure 2.3.1 Outline Drawing HC-F400GSG to 500GSG
11
Figure 2.3.2 Outline Drawing HC-F600GSG
12
Figure 2.3.3 Outline Drawing HC-F800GSG
13
Figure 2.3.4 Outline Drawing HC-F900GSG
14
Figure 2.3.5 Outline Drawing HC-F1250GSG
15
Figure 2.3.6 Outline Drawing HC-F400GXG
16
Figure 2.3.7 Outline Drawing HC-F500GXG
17
Figure 2.3.8 Outline Drawing HC-F630GXG
18
Figure 2.3.9 Outline Drawing HC-F800GXG
19
Figure 2.3.10 Outline Drawing HC-F1000GXG
20
Figure 2.4.1 Foundation Drawing HC-F400GSG to 500GSG
21
Figure 2.4.2 Foundation Drawing HC-F600GSG
22
Figure 2.4.3 Foundation Drawing HC-F800GSG
23
Figure 2.4.4 Foundation Drawing HC-F900GSG
24
Figure 2.4.5 Foundation Drawing HC-F1250GSG
25
Figure 2.4.6 Foundation Drawing HC-F400GXG to 500GXG
26
Figure 2.4.7 Foundation Drawing HC-F630GXG to 800GXG
27
Figure 2.4.8 Foundation Drawing HC-F1000GXG
28
3. Model Selection Table 3.1 How to use the table (HC-F-GSG/GXG Type) (1) Model representation Hitachi Centrifugal Chiller models are represented by the standard refrigerating capacity of the compressor used.
ＨＣ- Ｆ Name of chiller series
４００
Applicable type for alternate fleon (adopting HFC134a)
ＧＳＧ Chiller series code Standard refrigerating capacity of the compressor
(2) Formula for selecting an available model 1 USRT (U.S. refrigeration ton) = 3,024 kcal/h = 3.516 kW 1 JRT (Japan refrigeration ton) = 3,320 kcal/h = 3.86 kW Chilled water inlet temperature = Chilled water outlet temperature + Temperature difference between chilled water inlet and outlet
GSG:Standard efficiency type GXG:High efficiency type
Cooling water flow rate (m3/h) [Refrigerating capacity (RT) x 3.024]+(0.86xMotor input KW) = Temperature difference between cooling water inlet and outlet Refrigerating capacity (RT)×3.66 (High efficiency type) *1
≒ Temperature difference between cooling water inlet and outlet *1 : 3.72 (Standard type)
Cooling water outlet temperature = Cooling water inlet temperature + Temperature difference between cooling water inlet and outlet
Note : In this technical information, U.S. Refrigeration ton (USRT or RT) is used as the unit for expressing refrigerating capacity.
Chilled water flow rate (m3/h)= Refrigerating capacity (RT) x 3.024 Chilled water temperature difference
(3) Selection procedure and an example This technical information provides the maximum capacity available for each model based on the fouling factor of 0.000086 m2K/W (0.0001 m2h℃ /kcal) and within the range not exceeding the motor output. If you wish to obtain lower power through any possible combination of devices, or you need any specifications of the range not offered in this technical information, please contact your nearest dealer.
(b) Temperature difference calculation: Difference between at the inlet and the outlet of the chilled water: 12-7 = 5 (℃) Difference between at the inlet and the outlet of the cooling water: 37-32 = 5 (℃)
(a) Example specifications Power source : 50 Hz, 400 V Refrigerating capacity : 373 RT Chilled water temperature : 12℃ at the inlet, 7℃ at the outlet
(c) Calculation of required power The power required for the desired specifications is calculated following the example given below after obtaining the correction factor from Figure 3.1. (kW of the motor represents the output.)
Cooling water temperature : 32℃ at the inlet, 37℃ at the outlet
29
Chilled water Cooling water
Specifications RT (373RT) Capacity ratio =
= 0.933
Capability RT (400RT) The correction factor can be read as 0.95 in Figure 3.1. Therefore, Required power = Capability kW (240 kW) × Correction factor (0.95) = 228 kW The required power obtained through the above calculation is only a rough estimate and may be altered. For a more detailed value, please inquire via your nearest dealer.
6.9 mAq 6.2 mAq
Take the following points into account when calculating the water head loss: (1) The lower limit of the water head loss of the chilled water for the water flow of the specifications will be 4 mAq or above depending on the operating condition of the water cut-off relay. (2) Since the water head loss varies for each individual device, the water head loss of the chiller should be the value calculated from the curve with 1 mAq or more allowance when selecting the specified water head of the pump.
(d) Capacity control characteristics The inlet guide vane incorporated in the compressor allows capacity control for a wide range while maintaining a constant temperature at the chilled water outlet. Figure 4.1 in Chapter 4 illustrates the relationship between the refrigerating capacity and the required power; the required power varies with the temperature of the cooling water (an estimated value when the temperature at chilled water outlet and the water volume stay constant).
(f) Chilled water temperature condition As for the specifications conditioned to have the temperature of less than 5℃ at the chilled water outlet, only a limited possible combination of devices or a limited operation control system may be allowed to prevent freezing. Please inquire your nearest dealer.
(e) Water flow rate and water head loss 373×3.024 Chilled water flow = = 225.6 (m3/h) rate 5
(g) Fouling factor When the fouling factor is 0.000172 m2k/W (0.0002 m2h℃/kcal), correct the temperature at the chilled water outlet to be lowered by 1℃ and at the
373×3.72 Cooling water flow = = 277.5 (m3/h) rate 5 Use the number of passes obtained in (c) and the above-mentioned water flow to calculate the water head loss from the water head loss curve in the capability table.
cooling water outlet higher by 1.5℃. Then use the refrigerating capacity table with the corrected temperature conditions. For the fouling factors higher than this, inquire your nearest dealer. The appoximate correction factors are as follows:
Figure 3.1 Required power calculation 30
Water
Refrigerating capacity
Motor Power
Chilled water
0.94
1.0
Cooling water
0.96
1.0
4. Characteristics Infomation 4.1 Control Characteristics 4.1.1 Capacity control characteristics (a) Part load characteristics The inlet guide vane allows, using a chilled
The capacity of the centrifugal chiller can be controlled by opening and closing the inlet guide vane
water outlet temperature regulator, a continuously-
installed at the inlet of the compressor to vary the
stable capacity control within the range of 100% to
amount of circulating refrigerant; the guide vane is
approximately 20% of the refrigerating capacity. Figure 4.1 shows the relationship between the
provided for assuring a constant temperature at the
refrigerating capacity and the required power.
chilled water outlet.
Required power (%)
Cooling water inlet temperature
Vane opening lower limit
Conventional Vane opening lower limit
Solid line: [GSG, GXG Type] Normal Specifications Broken line: [GXG Tyte] Option Specifications
Refrigerating capacity (%)
Figure 4.1 Example part load characteristics of the standard type ①
Continuously operable without worry even on very hot days Even when cooling water temperature rises on very hot days or condensing pressure increases due to stained tubes, the system continues to stably operate. the trouble of outage being minimized,you can operate the system without worry.
②
Low-load operation is available throughout the year without special devices Conventionally the lower limit point for capacity control has been set mechanically,so that the capacity at the lower limit point increases in intermediate seasons or winter. With the GXG series,operation is stable up to 20% even at low cooling water temperatures, without any special devices(hot gas bypass valve,etc.),due to microcomputer control.
③
Even in seasons where external air temperature is low, the expanded operating range of single unit chiller assures a high energy saving effect. While conventional models require a controlling cooling water inlet temperature of 20℃ or higher, GXG series can operate up to a cooling water inlet temperature of 12℃, expanding further the capacity range.
31
4.1.2 Temperature control characterstics (a) Temperature control characteristics The load change of the standard type appears as a change in the chilled water inlet temperature, given the chilled water flow is constant.
Against such a load change, the temperature controller will control the chilled water outlet temperature to be constant. A control example is given in Figure 4.3 below.
Figure 4.3 Temperature control characteristics
(b) Temperature characteristics at startup The follow-up characteristics of the standard type depends on the relationship between the total
quantity of heat of the chilled water system and the capacity of the chiller. See Figure 4.4 for an example.
Figure 4.4 Example temperature characteristics at startup 32
4.2 Motor Characteristics 4.2.1 Starting current characteristics The main motor for the hermetic centrifugal chiller has a squirrel-cage induction type structure which generally adopts the reduced voltage starting system to save the starting current. Various types of starting systems are used depending on source voltage and source capacity; the general characteristics of the starting current are shown in Figure 4.5 to 4.9. For further information on the starter, see Section 6. The starting current varies with the chilled water temperature immediately before starting up; the higher the temperature of the chilled water, more the transient current flows at startup. When determining the source capacity, take such differences into consideration and make selection with 130% or more of the value given in the figure.
33
Table 4.1 Starting system and characteristics of the motor for the closed-type centrifugal chiller (1/2)
Starting system
Starting compensator
Direct starter
(Automatic compensator,
(DOL)
Reactor starter
condorfer)
Applied voltage (V)
400,3000,6000
400,3000,6000
400,3000,6000
Starting voltage (%)
100
65
65
550～750
165～225
300～410
200
60
60
Starting voltage change
Constant during startup
Constant during startup
Motor terminal
───
───
───
3 to 6 seconds
10 to 15 seconds
5 to 10 seconds
Starting current (%) (compared with rated current)
St a r t i n g t o r q u e ( % ) (compared with rated torque, approx.)
Begin increasing from startup
Starting time (till reaching the maximum rate)
Starter characteristics (in order of facility cost incurred)
Desirable in case where a large source capacity is required for
For facilities where minimized
construction facilities etc. (1)
starting current is desired (5)
Circuit
34
(4)
Table 4.1 Starting system and characteristics of the motor for the closed-type centrifugal chiller (2/2)
Open transition
Closed transition
star-delta starter
star-delta starter
Applied voltage (V)
400,3000
400
Starting voltage (%)
57.5
57.5
180～250
180～250
66
66
Starting voltage change
Constant during startup
Constant during startup
Motor terminal
6 lead wire type only
6 lead wire type only
10 to 15 seconds
10 to 15 seconds
Starter characteristics
Large rush current at
Small rush current at
(in order of facility cost
switching
switching
incurred)
Star-delta (2)
Star-delta(3)
Starting system
Starting current (%) (compared with rated current)
St a r t i n g t o r q u e ( % ) (compared with rated torque, approx.)
Starting time (till reaching the maximum rate)
Circuit
35
Chilled water 25℃
Starting current（％）
Chilled water 15℃
Time
(second)
Figure 4.5 Direct starting characteristics
Chilled water 25℃
Starting current（％）
Chilled water 15℃
Time
(second)
Figure 4.6 Reactor starting characteristics (65％ tap) 36
Chilled water 25℃
(500 to 1500%)
Chilled water 15℃
Starting current
（％）
Rush current of 1 to 2 Hz
Time
(second)
Figure 4.7 Automatic compensator starting characteristics (65% tap) ※Rush current may occur due to the residual voltage in the starting transformaer at startup. Take this into account when selecting the primary over current relay.
Chilled water 25℃ Chilled water 15℃ Rush current of 1 to 2 Hz
Starting current
（％）
(500 to 1500%)
Time
(second)
※The maximum value of the rush current when switching from 1 to D ( →△) may be 15 times of the rated value. Take this into account when selecting the primary over current relay particularly for the 400V models.
Figure 4.8 Open transition star-delta characteristics
37
Chilled water 25℃
Starting current
（％）
Chilled water 15℃
Time
(second)
Figure 4.9 Closed transition star-delta starting characteristics
38
4.3 Noise Noise ( In case of HC-F400GSG )
Figure 4.10 Noise measuring positions
Table 4.2 Example noise measurements â„– 1
Measurement condition Before Thermal Insulation
Unit dB (A) Measuring position
1
2
3
4
5
6
7
88
86
81
88
87
85
63
Noise measurements dB (A)
Note: 1. The measuring points are located at 1m from the side of the chiller and 1.5m above ground. 2. The table gives measurements for reference; actual values may differ depending on the echo of the machinary room, capability of individual machines, or the insulation condition.
Octave central frequency (Hz) Figure 4.11 Example noise frequency analysis
39
4.4 Vibration Vibration ( In case of HC-F400GSG )
Figure 4.12 Vibration measuring position
Table 4.3 Example noise measurements
Unit μ (total
amplitude) Measuring position
①
②
③
④
⑤
⑥
⑦
⑧
⑨
⑩
⑪
⑫
⑬
V (Vertical direction)
－
4.0
15.0
－
6.0
－
－
3.0
12.0
－
－
－
7.0
A (Axis direction)
－
－
7.0
－
－
11.0
－
－
－
4.0
－
4.0
H (Horizontal direction)
4.0
－
8.0
13.0
－
－
4.0
－
－
－
4.0
－
Measuring direction
Vibration during refrigerating operation (typical example)
Figure 4.13 Example vibration frequency analysis (50 Hz-specifications model) 40
5.
Instrumentation and Control
5.1 Operation Control System The load limiting control operates in two phases;
The Hitachi Centrifugal Chiller adopts as standard entire automatic operation system based on
one is to stop the vane opening action (limits opening
the micro computer incorporated in the console panel.
action only to stop the vane operation), and the other is to force vane closing action.
(a) Startup operation (d) Automatic start and stop
Pressing the start switch on the console panel
The signal detecting the chilled water outlet
first starts the oil pump. About 20 seconds after the oil pressure has increased, the main contactor is
temperature is processed in the micro computer to
activated and the main motor is started via the
activate the automatic start and stop switch. If the
reduced voltage starter. Once, after a certain period, it
load is lowered below the range of capacity control,
is switched to full voltage setting with the main motor in
the automatic start and stop switch stops the chiller
full-speed operation, the inlet guide vane (hereinafter
temporarily. After 15 minutes has passed and the load
referred to as the vane) is automatically started to
is recovered, the chiller is automatically restarted.
open via the temperature regulator circuit and the load (e) Failiure stop
limiter circuit without being over loaded. Then the
In case the safety switch is activated, the chiller
Chiller gets into routine operation to keep the chilled
stops operation with alarming beep while the cause of
water outlet temperature at a certain level.
the failure is indicated on the console panel. (b) Stop operation (f) Oil heater
Pressing the stop switch on the console panel
To prevent foaming of oil at startup, the oil
stops the operation of the Chiller, after the minimum vane openings, with the vane automatically closed completely. The oil
heater is automatically activated while the chiller is out
pump also automatically stops after about 4 minutes.
of operation so that the oil is kept at an appropriate temperature. (In order to do so, electric source for control system will be activated even when the chiller is off.)
(c) Automatic temperature regulator (with load limiting function)
(g) Emergency stop
The temperature regulator provides stable
Pressing the Emergency stop switch on the console
temperature control and load limiting control by applying the load limiting function to the entire circuit
panel stops the operation of the Chiller with the vane
and by adopting circuits unique to Hitachi such as
automatically closed completely. The oil pump also
integration and differential control functions.
automatically stops after about 4 minutes.
41
< OPERATIONAL FLOW DIAGRAM >
42
1
43
5.2 Safety Control Equipment (1) Electrical safety mechanism
(2) Functional safety mechanism ●Prevention of an abnormal high pressure inside the chiller
The safety equipment consists of the following
････････ Safety valves (in case of fire etc.)
components. When these components activated, the main motor automatically stops while warning by
●Interlocking by fully closing the vane (starting interlock)
beeping as well as indicating the cause of the failure.
●Vane surging prevention switch
●Oil temperature switch ････････
●Lowering tank oil temperature
In case of an abnormal oil temperature rise ●Oil differential pressure switch ････････
■Automatic temperature controller
In case of an abnormal oil pressure drop
Adopted for controlling temperature are the
●Chilled water cut-off switch ････････
circuits unique to Hitachi such as the PID circuit
In case of an abnormal chilled water decrease
providing stable control, the overshoot prevention
●Cooling water cut-off switch ････････
circuit, the motor overload prevention circuit, and the
In case of an abnormal cooling water decrease
circuit for preventing the evaporator low pressure
●Chilled water temperature switch ････････
drop at a low cooling water level.
In case of abnormal chilled water temperature decrease ●Evaporator pressure switch ････････
■ Load limiter The load limiter provides control operation in
In case of an abnormal evaporator pressure drop
two phases; one is to stop the vane opening action
●Condenser pressure switch ････････
and the other is to force the vane to close. ■ Re-start restriction
In case of an abnormal condenser pressure rise ●Overload relay ････････
To protect the motor from overheat caused by
In case of overloaded main motor (overcurrent in starter) ●Coil temperature switch ････････
repetitive starting, a timer is provided to restrict restarting for 15 minutes after the operation is stopped.
In case of overheated main motor coil (3) Automatic safety equipment Switch
Part No.
Chilled water temperature switch (electronic) Evaporator low pressure switch Condenser high pressure switch Chilled water cut-off switch Cooling water cut-off switch Oil feeding temperature switch(electronic) Oil feeding differential pressure switch Motor coil temperature switch Automatic start and stop switch(electronic type) Oil heater temperature switch (electronic type)
26WLX 63EL 63CH 69WC2 69WC1 26QBX 63QL 49M 23ASX 26QHX
For Safety Circuit OFF Circuit ON 4.5℃ 12℃ 0.19MPa 0.3 MPa 1.0MPa 0.7 MPa 0.015 MPa 0.025 MPa 0.015 MPa 0.025 MPa 63℃ 58℃ 0.1MPa 0.15MPa 75℃ 53℃ ─── ─── ─── ───
For Operation Circuit OFF Circuit ON ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── ─── 5.5℃ 15℃ 55℃ 50℃
Notes: (1) The set values of the instruments are under condition where the chilled water outlet temperature is 7℃ and the cooling water outlet temperature is 37℃. (2) The chilled water temperature switch (26WLX), the automatic start and stop switch (23ASX), and the oil feeding temperature switch (26QBX) are incorporated in the micro computer with their fixed set values. (3) The set value of the motor coil temperature switch (49M) is fixed.
44
5.3 Sequential Operation with Pump and Cooling Tower Fan The centrifugal chiller is recommended to be
based on the instructions given from the console panel
sequentially operated (sequentially started and
of the chiller. Actions and receiving and sending of
stopped) with the chilled water pump, the cooling water
contact signals are proceeded in the sequences
pump, and the cooling tower fan in order to ensure
illustrated below.
proper and safety operation. All operation should be
â&#x20AC;ť In case that chilled water flow rate does not reach by more than 80% in 20 seconds after operation switch ON, chiller will stop due to the chilled water cut-off switch.
45
5.4 control panel Indication 5.4.1 Display items Display
・
Power
Screen
items
・
Cooling
display
・
Heat pump
・
Trouble
opening, Lubrication temperature, Operating hours, Startup
・
Remote
count
・
Direct
・
Auto stop
・
Anti recycle
・
Demand limit
・
Press control
・
Chiller ON
・
Chiller OFF
・
ON
・
OFF Main motor
・
ON
・
OFF Oil pump
・
ON
・
OFF Oil heater
・
Auto Capacity control
・
Manual
Standby
Chilled water temperature, Oil tank temperature, Restart time limit
Operation
Warning
Chilled water temperature, Main motor current, Vane
Lubrication temperature High(other items available as option)
Main motor
Oil pump
Failure
17 items, including Main motor stator temperature High, Chilled water Low, Compressor pressure High, Evaporation pressure Low+message
Menu selection
Operation information
Operation status, Operating hours, Operation count, Measurement values including temperature and pressure
display
Failure log
Failure occurrence date, Failure occurrence time,
Oil heater Measurement
values including temperature and pressure
Warning log
Warning occurrence date, Warning occurrence time, etc.
Operation log
Operating hours, Operation count, Failure
Capacity control
count, etc.
5.4.2 control panel display
46
5.5 External Signal Tie-in
Item
Signal type
Numb
Input/
er
Output
Standard
Condition
Operation, Stop
No-voltage contact (Contact a)
2
Output
○
indication
Failure
No-voltage contact (Contact a)
2
Output
○
Vane opening
DC4～20mA １
Output
Optional
Remark
Choose either one as standard. It is optional in case of both.
○
Motor current
DC4～20mA
Oil feeding pressure
DC4～20mA
１
Output
○
Evaporation pressure
DC4～20mA
１
Output
○
Condensation pressure
DC4～20mA
１
Output
○
Oil feeding temperature
DC4～20mA
１
Output
○
2
Output
○
１
Input
○
Monitoring
For sequential operation with accessory equipment No-voltage contact (Contact a) No-voltage (serial pulse) DC24V (serial pulse)
Lead-Lag operation signal etc.
Remote start and stop operation DC48V／AC24V (pulse)
Chilled water outlet temperature remote control
１
Flow change forecast signal
Choose either one as standard. It is optional in case of both.
DC4-20mA １
Load restriction setup.
○
Input
Input
○
DC4-20mA
No-voltage contact (Contact a)
○
１
Input Reduced water flow rate
No-voltage contact (Contact a)
Accessory equipment interlock
○
1
Increased water flow rate
No-voltage contact (Contact a)
47
１
Input
○
For switching the number of chilled water and cooling water pumps
Line in a series the contacts which are turned ON while the chilled water and cooling water pumps are running.
6. Start-up Panel (Starter) ■ -Δ starter (electromagnetic switch box in a high pressure air with automatic -Δ starter)
● The 400 V models are used as standard source voltage.
● The signal light is located on the panel and the disconnector, electromagnetic contactor in high pressure air for -Δ starter contactor, overload relay, and the current transformer are deliberately located in the panel so as to allow easy maintenance and inspection. ● This -Δ starter can be installed anywhere as you wish, because all operation is conducted through the operation panel built in the chiller.
400 V model ····· -Δ starter (electromagnetic switch box in a low pressure air with automatic -Δ starter)
*In addition, if the source capacity is enough, the chiller can be operated via direct start instead of using the starter panel.
■ Starting panel dimensions table Dimensiton Model（HC-)
Refrigerat ing Capacity (RT)
F400 GSG/GXG～ 400～500 F500 GSG/GXG F630 GSG/GXG～ 630～800 F800 GSG/GXG F1000 GSG/GXG～ 1000～1250 F1250 GSG/GXG
-Δ
Motor output (kW)
starter ( for 400/440 V, 50/60 Hz ) L (mm)
H (mm)
W (mm)
Weight (kg)
210～260
800
2,100
700
250
310～395
1,000
2,200
800
340
505～630
1,500
2,100
100
700
■ Starter outer drawing
800
Maintenance space
*
If there is a risk of causing surge voltage with the vacuum disconnector installed on the primary side, provide a surge absorber on the primary side.
48
7. Main Equipment Configuration and Main Options 7.1 Cycle Drawing (typical cycle flow)
CONDENSING PRESSURE
COMPRESSOR
MOTOR
EVAPORATING OIL PRESSURE PRESSURE
CONTROL PANEL
CW OUTLET
CHW OUTLET ECONOMIZER
69WC1
CONDENSER
CW INTLET
69WC2
EVAPORATOR
CHW INLET
SUB COOLER
OIL RECOVERY
NOTES 1. 2.
F1
to
segments indicate direct connecting parts. (not pipes) indicate flange numbers. F4 SYMBOL
NAME
SYMBOL
NAME
AUTOMATIC START/STOP SWITCH (ELECTRONIC TYPE)
MANUAL VALVE SOLENOID VALVE
CHILLED WATER TEMP. SWITCH(ELECTRONIC TYPE)
OIL FEEDING TEMP. SWITCH
BACKED VALVE
EVAPORATOR LOW PRESSURE SWITCH
CHECK VALVE
CONDENSER HIGH PRESSURE SWITCH OIL FEEDING DIFFERENTIAL PRESSURE SWITCH
69WC1 69WC2
CHILLED WATER CUT-OFF SWITCH
NITROGEN TUBE PIPINGS REFRIGERANT LIQUID FLOW DIRECTION REFRIGERANT VAPOUR FLOW DIRECTION OIL FLOW DIRECTION WATER FLOW DIRECTION
ORIFICE
PRESSURE TRANSDUCER
DRYER
RESISTANCE THERMOMETER
WIRINGS FOR TEMP. DETECTION
49
OIL PIPINGS CAPILLARY TUBE PIPINGS
VENTURI
SIGHT GLASS
OIL HEATER TEMP. SWITCH(ELECTRONIC TYPE)
NAME REFRIGERANT PIPINGS
STRAINER SAFETY VALVE
COOLING WATER CUT-OFF SWITCH
SYMBOL
THERMOCOUPLE
7.2 Compressor Unit
Motor
Step-up gear Part name Gear case Impeller Impeller shaft Step-up gear Main motor shaft Guide vane Diffuser
2-step impeller
1-step impeller
Material Gray cast iron Aluminum alloy casting Nickel-Chromium Steel Nickel-Chromium Steel Chromium-Molybdenum Steel Spherical graphite cast iron Structural steel plate
Figure 7-2 Compressor unit
7.3 Heat Exchanger Unit
A high performance and small-sized heat exchanger was intended by adopting a new-type high-performance heat transfer tube â&#x20AC;&#x153;Thermoexcelâ&#x20AC;?.
Part name
Carbon Steel
Tube plate
Carbon Steel
Tube
Seamless Copper Tube
Water chamber case
Carbon Steel
Supporting plate
Carbon Steel
Figure 7-3 Heat Exchanger Unit
50
Material
Shell
7.4 Main Options 7.4.1 Marine-type water chamber case (option) (1) Bonnet-type water chamber (Hitachi standard)
(2) Marine-type water chamber (For special use when frequent opening and closing of the cover is required for cleaning the tube because the water quality is low.)
51
7.4.2 Hot gas by-pass valve control Except for some smaller models, controlling the refrigerating capacity at the level lower than about 20% can be realized by installing a hot gas by-pass valve as shown in the figure below. The range of the capacity control is given in the following table.
The HC-F type centrifugal chiller controls refrigerating capacity down to about 20% of the specified point by adjusting the vane opening of the inlet guide vane control unit. The vane opening cannot be further reduced, since the compressor then enters in surging operation.
Model
Capacity control range
HC-F400 GSG/GXG～
Standard: 100％ to approx. 20％
HC-F1250 GSG/GXG
Option: 100％ to approx. 10％
Figure 7-4 Hot gas by-passing
52
7.4.3 Outdoor cover Installing the outdoor noise-proof cover will reduce the noise value to 80dB (A) or lower (at 1 m away from the chiller).
An outdoor cover is required for the chiller installed outdoor. (A noise-proof cover is also available.) Given in the figure below is an example structure of the cover.
Detailed part A
Figure 7-5 Outdoor noise-proof cover
53
8. Inspection 8.1
Inspection Items and Points
(1) Pressure-tight test of pressure vessels Device
Design pressure MPaG
Pressure test MPaG
Airtight test MPaG
Compressor
0.92
1.7
1.15
Evaporator
0.92
1.7
1.15
Condenser
1.22
2.03
1.34
(2) Impeller overspeed test Impellers are independently subject to an overspeed test for 1.2 times or more of the rated number of revolution to confirm that there exist no abnormal deformation nor internal defects. (3) Impeller dynamic balancing test Impellers are subject to a balance correction until the residual unbalance of the rotor reaches the reference of G2.5 or above stated in JIS B 0905 1992 "Good balance of a rotor". (4) Water chamber pressure inspection The water chambers of the condenser and evaporator are subject to a pressure test for 1.5 times or more of the design pressure. (5) Airtight inspection (a) Pressure leak inspection: An air pressure inspection for 1.15 MPaG is conducted after the assembling is completed. (b) Vacuum leak inspection: Leaving the chiller Minus 100.7 kPa or higher inside for 12 hours after the completion of the pressure leak inspection, and then confirm that the vacuum drop is 0.133 kPa or less. (6) Specifications confirmation inspection This inspection is to confirm that the refrigerating capacity is met within the output range of the motor given in the specifications with the chilled water flow, cooling water flow, and temperature kept at the specified value. (7) Capacity control test This test is to measure in the same manner described in paragraph (6) the lower limit of the capacity that the chiller can continuously control. (8) Vibration measurement This is to confirm that the vibration values at the major parts during load operation are 30 Îź or less for the total amplitude. (9) Noise measurement Noise is measured during full load operation on the basis of JIS Z 8731-1983 "Noise level measuring method". (10) Water head loss measurement This is to confirm that the water head loss stays 110% to 70% of the specified value when the amount of water specified in the specification is supplied. (11) Maintenance control device operation inspection All maintenance control devices are independently inspected for operation and then attached to the main body of the chiller after they are accepted.
54
9. Facility Design Considerations 9.1 Machinery Room and Maintenance Facilities opening of the water maintenance and repair.
(1) Do not install near fire or inflammable. (For example, be careful of the radiation heat when installing with a heat emissioning body like a boiler.)
chamber
case,
and
(2) Select a location with good ventilation and low humidity where the room temperature stays 40â&#x201E;&#x192; or lower. (Note that high humidity will cause electrical failures and accelerate corrosion. Allowable ambient humidity: Up to 95% RH, 40â&#x201E;&#x192;)
(6) Secure a room height enough for attaching a hanging hook on the ceiling or assembling posts so that the units are easily lifted and lowered.
(3) Select a location of less dust. (Dust may cause electrical failure.)
(8) Avoid direct sunlight.
(7) Provide adequate drainage.
(9) Secure a water source for maintenance and receptacles for working,
(4) Take into account the natural lighting and select suitable location for maintenance and inspection.
(10) Secure a space for maintenance. Also secure a logging exit.
(5) Allow enough space for replacement of tubes,
9.2 Notes for Operating the Chiller 9.2.1 Operation in winter period cooler. (Because the differential pressure between the evaporator and the condenser is used for sending the cooling refrigerant solution.)
Starting or operating the chiller in winter period or under other circumstances where the cooling water temperature is abnormally low, may cause the following trouble.
(b) Due to low differential pressure between the evaporator and the condenser, the refrigerant liquid flowing into the evaporator becomes insufficient and may cause a transient abnormal decrease of the evaporating pressure which trips the chiller.
(a) Due to low differential pressure between the evaporator and the condenser (this state is called lowhead operation), troubles may occur in cooling of the main motor or cooling of the lubricant oil by the oil
55
9.2.2 Standard range of operation The chiller is assured a stable operation within the range given in the following table. Specified value
Limit value
Chilled water inlet temperature
１２℃
Between 12℃(specified value)or higher and 25℃ or lower
Cooling water inlet temperature
３２℃
Between 12℃ or higher and 32℃(specified value) or lower
Chilled water inlet temperature
１２℃
15℃ or lower
Item At starting
At normal operation Chilled water outlet temperature Cooling water inlet temperature
─
5℃ or higher (according to specifications)
３２℃
Between 20℃ or higher and 32℃(specified value) or lower
─
Chilled water flow
─
Within ±5% of the specified value
─
Cooling water flow
─
Within ±5% of the specified value
─
Number of times of automatic start and stop
─
Less than 5 times/day (desirable)
─
Refrigerating capacity lower limit
─
20% of the specified value
9.2.3 Other notes (b) Alternate operation of the main and service units If you have both the main and service units, please plan alternate operation of the two in order to make equal the service life of both units.
(a) Procedure for leaving the chiller out of operation for a long period Leaving the chiller out of operation for a long period may allow, under certain condition and water quality, bacteria to propagate in the water staying within the tube and thus corrode the tube. So, if you want to stop the chiller for more than two weeks, open the drain valves from the bottom of the water chambers of both the condenser and the evaporator so that no water stays inside the tube. Also, decrease of outside temperature may freeze the water in the tube and thus burst the tube. In winter when the water may freeze, be sure to drain the tube.
9.3 Low Load Operation 9.3.1 Hot gas by-pass valve control The HC-F centrifugal chiller can control its refrigerating capacity within the range of 100% to about 20% of the specified value. For further range of capacity control, the hot gas by-pass valve control (optional) discussed in paragraph 7.4.2 is available.
56
9.4 Vibration and Earthquake Proofing 9.4.1 Effect of vibration proofing Rubber pad method (standard) (a rubber sheet) : transmissibility of vibration is approximately 25% or less Rubber pad method (optional) (two rubber sheets) : transmissibility of vibration is approximately 15% or less Spring vibration-proof method (optional) : transmissibility of vibration is approximately 1% or less Where, Transmissibility of vibration
τ=
(1 −ϖ
1+ ε 2 2
/ϖ 0
) +ε
2 2
fn：fixed vibration of frequency of the vibration system
ϖ
2
×100(%)
ϖ0 =
60 2×π
k⋅g w
: vibration frequency of the machine
g : gravity acceleration
ε : damping ratio (rubber=0.1 - 0.2,
metal spring=0)
w : Load (kg)
k : Spring constant
9.4.2 Earthquake proofing As for earthquake proof basic strength, horizontal acceleration of 0.6 G and vertical acceleration of 0.3 G are specified as standard earthquake factors. If earthquake factors higher than these values is required, contact your nearest dealer.
57
9.5 Variable Flow Control (optional) of the compressor rises allowing the compressor to
Be careful of the following in variable flow
easily get into surging. To prevent the compressor
control of the chilled water and the cooling water.
from getting into surging, program, when reducing the
9.5.1 Cooling water variable flow control
flow, to carry out the reduction while the cooling water inlet temperature is low enough.
Points to be noted when reducing the cooling water flow through variable flow control.
(c) Water head loss becomes great The operation value of the water cut-off relay is
(a) The performance of the condenser' s heat transfer
required to be determined on the basis of the lower
tube tends to deteriorate.
limit value of the flow variation. On the other hand,
Reducing the flow decreases the flow rate within the heat transfer tube and thus lets the scales or
however, since the lower limit value of the operation
slimes attach on the tube wall. This will reduce the
differential pressure of the relay is about 2 mAq,
performance of the condenser causing lower efficiency
variation flow control up to 50%, for example, requires
of the chiller or other troubles.
the water head loss of the chiller at 50% to be 2 mAq. Therefore, the water head loss becomes greater as shown in the following table than that when no variable
(b) Compressor tends to get into surging
flow control is conducted.
If the cooling water flow is reduced with the opening of the inlet guide vane kept constant, the head
Water head loss of the chiller (when using low differential pressure type water cut-off relay)
Chilled water side Water head loss (mAq) Cooling water side Water head loss (mAq)
At 50% flow
At 100% flow
2.0
10.0
2.0
10.0
58
flow control.
(d) Perform variable flow control slowly. If the cooling water flow is suddenly decreased, the pressure inside the condenser will transiently rise
(a) The water head loss increases.
Same as
to activate the safety unit and then to cause the chiller
described in paragraph of the cooling water variable
to trip.
flow control. Provide 2 minutes or more of the flow varying (b) Perform variable flow control slowly.
speed for every 10%.
If the flow is suddenly changed, the opening and
Taking the above into consideration, and on condition that the cooling water inlet temperature will
closing speed of the inlet guide vane cannot follow
be decreased if necessary, up to 100% to 50%
such change and thus the pressure inside the
variable flow control is practicable.
evaporator will suddenly drops to activate the safety unit and then causes the chiller to trip.
9.5.2 Chilled water variable flow control
Provide 2 minutes or more of the flow varying speed for every 10%.
The following points must be noted when
Up to 100% to 50% variable flow control is also
performing variable flow control for the chilled water
practicable for the chilled water.
just as they are required for the cooling water variable
Note: When changing the flow momentarily because of pole change or the like, follow as shown in the figure below for both the chilled water and the cooling water.
Other notes are as same as those for the aforementioned variable flow control.
9.6 Controlling Number of Units number of units maneuvering signal is provided as
The signal for controlling the number of units shall fall in the installation range on the part of the
standard.
facility constructor and thus stays beyond our scope of
(It is the same for the series operation of absorption
delivery. However, the receiving terminal of the
type and centrifugal type.)
59
10. Constructional Considerations 10.1 Rigging Work installation underground, the compressor and the main body as a whole can be carried in by vertically lifting or by laying. In this case, a lifting hook is added at the position suitable for the lifting method and the console panel alone is separated for shipment. The bearing strength in the compressor has been designed to fully support the weight of the rotor, but take care so that no excess shock is applied on the machine in order to protect the rotating part including the rotor. After carrying in the equipment, incorporate the console panel and provide wiring to the panel. b) Rigging after separating the compressor Where height limit is provided, the compressor is separated from the main body to be carried in. In this case, the compressor is removed after the factory test has been completed; a special cover is attached on the flange faces of the compressor and the heat exchanger with nitrogen gas filled before shipped. After carrying in the equipment, re-mount the compressor on the heat exchanger. Air tightness must be confirmed.
(1) Inspection after delivery: Inspect whether any damage is found on the facing or whether any accessory is missing, and check the number of supplied parts against the invoice to see if any part is lacking. (2) Lifting: When lifting the equipment, wire it from the bottom and pay the greatest possible care so that the load will be uniform and the accessory parts will not get damaged. a) Lift the equipment in full balance. b) Do not carry or lift the equipment tilted. It will cause the equipment damage. c) Handle the equipment with the greatest possible care. Any shock given to the equipment may cause damage to metallic parts or a bend in the axes which will lead to shortening of the service life of the machine. d) Watch out the footing when rolling the equipment so as to prevent the unit from falling. (3) Separate rigging a) Rigging by vertical lifting and laying Where height limit is provided, or in case of
10.2 Installation Work (6) Lift the chiller to place a vibration-proof rubber on the base plate, and then set the chiller on the rubber. (7) Fix the peripheral edge of the base plate and the liner with the mortar. (8) Secure the chiller with the anchor bolts.
(1) Make sure the concrete faces of the leg of the chiller is smooth and level. (2) Set the anchor bolts. (3) Place the base plate at the determined position. (4) Place the chiller on the base plate. (5) Set a liner between the base plate and the concrete foundation to eliminate any space between the base plate and the leg of the chiller, and adjust so that the chiller will be level (within 0.5 mm per 1 m).
60
10.3 Water Piping Facility Work See the installation diagram for water piping of both condenser and evaporator. Notes: (1) Support chilled water and cooling water pipes not to apply any load to both condenser and evaporator. (2) Install 10-mesh strainers to the inlet pipes of the chilled water and cooling water. (3) Make a plan so that the flow rate of the chilled water and cooling water will be adjusted on the outlet side (secondary side) of the machine. (4)The available models retain water as listed below. Unit (ď˝?3)
Quantity of water held in chiller Chilled water
Cooling water
(Evaporator)
(Condenser)
HC-F400GSG
0.26
0.36
0.62
HC-F500GSG
0.33
0.45
0.78
HC-F600GSG
0.40
0.50
0.90
HC-F800GSG
0.56
0.69
1.25
HC-F900GSG
0.67
0.75
1.42
HC-F1250GSG
0.92
1.2
2.12
HC-F400GXG
0.44
0.47
0.91
HC-F500GXG
0.44
0.47
0.91
HC-F630GXG
0.75
0.85
1.59
HC-F800GXG
0.75
0.85
1.59
HC-F1000GXG
1.18
1.83
3.01
HC-F1250GXG
1.18
1.83
3.01
Model
Total
(5) Make a plan so that excessive pressure pulsation that may cause a malfunction does not act on a water cut-off relay.
61
10.4 Electrical Work (1) Electrical wiring work Connect each electric device according to the wiring diagram.
Consumers need to purchase the power wiring between starter and motor, control wiring between starter and operating panel themselves.
Fig. 8 Electrical wiring diagram for centrifugal chiller Ⅰ.Raising position of main circuit power source: 400V class, 3φ, 3W Ⅱ.Raising position of main circuit power source: 400V class, 1φ Ⅲ.Power wiring between starter and motor: Cable type and cable tube size as in the below table Ⅳ.Control wiring between starter and control panel: 1 CVV20, 25-core cable, cable conduit tube size 39
62
Main motor electrical characteristic.（400V class） Motor Output(kW) Max 90 91-132 133-190 191-250 251-315 316-410 411-510 511-630 631-800
400V class Cable 600V,3C,CV, 60 ×2
Cable conduit tube
(63)×2
(75)×2
(82)×2
(92)×2
(104)×2
(104)×2
(104)×4
600V,3C,CV, 100 ×2 600V,3C,CV, 150 ×2 600V,3C,CV, 200 ×2 600V,3C,CV, 325 ×2 600V,3C,CV, 400 ×2 600V,3C,CV, 250 ×4 – –
Condition for selection of size of main motor cable The cable size is determined according to the following rules. (1)
Extract from Internal Wiring Rules (JEAC 8001-1982): “When protecting wires used for equipment which needs a large starting current from an overload current, limit the starting current to 2.5 times the allowable current of those wires.” (2) Extract from Internal Wiring Rules 305-4: “When the rated current is 50A or less, use wires having allowable current at least 1.25 times as large as that rated current. When the rated current is larger than 50A, use wires having allowable current at least 1.1 times as large as that rated current.” (3) Install the cables in air or in covered conduits. When installing two or more cables, secure distance of at least twice their diameter between them.
10.5 Cold Insulation Work (5) Do not embed the thermometer and the temperature sensing element of the thermostat in the cold insulator so that they can be removed for replacement. (6) The cold insulation work of accessory piping and instrument piping must be performed by winding glass wool. Avoid embedding the joints of piping in the cold insulator as much as possible. (In order to confirm leakage in air pressure and vacuum tests.) (7) For the double-bundle condenser type, use a cold insulator corresponding to glass wool or higher material so long as heat resistance is concerned. (8) Welding, drilling, and riveting of art metal to the devices are prohibited, since such work may cause damages to the machine body.
Provide cold insulation after completing the leakage test and air operation. Notes for cold insulation work (1) Do not embed the movable parts (damper driving unit, valves, handles, etc.) in the cold insulator or let them touch the cold insulator. (2) When cleaning the tube of the heat exchanger, do not embed the water chamber clamping bolts in the cold insulator in order to open the water chamber case. Also, the water chamber case should be opened with ease. (The flange for water piping should also be removed with ease.) (3) Allow recess for the cold insulator at the bolt fastening part of the compressor and the compressor' s inlet main pipe so that the bolts are easily removed for disassembly in case of an overhaul or inspection. (4) Do not embed the liquid level indicator and the peephole in the cold insulator.
63
INSULATION WORK CONDENSER MOTOR TERMINAL BOX
EVAPORATOR MOTOR COMPRESSOR CONTROL PANEL
B SIDE
A SIDE 64
Cold insulator, facing materials, and auxiliary materials Item Glass wool
General specifications JIS A9505 No.2 40K heat conductivity:0.03 kcal/m.hr.â&#x201E;&#x192; density:0.04g/cm3 thickness:25-50mm 3
Foam polystyrene [Styrofoam] JIS A9511 No.3 0.03kcal/m.hr.â&#x201E;&#x192; density:0.02g/cm thickness:50mm Galvanized sheet
JIS G3302A9511 2types thickess: 0.03-0.4mm
Aluminum sheet
JIS H4000 thickness: 0.6-0.8mm or more
Stainless sheet
JIS G4305 SUS304 Material thickness:0.3mm or more
Cotton sheet
115g/m or more
Vinyl tape
JIS Z1901 thickness:0.2mm
Water-proof hemp cloth
JIS L3405 No.7+JIS K2207
Mortar
JIS thickness: 10mm
Plaster
JIS thickness: 5mm
Stencil
JIS 370g/m or more
Asphalt roofing
JIS A6005 17kg or more per roll (21m )
Adhesive tape
JIS Z1525 thickness: 0.2mm
Metal lath
JIS A5505 flat lath No.1, lib lath (A) No.1
Iron ring
JIS G3532 galvanized iron
Paper
2
2
2
--------------For polystyrene: vinyl acetate type adhesive
Adhesive For rivet: chloroprene type synthetic rubber adhesive
65
11. Reference 11.1 Properties of refrigerant The refrigerant (HFC134a) used for this refrigerating machine has the following properties. ①Gaseous at the normal temperature and normal pressure. ②Odorless. ③Noncombustible. HFC134a does not explode when mixed with air at any ratio. ④HFC134a in the liquid state is colorless and transparent. Since it does not mix with water and is heavier than water, water floats in a layer on it. ⑤Pure HFC134a, in either liquid state or gas state, does not corrode metals. If any air enters the refrigerating machine, however, moisture in the air may rust the metals, particularly the ordinary steel.
⑥Mineral lubricating oil dissolves in HFC134a very little at any ratio. Accordingly, special oil (ester oil) having some solubility must be used for the refrigerating machine which uses HFC134a. ⑦Harmless to men and animals. (Ventilate the machine room well, however.) ⑧HFC134a in gas state is about 5 times as heavy as air. Accordingly, when the refrigerating machine is disassembled, the gas leaks from the machine flow in a layer on the floor.
Materialistic properties of HFC134a Molecular weight
102.031
Boiling point (under atomospheric pressure)
-26.18 ℃
Specific gravity in liquid state (at 25℃)
1,206 kg/ λ
Specific gravity in gas state (at boiling point)
5.26 ..kg/cm3
Specific heat in liquid state (at 25℃)
1.427 kJ/kg･K
Latent heat of vaporization (at 25℃)
178.7 kJ/kg･K
Latent heat of vaporization (at 0℃)
199.2 kJ/kg･K
66
0
10
20
30
40
50
60(°C)
Temperature
(MPaG) 1.6
1.5
1.4
1.3
1.2
Saturated pressure
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1 0
10
20
30
40
50
60(°C)
Temperature
Saturation curve of refrigerant (HFC134a)
11.2 Lubricating Oil The synthesis oil (ester oil) has high hygroscopic property. Make sure no water element in the air can be mixed with the oil when supplementing or storing the oil. Do not use the same oil twice.
The lubricating oil is required to have heat stability, lubricity, as well as high insulation and compatibility. Hitachi is using a synthesized oil developed for HFC134a. If you wish to buy the oil for replenishment, please contact your nearest dealer.
11.3 Maintenance Item List Since maintenance and inspection of the chiller substantially govern the service life of the machine,
refer to Table 11-1 for providing proper maintenance and inspection.
67
Table 11.1
Maintenance and inspection item list Period
Once a month
Once a year Once in 3 years
Once in 6 years
Item Compressor
Replacement of lubricating oil
○
Replacement of oil strainer
○
Remark
○
Overhaul Main motor
○
Insulation measurement
○
Air gap measurement
Evaporator and Condenser
Other electric devices
○
Increase the number of times depending on the water quality condition.
Confirmation of water volume
○
Perfom twice a season or so.
Confirmation of safety relay operation
○
Safety relay insulation measurement
○
Confirmation of oil pump insulation
○
Confirmation of oil heater discontinuation and insulation
○
Cleaning of tube Water quality analysis
Confirmation of console fuse discontinuation Entire system
Leakage inspeciton
○
○ ○
Others
Cleaning of refrigerant strainer
○
Replacement of filter dryer
○
Refrigerant analysis
○
Perform as required according to the condition.
Note: 1. Since the list provides mere standard, the period may be shortened or lengthened according to your condition for use or inspection results. 2. The cpnditions of tubes should be investigated by non-destructive inspection with eddy current inspection apparatus if there is critically contamination of the water.
68
11.4 Water Quality Control cooling water and expedite corrosion. Although some appropriate water treatment agent can give a certain effect, replacement or blow of the water is also necessary in order to make sure. As a means for checking the corrosion state inside the finned tube, the non-destructive examination using an eddy current test equipment is available. This method can provide a lot of information on the condition of the tube in a relatively short time. Perform this examination regularly as well as the water quality analysis. The water quality and control standards are given in Table 11-3. Prepare criteria adequate for your condition of use in order to implement effective water quality control.
Hitachi classifies fresh water as shown in Table 11-2, and recommends "normal fresh water" for general use in the chiller. So long as the quality of the water you use constantly stays within this range, no corrosion is expected. Therefore, control the water quality aiming the "normal fresh water". The extreme limit of the usable water is "contaminated fresh water". The further it goes beyond the limit, the worse the condition for corrosion will be. Perform regular water analysis of the water used and control the quality to stay within the range of "normal fresh water" by implementing continual replacement and blow of the water. Especially, constant blowing is required for the cooling water in the cooling tower. This is because the corrosive factor in the air may be condensed in the
Table 11.2
Water quality component table
Cooling Water Quality Standards Cooling Water System Expelled Method
Circulation Water
Auxiliary supply water
Expelled water
Corrosion
Scale Formation
6.5-8.2
6.0-8.0
6.0-8.0
≦ 80 (≦ 800)
≦ 30 (≦ 300)
≦ 40 (≦ 400)
≦ 200
≦ 50
≦ 50
Sulfuric acid ions (mg SO4 /l)
≦ 200
≦ 50
≦ 50
Acid consumption amount (pH4.8) (mgCaCO3 / l)
≦ 100
≦ 50
≦ 50
Total hardness (mg CaCO3 / l)
≦ 200
≦ 70
≦ 70
Calcium hardness (mg CaCO3 / l)
≦ 150
≦ 50
≦ 50
Ionized calcium (mg SiO3 / l)
≦ 50
≦ 30
≦ 30
Iron (mg Fe/l)
≦ 1.0
≦ 0.3
≦ 1.0
≦ 0.3
≦ 0.1
≦ 1.0
Sulfured acid ions (mg S /l)
Undetected
Undetected
Undetected
Ammonium ions (mg NH4+/l)
≦ 1.0
≦ 0.1
≦ 1.0
Residual salts (mg Cl / l)
≦ 0.3
≦ 0.3
≦ 0.3
Free carbonic acid (mg CO2 / l)
≦ 4.0
≦ 4.0
≦ 4.0
Stability index
6.0-7.0
-
-
pH (25°C)
Standard Items
Electrical conductivity (mS/m)(25°C)
Reference Items
Tendency
Method
Circulation
Item
(μS/cm) (25°C) Chloride ions (mg Cl- / l) 2-
Copper (mg Cu / l ) 2-
69
Chilled Water Quality Standards Chilled Water System
Tendency
Reference Items
Standard Items
Item Circulation water (20 oC or less)
Auxiliary supply water
pH (25°C)
6.5-8.2
6.0-8.0
Electrical conductivity (mS/m)(25°C)
≦ 40 (≦400)
≦ 30 (≦ 300)
Chloride ions (mg Cl- / l)
≦ 50
≦ 50
Sulfuric acid ions (mg SO42-/l)
≦ 50
≦ 50
Acid consumption amount (pH4.8) (mgCaCO3 / l)
≦ 50
≦ 50
Total hardness (mg CaCO3 / l)
≦ 70
≦ 70
Calcium hardness (mg CaCO3 / l)
≦ 50
≦ 50
Ionized calcium (mg SiO3 / l)
≦ 30
≦ 30
Iron (mg Fe/l)
≦ 1.0
≦ 0.3
≦ 1.0
≦ 0.1
Sulfured acid ions (mg S /l)
Undetected
Undetected
Ammonium ions (mg NH4+/l)
≦ 1.0
≦ 0.1
Residual salts (mg Cl / l)
≦ 0.3
≦ 0.3
Free carbonic acid (mg CO2 / l)
≦ 4.0
≦ 4.0
-
-
(μS/cm) (25°C)
Copper (mg Cu / l ) 2-
Stability index
Note: 1. 2. 3. 4.
5. 6.
Corrosion
Scale Formation
Item names and units are based on JIS K0101-91. The symbol in the table indicates a factor relating to corrosion or scale formation tendencies. The units or numerical values in ( ) brackets are based on old units and are given for reference. In the case of high temperatures (over 40°C), corrosiveness is generally heavy, and particularly if iron or copper materials are indirect contact with water with no protective sheathing, it is desirable to carry out anti-corrosion measures such as adding an anti-corrosion agent or treating with purging. In a cooling water system which uses an airtight cooling tower, closed-circuit water and auxiliary supply water are based on the water quality standard of low order, hot water system, and sprinkling and its auxiliary water supply are based on the water quality standard of a circulating-type cooling tower system. Water sources used for water supply and auxiliary water supply should be piped water (tap water), industrial water or underground water. Pure water, intermediate water, softened water should not be used.
70
Table 11.3 Period Type of control
Every day
Remark
Every week Every month Every year
○
1
Blowing
Make sure blowing is performed every day.
2
Water quality analysis
○
3
Replacement of water
○
See Notes (1) and (2). Depending on the water quality analysis result.
4
○
Cleaning of tube
Perform
as
required
according
to
the
condition.
5
Eddy current test
Consult your service company.
6
Water treatment
Consult your service company.
Note: (1) Perform a water analysis for the makeup water and the circulating water respectively, and then determine the number of times of replacement and blowing of the water. (2) Perform water quality analysis seasonally (in spring, summer, fall, and winter) to prepare your criteria for judgement.
11.5 Law and Regulations Japanese standards. If any other local regulations
For centrifugal chiller using high pressure refrigerant HFC134a, High Pressure Gas regulation
specified, consult the nearest branch of Hitachi in your
Laws are adopted in Japan. Therefore, Hitachi
country.
centrifugal chiller is manufactured in accordance with
71