Screw Air Cooled Chiller/Heat Pump

Screw Air Cooled Chiller/Heat Pump
SCA230
Nominal Capacity 210.6 to 1263.6 kW
Refrigerant: R407C and R134a
Contents
Features
1
MV7 Control
3
Physical Data
5
Unit Performance
7
Chiller Section
8
Physical Dimension
9
Piping Schematic
10
Power Connection
11
Field Wiring Diagram
12
Electrical Data
13
Features
STRUCTURE
MULTISTACK Air Cooled Chillers are designed and constructed under the modular technology patent. A chiller bank consists of multiple
individual chiller modules connected in parallel to operate as a single machine, with cooling or heating capacity to match the load
demand by varying the number of operating modules. The chiller modules start from one module to eight, giving you full flexibility to
increase the capacity as your needs increase.
Each chiller module contains independent circuits, with each circuit including a screw compressor, evaporator, condenser, four fans
and sophisticated control and protection equipment. And each module operates as a completely independent refrigeration circuit.
Where load demand varies, the controller can change the chiller’s capacity accordingly either by control the number of modules in
operation or by adjust the capacity stage of the last start up compressor.
The Multistack Air Cooled line-up is available in cooling-only version or heat pump version for dual operation.
COMPACT AND SPACE-SAVING
The compact size of each module means easy access via standard lifts. You no longer need special access to install the chiller. In
comparison to conventional water cooled chillers you can gain up to 40% more space. Meaning larger capacity chiller can be easily
installed in confined and small places.
LOWER INSTALLATION COST
Connection of the modules has never been simpler – only two pipes to connect followed by communication cables and you’re in
business.
ADD-ON FLEXIBILITY
As your needs for cooling or heating increases, Multistack has the solution. Being a modular chiller, it has never been easier to expand
the system as larger cooling capacity is needed to meet increased building load demands, with no complicated changes to the room,
piping system or control system, and all work can be done quite easily. As many as 8 full modules can be connected together as a
chiller bank.
SAFE AND RELIABILITY
Every module works as an independent refrigeration circuit, with adjacent modules operating independently. In the event of a
malfunction in the system, the computer selects the next available standby module to provide back up. One failed module will not
disrupt the other chillers or system, giving you total piece of mind.
PEAK ECONOMY AT ALL LOADS
Automatic scheduling of the compressors allows the chiller to match the fluctuating cooling loads and conserve energy with each
individual unit running at its peak efficiency. This is much more economical when compared to a large single unit running at part load.
UNPARALLELED RELIABILITY
Every Multistack slave module is identical to each other, so in the event of a malfunction in the system, the computer automatically
selects the next available standby circuit to provide back up. For critical air conditioning and industrial process cooling a Multistack
modular chiller inherently provides economical standby capacity and unparalleled dependability.
SCREW COMPRESSOR







Semi-Hermetic double-screw compressor for wide applications
Motor is cooled by refrigerant and works under low temperature to obtain higher efficiency and better reliability
PTC temperature switch to protect from motor temperature overload
Protection module to avoid reverse operation, motor overheating and high oil temperature
Bearings have a 40,000 hours life,
High efficiency oil separator, separates 98% oil from refrigerant to ensure compressor lubrication and efficiency
4-stage slide valve ensures precise load control
1
CONDENSER AND EVAPORATOR
Stainless steel 316 brazed plate heat exchanger; Vacuum brazed, endure working pressure of 2.0MPa, small size and light weight, high
heat transfer efficiency.
PRE-CHARGED REFRIGERANT
R407C and R134a available for standard chiller; less refrigerant charge required and the Refrigerant charged prior to shipment and
undergone performance test
INTERNAL WATER STRAINER
Internal water strainer is made under the Multistack’s patent technology, and made from stainless steel. Internal water strainers are
supplied and fixed inside both chilled water header pipes and condenser water header pipes for each module. It can be easily
dismantled and removed. The internal water strainer can prevent particles contained in the water from getting into the heat exchanger.
MODEL NUMBER DESIGNATION
SC
A
230
C
1
2
3
4
-
6
A
.
R
V
5
6
7
8
9
7: Configuration
Blank for Standard
8: Refrigerant
E: R134a
R: 407c
9: Fan
V: Variable Speed Drive (VSD)
Blank for standard
1: Screw compressor
2: Cooling type:
A: Air cooled
W: Water cooled
3: Model Number:
4: Chiller type
C: Cooling Only
H: Air Cooled Heat Pump chiller
5: The number of modules per chiller (1~8)
6: Electrical Specifications
A: 400V ± 10%,50Hz,3 Phase
B: 380V, 60Hz,3 Phase
C: 440-460V,60Hz,3 Phase
2
MV7Control
The MV7 computer monitors the chiller's operation and schedules the on and off of each compressor and capacity control stages with
respect to the change in load demand. The computer continuously and comprehensively monitors the total operation of all modules
in the chiller bank. It will also shut down individual module or the entire bank in the event that a fault occurs. A maximum of 32
refrigeration circuits can be monitored at one time.
SYSTEM DATA AND VARIABLES DISPLAY
The controller’s 7” touch panel not only can display
the chiller’s operation data but also provides direct
access to all of the chillers setting and variables for
total system control.
Chiller operation status
 chilled water temperature
 condenser water temperature
 % of chiller cooling capacity
 % demand loading
 load / unload time delay
 current fault number
 % of loading limitation
 lead compressor
Chiller variables settings
 password
 chilled water temperature
 lead compressor
 temperature integrating time
 economy offset
 load / unload time delay
 time and date
Module operation status
 compressor suction pressure
 compressor discharge pressure
 evaporating temperature
 chilled water leaving temperature
 faults status
COMPRESSOR SEQUENCE
The MV7 controller accumulates the running hours of each compressor and hence establishes working sequence. A standby
compressor with the least working hours will be activated during loading. The same goes for a compressor with the most working
hours will be stopped during unloading. This ensures each compressor in the system has an even usage, which will save you time and
money in the long run for maintenance.
FAULT REVIEW
The controller will record and display the last 60 faults that occurred, giving detailed information such as time, date, location, cause,
current status, as well as the performance data collected at the moment each fault occurred.
LOAD PROFILE
The controller records all working hours of the chiller and compressor and records it accordingly in 10% brackets from 0% - 100%,
giving you detailed information for which percentage the chiller is running mostly.
3
PASSWORD
A two level password protection is included (for both customer and service personnel) to give you piece of mind. For example the
service password will give you full access to settings and variables, but the user password will only enable the user see but not change
settings and variables.
STANDBY CONTROL
Each module can be set for three modes: auto/ off/independent operation via the slave outstation card installed in the module. Default
setting is “auto”, with “off” mode for when maintenance is required and “independent” mode (where the module is controlled by its
own slave outstation card and operates independently from the controller), is usually for commissioning or emergency operation.
REMOTE CONTROL & MONITORING (OPTIONAL)
1) If direct RCM functionality is required, the MV7 HMI computer will be assembled with an Ethernet port, allowing it to be fully
managed from a remote computer via a VNC Client/Server protocol.
2) If BAS Communication is required, the MV7 System will be fitted with a BacNet IP/MSTP Gateway.
4
Physical Data
Per Module
R407c
Model
Nominal Cooling Capacity (kW)
Nominal Cooling Power Input (kW)
Nominal Heating Capacity (kW)
Nominal Heating Power Input (kW)
Type
Compressor
Number
Control Stages per module (%)
Type
Nominal Flow Rate (L/s)
Water Pressure Drop (kPa)
Evaporator
Fouling Factor (m2k/kW)
Pipe Connection
Max Working Pressure (kPa)
Type
Type of Fan
No. of Fan
Condenser
Air Flow Rate (m3/h each)
Fan Motor Power (kW/each)
Fan Max. Current (A/each)
Refrigerant charge (kg)
Shipping weight (kg)
Operation weight (kg)
Dimension (WxDxH) mm
Nominal Values based on:
Cooling:
Ambient
Chilled Water Entering Temp.
Chilled Water Leaving Temp.
SCA 230H
R134a
SCA 230C
231
74.7
-
194
53.8
-
Screw
1
50, 75, 100
Stainless Steel Brazed Plate Exchanger
10.8
8.9
50
37
0.018
8"
2000
Air Coil
Axial
4
28000
23500
2.5 x 4
1.8 x 4
4.5 x 4
4.2 x 4
64
66
2680
2740
2740
2800
2300x2200x2240
72
2750
2810
35oC
SCA 230C
186.6
56.2
Heating:
o
12 C
7oC
7oC DB / 6oC WB
Hot Water Entering Temp.
Hot Water Leaving Temp.
40oC
45oC
Minimum Chilled Water Flow Rate per module: Nominal Water Flow Rate less 10%
For low liquid temperature applications (≤6ᵒC) contact Multistack Ltd.
5
60
2675
2735
Ambient
Note:


SCA 230H
210.6
77.3
HEAT EXCHANGER WATER PRESSURE DROP
Pressure drop correction factor for chilled and hot water circuit
PRESSURE DROP CORRECTION FACTOR ()
1. Water pressure drop calculation
  
Water flow % =
× 100
  
Heat exchanger actual water pressure drop per module
= heat exchanger nominal water pressure drop × ξ
 is related to total number of modules (N) in the chiller bank
N

1
1.00
2
1.00
3
1.01
4
1.02
Total water pressure drop per chiller
=heat exchanger actual water pressure drop per module × 
2. Chiller minimum working water flow
(1) Constant water flow system, no less than 90% of chiller total nominal water flow
(2) Variable water flow system: no less than 90% of module nominal water flow
6
5
1.03
6
1.04
Unit Performance
Per Module
COOLING PERFORMANCE SCA230C
Ambient Air
Temp oC
25
30
35
40
45
Ambient Air
Temp oC
25
30
35
40
45
CAP
247.3
229.2
210.6
191.2
165.4
Leaving Chilled Water Temperature oC
8
10
PI
CAP
PI
CAP
PI
64.2
256.8
64.7
276.7
65.9
70.2
238.2
70.7
256.9
71.7
77.3
219.0
77.7
236.5
78.6
85.5
199.1
85.9
215.5
86.7
90.3
172.7
90.3
187.6
91.5
CAP
213.2
200.4
186.6
171.9
156.5
Leaving Chilled Water Temperature oC
8
10
PI
CAP
PI
CAP
PI
46.5
222.1
47.0
240.6
47.9
51.0
208.9
51.5
226.7
52.3
56.2
194.7
56.6
211.6
57.4
62.3
179.5
62.6
195.6
63.4
69.5
163.7
69.8
178.7
70.5
R407C
6
CAP
236.0
218.6
200.6
181.8
156.8
7
PI
63.6
69.7
76.8
85
89.8
R134a
6
CAP
202.8
190.4
177.1
162.9
148.0
7
PI
46.0
50.6
55.8
61.9
69.1
R407C
12
CAP
297.7
276.6
254.9
232.7
203.3
PI
67.3
72.9
79.5
87.4
92.3
R134a
12
CAP
260.3
245.6
229.7
212.7
194.8
PI
48.8
53.2
58.2
64.1
71.2
HEATING PERFORMANCE SCA230H
Ambient Air
Temp. oC
15
10
7
5
0
-5
Ambient Air
Temp. oC
15
10
7
5
0
-5
R407C
35
CAP
332.1
282.6
247.9
239.9
203.2
165.6
PI
67.0
63.0
61.3
60.3
58.9
57.8
R134a
35
CAP
283.4
237.8
206.2
199.0
166.2
133.9
PI
47.6
45.5
44.1
43.8
42.5
41.5
CAP
318.5
271.9
239.2
231.6
196.7
160.5
Leaving Hot Water Temperature oC
40
45
PI
CAP
PI
71.6
305.2
78.3
69.1
261.6
76.2
67.5
230.8
74.7
67.2
223.5
74.3
65.6
190.1
72.6
63.8
155.0
70.7
Leaving Hot Water Temperature oC
40
CAP
PI
CAP
274.2
52.1
264.5
230.4
50.1
222.8
200.0
48.6
193.7
193.1
48.3
187.1
161.4
46.8
156.9
130.4
45.6
127.1
PI
R407C
50
CAP
292.7
251.8
222.3
215.4
182.9
PI
86.5
84.5
82.9
82.5
80.6
R134a
50
45
PI
57.2
55.3
53.8
53.5
51.9
50.3
CAP
254.7
215.2
187.8
181.4
152.8
124.5
CAP
Cooling Capacity (kW)
Compressor Power input (kW)
Note:



This table is based on a 5 oC difference in water temperature.
Please contact your local Multistack Agent if you require performance data beyond the limits of the above table.
Interpolation is permissible. Do not extrapolate.
7
PI
63.2
61.4
59.9
59.5
57.8
55.9
Chiller Selection
SELECT AIR-COOLED CHILLER ACCORDING TO FOLLOWING CONDITIONS:
1. Cooling Capacity Required……………………………………………………………………………………….1250 kW
2. Heating Capacity Required……………………………………………………………………………………….1350 kW
2. Entering Chilled Water Temperature (ECHW).................................................................. 12 °C
3. Leaving Chilled water Temperature (LCHW)....................................................................... 7 °C
4. Ambient Temperature.................................................................................................... 35.0 °C
5. Leaving Hot Water Temperature.................................................................................... 45.0 °C
6. Entering Hot Water Temperature................................................................................... 40.0 °C
7. Ambient Temperature (AT)............................................................................................... 7.0 °C
8. Refrigerant....................................................................................................................... R407C
Calculation
1. Determine Water Flow (CHWF) (L/s)
(1) Chilled Water Flow (CHWF)
CHWF =
  
4.187 ×(−)
(2) Hot Water Flow (HWF)
1250
= 4.187×(12−7)
HWF =
= 59.7 /
  
4.187 ×(−)
1350
= 4.187×(45−40)
= 64.5 /
Note: Flow rate must not be less than Required Nominal Flow
2. From capacity chart above,
1 module at stated conditions will achieve;
(2) Heating CAP= 230.8 kW per SRA 230H module
(1) Cooling CAP= 210.6 kW per SRA 230C module
Required Number of Modules =
Required Cooling Capacity
=
CAP per Module
1250 
210.6 
Required Number of Modules =
=
= 5.9
Required Cooling Heating
CAP per Module
1350 
230.8 
= 5.8
Select 6 modules
Select 6 modules
The total cooling capacity of the chiller is:
The total heating capacity of the chiller is:
Number of Modules x CAP = 6 × 210.6 = 1263.6 kW
Number of Modules x CAP = 6 × 230.8 = 1384.8 kW
The capacity residue =
(1263.6 − 1250)
1250
× 100% = 1.1 %
The capacity residue =
(1384.8 − 1350)
1350
× 100% = 2.6%
The calculation result is acceptable
The calculation result is acceptable
3. Chilled water pressure drop calculation
(1) Nominal Water Flow = Number for Modules x Evaporator Water Flow
= 6 x 10.8
= 64.8 L/s
(2) Evaporator water pressure drop for nominal water flow per module is 50 kpa
Use the table Pressure drop correction factor: , =1.04 for the configuration: 6 modules.
Actual Evaporator water pressure drop is = 50 × 1.04 = 52.0 kPa
8
Physical Dimension
Notes: (for all configurations)
1. All installations much have: No.40 Mesh Stainless steel strainers in water inlet piping
2. Only one computer installed per chiller.
3. If Chiller is to be expanded, computer and mains termination should be located so as to allow access after expansion.
4. Chiller to be mounted on 4 x 100sq. RHS positioned as shown (RHS not supplied by manufacturer).
5. Rails must be mounted on machinery mounting pads (not supplied by manufacturer)
6. If unit is to be expanded in back to back configuration a Minimum of 4000mm rear clearance is required
7. Units expanded from 1 module to 1.5 or more will require the fitting of mains termination external to the compressor electrical
box.
9
Piping Schematic
CHILLED WATER PIPING
Item
1
2
3
4
5
6
7
8
9
10
11
12
Note:
Description
Drain Valve DG50
Chilled Water Temp Sensor
Pressure Gauge
Vibration Eliminator
Qty
2
2
2
2
Isolation Gate Valve
Water Pump
Water Strainer
Chiller side differential pressure by-pass valve
Terminal air handling equipment
Motorized valve
5
Water flow switch
Back Flush By-Pass Valve (*)
1
1
Remarks
1
1
Supplied by others
Supplied by manufacturer
Supplied by others
1
1. It is customer's responsibility for all piping parts, except those included with the chiller.
2. During the whole installation process, the isolation gate valves on both entering/leaving line to the chiller should be closed. The
valves will remain closed until the piping installation; leakage check and cleaning are all completed.
3. To prevent stress on the headers and Victaulic couplings all water pipe work must be properly supported.
4. To prevent water accumulation inside the sensor socket grease should be filled in the sensor socket before inserting the chilled
water temperature sensor.
(*) 6. The chiller’s piping system should be cleaned thoroughly to get rid of any mechanical debris prior to operation. During pipe
cleaning, close chiller’s entering/leaving isolation gate valves and open the bypass valve to prevent the water circulation through the
chiller.
(*) 7. During chiller operation, the back flush by-pass valve must be closed.
10
Power Connection
Model
SCA230
Power supply wiring
Location
Connection method
Module electrical box
Terminal Block
Note:
1.
2.
3.
The cable selection for main power supply should conform to the maximum running current, power supply voltage,
ambient temperature, local electrical codes and allowance for voltage imbalance.
Each power supply circuit should use separate protection devices and warning labels is required to indicate cutoff
procedures.
Ground connection terminals installed inside the electrical box of each module must be grounded.
11
Field Wiring Diagram
12
Electrical Data
Model
Refrigerant
Power
Compressor (each)
Fan (each)
Num. of
Compressors
1
2
3
4
5
6
N
1
2
3
4
5
6
SCA 230H
SCA 230C
SCA 230H
R407c
AC400V ± 10% / 50Hz / 3Ph
162
MCC (A)
RLA (A)
LRA (A)
RLA (A)
LRA (A)
110.1
93
423
4.5
15.8
12.2
R407c
RLA (A)
128.1
256.2
384.3
512.4
640.5
768.6
SCA 230C
R134a
R134a
LRA (A)
423.0
569.1
751.2
969.3
1223.4
1513.5
RLA (A)
111.0
222.0
333.0
444.0
555.0
666.0
LRA (A)
423.0
552.0
717.0
918.0
1155.0
1428.0
Note:
N:
LRA:
No. of modules
Locked Rotor Amperage
MCC:
RLA:
Maximum Continuous Current
Rating Load Amperage
Note:
-
When selecting mains cable size, apply allowances for voltage imbalance, under voltage ambient temperature and
other conditions in compliance with relevant local electrical codes.
When starting the chiller, the compressor is start up one at a time. The chiller starting current is equal to the total
current of operating compressors plus the starting current of the compressor.
13
MULTISTACK INTERNATIONAL LIMITED
140 BERNARD STREET, CHELTENHAM, VICTORIA 3192, AUSTRALIA
TELEPHONE: 61 3 8586 8225 FACSIMILE 61 3 8586 8202
Email: slaes@multistack.com.au
Website: www.multistack.com.au
Since MULTISTACK INTERNATIONAL LIMITED has a policy of continuous product improvement,
it reserves the right to change design and specification without notice.
09/2015 Rev. 1.0
03/2016 Rev. 1.0 - AUS
14
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