Upload
others
View
2
Download
0
Embed Size (px)
Citation preview
COMPACT CO2/NH3 REFRIGERATIONREFRIGERATION
UNIT FOR THE COLD STORAGE
WITH USEING CO2 FORCED CIRCULATION SYSTEM
TOYO ENGINEERING WORKS.LTD
C-dig meeting : 28 August 20072
・・In the first half, I introduce a compact CO2/NH3 In the first half, I introduce a compact CO2/NH3
refrigeration unit for the cold storage. refrigeration unit for the cold storage.
・・In the second half, I introduce aIn the second half, I introduce a cold storage cold storage ・・In the second half, I introduce aIn the second half, I introduce a cold storage cold storage
exhibition system of the mammoth in the Aichi exhibition system of the mammoth in the Aichi
world exhibition, although it is not in agenda. world exhibition, although it is not in agenda.
TOYO ENGINEERING WORKS.LTD
1
Introduction
We have constructed many cold storage warehouse with a small
water cooled condensing unit "LTS" in Japan from 25 years ago.
Like this, we have delivered many LTS. Therefore, it is
necessary that shall be renewal the aged LTS and also
HCFC refrigerant.
Refrigerant of this unit is the HCFC-22.
Therefore, we developed CO2/NH3 circulation system "C-
LTS". The development point in the renewal is to make the unit
compactly.
We think、、、、 it is necessary to diffuse the natural refrigerant
system for earth environment.
HCFC refrigerant.
3
Example that Used the LTS Unit
・・・・This example shows the LTS unit at the outside
of a cold storage warehouse of every floor.
Water Cooling Tower
LTS
UnitCold Storage
Warehouse
Unit
・・・・The system is a direct expansion refrigeration of the HCFC-22.
・・・・The cold room temperature is the range of minus 30 degrees
from minus 5 degrees.
・・・・There are many LTS unit in one cold storage warehouse,
because a small unit needs no maintenance person in law.
・・・・We delivered about 5,000 units in Japan. 4
Example that Used the LTS Unit
LTS
・・・・This example shows one LTS unit in the upper side
vacancy of the freezing room entrance.
LTS
Unit
Cold
Room
5
Example that Used the LTS Unit
・・・・This example shows the plural LTS unit in a machine room.
6
LTS
Unit
Series of CompactSeries of Compact CC--LTSLTS
ModelsModels 220F220F--WPWP 370F370F--WPWP 550F550F--WPWP
Cooling Capacity [kW]Cooling Capacity [kW] 32 / 3832 / 38 52 / 6352 / 63 72 / 8772 / 87
Shaft Power [kW]Shaft Power [kW] 20 / 2420 / 24 31 / 3731 / 37 43 / 5143 / 51
Power SupplyPower Supply AC 3φAC 3φ××××××××200V200V××××××××5050////////60 Hz60 Hz
RefrigerantRefrigerant ////////RefrigerantRefrigerant NH3NH3////////CO2(Secondary Refrigerant)CO2(Secondary Refrigerant)
Comp.Comp. TypeType Open type TwoOpen type Two--stage Screwstage Screw
Motor Rated Motor Rated Power [kW]Power [kW]
2222 3737 5555
CO2 pump [kW]CO2 pump [kW] 0.150.15 0.150.15 0.150.15
Size : WSize : W××××××××LL××××××××H [m]H [m] 1.51.5××××××××2.52.5××××××××1.91.9 1.61.6××××××××2.72.7××××××××2.02.0 1.61.6××××××××3.03.0××××××××2.02.0
Weight [kg]Weight [kg] 2,6002,600 3,7003,700 4,0004,000
7
Cascade
Condenser
NH3
Compressor
NH3
Condenser
CO2/NH3 System
Flow Sheet
Schematic diagram of system flow
C-LTS
UNIT
1
Condenser
NH3
Receiver
CO2
Receiver
CO2
Pump
Evaporator
Expansion
Valve38
Outside Photograph of Compact C-LTC
New model
9
NH3 Compressor
NH Condenser
Cascade condenser
CO2 Receiver
Inside of Compact C-LTC
NH3 Condenser
NH3 Receiver10
Cascade condenser
CO Receiver
CO2 liquid
outlet
CO2 Receiver
NPSH=800mm
11CO2 Liquid pump
NPSH : Net positive suction head
We make Compact CWe make Compact C--LTS smaller than LTS smaller than
prototype CO2/NH3 unit.prototype CO2/NH3 unit.
New Compact CNew Compact C--LTSLTS40% Volume Decrease
Prototype CO2/NH3 Prototype CO2/NH3
circulation unitcirculation unit
1.9m1.9m××××××××3.8m3.8m××××××××3.5mH3.5mH 1.5m1.5m××××××××2.5m2.5m××××××××1.9mH1.9mH
New model
As a result, the size of compact CAs a result, the size of compact C--LTS LTS
became equal with the old HCFCbecame equal with the old HCFC--LTS.LTS.12
Method for Downsizing
////Adoption of a CO2 Subcooling System
・・・・A CO2 Subcooling System has the biggest effect for downsizing.
・・・・The CO2 liquid of the receiver is cooled by the evaporation
of NH3.
・・・・The purpose of subcooling is to make NPSH of the CO2 liquid
pump smaller. (NPSH : Net positive suction head)
13
pump smaller. (NPSH : Net positive suction head)
・・・・In this way, we can reduce the height of the unit.
・・・・The NPSH of the CO2 liquid pump is 1.4 m.
・・・・The subcooling degree of 1K is equal to NPSH of
about 3.5 m.
・・・・The subcooling of the CO2 liquid is effective to "the reduction
of necessary NPSH" and "the downsizing of the unit".
10.0
20.0
30.0
ooler temperature、℃
10
15
lectric currunt value of CO
2 liquid
C ooler w ind
Electric current value of C O 2 liquid pum p
The example of the operation condition without subcooling
(1)
Cooler air
temperature Current value of CO2
liquid pump
Relationship Electric current value of C O 2 liquid pum pto cooler tem perature (N o super cooling)
-30.0
-20.0
-10.0
0.0
10.0
1 301 601 901 1201 1501 1801
Tim e、m in
Cooler temperature
0
5
10
Electric currunt value of CO
pump、A
14
Cavitation
0.0
5.0
10.0
15.0
、℃
10
15
Electric current value of CO
2 liquidC ooler w ind
The example of the operation condition with subcooling
(a)
Cooler air temperature
Relationship Electric current value of C O 2 liquid pum p and cooler w ind tem perature
(Super cooling)
-30.0
-25.0
-20.0
-15.0
-10.0
-5.0
0.0
0 10 20 30 40 50 60
Tim e,m in
Cooler temperature、℃
0
5
10
Electric current value of CO
pump 、A
Electric current value of C O 2 liquid pum p
15
Stable driving
Current value of CO2
liquid pump
Characteristic of CompactCharacteristic of Compact CC--LTSLTS
• We use the natural refrigerant (CO2 and NH3) that defends
earth environment ////ODP is a zero and GWP is 1 or less.
• We can renewal from HCFC-LTS to C-LTS with a compact
design.
3. We can keep highly safe by supplying CO2 to a load side and 3. We can keep highly safe by supplying CO2 to a load side and
minimum charge of NH3 in the unit.
4. Comparison with a brine (Ex. Ethylene glycol) system by NH3
cooling
1) Pump power is smaller////Because it uses the latent heat of CO2
2) Brine control is unnecessary
16