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1
High Ambient Energy Efficient CO2 Refrigeration Unit for Supermarket and CVS.
Oct. 11th 2011 SANYO Electric Co., Ltd.
Commercial Solutions Company Gaku Shimada
2
Agenda
1. Introduction of LAWSON Activity (Japanese CVS chain)
2. Refrigerant Transition in Japan for Commercial refrigerator (SANYO’s view)
3. Efficiency Analysis (CO2 and R404A)
- Labo test at Rated Test Condition
- Measured data from the field (Winter ~ Summer)
- Theoretically calculated efficiency
4. Consideration and Summary
3
Introduction of LAWSON’s Endeavor to convert to Natural Refrigerant
Total 50 demonstration stores covering all 7 branches will open before March 2012.
Verify the energy consumption difference by location and climate. Spread out 500 stores by 2016.
Kanto
Tohoku
Hokkaido
Chubu
Kinki
Kyusyu
Chugoku Shikoku
1st Model Store opened at Kyo-tanabe since Dec. 2010.
4
Demonstration Store to verify the CO2 units (Y2015 Candidate)
Outdoor units for Refrigerators and Freezers were replaced by SANYO CO2 Units (10HP and 2HP)
The Total Energy Save: 32%
CO2冷凍機 2HP
Walk –in Show CasesOpen Show Cases
Glass Door Freezer
Dessert Cases
R404A Ice Case
R410A PAC
R404A Com. Ref.
R404A Drink Case
2 HP CO2 Outdoor Unit
10 HP CO2 Outdoor Unit
Can be replaced by
CO2 unit eventually
5
Agenda
1. Introduction of LAWSON Activity (Japanese CVS chain)
2. Refrigerant Transition in Japan for Commercial refrigerator (SANYO’s view)
3. Efficiency Analysis (CO2 and R404A)
- Labo test at Rated Test Condition
- Measured data from the field (Winter ~ Summer)
- Theoretically calculated efficiency
4. Consideration and Summary
6
Refrigerant Transition in Japan (SANYO’s view)
R22
R410A
R404A
CO2
2007 2008 2010 2006 2009 2011 2012
GWP:1,900
GWP:3,300
GWP:1,750 GWP:1
Considering the Environment Impact, CO2 is the best refrigerant for Commercial Refrigeration System.
7
Transition of COP at Rated Condition (AT 32C)
◆ Freezer (- 40C Eva. Temp.) AT: 32C Year 2000 2008 2010 2011
Model Code OCU-S2002DF OCU-NS2000MVF OCU-
GS2000MVF Sales started in 2010
Motor Type Single Speed Single Speed INVERTER INVERTER
Refrigerant R22 R404A R404A R744
Cooling Capacity (kW)
11.0 12.4 12.4 14.3
Input (kW) 12.7 14.9 14.9 14.2
COP 0.87 0.83 0.83 1.01
Year 2000 2008 2010 2011
Model Code OCU-S2002DF OCU-NS2000MVF OCU-GS2000MVF To be determined
Motor Type Single Speed Single Speed INVERTER INVERTER
Refrigerant R22 R404A R404A R744
Cooling Capacity (kW)
37.3 42.6 42.6 32.5
Input (kW) 17.3 21.4 21.3 16.3
COP 2.16 1.99 2.00 1.99
◆ Refrigerator (- 10C Eva. Temp.) AT: 32C
At Rated Condition Comparison, there is no big COP improvement.
8
Measured Energy Consumption Comparison
◆ Freezer Application Room temp: -25C
◆ Refrigerator Application Room temp: +5C
20
40
60
80
100
120
140
160
180
0 10 20 30 40外気温 〔℃〕
消費
電力
量 〔kWh/day〕
CO 2冷凍機
R404A冷凍機
0
20
40
60
80
100
120
140
160
180
0 10 20 30 40
外気温〔℃〕
R404A冷凍機
CO 2冷凍機消費電力量 〔kWh/day〕
Energ
y
Consum
ption
Ambient Temp.
(24h averaged) Ambient Temp.
(24h averaged)
Energ
y
Co
nsu
mp
tio
n
R404A
CO2
R404A
CO2
Though we don’t see big difference at rated condition comparison, CO2 is confirmed to outperform R404A system at Measured Energy Consumption Comparison. Why ??
CO2 is better than
R404A by 16 ~ 26%.
Cross Point at 38~40C AT.
CO2 is better than
R404A by 0 ~ 30%.
Cross Point at 32C AT.
9
Why CO2 unit works better than expected?
CO2 refrigerant is said to be less efficient. But the actual data is different. Why ??
Though we don’t see big difference at rated condition comparison, CO2 is confirmed to outperform R404A system at Measured Energy Consumption Comparison. Why ??
1. CO2 performs relatively better at cold climate.
AT 32C comparison may not be fair.
2. Components are different (HX, DC INV motor, etc..).
3. Refrigeration Cycle is different.
Good cycle for R404A is not best for CO2.
10
Definition of Theoretical Efficiency
◆ Temperature Trend at “Gas Cooler Inlet ~ Outlet”
20
30
40
50
60
70
300 350 400 450 500
比エンタルピー 〔kJ/kg〕
温度
〔℃
〕 R 404A (≒実際) 〔凝縮42℃, 出口37℃〕
CO 2計算:出口温度同一条件
CO 2計算:伝熱性能同一条件
CO 2実際
入口
出口
Enthalpy
CO
2 T
em
pera
ture
GC Inlet
GC Outlet
GC Inlet GC Outlet
Actual CO2 Temp.
Calculated CO2 temp based on same outlet temp.
Calculated CO2 temp based on same Heat
Transfer Coefficient during GC flow.
R404A (≒ Actual)
CT: 42C, Outlet: 37C
Calculated CO2 temperature trend based on same Heat Transfer Coefficient matches the actual temperature trend.
11
Definition of Cycle
◆ Refrigeration Cycle Compared in this study
CO2 Split Cycle CO2 Conventional Cycle R404A Conventional Cycle
Compression Two-stage (utilize Intercooler) One-stage
SLHX Yes No
Split
(Economizer) Yes No
PH Diagram
12
0
0.5
1
1.5
2
2.5
3
3.5
4
5 15 25 35
外気温〔℃〕
COP
CO 2スフ リ゚ットサ イクル
(2段圧縮)
CO 2通常サイクル(2段圧縮)
R 404A通常サイクル
Theoretically Calculated Efficiency Comparison
Using the same Heat Transfer Coefficient, the system COP of CO2 split cycle can outperform R404A. same trend as measured data.
◆ Freezer Application - 40C Eva. Temp.
◆ Refrigerator Application - 10C Eva. Temp.
Ambient Temp.
1
2
3
4
5
6
7
8
9
10
11
5 15 25 35
外気温 〔℃〕
COP
CO 2スフ リ゚ットサ イクル(2段圧縮)
CO 2通常サイクル(2段圧縮)
R 404A通常サイクル
CO2 Split Cycle
2-stage
CO2 Conventional
2-stage
R404A Conventional
CO2 Split Cycle
2-stage
CO2 Conventional
2-stage
R404A Conventional
CO2 is better than
R404A by 3 ~ 7%. CO2 efficiency is
almost same as R404A
Ambient Temp.
13
Consideration and Summary
1. The superiority of CO2 cycle efficiency is difficult to be confirmed at rated condition (AT32) comparison. But, actually CO2 outperforms R404A in the market.
2. The measured data comparison showed that CO2 split cycle is better than R404A original system by 16-26% at LT use and 0-30% at MT use. Cross point exists at high ambient temp. more than 32C.
3. Theoretically calculated efficiency based on the same Heat Transfer Coefficient showed that CO2 split cycle is better than R404A original system by 3-7% at LT use and almost same at MT use.
4. The remaining GAP of efficiency comparison (measured v.s. calculated) might be resulted from the components improvement.
It is fair. New technology shall be used for new refrigerant. It is natural to pursue the best performance with available technology.
Next steps?