Hilde Dhont – Daikin Europe N.V.

Hilde Dhont – Daikin Europe N.V.
ODBORNÁ KONFERENCE SCHKT– 28. LEDNA 2014, HOTEL STEP, PRAHA

Part 1 : Why R32 ?

Part 2 : Design optimization aspects

Part 3 : Installation/service aspects
ODBORNÁ KONFERENCE SCHKT– 28. LEDNA 2014, HOTEL STEP, PRAHA
R32 Air Conditioners
and Heat Pumps
PART 1
• Why R32 ?
• Characteristics of R32 refrigerant
3
Many factors to consider..
Energy
Use
Ozone
Protection
Seasonal
Efficiency
CFC Phase-out
Climate
Change
Lower GWP
Reduced
Charge
Peak load
Efficiency
Affordability
Safety
Compact
No/Low
Flammable
Low
Emissions
Low Toxic
HCFC Phase-out
Energy
efficiency
Patents
Market
Penetration
Easy Installation
& Maintenance
Natural
Resources
Efficient Use
Downsizing
Recycle
Reuse
Next generation refrigerants ?
4
Summary of Refrigerant Options for
Stationary AC and Heat Pumps
Refrigerants
R22 (baseline)
HFC
Properties
Pcond
(MPa)
Single
1.73
GWP
Vol Cool Theoretical
ODP
Capacity
COP
（IPCC 4th）
100%
100% 0.05
1810
R407C
Zeotrope
1.86
98%
95%
0
1770
R410A
Azeotrope-like
2.73
141%
91%
0
2088
Single
2.79
160%
96%
0
675
Zeotrope Various
Various
Various
0
Various
0
4
R32
R32 HFO
blends
R1234yf
Single
1.15
56%
92%
R1234ze(E)
Single
0.88
45%
98%
R717 NH3
Single
1.78
115%
105%
0
0
Single
1.53
83%
97%
0
<3
SIngle
10
256%
41%
0
1
Non HFC R290 Propane
R744 CO2
6
Conditions: Tevap = 0℃, Tcond=45℃, Tsub cool = 0℃, Tsuper heat = 0℃, Compressor efficiency =70
CO2:
Gas cooler outlet temperature=45℃, high side pressure = 10Mpa
Database: CYCLE_D, Version 5.0, NIST Standard Reference Database 49
5
International Adoption of R32
6
Why R32 for air conditioners & heat pumps?
R32 IS THE MOST BALANCED SOLUTION
› Not depleting the ozone layer
› Smaller Global Warming Impact (LCCP) compared to R410A & R22
› Higher Energy Efficiency compared to R410A & R22
› Reduced refrigerant charge possible
› More compact design possible
› Acceptably safe because only slightly Flammable (Class A2L)
› Refrigerant Production capacity is available
(R32 is a component of R410A)
› Easy to recycle and reuse (single component refrigerant)
› Affordable for developing countries
7
Flammability classification of R32 = 2L
Class 1
Class 2L
Class 2
Class 3
Not flammable
Slightly
flammable
Low flammable
Highly
flammable
R152a
R290
burning velocity
≤10 cm/s
R744 (CO2)
R1234yf / ze
R410A
R32
R717
(Ammonia)
Flammability of 2L refrigerants is very low.
The burning velocity (≤ 10 cm/s) is too slow to cause horizontal
flame propagation or explosion.
Classification according to ASHRAE34 & draft ISO817.
8
Ignition Test
Slowly leak the test gas into 1m cubic box:
Density (kg/m3)
1m
Critical point
LFL(Low Flammable Limit)
1m
Ignition
source
Ignition
source
1m
Charge Amount (kg)
9
9/10/2012
Example flammability behaviour
of Class 2L refrigerant (R32)
300 gram R32 / 1m³
Ignited by flame
No fire
10
Example flammability behaviour
of Class 2L refrigerant (R32)
320 gram R32 / 1m³
Ignited by flame
Slow vertical flame
but no explosion
11
Simulation R32 leak – no explosion occurs
0g
400g
800g
Example current EN378 standard :
charge limitations in view of room size –
WALL MOUNTED INDOOR
HC-allowed
R410A
R32/R1234yf
14,00
non flammable
R410A
12,00
charge (kg)
10,00
8,00
6,00
3 kg Limit GWP750 EU F gas regulation
review
4,00
2,00
No limitations for
R32 below 1,23kg.
highly
flammable
R290
Current charges split outdoors
R410A @ 0,1kW /m²
-
Seite 13
mildly flammable
R32
20,00
40,00
60,00
Floor area (m²)
80,00
100,00
Example current EN378 standard :
charge limitations in view of room size –
FLOOR STANDING INDOOR
hc fl
R410A
R32/R1234yf
14,00
non flammable
R410A
12,00
charge (kg)
10,00
There may be
borderline cases but
charge for R32 can be
lower than R410A
8,00
6,00
3 kg Limit GWP750
EU F gas regulation
review
mildly flammable
R32
4,00
2,00
No limitations for
R32 below
1,23kg.
Seite 14
Current charges Split
outdoors R410A @ 0,1kW /m²
highly flammable
R290
-
20,00
40,00
60,00
Floor area (m²))
80,00
100,00
R32 Air Conditioner and Heat Pump
System Design Optimization
PART 2
15
Presentation Contents
This part provides the latest information on R32 system
design optimization aspects for various use conditions.
1. Summary of Refrigerant Options for Stationary AC
and Heat Pumps
2. Design Factors Affecting System Efficiency
3. Impact of Blending
4. Compressor Discharge Temperature
5. Oil and System Reliability
6. Benefits of Single Component Refrigerant
7. Reduced System Dimensions
8. Conclusions
16
1. Summary of Refrigerant Options for
Stationary AC and Heat Pumps
Refrigerants
R22 (baseline)
HFC
Properties
Pcond
(MPa)
Single
1.73
GWP
Vol Cool Theoretical
ODP
Capacity
COP
（IPCC 4th）
100%
100% 0.05
1810
R407C
Zeotrope
1.86
98%
95%
0
1770
R410A
Azeotrope-like
2.73
141%
91%
0
2088
Single
2.79
160%
96%
0
675
Zeotrope Various
Various
Various
0
Various
0
4
R32
R32 HFO
blends
R1234yf
Single
1.15
56%
92%
R1234ze(E)
Single
0.88
45%
98%
R717 NH3
Single
1.78
115%
105%
0
0
Single
1.53
83%
97%
0
<3
SIngle
10
256%
41%
0
1
Non HFC R290 Propane
R744 CO2
6
Conditions: Tevap = 0℃, Tcond=45℃, Tsub cool = 0℃, Tsuper heat = 0℃, Compressor efficiency =70
CO2:
Gas cooler outlet temperature=45℃, high side pressure = 10Mpa
Database: CYCLE_D, Version 5.0, NIST Standard Reference Database 49
17
2. Design Factors Affecting System
Efficiency
Several factors affect system efficiency
including the following:
 Refrigerant properties
 Compressor performance
 Heat exchanger performance
 Pressure loss in refrigerant tubing
 Expansion valve control
 Refrigerant charge volume
 Lubrication performance
18
3A. Impact of Blending -TheoreticalIf R32 is mixed with R1234ze(E), the average heat transfer
coefficient drops. As it becomes more prominent at lower mass
flow, seasonal efficiency will be affected further.
1) Average condensing heat transfer coefficient
R32-R1234ze(E) blend [R32 mass%]
2) Average evaporating heat transfer coefficient
R32-R1234ze(E) blend [R32 mass%]
Source:Akio Miyara et.al. Proeedings from 46th The society of Heating, Air-Conditioning Sanitary Engineers of Japan (2012)
19
3B. Impact of Blending - System test Generally, energy efficiency for drop-in models is shown at
different capacities than the base model, as demonstrated by the
graph below. It is understood that increasing capacity in the
system will cause efficiency to decrease. For valid system test
comparisons, it is important to compare different refrigerant
options based on same capacity as a reference.
EER
Ambient temperature 35℃
1.04
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
DR-5
L41a
R32
R410A
0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05
Capacity
*EER and capacity correlation may vary
depending on original system design
Source: based on AHRI’S Low-GWP AREP Test Report #22, which consists of drop-in testing with 3.0 ton capacity split system
(Aug 5, 2013)
20
3C. Impact of Blending - System test Comparison for EER of R32 and R32/HFO blend vs R410A
at the same capacity
Relative EER (vs R410A at 35℃ %)
*Residential split system
110%
Indoor : DB/WB = 27℃ / 19℃
105% +7% for
100% R410A
6.0kW System
-5% for
R32
R410A
95% R410A
90%
85%
80%
75%
4.0kW System
Same Capacity
at 35℃ Outdoor temp.
R32
R32/HFO1234ze
(E) blend (70:30)
70%
65%
60%
55%
50%
30
35
40
45
Outdoor temp.(℃)
50
55
60
21
4. Compressor Discharge Temperature
•R32 compressor discharge temperature is generally higher
than R32/HFO blends, however it is not an issue in most
conditions, even in high ambient cooling condition.
•In very low ambient heating condition, discharge temperature
may need to be controlled, e.g. by wet suction control.
Impact of wet suction control on R32 discharge temperatures
Te = -20 [deg]
Discharge Temp. [deg]
Tc [deg]
Comp. Efficiency [%]
200
◆
50
50
180
▲
45
40
40
60
－
－
160
Te = -30 [deg]
220
Discharge Temp. [deg]
220
140
120
100
80
60
40
Tc [deg]
200
180
50
50
▲
45
40
60
－
160
Comp. Efficiency [%]
◆
140
120
100
80
60
40
0.8
0.85
0.9
X.suc [-]
0.95
1
0.8
0.85
0.9
0.95
1
X.suc [-]
22
5A. Oil and System Reliability
• POE oils currently used for R410A have poor miscibility
with R32.
• New POE oils have good miscibility with R410A and
with R32.
Source: the presentation of JX Nippon Oil & Energy Corporation (June 25, 2013)
23
5C. Oil and System Reliability
New POE oils are available now which are excellent
for both R32 and R410A.
Source: the presentation of JX Nippon Oil & Energy Corporation (June 25, 2013)
24
5D. Oil and System Reliability
Source: the presentation of JX Nippon Oil & Energy Corporation (June 25, 2013)
25
6. Benefits of Single Component Refrigerant
Because R32 is a single component refrigerant,
1. It is easier to handle.
• can be charged in both gas and liquid
phase
• no need to worry about composition
change after leakage
2. It is easier to recycle and reuse.
26
7. Reduced System Dimensions
Case of Japan sales model (Nov.2012 on sale )
R410A
H693×W795×D300
R32
High
Energy
Efficiency
H693×W795×D300
Same
Size
Unit size
795
795
APF(Energy
efficiency)
6.6
7.0
Class
1.7HP(4.0kW/13,600Btu)
1.7HP(4.0kW 13,600Btu)
R410A
R32
H693×W795×D300
Down
Sized
6%
H599×W718×D315
Unit size
APF:6.6
795
1250ｇ
Amount of Ref.
1.0HP(2.2-.5kW/8500Btu)
Class
APF:6.6
718
1000ｇ
Volume
△18%
Charge
△20%
1.0HP(2.2-2.5kW/8500Btu)
27
8. Conclusions
 R32 has excellent energy performance characteristics
in air conditioners and heat pumps.
 R32 allows for reduced refrigerant charge and system
dimensions while maintaining or increasing energy
efficiency.
 The higher discharge temperature of R32 is manageable.
 Suitable oils for R32 are available.
 R32 has the advantage of being a single component
refrigerant.
28
R32 Air Conditioner and Heat Pump
Installation/service aspects
PART 3
29
1. Technically, installation of R32 unit is the same as R410A
2. Tooling is slightly different
Tooling
R410A
R32
Manifold
Normal
Different scale but
solution can be found
Scale
Normal
Normal
Vacuum pump
Normal
Normal
Leak detector
Normal
Different
Recovery unit
Normal
Different
Ventilation
Recommended
Necessary
Recovery bottle
40 bar, right thread
48 bar, left thread
Thank you!
31