challenges in retrofitting r-404a with lower gwp refrigerants · challenges in retrofitting r-404a...

Challenges in Retrofitting R-404Awith Lower GWP Refrigerants

Sarah Kim, Laurent Abbas, Wissam Rached

Arkema

2015 ASHRAE Summer ConferenceAtlanta, GAJune 30th, 2015

Seminar 37 - Lower GWP Alternatives for R-404A in Commercial and

Transport Refrigeration

Learning Objectives

1. Understand recent and proposed changes in regulations, such as the EU F-Gas Regulations and EPA SNAP, which will drive the transition from R-404A to lower GWP alternatives.

2. Explain options to replace R-404A in commercial and transport refrigeration systems and condensing units.

3. Describe the performance and efficiency of refrigeration systems with lower GWP refrigerants (GWP<2500), in low- and medium-temperature applications.

4. Describe how the behavior of these replacement refrigerants differs from R-404A and other azeotropes and how to manage these differences (i.e., temperature glide, discharge temperature, etc.) in design, construction and commissioning.

2

ASHRAE is a Registered Provider with The American Institute of Architects Continuing Education Systems. Credit earned on completion of this program will be reported to ASHRAE Records for AIA members. Certificates of Completion for non-AIA members are available on request.

This program is registered with the AIA/ASHRAE for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product. Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

Regulatory Policy on refrigerants

European Union F-gas : Reduction of HFC emission by 2/3 by 2030

● Main measures – Cap and Phase Down – Selected use bans

EPA Proposal

● Notice of Proposed Rulemaking (NOPR) issued in Summer 2014 to change the status (delist) materials

● Propose to ban the use of some high GWPs refrigerants like R-404A in applications for commercial refrigeration. Lower targets for stand alone and vending machines

ApplicationsDate of

ban

Refrigerators & Freezers for commercial use (Hermetically sealed) with GWP > 2500 2020

Stationary refrigeration with GWP>2500 2020

Multipack centralized refrigeration systems for commercial use with

CAP>40kW : GWP>150 (GWP>1500 in the primary refrigerant circuit of cascade systems)

Refrigerators & Freezers for commercial use (Hermetically sealed) with GWP>150

2022

Global regulatory policy on HFCs picking up momentum3

Regional Regulatory Programs- commercial refrigeration

USA

4

Europe

Stationary refrigeration with GWP>2500

Refrigerators & Freezers for commercial use (Hermetically sealed systems) with GWP > 2500

Servicing/maintenance of refrigerating equipment with charge size > 40t CO2 eq. with GWP>2500

Ban on some high GWP refrigerants. Supermarket Systems, field charged Condensing

Units

National regulations under

discussion in other countries like

Japan and Canada.

2016 + (?) 2020 2022

CA EPA

R-449B*, Others

R-407A

R-407A, Others

R-449B, Others

Cascade system with charge size > 40t CO2

eq. with GWP>1500

*Pending final approval from ASHRAE BOD

**GWP value for 100-year time horizons according to IPCC 2007 4th Assessment Report

5

R-404A Substitutes with Reduced GWP - Non-flammable

R-404A R-449B R-448A R-449A

ASHRAE Safety Rating Class A1 Class A1 Class A1 Class A1

GWP Reduction

vs R-404A (%)*- 64% 65% 64%

HFO Content (%) - 23.2% 27% 25.3%

Normal Boiling Point- 51.2˚F/ -46.2˚C

-51.0˚F/ -46.1˚C

- 50.6˚F/ -45.9˚C

- 50.7˚F/ -46.0˚C

*GWP value for 100-year time horizons according to IPCC 2007 4th Assessment Report

Thermodynamic Cycle Performance

6

GWP~1500 blends showed superior performance compared to R-404A

Mean Evaporator Temperature

Mean Condenser Temperature

Evaporator Outlet Superheat

Compressor Suction Superheat

= -25˚F/-31.7˚C= 105˚F/40.5˚C

= 10˚F/-12.2˚C= 40˚F/4.4˚C

0

20

40

60

80

100

120

COP CAP CondenserPressure

EvaporatorPressure

% w

ith R

esp

ect

to R

-404A

R-407A R-449B R-448A R-449A

Test Unit – Walk-in Freezer with External Evaporator

“Drop-in” tests

R-404A, 1 HP, Walk-in Freezer

with matching evaporator

● Reciprocating Compressor

● No liquid injection

1 ton capacity TXV

2 Outdoor Box Temperatures :

60˚F (15.5˚C) and 85˚F (29.4˚C)

7

PP

TT

T

P

T

P

P

T

T

P

Adjustable

Expansion

Valve

Over 20 feet of line

with several 90º

angles

Outdoor Chamber Indoor Chamber

Mass Flow Meter

System Set-Up

8

-6

-4

-2

0

2

4

6

15˚F/-9.4˚C

0˚F/-17.7˚C

-20˚F/-28.9˚C

-6

-4

-2

0

2

4

6

15˚F/-9.4˚C

0˚F/-17.7˚C

-20˚F/-28.9˚C

R-449B R-449A

Test Results – Efficiency

9

Outdoor Box Temperature = 60ºF/15.5ºC

% C

hange R

ela

tive

to R

-404A

Experimental uncertainty = +/- 2%

Both refrigerants show similar efficiency within uncertainty

Efficiency of lower GWP options noticeably lower for low temperature (-20˚F)


% C

hange R

ela

tive

to R

-404A

-10

-8

-6

-4

-2

0

2

4

-12

-10

-8

-6

-4

-2

0

2

4

R-449B R-449A

Test Results – Volumetric Capacity

10


% C

hange R

ela

tive to

R-4

04A

Experimental uncertainty = +/- 2%

R-449B showed slightly higher volumetric capacity

For most conditions, the blends tested have comparable or lower volumetric capacity than R-404A


% C

hange R

ela

tive

to R

-404A

15˚F/ 0˚F/ -20˚F/

-9.4˚C -17.7˚C -28.9˚C

-9.4˚C -17.7˚C -28.9˚C

15˚F/ 0˚F/ -20˚F/

Test Results – Mass Flow

11

% R

ela

tive t

o R

-404A

Average Mass Flow Rate

Refrigerant15˚F/

-9.4˚C

0˚F/

-17.7˚C

-20˚F/

-28.9˚C

R-449B 4 ¼ 3 ½ 2 ¼

R-449A 4 ½ 4 3 ½

Change in TXV setting for each Indoor Temperature

60ºF/15.5ºC Outdoor

85ºF/29.4ºC Outdoor

100

90

80

70

60

95

85

75

65

55

R-449B R-449A

0

5

10

15

20

-25 -20 -15 -10 -5 0 5 10 15 20

ΔT D

ischarge(°F)

TIndoor(°F)

R-449B R-449A

Test Results – Temperature Management

12

Both blends showed higher discharge temperature compared to R-404A but remains within the R-404A compressor limit

Figure. Difference in Discharge Temperature versus R-404A (˚F )

Outdoor Box Temperature = 85ºF/29.4˚C

Vapor pressure

13

P (Psia)

T (ºF)

0

50

100

150

200

250

300

-40 -20 0 20 40 60 80 100

R-449B

R-404A

R-448A

R-449A

Lower GWP refrigerants showed lower vapor pressure ranging from 7 to 23%

0

0.4

0.8

1.2

1.6

2

15ºF/-9.4ºC

R-449B R-449A

0

0.4

0.8

1.2

1.6

2

15ºF/-9.4ºC -20ºF/-28.9ºC

R-449B R-449A

Pressure Ratio

14


Va

lue

rela

tive

to R

-404A

Both refrigerants showed higher pressure ratio than R-404A ranging up to 16%

Outdoor Box Temperature = 85ºF/29.4ºCV

alu

e re

lativ

e to

R-4

04

A

-20˚F/-28.9˚C

Oil management

Reduced liquid and vapor line velocity compared to R-404A

No oil return issues during experimental testing

15

40

50

60

70

80 % w

ith R

esp

ect to

R-4

04A

R-449B R-449A

15˚F/ 0˚F/ -20˚F/-9.4˚C -17.7˚C -28.9˚C


Vapor line velocityLiquid line velocity

40

50

60

70

80

90

100

% w

ith R

esp

ect to

R-4

04A

R-449B R-449A

15˚F/ 0˚F/ -20˚F/-9.4˚C -17.7˚C -28.9˚C

Summary of Experimental Results*

16

Efficiency Superior to R-404A at medium

temperature

Capacity Comparable or lower volumetric

capacity than R-404A

Mass Flow ~70% of R-404A

Discharge Temperature

Higher than R-404A but below limit of the compressor

Pressure ratio Slightly higher pressure ratio

Oil return No operational issue without oil

replacement

*This is not a retrofit guideline

17

Efficiency Capacity

Superior efficiency and similar or higher volumetric capacity at high condensing temperature

R-449B vs R-404A – Different condensing temperatures

-8

-6

-4

-2

0

2

4

6

8

10

-20°F/-28.9°C 30°F/-1.1°C

% c

hange r

ela

tive t

o R

-404A

Tindoor(ºF)

60°F/15.5°C 105°F/40.5°C

-8

-6

-4

-2

0

2

4

6

8

10

-20°F/-28.9°C 30°F/-1.1°C

% c

hange r

ela

tive t

o R

-404A

Tindoor(ºF)

60°F/15.5°C 105°F/40.5°C

Conclusion

R-407A is available for R-404A retrofits

Non-flammable alternative options to R-404A have been tested in a commercial Walk-in Freezer

Lower GWP HFO/HFC blends offer new opportunities to replace R-404A

● R-449B and R-449A showed comparable performance to R-404A with

GWP~1500

● Trade-off to lower GWP options are likely a higher discharge temperature

and reduced flow

● Same POE oil can be used*

*Always consult with compressor OEM for recommended lubricant

18

Questions?

S.Kim

[email protected]

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