r32 acr journal webinar a-gas slides march 2016
TRANSCRIPT
R32 Your Low GWP Air Conditioning
Solution
ACR Journal – Webinar - 17th March 2016
Why another refrigerant? The F-Gas Revision New Equipment Ban:
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What is R32? A low GWP HFC refrigerant
• GWP of 675 • Significantly lower than R410A
Preferred replacement for
R410A
Uses similar technology Improved Cooling Capacity
Better Energy Efficiency
Physical Properties • Non-toxic
• Excellent thermal properties
– Pressures are slightly higher than R410A
– R410A 296psi/20.4bar @ 35oC
– R32 303psi/20.9bar @ 35oC
• High volumetric capacity
• Low boiling point of -52oC
• Odourless
• Mildly flammable
Several legislative issues to be aware of:
ADR (transport of dangerous goods) • R32 is classified as Class 2.1 Flammable for transport
• Treat the same way as propane etc.
Flammability ?
Design and Construction of refrigeration systems • A2L is a new ASHRAE category for “mildly flammable
refrigerants”
• EN378 currently under revision to take account of this new category
Dangerous substances & Explosive Atmospheres Regulations (DSEAR) • Ignition sources, avoidance of flammable atmospheres
etc
How easy is R32 to ignite?
How easy is R32 to ignite?
• Lower flammability limit 14% in air (~300g/m3)1
• Upper flammability limit 31% in air (~660g/m3)1
• A naked flame is required for R32 to ignite
• Low burning velocity makes ignition & flame propagation difficult (but not impossible)
• Risks are lower than propane and other hydrocarbons
– However don’t ignore obligations under DSEAR
– No venting, no sources of ignition, appropriate equipment
EN378 - application EN378-1 2008 restricts the application of flammable refrigerants
M = 2.5 x LFL1.25 x h x √A ** M = max charge, kg LFL = lower flammability limit, kg/m3 h = height of unit, m, (0.6 for floor mounted, 1.0 for window, 1.8 for wall, 2.2 for ceiling) A = floor area, m2
R32 R290 (propane)
Max refrigerant charge
8.84kg 0.65kg
Example: Comfort cooling, cassette in a 9m x 5.5m room *2
** For comfort cooling applications only. Other limits exist for depending on application. Please see EN378
The Cylinders: • Valve outlet is DIN-477 left
hand thread
– Adaptors will be required to suit refrigeration hoses
• A range of sizes available:
– 5kg, 10kg, 20kg & 45kg
• Red topped to aid easy recognition that it is flammable
“Best practice” procedures are required:
Good Quality Brazed Joints
Purge Whilst Brazing
Leak Prevention and Detection Flammable Recovery/Receiver Cylinders
Special Tools
Summary:
R32 should prove no more difficult to handle than R410A Be aware of the properties – risks are easily managed-Follow good refrigeration practice Experience with R32 is a good grounding for many new Low GWP refrigerants which are likely to be mildly flammable Keep up to date with industry developments
Remember: …Look for the logo to ensure what you are using is:
References 1. Flammability limits from Air Liquide Gas Encyclopedia. Quoted at STP. 2. IOR Technical bulletin 39
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