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Service Section Technical Training December 2003. Alternative Refrigerant R410A. Index. Introduction Cause for Change Refrigerants Service Procedures Caution Safety Conclusions. Introduction. Introduction. Introduction. WHAT IS A REFRIGERANT?.
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Service Section Technical Training December 2003
Alternative Refrigerant R410A
Index • Introduction • Cause for Change • Refrigerants • Service Procedures • Caution • Safety • Conclusions
Introduction Introduction
Introduction WHAT IS A REFRIGERANT? • Substance that is used to absorb and transport heat • Example: CO2 , NH3 , CFC, HCFC, etc. • Modern refrigerants (Fluorinated Hydrocarbon) are noncorrosive, nonflammable, nontoxic, nonexplosive, clear water-white and have a slightly sweet odor
Introduction REFRIGERANT STRUCTURE R 1 2 3 4 R – ASHRAE numbering system 1 – Number of unsaturated C – C 2 – Number of Carbon atom - 1 3 – Number of Hydrogen atom + 1 4 – Number of Fluorine
F C F Cl H HCFC (R22) Introduction EXAMPLE For R22 Number of Fluorine = 2 Number of Hydrogen = 2 - 1 = 1 Number of Carbon = 0 + 1 = 1
F F C C F F H H HFC(R134a) F F F F F + C C C C C F F F H F F H H F Cl Cl Cl H 50% R32 50% R125 CFC(R12) HCFC(R22) HFC(R410A) F F F F F C + C C + C C F F F F F H H H F H H 23% R32 25% R125 52% R134a HFC (R407C) Introduction
Cause for Change Cause for Change
0 0 0.055 1.0 Cause for Change 90% Ozone
0.44 0.36 0.33 3.0 Cause for Change
Cause for Change PHASE OUT SCHEDULE OF REFRIGERANT
Refrigerants Refrigerants
Refrigerants For R22 • Standard refrigerant used worldwide • Used in a broad spectrum of different applications • Replacement for CFC 12 • With excellent physical and thermodynamic properties
Refrigerants For R407C • Designed to substitute R22 • Physical and thermodynamic properties comparable to R22 • Zeotropic refrigerant blend containing R32, R125 & R134a (23/25/52% by weight) • Temperature glide approximately 7K (zeotropic behavior)
Refrigerants For R407C • Shifting blend composition resulting from leaks and charging operations • Different concentration of the individual components at different points in the cycle • Refrigerant must be charged in liquid form
Refrigerants For R407C • Miscible with polyoester oils (POE) • Environmentally acceptable (ODP = 0) • Able to retrofit existing R22 units • Non-flammable and safe to use • Commercially available
Refrigerants For R410A • Favoured worldwide as long-term alternative to R22 • Excellent thermodynamic properties • Higher working pressure (~1.6 times > R22 systems) • Higher refrigerating capacity achievable (~50% > R22) • Relatively low critical temperature (~73°C)
Refrigerants For R410A • Near azeotropic refrigerant containing R32 and R125 (50/50% by weight) • Negligible temperature glide < 0.17 K • Refrigerant must be charged in liquid form • Able to top up if losses are low (<25% from initial charge)
Refrigerants For R410A • Compressors must be charged with polyolester oils • Environmentally acceptable (ODP = 0) • Unable to retrofit existing R22 units • Non-flammable and safe to use • Commercially available • More expensive compared to R22
HFC: R410A HCFC: R22 CFC: R12 Evaporation Pressure at 45ºF and Condensing Pressure at 115ºF Refrigerants
Comparison of Vapour Pressure Refrigerants
Service Procedures Service Procedures
Service Procedures Tools Used • Tools used when servicing R410A units can be separated in 2 categories: a) Specifically for R410A b) Commonly used for R22, R407C, R410A. • Tools used in (a) should be designed to withstand the higher pressures and temperatures of R410A.
Coated in Pink Service Procedures Tools Used Specifically for R410A • Gauge manifold • Charging hose • Refrigerant cylinder • Charging cylinder
Service Procedures Tools Used Specifically for R410A • Refrigerant recovery unit a) Recovery machine - maximum shut off pressure of 550 psi - capable to operate at high ambient temperatures b) Recovery cylinder - minimum working pressure of 400 psi and relief pressure of 600 psi
Service Procedures Tools Used Specifically for R410A • Gas leak detector • Vacuum pump a) New pump that comes built-in anti-reverse flow b) Conventional pump with additional anti-reverse flow adaptor
Service Procedures Tools Used Specifically for R410A • Electronic scale for charging refrigerant • Flare tool a) Clutch-type flare tool (recommended) b) Conventional flare tool
Service Procedures Tools Used Commonly for R22, R407C, R410A • Copper pipe bender • Torque wrench • Copper cutter and reamer • Welding / brazing equipment • Nitrogen gas cylinder
Service Procedures Installation & Service checklist • Size of flare • Flare nut used • Tubing used a) Narrow tube (ø6.35 x t0.8 mm) b) Wide tube (ø19.05 x t1.0 mm) • Compressor oil used • Refrigerant used (only R410A)
Service Procedures Installation & Service checklist • Refrigerant recovery method a) Pre-fill procedure b) Filling procedure c) Post-fill procedure
Service Procedures Refrigerant recovery method • Pre-fill procedure Identify refrigerant to be recovered Ensure cylinder retest date has not expired Determine maximum allowable gross (filled) weight Ensure cylinder is marked and labeled for this refrigerant Inspect cylinder for damage Carry out filling procedure Inspect valve for damage and ease of operation Read all labels
Service Procedures Refrigerant recovery method • Filling procedure Ensure proper equipment is available Ensure maximum service pressure is not exceeded Close cylinder valve securely Ensure cylinder is free standing on scale Ensure overfilling does not occur Check cylinder weight
Service Procedures Refrigerant recovery method • Post-fill procedure Check cylinder for leakages Confirm maximum allowable gross (filled) weight Ensure cylinder bears all appropriate labels and markings Apply outlet cap on cylinder Inspect valve for damage and ease of operation Send for retest Apply steel valve protector cover on cylinder
Service Procedures Installation & Service checklist • System evacuation a) Vacuum pump b) Measuring instrument
Service Procedures General guide to recommended vacuum pump capacity based on air conditioning size
Service Procedures System evacuation • Select measuring instruments Use an absolute vacuum measuring meter (vacuum or torr meter)
Service Procedures Installation & Service checklist • Refrigerant charging Invert cylinders to charge in liquid (no dip-pipe anymore)
Caution Caution
! Caution • Extra attention to moisture prevention is necessary • Recommended to use liquid-line filter drier • Remove filter drier with copper cutter • Always charge the refrigerant in liquid phase
! Caution • Ensure system is properly evacuated • Always work with absolute cleanliness • Ensure safety gas is always used during brazing works • Do not retrofit R22 systems to use R410A
Safety Safety
Safety • Ensure only certified technicians (by your own local body) are allowed to handle refrigerants • Ensure the use of proper personal protective equipment: a) Side shield glasses b) Gloves c) Safety shoes d) Hard hat
Safety • R410A is environmentally friendly but deadly in confined spaces • Avoid skin contact with liquid refrigerant • Do not heat cylinder or apply open flame above 52ºC (125ºF) • Do not artificially cool cylinder
Safety • Air and refrigerants mixed together under pressure can become combustible • Do not reuse cylinders intended for virgin refrigerant • Check, read, and understand all labels before use
Conclusions Conclusions
Conclusions R410A • High energy efficiency • More advantages in comparison to zeotropic mixture • Long term reduction in machinery sizes and costs. • Substitute refrigerant for R22 in future and development is taking part worldwide
Conclusions R410A • Proven safety and reliability if procedures are followed and proper equipments are used • Clean and dry as you go • Don’t assume you know everything about R410A