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Service Section Technical Training December 2003
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Alternative Refrigerant R410A
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Introduction Cause for Change Refrigerants Service Procedures Caution Safety Conclusions Index
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Introduction Introduction
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Substance that is used to absorb and transport heat Example: CO 2, NH 3, CFC, HCFC, etc. Modern refrigerants (Fluorinated Hydrocarbon) are noncorrosive, nonflammable, nontoxic, nonexplosive, clear water-white and have a slightly sweet odor WHAT IS A REFRIGERANT? Introduction
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R 1234 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 REFRIGERANT STRUCTURE Introduction
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EXAMPLE For R22 Number of Fluorine = 2 Number of Hydrogen = 2 - 1 = 1 Number of Carbon = 0 + 1 = 1 ClCl F C F H HCFC (R22) Introduction
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Introduction H F C F H 23% R32 F F C F H 52% R134a C F H ++ F F C F H 25% R125 C F F HFC (R407C) ClCl C F F ClCl CFC (R12) ClCl F C F H HCFC (R22) F F C F H HFC (R134a) C F H H F C F H 50% R32 + F F C F H 50% R125 C F F HFC (R410A)
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Cause for Change
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1.0 0.055 00 90% Ozone Cause for Change
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0.33 0.360.443.0
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PHASE OUT SCHEDULE OF REFRIGERANT Cause for Change
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Refrigerants Refrigerants
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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
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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
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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
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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
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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
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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
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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 Refrigerants
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Refrigerants Evaporation Pressure at 45ºF and Condensing Pressure at 115ºF HCFC: R22 CFC: R12 HFC: R410A
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Refrigerants Comparison of Vapour Pressure
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Refrigerants Conditions: t o = 10°C, t c = 45°C, t u = 6.5K, t h = 7K, η is = 0.8 COP = Capacity / Power Vol. Capacity = Capacity / Volume Theoretical calculation based on different physical and thermodynamic properties
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Refrigerants 8% Comparison of COP
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Refrigerants 52% 16% Comparison of Volumetric Capacity
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Service Procedures
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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. Service Procedures
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Tools Used Specifically for R410A Gauge manifold Charging hose Refrigerant cylinder Charging cylinder Coated in Pink Service Procedures
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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
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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
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Tools Used Specifically for R410A Electronic scale for charging refrigerant Flare tool a) Clutch-type flare tool (recommended) b) Conventional flare tool Service Procedures
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Tools Used Commonly for R22, R407C, R410A Copper pipe bender Torque wrench Copper cutter and reamer Welding / brazing equipment Nitrogen gas cylinder Service Procedures
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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
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Installation & Service checklist Refrigerant recovery method a) Pre-fill procedure b) Filling procedure c) Post-fill procedure Service Procedures
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Refrigerant recovery method Pre-fill procedure Identify refrigerant to be recovered Ensure cylinder is marked and labeled for this refrigerant Read all labels Ensure cylinder retest date has not expired Inspect cylinder for damage Inspect valve for damage and ease of operation Determine maximum allowable gross (filled) weight Carry out filling procedure Service Procedures
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Refrigerant recovery method Filling procedure Ensure proper equipment is available Ensure cylinder is free standing on scale Ensure maximum service pressure is not exceeded Ensure overfilling does not occur Close cylinder valve securely Check cylinder weight Service Procedures
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Refrigerant recovery method Post-fill procedure Check cylinder for leakages Apply outlet cap on cylinder Apply steel valve protector cover on cylinder Ensure cylinder bears all appropriate labels and markings Inspect valve for damage and ease of operation Confirm maximum allowable gross (filled) weight Send for retest Service Procedures
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Installation & Service checklist System evacuation a) Vacuum pump b) Measuring instrument Service Procedures
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Air conditioning size Pumping capacity Small air conditioners up to 2.5 kW cooling capacity Sv = 1 m 3 /h Small and middle air conditioners from 2.5 up to 11 kW cooling capacity Sv = 4-8 m 3 /h Big air conditioners above 11 kW cooling capacity Sv = 8 - 15 m 3 /h General guide to recommended vacuum pump capacity based on air conditioning size Service Procedures
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System evacuation Select measuring instruments Use an absolute vacuum measuring meter (vacuum or torr meter) Service Procedures
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Installation & Service checklist Refrigerant charging Invert cylinders to charge in liquid (no dip-pipe anymore) Service Procedures
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Caution Caution
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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
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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 ! Caution
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Safety Safety
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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
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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
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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 Safety
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Conclusions Conclusions
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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
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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 Conclusions
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Thank you…
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