P atech www.patechfc.com.tw Refrigerant Classification
P atech www.patechfc.com.tw Basic Data of Refrigerants
P atech www.patechfc.com.tw Refrigerant Nomenclature
P atech www.patechfc.com.tw Chemical Structure Effect
P atech www.patechfc.com.tw Safety Classification (ASHRAE) A lot of low GWP refrigerants meet A2L group Safety Group(ASHRAE 34--2007)
P atech www.patechfc.com.tw Flammability Consideration The GWP and LFL data of some alternatives Lower flammability limit (LFL) is the lower end of the concentration range of a flammable solvent at a given temperature and pressure for which air/vapor mixtures can ignite.
P atech www.patechfc.com.tw Refrigerant Progression
P atech www.patechfc.com.tw Environmental Consideration Environmental Drivers Affecting Industry Ozone Depletion Effect Montreal Protocol ODP Climate Change Effect Kyoto Protocol GWP
P atech www.patechfc.com.tw Environmental Drivers Affecting Industry Ozone Depletion Effect Protective Ozone Layer Damaged By Chlorine & Bromine Gases. Montreal Protocol In September 16,1987 Bans CFCs HCFC R22 Elimination ODP must be zero The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause, with R-11 being fixed at an ODP of 1.0.
P atech www.patechfc.com.tw Ozone Depletion Effect HCFC Phase-out
P atech www.patechfc.com.tw Environmental Drivers Affecting Industry Climate Change Effect Greenhouse Gases Contribute To Global Warming Is Theory. Kyoto Protocol (1997) Aims To Curb All Greenhouse Gases. Most Refrigerants In Use Today Are Classified As Greenhouse Gases. Global-warming potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere.
P atech www.patechfc.com.tw Climate Change Effect HFC Phase-out
P atech www.patechfc.com.tw Another Assessment for Global Warming GWP is important but not the only measure of environmental impact! Refrigerants should be measured on TEWI or LCCP analysis TEWI : Total equivalent warming impact LCCP : Life-Cycle Climate Performance
P atech www.patechfc.com.tw TEWI & LCCP Analysis Typical Low Charge Systems: AC, Heat Pump, Reach-In, Walk-In, Transport Applications Life Cycle Performance For Hermetic Systems, Global Warming Is An Efficiency Issue. Future Refrigerants Must Be Equal Or Higher Efficiency. Typical Large Refrigeration Systems: Global Warming Becomes An Efficiency Issue If Charge/Leaks Are Reduced. Future Refrigerants Must Be Equal Or Higher Efficiency.
P atech www.patechfc.com.tw HoneyWell HFO Refrigerants
P atech www.patechfc.com.tw HFO-1234yf. Excellent environmental properties – Very low GWP of 4, Zero ODP, Favorable LCCP – Atmospheric chemistry determined and published. Low toxicity, similar to R-134a – Low acute and chronic toxicity – Significant testing completed. System performance very similar to R-134a – Excellent COP and Capacity, no glide from both internal tests and OEM tests – Thermally stable and compatible with R-134a components – Potential for direct substitution of R-134a. Mild flammability (manageable) – Potential to use in a direct expansion A/C system - better performance, lower weight, smaller size than a secondary loop system
P atech www.patechfc.com.tw HFO-1234yf or CO2 in MAC? EU: GWP of passenger car refrigerants < 150 (2011) VDA (German Association of the Automotive Industry ) hadGerman Association of the Automotive Industry re-affirmed intention to adopt CO2, based on flammability risks assessments in Europe. H-D re-affirms validity of flammability risks assessments : SAE CRP-1234 & U.S EPA. CO2& HFO-1234yf both remain as options
P atech www.patechfc.com.tw HFO-1234ze for Chiller Low GWP Replacements for Chillers Equal (or better) efficiency compared to R-134a 99.7% reduction in GWP
P atech www.patechfc.com.tw Trade Off: GWP vs. Performance
P atech www.patechfc.com.tw R410a Replacement- L41 Blend Composition wt%R32HFO-1234yfHFO-1234ze L41-Blend73%15%12% L-41 offers good performance and a significant GWP reduction from R-410A (>75%) It enables compact high efficiency systems in many regions. No problems with high discharge temperatures. L-41 shows lower operating pressures than R-410A and R-32.
P atech www.patechfc.com.tw Operating Pressure Consideration
P atech www.patechfc.com.tw R410a Replacement- L41 Blend Haier A/C unit – Solstice L41 Safer than HCs Using R410A technology. More than 75% reduction in GWP versus R410A. 30% reduction in GWP versus R32. Lower discharge pressure than R32. Lower Discharge temperature than R32. Lower power consumption than R410A and R32 at high ambient temperature regions.
P atech www.patechfc.com.tw CO 2 Refrigerant The main advantages are a very low environmental impact, non- flammability and non-toxicity. The disadvantage is high pressure at low temperatures. Hot water Heat Pump applications: the application matches the supercritical temperature glide in the CO 2 gas cooler providing good efficiencies inside a compact system. Auto A/C applications
P atech www.patechfc.com.tw R-32 Refrigerant CH 2 F 2 Difluoromethane (R32) CAS Number : 75-10-5 Molecular weight : 52.02 g/mol Boiling point : -51.7 °C Latent heat of vaporization (1.013 bar at boiling point) : 360.24 kJ/kg Vapor pressure (at 20 °C or 68 °F) : 13.8 bar Critical temperature : 78.4 °C Critical pressure : 53.8 bar
P atech www.patechfc.com.tw R-410 Replacement R-32 is one of the primary constituents of both R-410A and R-407C. R-32 is an A2L refrigerant having a GWP (675) approximately 70% less than that of R-410A, which makes it a lower GWP alternative to R-410A. R-32 exhibits slightly higher capacity and efficiency than R- 410A. R-32 has an A2L flammability rating, the flammability would need to be mitigated in the design of the product by compliance with an applicable safety standard such as IEC 60335-2-40. R-410A systems should be able to be redesigned for R-32 with minor modifications.
P atech www.patechfc.com.tw R410a Replacement As R-32 concentration becomes richer, R-32/HFO-1234yf mixtures develop the same characteristics as those of R-410A.
P atech www.patechfc.com.tw R-22 Replacement R-32 is not a drop in for R-22 since its pressure is around 60% higher and its capacity is also approximately 60% greater than R-22. R-22 systems would require significant redesign including: lower displacement compressors and other changes to the refrigeration system components to address the higher operating pressures; which will be nearly the same changes needed to redesign R-22 equipment to use R-410A. The refrigeration capacity can increase 8. 5% of the R22 system and the EER can increase by up to 7. 1%.
www.patechfc.com.tw Hydrocarbon systems are commercially available in a number of low charge air conditioning applications, such as small split, window and portable air conditioners. R-290 is the most frequently used hydrocarbon refrigerant in air conditioning applications. When used to replace R-22, R-290 has performance characteristics which yield slightly better performance than R-22. Compared to HFCs, hydrocarbon refrigerants have: reduced charge levels (approximately 0.05 - 0.15 kg/kW of cooling capacity), miscibility with mineral oils (synthetic lubricants are not required), reduced compressor discharge temperatures, and improved heat transfer due to favourable thermo-physical properties. R-290 Refrigerant R-290 --Propane (C 3 H 8 )
P atech www.patechfc.com.tw R-290 Refrigerant The factor that works against the safe application of R-290 in air conditioning systems is its high flammability, which creates significant safety concerns in application, installation and field service. European and international standards limit the quantity of R-290 that can be used in a system. The risk of ignition during normal operation is extremely low. The situation leading to highest risk is sudden leaks, refrigerant handling, and servicing activities. Thus, installation and service practices must be modified to avoid exposing consumers and service technicians to the additional risks associated with highly flammable refrigerants.
P atech www.patechfc.com.tw Another factor that must be considered with flammable refrigerants will be refrigerant reclaim and recovery requirements. Current recovery and recycling practices depend largely upon national or regional regulations. options. Compare to MO/R-290 system, the miscibility of POE/R290 is poor, so the phenomenon of viscosity dilution is less than MO/R-290. This result in good lubrication. R-290 Refrigerant
P atech www.patechfc.com.tw Vapor Pressures Consideration
P atech www.patechfc.com.tw Approach To Refrigerant Selection Safety Performance Economics Environment Flammability A1,A2,A2L,LFL Toxicity GWP & (TEWI/LCCP) (Montreal Protocol) Stratospheric Ozone Energy Capacity (Annual/Peak) Physical Properties Temp glide, Vapor pressure… COP, Discharge Temp…. Total Cost Technology Changes Drop-in consideration Integrated Analysis Leading To The Selection Of The Best Refrigerant
P atech www.patechfc.com.tw Respective Properties Comparison
P atech www.patechfc.com.tw Benefits and Drawbacks
P atech www.patechfc.com.tw Definition Coefficient of performance (COP) This is used to define heat pump efficiency. COP = Q / W Where: COP = Coefficient of performance (Unit-less) Q = Energy output (kWh or kJ). W = Electrical or mechanical energy input (kWh or kJ). Energy Efficiency Ratio (EER)
P atech www.patechfc.com.tw Energy Efficient Refrigerants No refrigerant represents the ideal solution in all cases and for every equipment – each cooling application has to be looked at in its own merits and a professional choice must be made taking into account many more factors than simply GWP. Energy efficiency is the most relevant criterion to assess the suitability of a refrigerant in R&AC systems. On small systems: HCs tend to be more energy efficient. On large systems: CO 2 or NH 3 are more energy efficient. On Air-condition systems: HCs HFO-1234yf CO 2 On Refrigeration systems: HCs HFO-1234yf CO 2 On Heating Pumps: CO 2 HCs HFO-1234yf
P atech www.patechfc.com.tw Most would be restricted in Japan, U.S., EU. Not just technical barriers but also legislative and regulatory barriers. CO 2 : No major regulatory barriers in any region. Ammonia : Likely to remain restricted to industrial applications due to toxicity. Hydrocarbons : Likely to be limited to small refrigeration or room AC applications due to flammability concerns, unless additional research can alleviate these concerns. A2L Fluids : Gaining increased acceptance, but will require: – Risk assessments to address safety. – Changes to building codes. – Changes to equipment safety standards. Approval to Use
P atech www.patechfc.com.tw Oil in Refrigeration System
P atech www.patechfc.com.tw Refrigeration Oil Requirements
P atech www.patechfc.com.tw The Structure of Refrigeration Oils MO AB Mineral Oil (MO): Refined petroleum product, straight or branched chain hydrocarbons. Non- polar chemistry means they mix well with CFCs, OK with HCFCs, not with HFCs. Alkyl Benzene (AB): Synthetic lubricant made to act like mineral oil, long chain hydrocarbons with closed rings. Somewhat polar - better HCFC miscibility.
P atech www.patechfc.com.tw The Structure of Refrigeration Oils PAG PVE Polyalkylene Glycol (PAG): Long chain hydrocarbons with alcohol functions. Manufactured chemical that is slippery like oil, but has chemical functions that make it polar - so it will mix with HFCs. Because of its relatively low electric resistivity, however, PAG could not be used in the hermetic compressors used in domestic refrigerators. Polyvinylether (PVE): The chemical chain of PVE oil shows similar characteristics to mineral oil (Hydrocarbon) with both good lubricity and similar dialectic strength. In addition, the chemical structures side chain has characteristics of PAG oil, with good solubility and no hydrolysis.
P atech www.patechfc.com.tw The Structure of Refrigeration Oils POE Polyol Esters (POE): Synthetic lubricants with ester functions in the middle of long chain hydrocarbons. More polar so they mix better with HFCs. POE lubricants are desirable because of their environmental benefits. They can be synthesized from renewable resource and are biodegradable. They are used mainly in domestic and commercial refrigerant systems. They are miscible with mineral oils, hence can be used for retrofits.
P atech www.patechfc.com.tw Advantage of POE Lubricants Advantages of POE Lubricant
P atech www.patechfc.com.tw Refrigeration Oil Comparison
P atech www.patechfc.com.tw Experimental Parameters There are a number of interactions between the refrigerant and the lubricant that need to be investigated in order to produce systems that are optimized for use. Miscibility Solubility (P-V-T) Thermal Stability Lubricity Life Cycle Test
P atech www.patechfc.com.tw Miscibility & Solubility Miscibility The ability of two liquids to mix and form a single phase Miscibility Curves Solubility The ability of a gas to dissolve into a liquid P-V-T Charts Pressure-Viscosity- Temperature-composition relationship
P atech www.patechfc.com.tw Miscibility Curves Different Refrigerants, Different Miscible Phenomena
P atech www.patechfc.com.tw PVT Charts (Solubility Curves) Different Refrigerants, Different Soluble Phenomena P-V-T Charts Pressure-Viscosity-Temperature-composition relationship
P atech www.patechfc.com.tw Compatibility & Energy Efficiency The more miscible one makes the lubricant with the refrigerant, the more soluble the refrigerant becomes in the lubricant. Ensure sufficient miscibility of lubricant with the refrigerant to maximize heat exchanger efficiency in the refrigeration circuit and assure required oil return to compressor sump. Optimizing the solubility of the refrigerant in the lubricant in the compressor to ensure fluid film lubrication while minimizing viscous drag.
P atech www.patechfc.com.tw Thermal Stability in HFC Different Refrigerants, Different Thermal Test Phenomena
P atech www.patechfc.com.tw Thermal Stability in Low GWP Refrigerants
P atech www.patechfc.com.tw Lubricity Test Lubricity tests were performed using a high-pressure tribometer and test pieces. When the test was complete, vane wear depth was measured and the antiwear properties of the test oils were evaluated.
P atech www.patechfc.com.tw Life Cycle Test Test RO for characteristic change after running for 2,000 hrs 3,000 hrs 4,000 hrs. (i.e. color, AV, metal, and viscosity). Measure wear and tear on compressor parts.
P atech www.patechfc.com.tw P-V-T Charts Comparison Good miscibility of 1234ze lead to lower viscosity and lower pressure
P atech www.patechfc.com.tw Miscibility Comparison (CO 2 ) The miscibility gap of POE is smallest
P atech www.patechfc.com.tw Miscibility Problem Miscibility Improvement : New Structure Designed
P atech www.patechfc.com.tw Low GWP R32 – Our Solution Miscibility RB series & RH series in R410a RB-68-LD-R(20%) : 10 RH-68-LD-R(20%) : -50 Miscibility RB series & RH series in R32
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