Next Generation Refrigerants & Their Lubricants Jeng-Shiang Tsaih Patech Fine Chemicals Co., Ltd. .
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Transcript of Next Generation Refrigerants & Their Lubricants Jeng-Shiang Tsaih Patech Fine Chemicals Co., Ltd. .
Next Generation Refrigerants & Their
Lubricants
Jeng-Shiang TsaihPatech Fine Chemicals Co., Ltd.
www.patechfc.com.tw
www.patechfc.com.tw
CFC
HCFC
HFC
HFO
NH3 &CO2
R32
Hydrocarbons
Major Refrigerants
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Refrigerant Classification
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Basic Data of Refrigerants
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Refrigerant Nomenclature
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Chemical Structure Effect
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Safety Classification (ASHRAE)
A lot of low GWP refrigerants meet A2L group
Safety Group(ASHRAE 34--2007)
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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.
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Refrigerant Progression
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Environmental Consideration
Environmental Drivers Affecting Industry
Ozone Depletion EffectMontreal Protocol
ODP
Climate Change EffectKyoto Protocol
GWP
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Environmental Drivers Affecting Industry
Ozone Depletion Effect Protective Ozone Layer Damaged By Chlorine & Bromine Gases.
Montreal Protocol In September 16,1987 Bans CFCsHCFC R22 EliminationODP 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.
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Ozone Depletion Effect HCFC Phase-out
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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.
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Climate Change EffectHFC Phase-out
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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
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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.
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HoneyWell HFO Refrigerants
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HFO-1234yf
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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
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HFO-1234yf or CO2 in MAC?
EU: GWP of passenger car refrigerants < 150 (2011)VDA (German Association of the Automotive Industry ) had 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
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HFO-1234ze
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HFO-1234ze for Chiller
Low GWP Replacements for Chillers
Equal (or better) efficiency compared to R-134a
99.7% reduction in GWP
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Trade Off: GWP vs. Performance
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R410a Replacement- L41 Blend
Composition wt% R32 HFO-1234yf HFO-1234ze
L41-Blend 73% 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.
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Operating Pressure Consideration
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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.
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CO2 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 CO2 gas cooler providing
good efficiencies inside a compact system.Auto A/C applications
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R-32 Refrigerant
CH2F2 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
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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.
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R410a Replacement
As R-32 concentration becomes richer, R-32/HFO-1234yf mixtures develop the same characteristics as those of R-410A.
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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%.
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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 (C3H8)
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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.
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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
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Vapor Pressures Consideration
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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 CostTechnology Changes
Drop-in consideration
Integrated Analysis Leading To The Selection Of The Best Refrigerant
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Respective Properties Comparison
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Benefits and Drawbacks
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Definition
Coefficient of performance (COP)This is used to define heat pump efficiency.
COP = Q / WWhere:COP = Coefficient of performance (Unit-less) Q = Energy output (kWh or kJ). W = Electrical or mechanical energy input (kWh or kJ).
watts)(inpower electricalinput
Btu/hr) Energy(incoolingoutput EER
Energy Efficiency Ratio (EER)
COPhrWattBtuEER 412.3)/(
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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: CO2 or NH3 are more energy efficient. On Air-condition systems: HCs > HFO-1234yf > CO2
On Refrigeration systems: HCs > HFO-1234yf CO≒ 2
On Heating Pumps: CO2 > HCs > HFO-1234yf
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Most would be restricted in Japan, U.S., EU. Not just technical barriers but also legislative and regulatory barriers.CO2 : 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
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Oil in Refrigeration System
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Refrigeration Oil Requirements
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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.
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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 structure’s side chain has characteristics of PAG oil, with good
solubility and no hydrolysis.
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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.
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Advantage of POE LubricantsAdvantages of POE Lubricant
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Refrigeration Oil Comparison
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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
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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
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Miscibility Curves
Different Refrigerants, Different Miscible Phenomena
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PVT Charts (Solubility Curves)
Different Refrigerants, Different Soluble Phenomena
P-V-T Charts Pressure-Viscosity-Temperature-composition relationship
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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.
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Thermal Stability in HFC
Different Refrigerants, Different Thermal Test Phenomena
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Thermal Stability in Low GWP Refrigerants
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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.
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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.
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P-V-T Charts Comparison
Good miscibility of 1234ze lead to lower viscosity and lower pressure
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Miscibility Comparison (CO2)
The miscibility gap of POE is smallest
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Miscibility Problem
Miscibility Improvement : New Structure Designed
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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
Thank you for your attention
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