atech

Report
Next Generation
Refrigerants & Their
Lubricants
Jeng-Shiang Tsaih
Patech Fine Chemicals Co., Ltd.
www.patechfc.com.tw
Major Refrigerants
CFC
HCFC
HFC
HFO
NH3 &CO2
R32
Hydrocarbons
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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)
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Safety Group(ASHRAE 34--2007)
A lot of low GWP refrigerants meet A2L group
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Flammability Consideration
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 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.
The GWP and LFL data of some alternatives
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Refrigerant Progression
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Environmental Consideration
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Environmental Drivers Affecting Industry
Ozone Depletion Effect
Montreal Protocol
ODP
Climate Change Effect
Kyoto Protocol
GWP
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Environmental Drivers Affecting Industry
Patech
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.
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Ozone Depletion Effect
HCFC Phase-out
Patech
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Environmental Drivers Affecting Industry
Patech
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 Effect
HFC Phase-out
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Another Assessment for Global Warming
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 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
Patech
Life Cycle Performance
 Typical Low Charge Systems:
AC, Heat Pump, Reach-In, Walk-In, Transport
Applications
 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
Patech
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HFO-1234yf
Patech
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HFO-1234yf
Patech
. 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?
Patech
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
Patech
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HFO-1234ze for Chiller
Patech
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
Patech
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R410a Replacement- L41 Blend
Patech
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
Patech
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R410a Replacement- L41 Blend
Patech
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
Patech
The main advantages are a very low environmental impact, nonflammability 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
Patech
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
Patech
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 R410A.
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
Patech
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
Patech
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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R-290 Refrigerant
R-290 --Propane (C3H8)
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.
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R-290 Refrigerant
Patech
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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R-290 Refrigerant
Patech
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.
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Vapor Pressures Consideration
Patech
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Approach To Refrigerant Selection
Patech
Safety
A1,A2,A2L,LFL
Flammability
Toxicity
(Montreal Protocol)
Environment
Stratospheric
Ozone
Temp glide, Vapor pressure…
Performance
Physical
Properties
Drop-in consideration
Technology
Changes
GWP
&
(TEWI/LCCP)
COP, Discharge Temp….
Energy Capacity
(Annual/Peak)
Economics
Total Cost
Integrated Analysis
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Leading To The Selection Of The Best Refrigerant
Respective Properties Comparison
Patech
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Benefits and Drawbacks
Patech
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Definition
Patech
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)
EER 
output cooling Energy(in Btu/hr)
input electrical power (in watts)
EER ( Btu / hrWatt )  3.412  COP
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Energy Efficient Refrigerants
Patech
 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 ≒ CO2
 On Heating Pumps: CO2 >HCs> HFO-1234yf
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Approval to Use
Patech
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.
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Oil in Refrigeration System
Patech
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Refrigeration Oil Requirements
Patech
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The Structure of Refrigeration Oils
Patech
 Mineral Oil (MO):
MO
Alkyl Benzene (AB):
Synthetic lubricant made to act like
mineral oil, long chain hydrocarbons
with closed rings. Somewhat polar better HCFC miscibility.
Refined petroleum product, straight or
branched chain hydrocarbons. Nonpolar chemistry means they mix well
with CFCs, OK with HCFCs, not with
HFCs.
AB
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The Structure of Refrigeration Oils
Patech
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.
PVE
PAG
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
Patech
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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Advantages
POELubricants
Lubricant
Advantage ofofPOE
Patech
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Refrigeration Oil Comparison
Patech
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Experimental Parameters
Patech
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
Patech
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-ViscosityTemperature-composition relationship
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Miscibility Curves
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Different Refrigerants, Different Miscible Phenomena
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PVT Charts (Solubility Curves)
Patech
P-V-T Charts
Pressure-Viscosity-Temperature-composition relationship
Different Refrigerants, Different Soluble Phenomena
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Compatibility & Energy Efficiency
Patech
 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
Patech
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Different Refrigerants, Different Thermal Test
Phenomena
Thermal Stability in Low GWP Refrigerants
Patech
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Lubricity Test
Patech
 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
Patech
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
Patech
Good miscibility of 1234ze lead to lower viscosity and
lower pressure
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Miscibility Comparison (CO2)
Patech
The miscibility gap of POE is smallest
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Miscibility Problem
Patech
Miscibility Improvement : New Structure Designed
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Low GWP R32 – Our Solution
Patech
 Miscibility RB series & RH series in R32
 Miscibility RB series & RH series in R410a
RB-68-LD-R(20%) : 10℃
RH-68-LD-R(20%) : -50℃
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Thank you
for your attention
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