GLOBAL WARMING IMPACT OF LOW GWP CHILLER REFRIGERANTS: LCCP/TEWI vs GWP LCCP/TEWI vs Other Factors

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1 GLOBAL WARMING IMPACT OF LOW GWP CHILLER REFRIGERANTS: LCCP/TEWI vs GWP LCCP/TEWI vs Other Factors IIR Working Party Life Cycle Climate Performance Evaluation Delft, The Netherlands -- June 28, 2012 HFOs Kostas Kontomaris, Ph.D. DuPont Fluorochemicals R&D Disclaimer: The information set forth herein is furnished free of charge and based on technical data that DuPont believes to be reliable. It is intended for use by persons having technical skill, at their own risk. Since conditions of use are outside our control, we make no warranties, expressed or implied and assume no liability in connection with any use of this information. Nothing herein is to be taken as a license to operate under, or a recommendation to infringe any patents or patent applications.

2 Hydro-Fluoro-Olefins CFCs HCFCs HFCs HFOs CFC-12 HFC-134a HFO-1234yf CFC-114 HFC-245fa CFC-11 HCFC-123 DR-2 Less Chlorine No Chlorine Double Bond Conventional Wisdom: Unsaturated fluorocarbons are not sufficiently stable to be used as refrigerants! Paradigm Shift: Unsaturated fluorocarbon refrigerants decompose rapidly in the atmosphere but can remain stable in a system!

3 Weighing the Tradeoffs Safety Flammability: no or low Toxicity: low Environmental: no ODP, LOW CLIMATE IMPACT Performance Energy Efficiency Cooling Capacity Chemical Stability Cost Near Drop-In First & Operating No Perfect Refrigerant Best Balance for each Application

4 Centrifugal Water Chillers Condenser Electricity Expansion Valve Centrifugal Compressor Water Evaporator Number of centrifugal chillers in Operation around the world: Over 130,000 Chilled Water To Building Total refrigerant bank: ca. 60,000 tonnes Previous centrifugal chiller refrigerants and transitions CFC-11 HCFC-123 Ozone Depleting CFC-12 HFC-134a High GWP

5 Mid-Pressure Chiller Fluids: HFO-1234yf HFC-134a HFO-1234yf Chemical Formula MW Flammability CH 2 FCF CF 3 CF=CH L Marginally Flammable ALT [yrs] ODP GWP , (11 days) 4 Very Low GWP T cr [ o C] P cr [MPa] T b [ o C]

6 Mid-Pressure Chiller Fluids: XP10 Marginally Flammable Non-flammable HFC-134a HFO-1234yf XP10 Chemical Formula CH 2 FCF 3 CF 3 CF=CH 2 Azeotrope Flammability 2L ODP GWP 100 1,430 4 ~600 T cr [ o C] P cr [MPa] T b [ o C] Glide [ o C] N/A N/A Negligible

7 Mid-Pressure Chiller Fluids: DR-14 HFC-134a HFO-1234yf XP10 DR-14 Chemical Formula CH 2 FCF 3 CF 3 CF=CH 2 Azeotrope Azeotrope Flammability 2L ODP GWP 100 1,430 4 ~600 ~380 T cr [ o C] P cr [MPa] T b [ o C] Glide [ o C] N/A N/A Negligible Negligible

8 A Low Pressure Chiller Candidate: DR-2 Flammability Atmospheric life time [yrs] ODP GWP 100 YR ITH Critical Temperature [ºC] Critical Pressure [MPa] Normal Boiling Point [ºC] HCFC DR (24 days) <

9 Low GWP Replacements for HFC-134a in Chillers: Summary HFO-1234yf XP10 DR-14 FLAMMABILITY Marginal Nonflammable Nonflammable Theoretical Energy Efficiency vs HFC-134a -4.5% -2.5 % +0.7 % Cooling Capacity vs HFC-134a -6.5% +1.5% % HFC-134a Retrofit - Near drop-in -- GWP ~600 ~380 Preferred Refrigerant? XP10: would require no major equipment and no safety code modifications; it could be adopted earlier and more widely

10 Low GWP Chiller Refrigerants: Performance COP Cool vs HFC-134a DR-2 HCFC-123 DR-14 HFO-1234yf HFC-134a DR-11 XP Vol Cool Cap vs HFC-134a DR-2 vs DR-14 XP yf COP 3.6% 7.2 % 9.5%

11 Warming Impact of Low GWP Chiller Refrigerants TEWI = EM NRG + EM RFG + EM EOLrf EM NRG [kgco 2 -eq] = CI x E E [kwh] = P(COP) x HRS x N EM RFG = M r x S ANN x N x GWP EM EOLrf = M r x S EOL x GWP S ANN = annual % charge loss S EOL = End-Of-Life % charge loss

12 TEWI: High Carbon Intensity Scenario ( kgco 2 -eq/kwh--china) TEWI/TEWI_max High CI; High Refrigerant Emissions Based on Theoretical COPs S ANN = 5.0 %/yr; S EOL = 5.0 % XP10 HFC-134a HFO-1234yf DR-11 XP10 DR-14 HCFC-123 DR-2 RFG NRG GWP=1,430 4 ~600 ~ ~10 Minimization of GWP does not necessarily lead to maximum Warming Impact reduction

13 TEWI: Low Carbon Intensity Scenario ( kgco 2 -eq/kwh--switzerland) TEWI/TEWI_max Low CI; High Refrigerant Emissions Based on Theoretical COPs S ANN = 5.0 %/yr; S EOL = 5.0 % XP10 HFC-134a HFO-1234yf DR-11 XP10 DR-14 HCFC-123 DR-2 RFG NRG GWP=1,430 4 ~600 ~ ~10

14 Summary-Conclusions HFOs: a rich class of low GWP compounds each with each own idiosyncrasies; pipeline of candidates tailor-made for various applications emerging XP10: a sensible nearer-term replacement for HFC-134a in emissive chiller applications DR-2: promising longer-term, low-pressure fluid for commercial air conditioning and low temperature heat utilization Refrigerant selection should consider application impact, not just refrigerant attributes: e.g. refrigerant with lowest GWP may not lead to maximum warming impact reduction Flexible climate protection regulations to allow acceptance of optimum refrigerants/trade-offs

15 Thank you!