TRANSCRITICAL CO 2 IN AUSTRALIAN SUPERMARKETS. Mike Baker Baker Refrigeration M. IE Aust, C P ENG, M. AIRAH

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2 TRANSCRITICAL CO 2 IN AUSTRALIAN SUPERMARKETS Mike Baker Baker Refrigeration M. IE Aust, C P ENG, M. AIRAH

3 TRANSITION TO TRANSCRITICAL Drakes Angle Vale, SA First Generation Coles Coburg North, Vic Second Generation, Parallel AJ Baker & Sons 10 sites completed

4 TRANSCRITICAL BOOSTER SCHEMATIC MT Ref Component 1 Low stage (LT) comp 2 High stage (MT) comp 3 Oil Separator & oil return system 4 Gas cooler 5 High pressure regulating valve 6 Liquid receiver 7 Receiver pressure reg (flash gas) v/v 8 Expansion device 9 System evaporators LT

5 HIGH AMBIENT INSTALLATIONS Has been found problematical Mid 2010 s seen as a ground-breaking for Transcritical CO 2 : COP21 & 2015 F-Gas Reg & 2016 Kigali Amend. ATMO 2016 Europe Site trials in GCOT reduction technologies to reduce energy consumption First Australian transcritical CO 2 supermarket installations

6 HIGH AMBIENT INSTALLATIONS AJ Baker Australian installations x1 x6 x1 x2

7 HIGH AMBIENT INSTALLATIONS AJ Baker Australian installations Store Ref LT / MT loads & Qty of compressors Location GCOT Control Method A 26kW (3) /111kW (3) Northern Perth R134A DX PHE desuperheater B 4kW (1) / 77kW (3) Western Melbourne R290/Chilled water PHE & adiabatic spray C 19kW (2) / 77kW (3) Western Perth R134A DX PHE & adiabatic spray D 29kW (3) / 118kW (4) Southern Perth R513A (XP10) DX PHE & adiabatic spray E 29kW (3) / 121kW (4) Northern Perth R513A (XP10) DX PHE & adiabatic spray F 4kW (1) / 81kW (3) Western Sydney R290/Chilled water PHE & adiabatic spray G 4kW (1) / 81kW (3) Eastern Perth Evaporative cooling on gas cooler intake H 4kW (1) / 79kW (3) Western Brisbane R134A DX PHE & adiabatic spray I 20kW (3) /148kW (5) Southern Perth R513A (XP10) DX PHE & adiabatic spray J 4kW (1) / 81kW (3) Western Melbourne Evaporative cooling on gas cooler intake ** Parallel compression ** 60bar liquid system

8 GAS COOLER OUTLET TEMPERATURE CONTROL Sites utilising PHE for high pressure desuperheating Secondary system of adiabatic water sprays Two sites trialling evaporative pre-cooler system on gas cooler inlet

9 GAS COOLER OUTLET TEMPERATURE CONTROL High Pressure Desuperheating Increases overall efficiency when Tamb>20 C Controls compressor discharge temp & pressure Trials in service with a number of refrigerant options and designs HFC, HFC replacement, HC ; DX / water A simple & effective solution in warm climates

10 GAS COOLER OUTLET TEMPERATURE CONTROL Adiabatic Sprays Effective for secondary GCOT control after desuperheater Can reduce GCOT by 3 C. Both proprietary and local manufactured units on trial. Water quality can be an issue, plus overspray

11 GAS COOLER OUTLET TEMPERATURE CONTROL Adiabatic Sprays Spray initiation

12 GAS COOLER OUTLET TEMPERATURE CONTROL Evaporative Pre-cooling Results have shown can be used without high pressure desuperheating Water usage is minimal Ideal where water quality is poor (no direct water contact with gas cooler coil) Only suitable in low RH climates

13 OTHER ENERGY SAVING INITIATIVES Suction temperature optimisation Installing high performance display case evaporators Medium temp suction temperature floated up to -2.8 C. Coil diff temp reduced to 2K. Still achieving M1 (even M0) case conditions

14 OTHER ENERGY SAVING INITIATIVES Defrost on Demand Utilising the intelligent control system LT case defrost intervals of up to 14 days experienced. No degradation of product quality Case TEC reduced by 3%

15 OTHER ENERGY SAVING INITIATIVES Defrost on Demand

16 FUTURE INITIATIVES Parallel Compression Uses additional MT comp for flash gas removal Complex Only works when flash gas is produced (in TC). MT comp discharge remains high

17 FUTURE INITIATIVES Ejectors Liquid Gas Complex Requires parallel compressor Only suitable when system running in transcritical mode Savings only seen when T amb is high Oil return issues Not commercially available

18 FUTURE INITIATIVES Ejectors

19 FUTURE INITIATIVES FTE (Full Transcritical Efficiency) - Uses liquid overfeed on MT cases to then feed LT cases - Has the benefit of reducing liquid temp to MT cases, and then MT comp discharge T. - LT cases also aided by cooler liquid temp - Oil return is uninterrupted in entire circuit - Works both in sub & trans critical states. - Europe studies 10% gain; Australia 7%

20 F.T.E. / LOW PRESSURE TANK IT Patent Pending: IT AU Patent Issued: AU

21 CLOSE F.T.E. / LOW PRESSURE TANK IT Patent Pending: IT AU Patent Issued: AU SH

22 FUTURE INITIATIVES FTE (Full Transcritical Efficiency) 13 units in operation: ITA, GER & AUS

23 CONCLUSIONS TC CO 2 is being designed to allow operation in high ambient climates The number of installations in Australia is growing No major penalty in system efficiency or complexity Simple plant designs making the technology to be understood by mechanics It should definitely be the system design of choice for supermarkets and other commercial installations.

24 Thank you

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