Hydracarbons in Commercial Refrigeration

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Hydracarbons in Commercial Refrigeration

  1. 1. Hydrocarbons in Commercial Refrigeration Authors:Les King F.Inst.R (Waitrose, John Lewis Partnership) Ian Garvey M.Inst.R (Carter Retail Equipment) Contributors: Stephen Benton F.Inst.R (Cool Concerns Ltd) Jane Gartshore F.Inst.R (Cool Concerns Ltd)
  2. 2. Outline • Background • The Waitrose refrigeration concept • The use of HC refrigerants • Water cooled HC cabinet development • Future plans
  3. 3. Background
  4. 4. Challenges • Eliminate refrigerant leakage • Reduce total store energy use • Improve reliability • Use a natural refrigerant • Maintain look and feel of current cabinets
  5. 5. Traditional approach • Centralised plant – Pack system, pipework distributed to cases and coldstores – Large quantities of R404A • Separate ventilation and heating system
  6. 6. Overview of Solution • HC refrigerant – Energy efficiency and low GWP • Use of integral cabinets – Minimal leakage + HC refrigerant • Water cooled display cabinets – Reduces heat and noise to shop floor – Enables easy integration with store heating / cooling systems to reduce store total energy consumption • Water / glycol chillers – Minimal leakage + HC refrigerant – Conditions selected to allow free cooling at low ambient
  7. 7. The Waitrose Refrigeration Concept
  8. 8. Water Cooled Display Cabinets Water pump Chillers Chilled water circuit Heat reclaim to fresh air Integral display cases
  9. 9. Water / Glycol Circuit • Flow at 18OC, return at 24OC – Optimum chiller / cabinet performance – Maximum free cooling (when ambient < 16OC) – Minimal heat gain / loss • Vented circuit
  10. 10. Integralised Refrigeration • All refrigerated cabinets, counters & cold rooms are HC integral systems (R290 or R1270) • Heat rejection to air and / or water – Display cabinets reject 25% of heat to sales floor for heating • Primary plant comprises air cooled HC chillers (R290) utilising: – Free cooling coil • Heat transfer between refrigeration units & chillers is provided chilled water or glycol
  11. 11. Water Cooled Display Cabinets
  12. 12. Water Cooled Cold Room Mono Blocks
  13. 13. Water / Glycol Chillers
  14. 14. Typical Shop Floor Layout Water cooled integral Air cooled integral
  15. 15. Air Cooled Integrals
  16. 16. Integration with H & V• Cold air retrieval – Remove cold air from front of cases and re-utilise within the store, conditioning warm sales floor or partner areas• Heating fresh air makeup – Use return water (up to 24OC) via a coil in the fresh air makeup duct, to heat fresh air• Cold aisles heated by warm air rejected from display cabinets
  17. 17. Store Ambient
  18. 18. Water Cooled HC Cabinet Development
  19. 19. Waitrose Specification • “Look and feel” of remote cabinet – No large unit on top or underneath cabinet • No significant increase in noise – Not air cooled – Scroll compressor (horizontal) • Minimal leakage – All brazed joints, hermetic compressor • HC refrigerant
  20. 20. System Overview Scroll Condensing Unit Suction / Liquid Lines Twin Interlaced Evaporator
  21. 21. Heat Rejection • 25% to air • 75% to water – Plate heat exchanger – Water at 18OC Primary Condenser Electrical Box Scroll Compressor Pressure Switch PHE
  22. 22. Compressor Selection Hitachi Scrolls • Condensing temperature out of range – Data extrapolated • No information for R1270 – Factor applied to R404A data
  23. 23. HC Performance
  24. 24. Energy Efficiency
  25. 25. HC Charging Process – Pre-vac – Evac, Leak Check, Charge – Seal & Test – Once adopted as standard design • Carter automated the process • All parameters controlled by Database - repeatability • Minimum space required • Standard labour • High throughput
  26. 26. HC Charging
  27. 27. Test Charge Pre-vac
  28. 28. Split AC • Factory-built for HC based on R407C units • Electrics moved outside potentially flammable zone
  29. 29. The Use of HC Refrigerants • HC systems can develop flammable atmosphere in event of leak so should comply with ATEX • EN60079 is harmonised with ATEX – Extent of flammable zone determined by testing to EN60079 – Electrics within flammable zone should be to EN60079 (devices and enclosures)
  30. 30. Engineer Safe Working • Waitrose policy - all engineers working on HC systems must have attended HC safe handling awareness training > 5000 engineers on UK BOC register • Safe system of work developed for shop floor activities – e.g. un-brazing joints on HC cabinet
  31. 31. Refrigerant Comparison HFC DX system • Up to 70 cabinets and cold stores, connected by 2500 meters of pipe work, to up to 5 multiple compressor packs • Total HFC charge ~ 750kg • Largest individual charge 175kg Natural refrigeration • Up to 70 cabinets and cold stores, all integral, connected by 1500 meters of water pipe • Total HC charge ~ 75kg • Largest individual charge 1 kg inside, 10 kg outside
  32. 32. Total Carbon Comparison Integrated HC Water-cooled Traditional Centralised HFC HVAC/ Refrigeration Plant Solution CO2te CO2te Gas and Gas and 1,119.25 996.61 electricity electricity Refrigerant F-Gas leakage 336 0 leakage 1,455.25 996.61 Total Total 100% 68%
  33. 33. Other Key Advantages • Less installation time • Less on site commissioning – Control settings maintained • Lower service / maintenance cost • Flexibility to change store layout • Simplicity
  34. 34. Future Plans • Currently 30+ “New Concept” stores • All new stores / major refits use new concept • Total change out by 2020 • Continued: – System optimisation – Cabinet development – Further integration of R and H & V
  35. 35. Hydrocarbons inCommercial Refrigeration With thanks to:

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