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. Outline
• Background
• The Waitrose refrigeration concept
• The use of HC refrigerants
• Water cooled HC cabinet development
• Future plans

3. Background

4. Challenges
• Eliminate refrigerant leakage
• Reduce total store energy use
• Improve reliability
• Use a natural refrigerant
• Maintain look and feel of current cabinets

5. Traditional approach
• Centralised plant
– Pack system,
pipework
distributed to
cases and
coldstores
– Large quantities
of R404A
• Separate
ventilation
and heating
system

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. The Waitrose Refrigeration Concept

8. Water Cooled Display Cabinets
Water
pump
Chillers
Chilled water
circuit
Heat reclaim
to fresh air
Integral display
cases

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. 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. Water Cooled Display Cabinets

12. Water Cooled Cold Room Mono Blocks

13. Water / Glycol Chillers

14. Typical Shop Floor Layout
Water cooled integral
Air cooled integral

15. Air Cooled Integrals

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. Store Ambient

18. Water Cooled HC Cabinet Development

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. System Overview
Scroll Condensing Unit
Suction / Liquid Lines
Twin Interlaced Evaporator

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. Compressor Selection
Hitachi Scrolls
• Condensing temperature out of range
– Data extrapolated
• No information for R1270
– Factor applied to R404A data

23. HC Performance

24. Energy Efficiency

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. HC Charging

27. Test Charge Pre-vac

28. Split AC
• Factory-built for HC based on R407C units
• Electrics moved outside potentially
flammable zone

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. 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. 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. 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. Other Key Advantages
• Less installation time
• Less on site commissioning
– Control settings maintained
• Lower service / maintenance cost
• Flexibility to change store layout
• Simplicity

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. Hydrocarbons in
Commercial Refrigeration
With thanks to: