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Hydracarbons in Commercial Refrigeration
 

Hydracarbons in Commercial Refrigeration

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    Hydracarbons in Commercial Refrigeration Hydracarbons in Commercial Refrigeration Presentation Transcript

    • 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)
    • Outline • Background • The Waitrose refrigeration concept • The use of HC refrigerants • Water cooled HC cabinet development • Future plans
    • Background
    • Challenges • Eliminate refrigerant leakage • Reduce total store energy use • Improve reliability • Use a natural refrigerant • Maintain look and feel of current cabinets
    • Traditional approach • Centralised plant – Pack system, pipework distributed to cases and coldstores – Large quantities of R404A • Separate ventilation and heating system
    • 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
    • The Waitrose Refrigeration Concept
    • Water Cooled Display Cabinets Water pump Chillers Chilled water circuit Heat reclaim to fresh air Integral display cases
    • 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
    • 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
    • Water Cooled Display Cabinets
    • Water Cooled Cold Room Mono Blocks
    • Water / Glycol Chillers
    • Typical Shop Floor Layout Water cooled integral Air cooled integral
    • Air Cooled Integrals
    • 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
    • Store Ambient
    • Water Cooled HC Cabinet Development
    • 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
    • System Overview Scroll Condensing Unit Suction / Liquid Lines Twin Interlaced Evaporator
    • Heat Rejection • 25% to air • 75% to water – Plate heat exchanger – Water at 18OC Primary Condenser Electrical Box Scroll Compressor Pressure Switch PHE
    • Compressor Selection Hitachi Scrolls • Condensing temperature out of range – Data extrapolated • No information for R1270 – Factor applied to R404A data
    • HC Performance
    • Energy Efficiency
    • 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
    • HC Charging
    • Test Charge Pre-vac
    • Split AC • Factory-built for HC based on R407C units • Electrics moved outside potentially flammable zone
    • 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)
    • 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
    • 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
    • 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%
    • Other Key Advantages • Less installation time • Less on site commissioning – Control settings maintained • Lower service / maintenance cost • Flexibility to change store layout • Simplicity
    • 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
    • Hydrocarbons inCommercial Refrigeration With thanks to: