A Case Study into the latest evolution - r744.com · A Case Study into the latest evolution John...
Transcript of A Case Study into the latest evolution - r744.com · A Case Study into the latest evolution John...
Transcritical – WHY?
• It is a true solution – no additional cooling required– “Pumped CO2” requires an additional circuit to cool
the CO2, using what refrigerant?– “Cascade CO2” requires an additional circuit to cool
the CO2, using what refrigerant?• Additional circuit can be
– HFC (we want to eliminate)– HC (good refrigerant but limitations)– Ammonia (good refrigerant in limited application)
• Lowest cost when industrialised
• 1999 – First complete natural refrigerant solution … Iceland Harlesden
• 2002 – First Supermarket CO2 transcritical system … Coop Lestans Italy
• Installations in Italy, Sweden, Denmark, Norway Switzerland, Luxemburg, UK, Germany …
Our Knowledge
• 2006 – First CO2 transcritcal in UK … Tesco Swansea (inc design, build, install, maintenance)
Our Knowledge
Energy ModellingSINGLE STAGE
CHILLED FOOD SYSTEM
INTERNAL COMPOUND TWO-STAGE
FROZEN-FOOD SYSTEM
MT COP
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MT COP R404A
MT COPCO2
ambient temp
Lt COP
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LT COP R404A
LT COP CO2
ambient
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R404A R744
Commercial
MaterialSpecification
Benchmark
• CO2 systems have smaller compressors and pipework• Pressures are higher, and specification has be
appropriate• Components are purchased in low volumes and without
the commercial benefits of competitive negotiation
Practical requirements for a Supermarket Transcritical CO2 System
• Systems conform to Pressure Equipment Directivethrough use of specifically designed components
• Understanding of Power Off situations, will pressure relief valve settings be experienced?
• High quality required over the whole design, component, manufacture, installation and commissioning project
• Supply chain support for manufacture, installation, maintenance
• Training of ALL PERSONNEL involved• Clear Labelling on site
• Objectives– Prove to a customer “new to CO2” that this is
a practical and reliable concept– Provide a single pack to meet this market
sector needs with MT & LT load– Prove benefits of improved control of
transcritical / sub-critical change-over– Reduce liquid pipe pressures– Prove benefit of variable speed drive– Prove benefit of wet-cooled gas-cooler
Aldi Sud Jüchen – July 2006
• COP CO2 in winter conditions (Tamb: 6-13°C)
– MT : from 6.2 to 4 (R404A 4)– LT : from 1.9 to 2.5 (R404A 1.9)
• There is room for further improvements of the controlling parameters
Aldi Sud JüchenPerformances update: March 2007