Low Ammonia Charge and No Ammonia Charge Systems
Low Ammonia Charge Refrigeration Systems – Current Technology Terry L. Chapp, PE
Danfoss Industrial Refrigeration
Today’s Agenda • Background – What has driven the change? • Where is this headed? • Low Ammonia Charge Technologies • No Ammonia Charge Technologies • Comparison of Systems • Charge Comparison • Installed Cost Comparison • Energy Consumption Comparison
• Conclusions
Background - What has driven change? Ozone Depletion, Climate Change, Safety • OSHA – 1970 General Duty Clause (GDC) • Montreal Protocol – Ratified in 1987 by 190 Countries • OSHA – 1992 Process Safety Management (PSM) • EPA – 1993 Risk Management Planning (RMP) • Executive Order 13650 – 2013 • Working group co-chaired by DOL (OSHA), EPA, DHS • Updating PSM, RMP, and ultimately the GDC
• Civil Judgments related to Ammonia Leaks
Where is this headed? • Climate Change
• Montreal Protocol – continues to evolve • CFC’s gone, HCFC’s going soon • HFC’s now in the cross-hairs
• COP21 – 2015 Focused on global warming and all of the sources beyond refrigerants
• Safety
• Guidance on RAGAGEP – long overdue • Continuing effort in aligning OSHA PSM with EPA RMP • More inspections – More enforcement
The Bottom Line? Climate Change Policy and all of the implications are not going away PSM, RMP, GDC are going to continue to become better defined & Enforcement is going to be tougher
What’s the Answer? • Natural Refrigerants • Ammonia • CO2 • Hydrocarbons
• Low Ammonia Charge and No Ammonia Charge Systems • Central Systems – Pumped Recirculated Liquid (PRL) • • • • • •
Advanced DX Systems CO2/Ammonia Cascade Systems CO2/Ammonia Pumped Volatile Brine (PVB) Systems Packaged Systems Liquid Desiccant Systems Transcritical CO2 Systems
Technology Timeline Packaged Systems - Evapcold Transcritical CO2 Systems Packaged Systems - NXTCOLD Advanced DX Liquid Desiccant CO2/NH3 Pumped Volatile Brine CO2/NH3 Cascade Systems Packaged Systems - Azane Central Systems - PRL Conception
Design
Prototype
Testing
Data
Commercial
Data
History
Relationship between Technologies and Ammonia Charge Central Systems
“Hybrid” Systems
Packaged Systems
Conventional Pumped Recirculated Liquid System Non-optimized
Relative Ammonia Content
Conventional Pumped Recirculated Liquid System Optimized
Advanced Direct Expansion System Optimized
Desiccant Cooling
CO2/NH3 Cascade System
Azane TM Chiller Azane TM Freezer
Evapcold TM System
CO2/NH3 Pumped Volatile Brine System
NXTCold TM System
Transcritical CO2 System Classification of System
Low Ammonia Charge Systems
Advancements in Traditional Central Systems
Baseline Refrigeration System • Cold Storage Facility with Blast Freezing, Freezers, Dock Coolers – heavy emphasis on subzero temps. • Two-stage, pumped recirculated liquid with: • Thermosyphon oil cooling • Evaporative condensers
• 112,000 ft2, 753 Tons • 283 TR @ -10˚F • 390 TR @ -30˚F • 80 TR @ 45˚F
Reducing Charge in Central Systems • Component Manufacturers are reducing overfeed rates for evaporators. Impacts: • • • •
Size of Evaporators Size of Vessels Size of Wet Suction Piping Size of Suction Valves
• Component Manufacturers are reducing charge size through innovations in condenser designs.
Advanced DX Refrigeration Systems
Advanced DX Refrigeration System Basic Schematic
Advanced DX Refrigeration System Key Characteristics
• Central System • • • •
Machine Room – potentially smaller than PRL System Multiple Vessels – should be fewer and somewhat smaller Piping from machine room – somewhat smaller Piping to machine room – smaller diameter – no wet suction lines
• Evaporators
• No overfeed
• Smaller evaporator tubing diameters • Smaller suction line diameters
• Potentially smaller than previous DX versions
• Ammonia charge reduced by 60% or more
Advanced DX Refrigeration System Summary • Many similarities to PRL System • Machine Room • Refrigerant Distribution Piping • Many vessels
• More technically challenging* • Electronic Controls • Refrigerant Purity
• Dramatically reduced ammonia charge • Some savings on initial installation cost
Cascade CO2/NH3 Systems Compressed and PVB
CO2/NH3 Cascade Systems Basic Schematics
CO2/NH3 Cascade Systems Key Characteristics
• Central System
• Objective: Keep ammonia in machine room, CO2 used as refrigerant in all storage rooms • Temperature limitations of subcritical CO2 (practical) • - 67˚F • + 32˚F
• Compressed CO2 – essentially the booster side of a two stage system • PVB System - No CO2 compressor: liquid CO2 pumped as brine and recooled by NH3 side.
• No ammonia piping to evaporators or evaporative condensers • All evaporators are CO2 evaporators • All external piping is CO2 piping
• Ammonia charge should be reduced by at least 60% over that of a PRL System
CO2/NH3 Cascade Systems Summary • Similar to a PRL System but with more challenges • Ammonia stays in machine room • Traditional CO2/NH3 system compresses CO2 • PVB system simply pumps CO2 around loop • More efficient and likely more cost competitive than a glycol system • Mixed market reaction to the system merits: • Energy efficiency • Installed Cost • Technical requirements - high • Significant ammonia charge reductions • Installed cost – appears to be competitive
Star Azanechiller and Azanefreezer TM
TM
Star Azanechiller and Azanefreezer Basic Schematic TM
TM
Star AzanechillerTM and AzanefreezerTM Key Characteristics • Packaged System • Evaporators mounted remotely from the package • Condensers are air cooled and integral to the package • Current Package Sizes • Azanechiller 60 to 300 TR • Azanefreezer 25 to 71 TR • Glacier Package (for blast freezing) 21 to 128 TR • Production in Europe and North America • Ammonia charge reduced by nearly 80% • Dependent on location with respect to evaporators • Ratio of chillers to freezers
Star Azanechiller and Azanefreezer Summary TM
TM
• Simplified approach to: • • • •
Fabrication Testing Code compliance Field erection
• Cost relationship to conventional designs are relative to the facility size • Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
NXTCOLDTM Packaged Systems
NXTCOLDTM Packaged Systems Basic Schematic
NXTCOLDTM Packaged Systems Key Characteristics • Packaged System
• No machine room • No refrigerant distribution piping • Various options for condensing
• Advanced heat transfer technology
• Multiple liquid feeds based on optimized velocity ratios • Control based on the electrical properties of the ammonia – not superheat • End result is an ultra-low ammonia charge
• Package sizes from 15 to 200 TR • Cooling • Freezing • Blast freezing
NXTCOLDTM Packaged Systems Summary
• Simplified approach to: • • • •
Fabrication Testing Code compliance Field erection
• Ultra-low ammonia charge
• Expected to meet or exceed all current and anticipated code limitations • No ammonia handling by installation crew
• Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
EVAPCOLD Packaged Systems
EVAPCOLD Packaged Systems Basic Schematic
EVAPCOLD Packaged Systems Key Characteristics
• Packaged System – – – – –
No central machine room Roof mounted No refrigerant distribution piping Water cooled or air cooled condensing Variable speed screw compressor control
• Advanced heat transfer technology
– Low recirculation rates to minimize charge
• Package sizes from 10 to 100 TR – Cooling – Freezing – Blast freezing
EVAPCOLD Packaged Systems Summary
• Simplified approach to: – – – –
Fabrication Testing Code compliance Field erection
• Low ammonia charge
– Expected to meet all current and anticipated code limitations – No ammonia handling by installation crew
• Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
Liquid Desiccant System
Liquid Desiccant Refrigeration System Basic Schematic
Liquid Desiccant Refrigeration System Key Characteristics • A hybrid system design using desiccant brine as the secondary heat transfer fluid. • Direct contact heat transfer between brine and cooling air minimizes TD penalty of the secondary fluid. • Desiccant brine cools, dehumidifies, and cleans air to refrigerated spaces. • Because air is dehumidified, no coil defrost is required and ice build-up around freezer doors is minimized and/or eliminated.
Liquid Desiccant Refrigeration System Summary • A unique approach to space refrigeration offering benefits in terms of: • Dehumidified air • Clean air • No refrigerant in conditioned spaces, no defrost.
• Operating costs are economical and competitive with 2 stage refrigeration system. • When heat source is available for regeneration, operating costs can be even less than a conventional system.
No Ammonia Charge Systems
Transcritical CO2 Refrigeration System
Transcritical CO2 Refrigeration Systems Basic Cycle Gas Cooler
Expansion
Med. Temp Evaporation Low Temp Evaporation
Compression
Energy Performance Comparison between CO2/NH3 Cascade System & CO2 Transcritical System
Transcritical CO2 Refrigeration Systems Key Characteristics • Central System configuration
• Rack mounted compressor system • Distributed CO2 liquid to freezer and cooler evaporators
• All Refrigerant is CO2
• When ambient temperature is high, system runs in transcritical mode • When ambient temperature is low, system runs in subcritical mode
• When heat recovery needs are present, COPc can be quite high. • Can be operated in virtually any climate.
Transcritical CO2 Refrigeration Systems Summary • State of the art technology with no ODP, nominal GWP, and none of the toxicity issues associated with NH3. • Systems typically operate only part of the year in the transcritical realm. • When combined with heat recovery, overall COP is very good.
Today’s Results • Ammonia Charge • Power Consumption • Installed Costs
Ammonia Charge By System Type (updated June 2016)
Power Consumption By System Type (updated June 2016)
3 2.5 2 1.5 1 0.5 0
System Electrical Consumption – Design Electrical Consumption/Design Load KW/TR
Installed Cost By System Type (updated June 2016)
Conclusions • The regulatory and legal challenges facing the industrial refrigeration world are very real and intensifying • Ammonia continues to be the number one choice of the market, but today’s charge levels are a major concern and will likely become even more problematic in the future • Fortunately, technology advancements are paving the way to real-world solutions • At the component level • At the system level
• The market now has real options at its fingertips in minimizing ammonia charge without sacrificing energy performance or ROI viability • The Facility Owner has many different options available to meet his/her refrigeration requirements. • There is no evidence to suggest that first costs or operating costs are or will be out of line with current system costs. • And, even more solutions are on the horizon…
A Final Thought There are no “one size fits all” solutions and each technology discussed here today has its merits. There is no denying, however, that large charge systems pose significant challenges from a: • Regulatory • Liability • Practical perspective. Central, Hybrid, and Packaged Systems will all have a place in our world.
Questions
Danfoss Industrial Refrigeration
Today’s Agenda • Background – What has driven the change? • Where is this headed? • Low Ammonia Charge Technologies • No Ammonia Charge Technologies • Comparison of Systems • Charge Comparison • Installed Cost Comparison • Energy Consumption Comparison
• Conclusions
Background - What has driven change? Ozone Depletion, Climate Change, Safety • OSHA – 1970 General Duty Clause (GDC) • Montreal Protocol – Ratified in 1987 by 190 Countries • OSHA – 1992 Process Safety Management (PSM) • EPA – 1993 Risk Management Planning (RMP) • Executive Order 13650 – 2013 • Working group co-chaired by DOL (OSHA), EPA, DHS • Updating PSM, RMP, and ultimately the GDC
• Civil Judgments related to Ammonia Leaks
Where is this headed? • Climate Change
• Montreal Protocol – continues to evolve • CFC’s gone, HCFC’s going soon • HFC’s now in the cross-hairs
• COP21 – 2015 Focused on global warming and all of the sources beyond refrigerants
• Safety
• Guidance on RAGAGEP – long overdue • Continuing effort in aligning OSHA PSM with EPA RMP • More inspections – More enforcement
The Bottom Line? Climate Change Policy and all of the implications are not going away PSM, RMP, GDC are going to continue to become better defined & Enforcement is going to be tougher
What’s the Answer? • Natural Refrigerants • Ammonia • CO2 • Hydrocarbons
• Low Ammonia Charge and No Ammonia Charge Systems • Central Systems – Pumped Recirculated Liquid (PRL) • • • • • •
Advanced DX Systems CO2/Ammonia Cascade Systems CO2/Ammonia Pumped Volatile Brine (PVB) Systems Packaged Systems Liquid Desiccant Systems Transcritical CO2 Systems
Technology Timeline Packaged Systems - Evapcold Transcritical CO2 Systems Packaged Systems - NXTCOLD Advanced DX Liquid Desiccant CO2/NH3 Pumped Volatile Brine CO2/NH3 Cascade Systems Packaged Systems - Azane Central Systems - PRL Conception
Design
Prototype
Testing
Data
Commercial
Data
History
Relationship between Technologies and Ammonia Charge Central Systems
“Hybrid” Systems
Packaged Systems
Conventional Pumped Recirculated Liquid System Non-optimized
Relative Ammonia Content
Conventional Pumped Recirculated Liquid System Optimized
Advanced Direct Expansion System Optimized
Desiccant Cooling
CO2/NH3 Cascade System
Azane TM Chiller Azane TM Freezer
Evapcold TM System
CO2/NH3 Pumped Volatile Brine System
NXTCold TM System
Transcritical CO2 System Classification of System
Low Ammonia Charge Systems
Advancements in Traditional Central Systems
Baseline Refrigeration System • Cold Storage Facility with Blast Freezing, Freezers, Dock Coolers – heavy emphasis on subzero temps. • Two-stage, pumped recirculated liquid with: • Thermosyphon oil cooling • Evaporative condensers
• 112,000 ft2, 753 Tons • 283 TR @ -10˚F • 390 TR @ -30˚F • 80 TR @ 45˚F
Reducing Charge in Central Systems • Component Manufacturers are reducing overfeed rates for evaporators. Impacts: • • • •
Size of Evaporators Size of Vessels Size of Wet Suction Piping Size of Suction Valves
• Component Manufacturers are reducing charge size through innovations in condenser designs.
Advanced DX Refrigeration Systems
Advanced DX Refrigeration System Basic Schematic
Advanced DX Refrigeration System Key Characteristics
• Central System • • • •
Machine Room – potentially smaller than PRL System Multiple Vessels – should be fewer and somewhat smaller Piping from machine room – somewhat smaller Piping to machine room – smaller diameter – no wet suction lines
• Evaporators
• No overfeed
• Smaller evaporator tubing diameters • Smaller suction line diameters
• Potentially smaller than previous DX versions
• Ammonia charge reduced by 60% or more
Advanced DX Refrigeration System Summary • Many similarities to PRL System • Machine Room • Refrigerant Distribution Piping • Many vessels
• More technically challenging* • Electronic Controls • Refrigerant Purity
• Dramatically reduced ammonia charge • Some savings on initial installation cost
Cascade CO2/NH3 Systems Compressed and PVB
CO2/NH3 Cascade Systems Basic Schematics
CO2/NH3 Cascade Systems Key Characteristics
• Central System
• Objective: Keep ammonia in machine room, CO2 used as refrigerant in all storage rooms • Temperature limitations of subcritical CO2 (practical) • - 67˚F • + 32˚F
• Compressed CO2 – essentially the booster side of a two stage system • PVB System - No CO2 compressor: liquid CO2 pumped as brine and recooled by NH3 side.
• No ammonia piping to evaporators or evaporative condensers • All evaporators are CO2 evaporators • All external piping is CO2 piping
• Ammonia charge should be reduced by at least 60% over that of a PRL System
CO2/NH3 Cascade Systems Summary • Similar to a PRL System but with more challenges • Ammonia stays in machine room • Traditional CO2/NH3 system compresses CO2 • PVB system simply pumps CO2 around loop • More efficient and likely more cost competitive than a glycol system • Mixed market reaction to the system merits: • Energy efficiency • Installed Cost • Technical requirements - high • Significant ammonia charge reductions • Installed cost – appears to be competitive
Star Azanechiller and Azanefreezer TM
TM
Star Azanechiller and Azanefreezer Basic Schematic TM
TM
Star AzanechillerTM and AzanefreezerTM Key Characteristics • Packaged System • Evaporators mounted remotely from the package • Condensers are air cooled and integral to the package • Current Package Sizes • Azanechiller 60 to 300 TR • Azanefreezer 25 to 71 TR • Glacier Package (for blast freezing) 21 to 128 TR • Production in Europe and North America • Ammonia charge reduced by nearly 80% • Dependent on location with respect to evaporators • Ratio of chillers to freezers
Star Azanechiller and Azanefreezer Summary TM
TM
• Simplified approach to: • • • •
Fabrication Testing Code compliance Field erection
• Cost relationship to conventional designs are relative to the facility size • Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
NXTCOLDTM Packaged Systems
NXTCOLDTM Packaged Systems Basic Schematic
NXTCOLDTM Packaged Systems Key Characteristics • Packaged System
• No machine room • No refrigerant distribution piping • Various options for condensing
• Advanced heat transfer technology
• Multiple liquid feeds based on optimized velocity ratios • Control based on the electrical properties of the ammonia – not superheat • End result is an ultra-low ammonia charge
• Package sizes from 15 to 200 TR • Cooling • Freezing • Blast freezing
NXTCOLDTM Packaged Systems Summary
• Simplified approach to: • • • •
Fabrication Testing Code compliance Field erection
• Ultra-low ammonia charge
• Expected to meet or exceed all current and anticipated code limitations • No ammonia handling by installation crew
• Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
EVAPCOLD Packaged Systems
EVAPCOLD Packaged Systems Basic Schematic
EVAPCOLD Packaged Systems Key Characteristics
• Packaged System – – – – –
No central machine room Roof mounted No refrigerant distribution piping Water cooled or air cooled condensing Variable speed screw compressor control
• Advanced heat transfer technology
– Low recirculation rates to minimize charge
• Package sizes from 10 to 100 TR – Cooling – Freezing – Blast freezing
EVAPCOLD Packaged Systems Summary
• Simplified approach to: – – – –
Fabrication Testing Code compliance Field erection
• Low ammonia charge
– Expected to meet all current and anticipated code limitations – No ammonia handling by installation crew
• Regulatory authorities and codes need to catch up with the packaged system approach for industrial refrigeration
Liquid Desiccant System
Liquid Desiccant Refrigeration System Basic Schematic
Liquid Desiccant Refrigeration System Key Characteristics • A hybrid system design using desiccant brine as the secondary heat transfer fluid. • Direct contact heat transfer between brine and cooling air minimizes TD penalty of the secondary fluid. • Desiccant brine cools, dehumidifies, and cleans air to refrigerated spaces. • Because air is dehumidified, no coil defrost is required and ice build-up around freezer doors is minimized and/or eliminated.
Liquid Desiccant Refrigeration System Summary • A unique approach to space refrigeration offering benefits in terms of: • Dehumidified air • Clean air • No refrigerant in conditioned spaces, no defrost.
• Operating costs are economical and competitive with 2 stage refrigeration system. • When heat source is available for regeneration, operating costs can be even less than a conventional system.
No Ammonia Charge Systems
Transcritical CO2 Refrigeration System
Transcritical CO2 Refrigeration Systems Basic Cycle Gas Cooler
Expansion
Med. Temp Evaporation Low Temp Evaporation
Compression
Energy Performance Comparison between CO2/NH3 Cascade System & CO2 Transcritical System
Transcritical CO2 Refrigeration Systems Key Characteristics • Central System configuration
• Rack mounted compressor system • Distributed CO2 liquid to freezer and cooler evaporators
• All Refrigerant is CO2
• When ambient temperature is high, system runs in transcritical mode • When ambient temperature is low, system runs in subcritical mode
• When heat recovery needs are present, COPc can be quite high. • Can be operated in virtually any climate.
Transcritical CO2 Refrigeration Systems Summary • State of the art technology with no ODP, nominal GWP, and none of the toxicity issues associated with NH3. • Systems typically operate only part of the year in the transcritical realm. • When combined with heat recovery, overall COP is very good.
Today’s Results • Ammonia Charge • Power Consumption • Installed Costs
Ammonia Charge By System Type (updated June 2016)
Power Consumption By System Type (updated June 2016)
3 2.5 2 1.5 1 0.5 0
System Electrical Consumption – Design Electrical Consumption/Design Load KW/TR
Installed Cost By System Type (updated June 2016)
Conclusions • The regulatory and legal challenges facing the industrial refrigeration world are very real and intensifying • Ammonia continues to be the number one choice of the market, but today’s charge levels are a major concern and will likely become even more problematic in the future • Fortunately, technology advancements are paving the way to real-world solutions • At the component level • At the system level
• The market now has real options at its fingertips in minimizing ammonia charge without sacrificing energy performance or ROI viability • The Facility Owner has many different options available to meet his/her refrigeration requirements. • There is no evidence to suggest that first costs or operating costs are or will be out of line with current system costs. • And, even more solutions are on the horizon…
A Final Thought There are no “one size fits all” solutions and each technology discussed here today has its merits. There is no denying, however, that large charge systems pose significant challenges from a: • Regulatory • Liability • Practical perspective. Central, Hybrid, and Packaged Systems will all have a place in our world.
Questions
