Low Charge ADX AmmoniaPresented by:

Bruce Nelson, President, Colmac Coil Manufacturing

Rick Watters, Vice President, AMS Mechanical Systems

• Why use ammonia?

• It’s a ‘natural’ refrigerant

• ODP = zero, GWP < 1

• Abundant and low cost

• Widely used for over 100 years

• It is energy efficient!

Refrigerant

R744 56.8 3.52 2.779 1.698

R507A 43.5 4.60 1.833 2.573

R404A 45.1 4.44 1.817 2.595

R22 66.8 3.00 1.589 2.967

R717 463.9 0.43 1.569 3.007

Table 8 Comparative Refrigerant Performance (Te = -25F, Tc = 86F)Net

Refrigerating

Effect, Btu/lb

Refrigerant

Circulated,

lb/min

Power

Consumption,

Hp

Coefficient of

Performance

Background

Background

• Concerns with ammonia:• Toxicity• Flammability• Regulations (> 10,000 lbs)

• OSHA – Process Safety Management (PSM)

• EPA – Risk Management Program (RMP)

• DHS – Chemical Facility Anti-Terrorism Standards (CFATS)

Background

• Regulation and risk has driven interest in new low charge

ammonia technologies

• Advanced Direct Expansion (ADX) is one method of reducing

ammonia charge

Low Charge ADX Ammonia

• Benefits:

• Much smaller ammonia charge

• 7 lbs/TR vs 30+ lbs/TR for pumped bottom feed

• 30X to 50X charge reduction in evaporators

• Ammonia charge <10,000 lbs even for large systems

• Energy Efficient

• Lower first cost compared to pumped ammonia

Making ADX Ammonia work

Three critical issues must be addressed:

1. Separated flow in evaporator tubes- Tube ID enhancement

2. Management/removal of water- Only “dry” high pressure liquid is used- Trap and remove water at the accumulator

3. Refrigerant distribution- Tank Distributor technology

Low Charge ADX Ammonia

• Many systems now in operation• USA, Canada, Australia

• Large cold storage distribution centers

• Food service distribution centers

• Food processing facilities

Rick Watters, AMS Mechanical Systems

Vice President of Refrigeration/Food Process Piping

Low Charge ADX Case Studies

WHY USE ADX AMMONIA?

➢Lower refrigerant operating charge

➢Simplify Operation

➢Location Location Location

JCS aerial view

-10°F FREEZER -10°F FREEZER

-10°F/ +40°FCONVERTIBLE

ROOM-10°F FREEZER

+40°F DOCK

SUPPORTMECH ROOMOFFICE

+40°F DOCK

-10°F/ +40°FCONVERTIBLE

ROOM

-10°F/ +40°FCONVERTIBLE

ROOM

-10°F/ +40°FCONVERTIBLE

ROOM

JCS plan view with Phase 2

LCS aerial view

-10°F FREEZER-10°F/ +40°FCONVERTIBLE

ROOM

+40°F DOCK

SUPPORT

MECH ROOMOFFICE SUPPORT

MECH ROOM

+40°F DOCK

+40°FPRODUCTION

+40°F COOLER-10°F FREEZER

PRODUCTION

+40°F COOLER

+40

°F C

OO

LER

LCS plan view with Phase 2

JCS Refrigeration System Highlights

➢ Single stage economized -15/+20/+95

➢ Thermosyphon oil cooling

➢ Anhydrator System Cleaner

➢ H.A. Phillips transfer system

➢ Controlled pressure receiver

➢ +20 and -15 accumulators

➢ Nickel-Brazed Liquid Sub-Cooler

➢ Motorized TXV’s

Liberty Cold Refrigeration System Highlights

➢ Single stage economized -15/+20/+95

➢ Thermosyphon oil cooling

➢ H.A. Phillips transfer systems

➢ Controlled pressure receiver

➢ +20 and -15 accumulators

➢ Nickel-Brazed Liquid Sub-Cooler

➢ Pulse Width TXV’s

Refrigeration System Highlights

➢VFD’s on large evaporator fans

Refrigeration System Highlights

➢ADX Evaporators

➢VFD’s on large evaporator fans

Refrigeration System Highlights

➢ADX Evaporators

➢ Low Charge Condenser

➢VFD’s on large evaporator fans

Refrigeration System Highlights

➢ADX Evaporators

➢ Low Charge Condenser

➢ Low Charge Vessels

➢VFD’s on large evaporator fans

JCS vessels

LCS vessels

JCS engine room

LCS engine room

Operating Efficiency

➢Calculated 1.3% more Hp per ton compared to Liquid

Overfeed Systems as worst case

Refrigerant Charge ComparisonJCS – with Phase 2 Liberty Comparison

Freezer Temp. – Deg. F -10 -10 -10

Freezer sq. ft. 300,400 147,600 90,301

Convertible room. Deg. F -10/35 -10/28 -10/35

Convertible room sq. ft. 37,800 15,700 45,311

Dock Temp. – Deg. F 40 40 40

Dock/Cooler area – sq. ft. 63,600 88,500 35,958

Central Refrigeration System ADX ADX Pumped Liquid

Refrigeration – tons 1,060 647 335

Ammonia charge – lb. 8,500 7500 24,000

Total refrigerated sq. ft. 401,840 251,800 171,610

Charge per square foot .0212 #/sqft .0298 #/sqft 0. 138#/sqft

Charge per Ton of Refrigeration 8.02#/TR 11.59 #/TR 71.64 #/TR

Electrical Comparison

Comparison JCS – Phase 1 only

Liberty – Phase 1 only

Refrigerated space sq. ft. 137,448 ft² 201,805 ft² 135,807 ft²

Central Refrigeration Control System No Yes Yes

VFD’s on Large Evaporator Fan Motors No VFD’s VFD’s VFD’s

Motion Sensing LED Lighting No Yes Yes

Blast Freezing No Yes Yes

2015 Total Power Usage (KWH) 5,165,708 KWH 4,721,655 KWH 4,227,007 KWH

Annual Average Power per sq. ft. 37.6 KWH/ ft² 23.4 KWH/ ft² 31.1 KWH/ ft²

Percent Difference (%) 0% 38% 18%

Construction Cost

➢ 2.37% savings over a liquid over feed

➢ $100,000.00

Design Considerations

➢ Use the recommended oil (Frick #9 in this case)

➢ Keep the system dry and oil free

➢ You will have some liquid return. Defrost, under floor system. Be able to

deal with it

➢ Going to a fluid cooler for compressor oil cooling in place of

thermosyphon would have reduced the ammonia charge 750#

Design Considerations (cont.)

➢ Fluid cooler system would have added $300,000.00 of install cost to the

project

➢ Liquid injection would lower the install cost and refrigerant charge but

would have decreased operating efficiency's by and additional 4.5%

➢ Law of unintended consequences

In Summary

➢ ADX Evaporators worked as advertised

➢ System is easy to work on

➢ Restarts quickly after power failure

➢ Both Motorized and Pulse Width DX valves work great

➢ Add Hot Gas heat cycle to evaporators in Coolers/Dock

depending on location

➢ 5 projects completed, 1 under construction

Questions?