The document describes a new refrigeration plant for a meat processing factory that uses ammonia as the primary refrigerant and propylene glycol solutions as secondary refrigerants. Key aspects include: 1) The system includes a central ammonia refrigeration unit and seven secondary loops using propylene glycol to cool various areas of the factory totaling 21,250 square meters. 2) Ammonia is described as an efficient refrigerant with low environmental impact, though it requires safe handling due to toxicity and flammability risks. 3) The system is designed to refrigerate and freeze meat products with total cooling capacity of over 5,500 kW serving various cold storage rooms and processing equipment.

1. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
Franc Kosi, P.E.
The Society for Air-Conditioning, Heating and
Refrigeration (KGH)
Belgrade, Serbia
CASE STUDY:
A NEW REFRIGERATION PLANT
BASED ON AMMONIA WITH
SECONDARY FLUIDS LOOPS
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2. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
DESCRIPTION OF ASSIGNMENT
To design refrigeration system for an meat industry factory , capacity of about
7.000 chicken per hour (or 105.000 a day).
The product are frozen meat pieces, boiled and dried sausages and ham
product.
The total refrigerated area (two levels) is approximately of 21.250 m2; it
comprises 49 cold rooms and production spaces, a quick freezing tunnel, four
freezing plate heat exchagers and tunnel for precooling of chicken meat before
processing.
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3. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
SITE INFORMATION
The factory is situated about 60 km to the south from
Belgrade.
The design ouside dry and wet bulb air temperature are
+35°C and +24°C, respectively.
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4. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
THE SYSTEM:
The refrigeration system includes central refrigeration unit based on ammonia, and seven
sub-systems with water solution of propylene-glycol as a secondary refrigerant.
All of the ammonia evaporators: liquid overfeed, circulation numbers 3 to 6
high system efficiency and reduced operating expenses;
the evaporator surface is used efficiently and the compressors are
protected;
central unit (CP, PV, CP) are located in the machinery room; thus, they
are under operator surveillance or computer monitoring.
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5. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
AMMONIA AS A REFRIGERANT
Ammonia has greatest application as a refrigerant in industrial settings, primarily in the
food processing and food distribution sectors (also in the petrochemical and even
pharmaceutical sectors).
Ammonia has superior thermodynamic properties and ammonia refrigeration systems
are more efficient (3-10%) than most traditional and newer refrigerants in a wide
range of evaporating and condensing temperatures (+10 to –45° C);
Generally speaking, ammonia refrigeration systems cost 10-20% less to install than
systems using alternative industrial refrigerants.
zero ODP, zero GWP, low TEWI;
no cumulative effects on the environment;
very limited (a few days) atmospheric lifetime (it is considered to be “biodegradable.”)
self-alarming pungent odor! even the slightest traces of ammonia in the air can be
easy detected.
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6. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
FLAMMABILITY of AMMONIA
Ammonia is difficult to ignite and exhibits a narrow range of flammability (it is
flammable only at high concentrations and under extremely limited conditions).
Because ammonia will not sustain a flame on its own, ignition of ammonia vapor
requires an uninterrupted external flame source.
Ammonia's burning velocity, at a maximum of 8 cm/s, is substantially lower than other
flammable refrigerants, and is not high enough to create an explosion. For these
reasons, ammonia explosions are rare.
Properly designed ammonia refrigeration systems that are well ventilated and free of
open flames or ignition sources mitigate against potential explosion.
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7. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
WHY PROPYLEN GLYCOL (as a secondary fluid)?
Cost of maintaining: low;
Bio degradability in water: good, fluid is completely water soluble;
Toxicity: medium (based on mono propylene glycol and corrosion inhibitors);
Flash point: 420°
C;
Operational temperature: –30°to 50°
C;
Fluid is suitable for mixed metal systems;
Thermophysical properties: poor!
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8. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
REFRIGERATION LOAD
Evaporator
Temperature of Refrigeration
Nr. Refrigerant Temperature of the Consumer
Secondary Fluid Capacity
Primary System
/ / °C °C kW /
freezing tunnel, plate
1. ammonia -42 - 682.0
heat exchangers
2. ammonia -33 - 204.2 frozen food storage
3. ammonia -10 - 847.0 technology equipment
cooling chambers (25)
4. propylene-glycol, 40% -16 -12/-8 1361.8
at -5 to +0°C
cooling chambers (24)
5. propylene-glycol, 25% -10 -5/-1 1496.2
at +2 to +8°C
6. propylene-glycol, 25% -10 +7/12 451.7 air handling units
propylene-glycol, 25% -
-12/-8
7. “ice water” (tertiary -16 34.3 technology equipment
+0.5/+5.5
refrigerant )
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9. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES
Belgrade, May 10, 2011
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10. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
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11. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
SCREW COMPRESSOR UNITS
Installed
Working Swept volume Refrigeration
Nr. Swept volume electric
condititons (calculated) capacity
power
/ tO/ tC, °C m3/h m3/h kW kW
CP-1 2300,0 379,3 132
-42/-10 4157
CP-2 2300,0 379,3 132
CP-3 -33/-10 786 846,5 231,2 55
CP-4 1486,0 830,3 315
-16/+35 2391
CP-5 1126,1 613,6 250
CP-6 2311,6 1481,8 450
CP-7 -10/+35 6697 2311,6 1481,8 450
CP-8 2311,6 1481,8 450
Total: 2.234
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12. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
TABLE T-4. EVAPORATIVE CONDENSERS
Working condititons
Number of Make-up Installed electric
Nr. Capacity
condensers Water Flow power
TDB/TWB
/ kW / m3/h kW
1. +35/+24 1.500 5 2.62x5=13.1 5x42.0=210
2. +35/+24 2.000 1 3.6 51.0
Total: 9.500 / 16.9 261.0
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13. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
PRESSURE VESSELS
Temperature of Volume of Mass of
Nr. Type of Vessel Dimensions
Ammonia Amonia Amonia
- °C mm m3 kg
Low-Pressure Suction
1. -42 Φ1300x5000 1.66 1.150
Accumulator
Low-Pressure Suction
2. -33 Φ800x2600 0.33 225
Accumulator
High-Pressure Suction
3. -16 Φ1200x4000 1.15 605
Accumulator
High-Pressure Suction
4. -10 Φ1200x3250 0.92 600
Accumulator
High-Pressure Suction
5. Accumulator/Intercooler and -10 Φ1400x5000 1.95 1260
Subcooler
High-Pressure Suction
6. -10 Φ800x2500 0.32 205
Accumulator
7. Thermosiphon Accumulator +35 0.2604x20.000 0.53 310
8. High-Pressure Receiver +35 Φ1000x3500 1.37 805
Total: 5.160
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14. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
BENEFITS:
The amount of ammonia used in the system is relatively high. One of the reason is two-
stage compression.
However, ammonia system components are located just close to the compressor room;
thus there is not ammonia in the production and storage units;
The refrigeration system inludes the subsystem for using the waste heat (i.e. heat
extracted through compressor oil cooling); heat of cooling is used for sanitary water
heating;
The working fluid is an 40% water solution of propylene-glycol;
The total heat power of heating is as 802.9 kW ;
Energy efficiency of the refrigeration plant could be additionaly increassed by using a
certain part of condenastion heat for water heating purposses.
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15. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
Ammonia refrigeration safety features address minimizing the
refrigerant charge, suitable ventilation, ammonia absorbing systems,
restricting the use of ammonia in public locations, and promoting
indirect cooling systems
With regulations properly tailored to ammonia refrigeration systems,
the application of ammonia refrigeration systems will probably
become more widespread.
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16. ROUNDTABLE ON CLIMATE & OZONE-FRIENDLY TECHNOLOGIES Belgrade, May 10, 2011
THANK YOU!
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