Ammonia as a refrigerant in the Water Chiller for apple storage cooling

1. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
ANNUAL MEETING OF THE
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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ANNUAL MEETING OF THE REGIONAL OZONE NETWORK
FOR EUROPE & CENTRAL ASIA
BELGRADE, SERBIA, 10-13 MAY 2011

2. Case study:
Ammonia as a Refrigerant in the Water
Chiller for apple storage cooling
(cold storage capacity is 8000 t)
Dipl.-Ing. Slobodan Pejković
Filter Frigo - Serbia
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
E-mail=
[email protected]
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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3. For chilling and storing apples, cooling installation
has been planned with water chiller using Freon 404A
asarefrigerant,andcoolssecondaryfluid,mixofwater
and glycol to -6ºCtemperature and lower. Advantage
of the secondary fluid is the possibility of temperature
control in cold storages with small difference between
the
air
and
secondary
fluid’s
temperature
.
In
this
way
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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the
air
and
secondary
fluid’s
temperature
.
In
this
way
loss in weight of products is decreased. Besides that, it
is also important that the quantity of a refrigerant in
suchcoolingsystemsissmall.
Necessary cooling capacity for cooling and storing
8000tons ofapplesisaround1.1MW.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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4. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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5. Freon 404A as three component mixture of a
refrigerants R143a / R125 / R134a has high global
warming potential (GWP=3780). Therefore in the
European Union measures are contemplated which
would lead to decreased use of this refrigerant. The
first of the measures introduced by Denmark since
2011 is ecological tax for use of Freon 404A
amounting
to
79
€
/kg,
which
shall
be
collected
during
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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amounting
to
79
€
/kg,
which
shall
be
collected
during
Freonprocurement.
That made us think of envisaging some of the
natural refrigerants for this cold storage. The choice
wasammonia.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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6. Ammonia as a natural refrigerant has GWP=0,
meaning that it does not influence global warming of
the Earth, therefore its use is being stimulated.
Advantagesinusing ammoniawithstrongsmellisthat
during leakage which happens occasionally in cooling
installations
is
that
you
can
immediately
sense
it,
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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installations
is
that
you
can
immediately
sense
it,
remedy the failure and top-up the installation with
refrigerant without stopping. Differently fromthat,
Freons, even R404A are without smell and its leakage
fromthe cooling installation can not be observed until
pressuredrops,thatis,capacitydecreases.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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7. Because R404A is three-component mixture of
different Freons, in case of leakage one must
discharge the whole quantity fromthe installation
(installation charge is around 300 kg), the failure must
be
remedied,
than
the
installation
should
be
vacuumed
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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be
remedied,
than
the
installation
should
be
vacuumed
and refilled. This procedure requires several hours
work and during that period the cooling installation can
notoperate.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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8. Ammoniaasarefrigerantischeaper.Exploitation
costs and maintenance costs of modern ammonia
installationsarelowerthanforFreoninstallations.
Installations with ammonia as a refrigerant are
more
energy
efficient,
meaning
that
for
achieving
the
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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more
energy
efficient,
meaning
that
for
achieving
the
same cooling capacity they shall spend less
electricity. Due to poor mixing with oils for lubricating
compressor, ammonia can be used in flooded
evaporators at higher evaporating temperatures in
relation to Freons, simultaneously using less
electricity.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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9. In order to achieve the necessary glycol
temperature of -6ºCwith ammonia as a refrigerant,
the compressors can work with evaporation
temperature of -10ºCin flooded plate&shell
evaporatorandwithsuctiongassuperheatof1K.
In
order
to
achieve
the
same
conditions
(glycol
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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In
order
to
achieve
the
same
conditions
(glycol
temperature and capacity) with Freon R404A as a
refrigerant, the installation must have an direct
expansion evaporator where the evaporation
temperature can not exceed -12ºCwhile suction gas
superheatmustbefrom6to10K.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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10. Bitzer
screw
compressor
Ammonia R717 Freon R404A
Cooling
capacity
[kW]
Power
Consumption
[kW]
Energy
Efficiency
Ratio
EER
Cooling
capacity
[kW]
Power
Consumption
[kW]
Energy
Efficiency
Ratio
EER
Model
OSKA8581
-
K
324 83.4 3.88 293 94.7 3.09
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
In order to present real difference between the ammonia and Fre on
404A installations, we shall present table with the cooling capa city and power
consumption of screw compressor, product of Bitzer.
OSKA8581
-
K
Bitzer
screw compressor
Ammonia R717
OSKA8581-K
Freon R404A
OSKA8581-K
Evaporation Temperature [°C] -10 -12
Condensing Temperature [°C] 35 35
Liquid Subcooling [K] 3 3
Suction Gas Superheat [K] 1 10
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Operating regimes

11. Tables showthat in installations using ammonia
as a refrigerant for the same compressor model,
cooling capacity is 10% higher in relation to R404A
withsmallerabsorbedpowerfor11.3kW.
During the first 27 days of work of the cold
storage with full capacity, when the daily apple intake
exceeds 300 t/day, electricity savings during work of
4
screw
compressors,
products
of
Bitzer,
model
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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4
screw
compressors,
products
of
Bitzer,
model
OSKA8581-Kwithammoniaasarefrigerantwouldbe 29 MWh
. Simultaneously, these compressors would
have 10% higher cooling capacity than the Freon
ones, and would enable quicker cooling of apples,
whichisveryimportantforapplequality.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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12. Analyses of different solutions using ammonia
have been made. One of the solutions was a chiller
with one screwcompressor of 1150 kWcooling
capacity. Maximumcooling capacity for this type of
cold storage is necessary during the first 30 days of
work, fromstart of apple picking. After that, needs for
cooling
decrease,
as
well
as
the
external
temperature,
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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cooling
decrease,
as
well
as
the
external
temperature,
andthewater chiller hasbettercondensingconditions.
Therefore a solution with three water chillers has been
discussed – chillers invariant 1with water cooled
condenser, and in thevariant 2with air cooled
condenser. Both solutions have their advantages and
shortcomings.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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13. Advantage of the chiller with air cooled
condenser is installed in the container outside the cold
storage facility, so no special safety measures are
required. Besides that, apples are stored in the period
from
October
to
June,
when
we
don’t
have
extremely
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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from
October
to
June,
when
we
don’t
have
extremely
high air temperatures, and the condensing
temperatures are such that they render sufficiently high
EnergyEfficiencyRatio–EER.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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15. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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16. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
Microchannel Condenser
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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18. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
AUTOMATIC OIL RECOVERY SYSTEM
For a regular, efficient and continuous operation
of a chiller, it’s necessary to guarantee oil recovery to
the compressor.
Oil often collects in the bottom part of the
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Oil often collects in the bottom part of the
evaporator, with the risk to compromise efficiency and
heat exchange of the evaporator. For this reason an oil
recovery system has been introduced; thanks to an
ejector, oil at low pressure is conveyed from evaporator,
with high pressure ammonia to the compressor suction.

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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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23. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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24. Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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25. Unit prices for the equpment:
ćAmmonia water chiller; piston compressor,
water cooled condenser ---------- ----€135.000
ć
R134a water chiller; 2
Turbocor
compressors,
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
ć
R134a water chiller; 2
Turbocor
compressors,
water cooled condenser --------------€ 92.000
ćR134a water chiller; 2 screw compressors,
water cooled condenser ------------- -€ 59.000
Cooling capacity400 kW
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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26. Price for the cooling system:
ćR404a glycol chiller system;
cooling capacity –1.200 kW
4 screw compressors,
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
4 screw compressors, 1 evaporative condenser
for 4 compressors €260.000
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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27. CONCLUSION
Advantages of ammonia as a refrigerant:
Ammonia as a natural refrigerant does not influence gl obal warming of
Earth.
Ammonia as a refrigerant is cheaper than Freon.
Exploitation costs and maintenance costs of modern ammonia installations
are lower than for Freon ones.
Installations with ammonia as a refrigerant are more e nergy efficient.
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
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Shortcomings of ammonia as a refrigerant:
Investment costs in making ammonia installations significantl y exceed the
costs of making Freon installations.
Safety measures that should be undertook in using ammonia installations
due to its explosiveness cause fear with investors and influe nce the final
price of the installation.
Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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28. Thank You For Your Attention
Roundtable on climate & ozone-friendly technologies in refrigeration & air-conditioning
Question?
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Belgrade, May 10, 2011 Slobodan Pejković Ammonia as a Refrigerant in the Water Chiller for apple storage cooling
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Question?