2. Ammonia
Discovered centuries ago, Ammonia’s uses are
plentiful.
Colourless, but omits a pungent odour hard to
ignore.
Combined with specific materials in chemicals
such as bleach to form a highly toxic Chlorine
Gas.
3. Ammonia in
Refrigeration
With an Ozone Depletion Potential (ODP) of ZERO,
Ammonia is a practical and efficient refrigerant
primarily used in commercial applications.
Ammonia refrigeration systems usually work
under large tonnages.
The following are some examples of some
applications one would find in a commercially
operated, Ammonia-based system:
4. Evaporative Condenser
•
Water is cooled by the evaporative cooling
and rejects the heat into the atmosphere.
•
Condenses the high-pressure, high-temp.
vapour by spraying water over the tubes.
Fans pulls the ambient air over the coils to
help assist in the condensing process.
•
The ‘evaporation’ comes from the heat being
absorbed by the water being sprayed over the
coils. The resulting vapour is released,
disposing heat from the system.
•
As the water is evaporated it is replaced
with a makeup system using a float.
5. Evaporative Condenser
(Cont.)
•
In prevention of mineral deposits, as the
water’s minerals build up during evaporation,
the condensate needs to be able to escape
the system and be replaced with fresh water.
•
Use wet-bulb temperature to drive the
condensation process.
•
Approx. 3 gal/min of water is evaporated for
every 100-tons of refrigerant.
7. Reciprocating Comp.
(Cont.)
• Gas tested @ 313 PSIG, 130 F (high side) and 185 PSIG, 96 F
(low side).
• Water tested at 470 PSIG (high side), and 470 PSIG (low
side).
• Running pressures – High side @ 151 PSIG. Low side @ 21
PSIG.
• The Compressor is considered the heart of the refrigeration
system. A compressor turns low-pressure, low-temperature
vapour into high-pressure, high-temperature vapour, which
is then sent out to the Condenser.
• This compressor has water-cooled head gaskets to keep it from
overheating.
• In some systems (like ice rinks) the excess heat transfers to
the coolant - such as ‘Glycol’ - to heat the surfaces
underneath the ice.
8. Brine Chiller
(Abbotsford Arena) Used to lower the
temperatures of Calcium Chloride to be used to
freeze the Ice for the hockey rink.
Calcium Chloride is used because it has a
greater heat-transfer-coefficient than Glycol.
9. Brine Chiller (Cont.)
• ‘Shell-and-Coil’ are used when specific temperature
ranges need to be maintained.
• Abbotsford Arena’s Calcium Chloride was running
at 27% by weight which becomes crystallized at
-22 F, and has a PG of 1.25
• The Brine is sent from, and circulated through by
pumps.
• The Brine is chilled by the evaporative refrigerant
in the flooded evaporator containing the Brine
Tubes.
• Calcium chloride has a S.G. of 1.3. The PH levels
should be above 7.
• The Brine chiller has an electric heater which will
heat the calcium chloride when it is in need of a
quick defrost of the ice rink’s surface.
10. Ammonia. Not Bad.
As there are plenty of logical uses for NH3
(excluding its ingestion), there are many uses for it
in the Refrigeration industry. Thanks for watching
“This is horse-shit.” -Matt Matthews