Page 160 - Boiler_Operators_Handbook,_Second_Edition

Chapter 5

Refrigeration and Air Conditioning

With this edition I have added refrigeration, and and store them under straw (as an insulator) in a huge
air-conditioning, because many boiler plants have re- pile for use during the summer. The theater owner drew
frigeration equipment within the plant, attached, or outside air over blocks of the ice to cool it before blow-
in an adjacent room or building and the boiler plant ing it into the theater and the theater needed tons of ice.
operator is expected to operate and help maintain that Others employed the same provisions and the standard
equipment as well. Several states and municipalities unit of measure became a ton. It takes 80 Btus to melt a
include questions on refrigeration systems and air-con- pound of ice so a ton is 80 x 2000 ÷ 24 = 12,000 Btuh. Just
ditioning in their boiler operator exams. If this surpris- as we quantify electric power in kilowatt hours a quan-
es you, it shouldn’t, that’s because refrigeration is very tity of refrigeration is Ton hours.
similar to boiler operation, and refrigeration is simply
transferring heat from one location to another. Advanc-
es in SCADA systems and centralized monitoring of REFRIGERANTS
facility equipment have also served to drop responsi-
bility for the operation of the systems in the lap of the What’s a refrigerant, why don’t I just say Freon™?
boiler operator because the access terminals are in the Why is because there are many refrigerants and mate-
boiler control room. rials we wouldn’t normally think of as refrigerants, in-
Refrigeration has many applications. Principal cluding water. There are a considerable number of re-
uses include food preservation and comfort cooling but frigerants and the one used in any particular system is
refrigeration can also be used in production processes. dependent upon a number of factors.
Of the latter the most interesting one I’ve encountered Of course water can be a refrigerant. I love to
is making soap. While I was at PCI we had the oppor- point out what I understand to be a true point in his-
tunity to install a system designed to operate at -25°F at tory. It should make the boiler plant operator more
Lever Brothers. At that time Dove bars were made in the amenable to dealing with refrigeration. The first air
plant in Baltimore and we were helping install support conditioning system installed by Carrier himself was
systems for a new product line. The bars are formed in a in a printing plant in Brooklyn, New York, in 1902 and
press at a speed so fast that the heat of working the bars it was a steam powered system using water as a refrig-
would melt the soap without the cooling. When I was erant. Before you say “yeah, sure it was” look at your
working at Hercules I worked on the air-conditioning steam table in the Appendix. All we have to do to get
for a new Hystron fibers plant that made Trevira™, a water cold enough for air conditioning is to expose it
synthetic silk. I had to come up with a design for air to a vacuum at 29.75 inches of mercury and it will boil
cooling the synthetic fibers that were squeezed out of at 40°F. Carrier created a vacuum over a tank of water
the plastics extruder quickly enough to prevent their using steam jets to remove the evaporated water plus
sticking to each other as they were twisted into a single any air and non-condensable gases. The water in the
strand. I also designed some 130 Ton air handling units tank boiled until the heat absorbed by the evaporating
for that plant. water cooled the remaining water to 40°F. The cold wa-
A ton of refrigeration is a rate, not a quantity. The ter was pumped to coils that absorbed the heat in the
derivation of value is the amount of heat that can be ab- air in the printing plant and simultaneously condensed
sorbed by one ton of ice melting in 24 hours. I like to tell excessive moisture in that air to lower the humidity in
a story, that’s undoubtedly fiction, where it started with the printing plant. The slightly warmer water was then
a theater owner deciding he could get more customers returned to the tank where the heat absorbed from the
in the summer by having a cool theater and negotiated printing plant air was removed by evaporating some
with a contractor to cut blocks of ice from a nearby lake of the water. Why was a printing plant air condi-

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