Cooling Tower Thermal Design Video Lecture | Mass Transfer - Chemical Engineering

a cooling tower is an essential piece of
equipment in many production facilities
used to bring down the temperature of
the water used in many different
processes so it can be used in the hot
water would normally arrive from a
jacketed tank reactor or other equipment
to the tower in the case of our
calculator the inlet is placed at the
bottom this water is continuously
recirculated using a centrifugal pump
which moves the water through nozzles in
order to increase the surface area
available for heat transfer at the same
time a fan in this case located at the
top of the tower moves fresh air which
comes into contact with the hot water
during this contact part of the water
will evaporate as this evaporation needs
energy the temperature of the water
decreases and that of the air increases
the treated water can now be used again
for any cooling process needed in the
design of a cooling tower many
parameters intervene and it is normally
a lengthy and complex process Pet better
engineers we have created this
calculator so you can enter the data and
focus on the results to use it you need
to enter the following values liquid to
gas ratio this value is basically the
amount of water entering the tower
divided by the amount of air circulating
through system both expressed as mass
flow rate altitude this value needs to
be entered in meters and as you already
know is the height above sea level at
which the tower is operating Inlet air
temperature is a temperature of the
fresh air used for cooling purposes it
has to be input in centigrade Inlet air
relative humidity ratio this value is
normally expressed in percentage but
here needs to be input as a ratio if you
have a relative humidity of 80 percent
you should enter 0.8 hot water
temperature expressed in centigrade is
the temperature of the water being fed
to the tower to be treated the capacity
of the tower in cubic meters per hour is
the amount of water at the end late-- of
the tower cold water temperature in
centigrade refers to the water at the
outlet of the tower ready to be reused
in your process the last parameter is
the relative humidity ratio or the hot
air also in centigrade it needs to be
input in a race
format and not percentage please note
that all the boxes have set values which
can be changed by clicking on them once
you have input all this information
click on the calculate button the
calculator will instantly take you to
the results page where several
parameters are reported we will explain
the more important ones if you have any
questions please contact us on info at
better - engineers comm the range is a
common unit used in cooling tower sizing
which is basically the difference
between the hot water temperature and
the cold water temperature a high
cooling tower range means that the
cooling tower has been able to reduce
the water temperature effectively
approach the approach is the difference
in temperature of outlet to cold water
and ambient air wet bulb temperature the
lower the approach the better the
cooling tower performin tower efficiency
expressed in percentage in simple terms
this number tells us how much of the
ideal cooling is actually achieved in
the proposed tower more technically it
is equal to the range divided by the
range plus approach tower effectiveness
also in percentage is the ratio of the
range to the difference between the
temperature of the hot water and the
inlet air temperature in other words
this tells us how well the cooling tower
did in terms of using the delta
available for cooling ka v over l is a
solution to the merkel equation shown on
screen this results as you may already
know the total area under the curve
shown the equation basically says that
at any point in the tower heat and vapor
are transferred into the air due
approximately to the difference in the
enthalpy of the air at the surface of
the water and the main stream of the air
constant related to the tower design is
a constant which depends strongly on the
liquid to gas ratio chosen and the
specific design conditions of the tower
to understand this number in more detail
and the ins and outs of cooling towers
we advise a more in-depth study of their
design as this is not the purpose of
this video we cannot explain this area
any further we hope you find this piece
of software useful and please let us
know of any improvement you would make
to the calculator or any feedback on the
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