slides of our minor academic project

1. OPTIMAL DESIGN OF A
HYPERBOLOIDAL COOLING TOWER

2. INTRODUCTION
What is a (wet, atmospheric) cooling tower?
• A cooling tower is a heat rejection device, which extracts waste heat to
the atmosphere though the cooling of a water stream to a lower
temperature. The type of heat rejection in a cooling tower is termed
"evaporative" in that it allows a small portion of the water being cooled
to evaporate into a moving air stream to provide significant cooling to
the rest of that water stream. The heat from the water stream
transferred to the air stream raises the air's temperature and its relative
humidity to 100%, and this air is discharged to the atmosphere.
Evaporative heat rejection devices such as cooling towers are commonly
used to provide significantly lower water temperatures than achievable
with "air cooled" or "dry" heat rejection devices, like the radiator in a
car, thereby achieving more cost-effective and energy efficient operation
of systems in need of cooling. Think of the times you've seen something
hot be rapidly cooled by putting water on it, which evaporates, cooling
rapidly, such as an overheated car radiator. The cooling potential of a
wet surface is much better than a dry one.

3. Broad classification:-
• With respect to drawing air through the tower, there
are three types of cooling towers:
1. Natural draft — Utilizes buoyancy via a tall
chimney. Warm, moist air naturally rises due to the
density differential compared to the dry, cooler
outside air. Warm moist air is less dense than drier
air at the same pressure. This moist air buoyancy
produces an upwards current of air through the
tower.

4. 2. Mechanical draft — Uses power-driven fan motors to force
or draw air through the tower.
(A) Induced draft — A mechanical draft tower with a fan at the
discharge (at the top) which pulls air up through the tower. The
fan induces hot moist air out the discharge. This produces low
entering and high exiting air velocities, reducing the possibility
of recirculation in which discharged air flows back into the air
intake. This fan/fin arrangement is also known as draw-through.
(B) Forced draft — A mechanical draft tower with a blower type
fan at the intake. The fan forces air into the tower, creating high
entering and low exiting air velocities. The low exiting velocity is much
more susceptible to recirculation. With the fan on the air intake, the
fan is more susceptible to complications due to freezing conditions.
Another disadvantage is that a forced draft design typically requires
more motor horsepower than an equivalent induced draft design.

5. The basic components of a cooling
tower are:-
1.Frame and casing.
2.Fill.
3.Cold-water basin. The cold-water basin is located
at or near the bottom of the tower.
4.Drift eliminators.
5.Air inlet.
6.Nozzles.
7.Fans.

6. FUNCTIONAL
VIEW

7. HYPERBOLOIDAL COOLING TOWER (PARTIALLY CONSTRUCTED)

8. Hyperboloid (sometimes incorrectly known
as hyperbolic) cooling towers have become the design
standard for all natural-draft cooling towers because of
their structural strength and minimum usage of material.
The hyperboloid shape also aids in accelerating the
upward convective air flow, improving cooling efficiency.
These designs are popularly associated with nuclear
power plants. However, this association is misleading,
as the same kind of cooling towers are often used at
large coal-fired power plants as well. Conversely, not all
nuclear power plants have cooling towers, and some
instead cool their heat exchangers with lake, river or
ocean water.

9. PROBLEM CAUSE EFFECT PROPOSED
SOLUTION
Scale deposits form
on
the surface of the
fill, chemical
pipes, and nozzles.
Evaporation and
water treatment
problems
Amount of heat
transfer from water
to air reduced,
operation efficiency
reduced
Measure the water
treatment
chemicals in each
cycle circulation.
Spray nozzles
clogged
Algae and sediment
formation
Improper cooling,
reduced flow
Clean the strainer
very regularly.
Uneven water and
air flow
Spray nozzles
clogged
Unexpected higher
temperature
Sediment
suppression
Our idea is to use the soot blowers to remove the scale and sludge formation that
need not to sustain the shutdown thus increasing running time and higher
efficiency.

10. AS THE INDUSTRIES AT DIFFERENT LEVEL ARE MUSHROOMING
EVERY DAY, THEY INVOLVE DIRECT OR INDIRECT USE OF COOLING
TOWERS AS HEAT EXCHANGERS.
THUS TO MEET DOMESTIC AND OTHER INDUSTRIAL NEEDS IN THE
MOST EFFICIENT AND ECONOMICAL MEANS,IT NEEDS TO KEEP ON
UPGRADATION OF COOLING TOWERS. A VARIETY OF FIRMS SUCH
AS POWER SECTOR, STEEL PLANTS, CEMENT INDUSTRIES,
GALVANISING UNITS ETC EMPLOY COOLING TOWERS.
THUS IT HAS A VERY WIDE SCOPE OF IMPROVISATION AND
APPLICATION WHEREVER PHENOMENON OF EXCHANGE OF HEAT
OR COOLING IS SUPPOSED TO OCCUR.

11. We first aim to study thoroughly the hyperboloidal cooling
tower and study upon its following aspects:-
Familiarization
History and development
Uses of cooling tower , fields of application
Designing parameters
Efficiency
Water chemistry
Scopes of improvement
Improvisation over present design

12. APPLICATION
HEAT
EXCHANGING
THERMAL
POEWR PLANTS
MANY OTHER
INDUSTRIES
STEEL AND
ROLLING MILLS
NUCLEAR
POWER
PLANTS

13. Field erection type cooling tower

14. Air suction channels of a cooling tower.

16. PREPARED BY:-
GROUP NUMBER 7,MECHANICAL 7th (A)
PROJECT GUIDE:-Mr. NILMANI SAHU
GROP MEMBERS:-
1. SUMIT KUMAR SAHU-45
2. MINTU PRASAD-13
3. SOURAV LAHIRI-44
4. RAHUL KURMI-40