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.

15. 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