Cooling tower
- 1. ABSTRACT DETAILS COOLING TOWER Made by : Dev Mehta FTE MSU.
- 2. Cooling tower Basic definition: Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature
- 3. Uses Of Cooling Tower in industry Industrial cooling towers can be used to remove heat from various sources such as machinery or heated process material. The primary use of large, industrial cooling towers is to remove the heat absorbed in the circulating cooling water systems used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants, food processing plants, semi-conductor plants, and for other industrial facilities such as in condensers of distillation columns, for cooling liquid in crystallization, etc
- 4. Wet bulb temperature: Wet bulb temperature is the lowest temperature that can be reached by the evaporation of water only. It is the temperature you feel when your skin is wet and is exposed to moving air. Unlike dry bulb temperature, wet bulb temperature is an indication of the amount of moisture in the air.
- 5. Heat Transfer Method: There are different mechanisms for different cooling towers the method employed in this particular cooling tower design is on the principal of evaporation as the cooling tower designed is wet type.
- 6. Wet Type Cooling Tower: In a wet cooling tower, the warm water can be cooled to a temperature lower than the ambient air dry-bulb temperature, if the air is relatively dry. As ambient air is drawn past a flow of water, an small portion of the water evaporates, the energy required by that portion of the water to evaporate is taken from the remaining mass of water reducing its temperature. Evaporation results in saturated air conditions, lowering the temperature of the water process by the tower to a value close to wet bulb air temperature, which is lower than the ambient dry bulb air temperature, the difference determined by the humidity of the ambient air.
- 7. Air Flow Generation method employed: Mechanical draft, which uses power driven fan motors to force or draw air through the tower. Induced draft: Mechanical draft tower with a fan at the discharge which pulls air through 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. The main advantage over natural draft is that natural draft is a comparatively slower process and also it demands large height of the tower. Advantage over forced draft method is it has low discharge velocities so air may enter also it requires a motor with greater horsepower as compared to the induced draft .
- 8. Cooling Tower fills : To achieve better performance (more cooling), a medium called fill is used to increase the surface area and the time of contact between the air and water flows. Splash fill consists of material placed to interrupt the water flow causing splashing. Film fill is composed of thin sheets of material upon which the water flows. Both methods create increased surface area and time of contact between the fluid (water) and the gas (air). In this particular design both the types of fills are used
- 11. The large arrows show the Path of water first through the The small arrows show the sprinkler. Then on the metal direction of air. Atmospheric air plate which acts as a splash fill enters through various holes where tiny droplets are formed along all four sides of the plates, then the water passes through the small holes which are the Perforated mesh which provided on all four sides at the removes impurities from the shower and straw pad levels water and then the water travels and enters the system where through The straw pads which maximum dissipation of heat further act as a packing material takes place, then the air along for increased contact time with water vapor exits to the Then the water travels through atmosphere from the fan. the perforated plate having Slits at the bottom of the tower larger diameters and again also suck in air and discharge through the Straw pads . The the air from the top of the water then travels through the tower through the fan. inclined plates which act as film The positions of the holes are fill and increase the contact time such that leakage is prevented And finally the water is collected in the hopper and then removed from the system. So the air moving upward will get humidified and the water looses its heat as some of it is
- 12. Tower assembly
- 14. Closer view of the Sprinkler and the perforated plates
- 16. Material Used: The material used for the fabrication of this particular cooling tower is Mild Steel(M.S) The main advantages of mild steel are : 1. The structure has high strength and hardness . 2. Can withstand high pressures. 3. Has high salvage/scrap value. 4. Can be easily be cleaned and inspected . The disadvantages of mild steel are : 1. Corrosion- this has been dealt with applying a zinc primer along with paint. 2. Weight of the structure – cooling tower is not a mobile structure and so weight doesn’t play a major role
- 17. Cost Estimate: 1 . Scrap M.S angle/scrap MS plate 50kgs*19 /- per kg =950 2.Old fan =200 3.Over head shower =100 4.Piping/straw pad =100 5.S.S grill and wire mesh =200 6.Colour =150 7.Labour charges for fabrication 50*8 =400 Grand Total =2100 rs.
- 18. Thank you