Bissoy.com
Doctors Medicines MCQs Q&A

Consider the following statements in respect of natural-draft cooling towers: 1) Theoretically the water can be cooled to even below the dry-bulb temperature of the induced air flow. 2) Nature-draft cooling towers are 100 m or more in height. 3) The inner and outer surfaces are surfaces of revolution of a segment of a hyperbola about the vertical axis-affording improved strength rather than any thermodynamic augmentation. Which of the above statements are correct?

Consider the following statements in respect of natural-draft cooling towers: 1) Theoretically the water can be cooled to even below the dry-bulb temperature of the induced air flow. 2) Nature-draft cooling towers are 100 m or more in height. 3) The inner and outer surfaces are surfaces of revolution of a segment of a hyperbola about the vertical axis-affording improved strength rather than any thermodynamic augmentation. Which of the above statements are correct? Correct Answer 1,2 and 3

In natural draught cooling tower the flow of air occurs due to the natural pressure head caused by the difference in density between the cold outside air and the hot humid air inside.

The pressure head developed is

ΔPd = (ρo - ρi) gH

Where H = height of the tower above the fill ρo = density of outside air ρi is the density of inside air. Because of the relatively small difference between ρo and ρi the H must be large so as to result in the desired ΔPd which should be able to balance the air pressure losses in the tower. 

[ alt="F1 R.Y Madhu T.T.P 20.02.20 D2" src="//storage.googleapis.com/tb-img/production/20/02/F1_R.Y_Madhu_T.T.P_20.02.20_D2.png" style="width: 378px; height: 401px;">

The tower body has hyperbolic profile which offers superior strength and great resistance to the outside wind loading compared to other forms.

As the water comes into contact with the air, the water evaporates by taking away the energy from the remaining water, which reduces the temperature of water below the dry bulb temperature of the air if the air is relatively dry. 

Nature-draft cooling towers are 100 m or more in height.

Related Questions

Consider the following statements for cooling towers: 1. Cooling tower is an artificial device used to cool the hot cooling water coming out of condenser more effectively. 2. The amount of water usually lost with induced draft cooling tower ranges from 5% to 6% by evaporation. 3. The amount of water usually lost with induced draft cooling tower ranges from 7% to 8% by drift losses. 4. The rate of evaporation of water and its cooling effect on the remaining water depends upon the relative humidity of air passing through the tower. Which of the above statements are correct?
Pearl Towers is taller than Sky Towers but shorter than Unity Towers. Unity Towers and Cyber Towers are of the same height. Pearl Towers is shorter than Indus Towers. Among the aforementioned buildings, which is the second shortest?
Pearl Towers is taller than Sky Towers but shorter than Unity Towers. Unity Towers and Cyber Towers are of same height. Pearl Towers is shorter thanIndus Towers. Amongst the buildings, who is the second shortest?
In a certain city there are five towers. Tower III is taller than tower II. Height of Tower V is the average of the height of towers I and IV. Height of Tower II is the average of the height of towers I and III. Height of Tower I is the average of the height of towers II and V. Which tower is the shortest?
Segment CD is shorter than Segment MN, Segment MN is shorter than Segment TR, Segment AB is shorter than Segment CD and Segment MN is shorter than Segment PQ. Which segment is the shortest?
The lubricating oil for a large industrial gas turbine engine is cooled in a counter flow, concentric tube heat exchanger. The cooling water flows through the inner tube ( diameter = 25 mm) with inlet temperature 25 degree celsius and mass flow rate 0.2 kg/s. The oil flows through the annulus (diameter = 50 mm) with mass flow rate 0.125 kg/s and its temperature at entry and exit are 90 degree Celsius and 60 degree Celsius. Find outlet temperature of cooling water
Consider the following statements: 1. The relative humidity of air does not change with temperature as long as specific humidity remains constant. 2. Dew-point temperature is the temperature at which condensation begins when air is cooled at constant volume. 3. Saturated air passing over a water surface does not cause change of air temperature. 4. For saturated air, dry-bulb, wet-bulb and dew-point temperatures are identical. Which of the above statements are correct?
 There are seven persons A, B, C, D, E, F and G. Each has a different height. The height of only two persons is more than that of D. The height of B is more than that of C and F. The height of E is more than that of G. The height of A is less than that of D, but more than that of B. Height of F is not the least. Which of the following options regarding their height is correct?
Statement (I): Piston temperature profiles near full load are flattened in case of liquid cooled engines whereas for air cooled engines temperature profiles are steeper. Statement (II): The piston temperature profiles are different in nature for liquid cooled and air cooled engines because of the different values of heat capacities.
Height of 8 boys B1, B2, B3, B4, B5, B6, B7, and B8 are compared. Height of B3 will be the least or maximum. Height of B4 is more than B6. Height of B8 is less than only 3 boys. Height of B2 is more than B1 but less than B8. Height of B2 is less than B3. If the height of B4 is less than B1, then which of the following sequence of their heights may be correct?