When specifying a cooling tower, should I look up historic wet bulb temperatures for my area or should I take measurements?

When specifying a cooling tower, should I look up historic wet bulb temperatures for my area or  should I take measurements?
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1 Answer

Answer :

If this is a new installation, look up historical wet bulb temperatures for area and be sure to report them  to the cooling tower manufacturer as “ambient wet bulb temperatures”. The manufacturer will adjust  this temperature accordingly to estimate an “entering wet bulb temperature”.
If you have an existing tower that is to be replaced, take several wet bulb temperature measurements  near the air inlet during the hottest months. Report this as the “entering wet bulb temperature” to the  tower manufacturer.
The difference between the ambient and the entering wet bulb temperatures is to account for wet  recirculation from the tower exit back to the tower entrance. The entering wet bulb temperature always  higher than the ambient wet bulb temperature.
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Related questions

The term "cooling range" in a cooling tower refers to the difference in the temperature of (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air(B) Hot water entering the tower and the wet bulb temperature of thesurrounding air(C) Hot water entering the tower and the cooled water leaving the tower(D) None of these

Description : The term "cooling range" in a cooling tower refers to the difference in the temperature of (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B) Hot water entering the ... air (C) Hot water entering the tower and the cooled water leaving the tower (D) None of these

Last Answer : (C) Hot water entering the tower and the cooled water leaving the tower

In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Can a cooling tower cool water below the wet bulb temperature of inlet air? (A) Yes (B) No (C) Yes; but height of cooling tower will be prohibitively high (D) Yes; but the air flow rate should be excessively high

Description : Can a cooling tower cool water below the wet bulb temperature of inlet air? (A) Yes (B) No (C) Yes; but height of cooling tower will be prohibitively high (D) Yes; but the air flow rate should be excessively high

Last Answer : (B) No

Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of theoretical plate calculation for distillation column (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Description : Pick out the wrong statement. (A) Different solids have different equilibrium moisture curves (B) Total condenser or reboiler is considered equivalent to one theoretical plate in McCabe-Thiele method of ... (D) Even a forced draft cooling tower cannot cool water below the wet bulb temperature

Last Answer : (C) Heat removal load on cooler remains constant, even with increase of the reflux ratio in a distillation column

The term "approach" in a cooling tower refers to the difference in the temperature of the (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B) Hot water entering the tower and the wet bulb temperature of the surrounding air (C) Hot water entering and the cooled water leaving the cooling tower (D) None of these

Description : The term "approach" in a cooling tower refers to the difference in the temperature of the (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air (B ... (C) Hot water entering and the cooled water leaving the cooling tower (D) None of these

Last Answer : (A) Cold water leaving the tower and the wet bulb temperature of the surrounding air

The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb

Description : The temperature of water cooled in cooling tower is always __________ temperature of entering air. (A) More than the wet bulb (B) Less than the wet bulb (C) Equal to the wet bulb (D) Equal to the dry bulb

Last Answer : (A) More than the wet bulb

Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of forced draft cooling tower is reduced by the recirculation of the humid and hot discharged air (C) A natural draft cooling tower is recommended to be used, when the air humidity is low and air temperature is also low (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Description : Pick out the wrong statement pertaining to the cooling towers. (A) In case of induced draft cooling tower, the fan is placed at the top of the tower (B) Effectiveness of ... Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

Last Answer : (D) Effectiveness of a mechanical draft cooling tower is reduced with increase in air wet-bulb temperature

The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb

Description : The minimum temperature to which the water can be cooled in a cooling tower is the __________ temperature of air. (A) Ambient (B) Dry bulb (C) Dew point (D) Wet bulb

Last Answer : C) Dew point

In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : In a forced draft cooling tower, water is cooled from 95 to 80°F by exposure to air with a wet bulb temperature of 70°F. In this case, the (A) Range is 15°F (B) Approach is 10°F (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point

Description : Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the __________ temperature of air. (A) Wet bulb (B) Dry bulb (C) Saturation (D) Dew point

Last Answer : Option A

Which one of the following is true to estimate the range of cooling tower? a) Range = cooling water inlet temperature – wet bulb temperature b) Range = cooling water outlet temperature – wet bulb temperature c) Range = heat load in kcal per hour / water circulation in lines per hour d) None of the above

Description : Which one of the following is true to estimate the range of cooling tower? a) Range = cooling water inlet temperature - wet bulb temperature b) Range = cooling water outlet temperature - wet bulb temperature ... = heat load in kcal per hour / water circulation in lines per hour d) None of the above

Last Answer : Range = heat load in kcal per hour / water circulation in lines per hour

A better indicators for cooling tower performance is _____. • Wet bulb temperature • Dry bulb temperature • Range • Approach

Description : A better indicators for cooling tower performance is _____. • Wet bulb temperature • Dry bulb temperature • Range • Approach

Last Answer : Approach

Which of the following faction affect the cooling tower performance? • The range • Heat load • Wet bulb temperature • All of the above

Description : Which of the following faction affect the cooling tower performance? • The range • Heat load • Wet bulb temperature • All of the above

Last Answer : All of the above

When sizing a cooling tower the highest anticipate__________ should be used? • Dry bulb • Wet bulb • Both dry and wet bulb • None of the above

Description : When sizing a cooling tower the highest anticipate__________ should be used? • Dry bulb • Wet bulb • Both dry and wet bulb • None of the above

Last Answer : Wet bulb

The cooling effect in a cooling tower can be speeded up by (A) Increasing the air velocity and area of exposed wet surface (B) Reducing the barometric pressure (C) Reducing the humidity of the air (D) All (A), (B) and (C)

Description : The cooling effect in a cooling tower can be speeded up by (A) Increasing the air velocity and area of exposed wet surface (B) Reducing the barometric pressure (C) Reducing the humidity of the air (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and (A) Humidified with wet bulb temperature decreasingB) Humidified at constant wet bulb temperature(C) Dehumidified(D) None of these

Description : Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and (A) ... temperature decreasing B) Humidified at constant wet bulb temperature (C) Dehumidified (D) None of these

Last Answer : (A) Humidified with wet bulb temperature decreasing

Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve. (A) 100 (B) 50 (C) 78 (D) None of these

Description : Wet bulb and dry bulb temperatures becomes identical at __________ percent saturation curve. (A) 100 (B) 50 (C) 78 (D) None of these

Last Answer : (A) 100

Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be (A) Cooled (B) Humidified (C) Both (A) & (B) (D) Dehumidified

Description : Unsaturated air (with dry and wet bulb temperatures being 35 and 25°C respectively) is passed through water spray chamber maintained at 35°C. The air will be (A) Cooled (B) Humidified (C) Both (A) & (B) (D) Dehumidified

Last Answer : (B) Humidified

The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

Description : The cooling effect in a cooling tower cannot be increased by (A) Increasing the air velocity over the wet surfaces (B) Reducing the humidity of entering air (C) Lowering the barometric pressure (D) None of these

Last Answer : (D) None of these

Which of the following remains constant during evaporative cooling process with recirculated water supply? (A) Relative humidity (B) Partial pressure of vapour (C) Wet bulb temperature (D) None of these

Description : Which of the following remains constant during evaporative cooling process with recirculated water supply? (A) Relative humidity (B) Partial pressure of vapour (C) Wet bulb temperature (D) None of these

Last Answer : (C) Wet bulb temperature

During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the __________ remains constant. (A) Wet bulb temperature (B) Partial pressure of water vapor (C) Relative humidity (D) None of these

Description : During dehumidification of unsaturated air wet bulb temperature & partial pressure of vapor are not constant. However, during evaporative cooling process with recirculated water supply, the __________ remains ... pressure of water vapor (C) Relative humidity (D) None of these

Last Answer : (A) Wet bulb temperature

Which of the following decreases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) None of these

Description : Which of the following decreases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) None of these

Last Answer : (D) None of these

Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure to the air with a wet bulb temperature of 60°C, then both the approach & the range would be 10°C (C) For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature & adiabatic cooling lines are the same (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Description : Pick out the wrong statement (A) A horizontal line on the humidity chart indicates the temperature changes at constant molal humidity (B) When water is cooled from 80 to 70°C by exposure ... & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Last Answer : (D) Relative saturation of unsaturated mixture of water vapor & air cannot be increased by either reducing the mixture temperature or by increasing the total pressure

Which of the following increases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) Both (B) and (C)

Description : Which of the following increases during evaporative cooling process with recirculated water supply? (A) Wet bulb temperature (B) Relative humidity (C) Partial pressure of vapour (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

During sensible cooling process (A) Relative humidity decreases (B) Relative humidity increases (C) Wet bulb temperature decreases (D) Both (B) and (C)

Description : During sensible cooling process (A) Relative humidity decreases (B) Relative humidity increases (C) Wet bulb temperature decreases (D) Both (B) and (C)

Last Answer : (D) Both (B) and (C)

Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent? (A) Cooling and dehumidification (B) Heating and dehumidification at almost constant wet bulb temperature (C) Dehumidification with dry bulb temperature remaining constant (D) None of these

Description : Which of the following psychrometric processes is followed by water vapour laden unsaturated air, when it is passed through solid or liquid adsorbent? (A) Cooling and dehumidification ... (C) Dehumidification with dry bulb temperature remaining constant (D) None of these

Last Answer : (B) Heating and dehumidification at almost constant wet bulb temperature

During sensible cooling of air, its wet bulb temperature (A) Decreases but dew point remains constant (B) Increases but dew point remains constant (C) Increases & the dew point decreases (D) Decreases & the dew point increases

Description : During sensible cooling of air, its wet bulb temperature (A) Decreases but dew point remains constant (B) Increases but dew point remains constant (C) Increases & the dew point decreases (D) Decreases & the dew point increases

Last Answer : (B) Increases but dew point remains constant

Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Description : Moist air is cooled along the line of constant __________ , when it is passed over a cold & dry cooling coil, such that no condensation occurs? (A) Enthalpy (B) Relative humidity (C) Wet bulb temperature (D) Dew point temperature

Last Answer : (D) Dew point temperature

__________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity

Description : __________ remains constant during the adiabatic cooling of moist air. (A) Wet bulb temperature (B) Dry bulb temperature (C) Relative humidity (D) Specific humidity

Last Answer : Option A

In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower

Description : In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower

Last Answer : Atmospheric cooling tower

In which system is Cooling of hot water is done on tray as step by? a. Mechanical draught cooling system b. Hyperbolic cooling tower c. Atmospheric cooling tower d. Wet cooling tower

Description : In which system is Cooling of hot water is done on tray as step by? a. Mechanical draught cooling system b. Hyperbolic cooling tower c. Atmospheric cooling tower d. Wet cooling tower

Last Answer : Atmospheric cooling tower

. In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower

Description : . In which system is Cooling of hot water is done on tray as step by? a) Mechanical draught cooling system b) Hyperbolic cooling tower c) Atmospheric cooling tower d) Wet cooling tower

Last Answer : Atmospheric cooling tower

The cooling water reduces the water temperature close to _____. • Dry bulb temperature • Ambient wet bulb temperature • Dew point temperature • None of the above

Description : The cooling water reduces the water temperature close to _____. • Dry bulb temperature • Ambient wet bulb temperature • Dew point temperature • None of the above

Last Answer : Ambient wet bulb temperature

. Most cooling towers are capacity rated at a "standard" wet bulb temperature of ___of • 72°F • 52°F • 78°F • 75°F

Description : . Most cooling towers are capacity rated at a "standard" wet bulb temperature of ___of • 72°F • 52°F • 78°F • 75°F

Last Answer : 78°F

A hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case, (A) The cooling rate will be the same for the two spheres and hence the two spheres will have equal temperatures at any instant (B) Both the spheres will emit equal amount of radiation per unit time in the beginning (C) Both will absorb equal amount of radiation from the surrounding in the beginning (D) Both (B) & (C)

Description : A hollow sphere and a solid sphere of the same material and equal radii are heated to the same temperature. In this case, (A) The cooling rate will be the same for the two spheres and hence the ... equal amount of radiation from the surrounding in the beginning (D) Both (B) & (C)

Last Answer : (D) Both (B) & (C)

Make up water is supplied during cooling tower operation to compensate for water losses due to (A) Evaporation(B) Blowdown(C) Entrainment(D) All (A), (B) & (C)

Description : Make up water is supplied during cooling tower operation to compensate for water losses due to (A) Evaporation (B) Blowdown (C) Entrainment (D) All (A), (B) & (C)

Last Answer : (D) All (A), (B) & (C)

Make up water is required in a cooling tower to replace the water lost by (A) Evaporation (B) Drift (C) Blowdown and leakage (D) All (A), (B) and (C)

Description : Make up water is required in a cooling tower to replace the water lost by (A) Evaporation (B) Drift (C) Blowdown and leakage (D) All (A), (B) and (C)

Last Answer : (D) All (A), (B) and (C)

The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is (A) Natural draft cooling tower (B) Induced draft cooling tower (C) Spray chamber (D) None of these

Description : The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is (A) Natural draft cooling tower (B) Induced draft cooling tower (C) Spray chamber (D) None of these

Last Answer : (C) Spray chamber

When the temperature and humidity of air is low, we usually use __________ draft cooling tower. (A) Natural (B) Forced (C) Induced (D) None of these

Description : When the temperature and humidity of air is low, we usually use __________ draft cooling tower. (A) Natural (B) Forced (C) Induced (D) None of these

Last Answer : (A) Natural

Heat load in a cooling tower (A) Means the amount of heat thrown away (KCal/hr.) by the cooling tower (B) Is equal to the number of kg, of water circulated times the cooling range (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Heat load in a cooling tower (A) Means the amount of heat thrown away (KCal/hr.) by the cooling tower (B) Is equal to the number of kg, of water circulated times the cooling range (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)

A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream

Description : A packed tower compared to a plate tower for a particular mass transfer operation (A) Incurs smaller pressure drop (B) Allows installation of cooling coils (C) Is less costly when built in large sizes/diameters (D) Is more suitable, if suspended solids are present in fluid stream

Last Answer : (A) Incurs smaller pressure drop

Drift in a cooling tower is (A) The water entrained by the circulating air (B) Dependent on the water lost by evaporation (C) Desirable (D) All (A), (B) & (C)

Description : Drift in a cooling tower is (A) The water entrained by the circulating air (B) Dependent on the water lost by evaporation (C) Desirable (D) All (A), (B) & (C)

Last Answer : (A) The water entrained by the circulating air

__________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower. (A) Sherwood (B) Stanton (C) Lewis (D) Peclet

Description : __________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower. (A) Sherwood (B) Stanton (C) Lewis (D) Peclet

Last Answer : (C) Lewis

Which of the following employs an accessory known as 'drift eliminator'? (A) Multiple effect evaporator (B) Mechanical draft cooling tower (C) Rotary dryer (D) Rotating disc contacto

Description : Which of the following employs an accessory known as 'drift eliminator'? (A) Multiple effect evaporator (B) Mechanical draft cooling tower (C) Rotary dryer (D) Rotating disc contacto

Last Answer : (B) Mechanical draft cooling tower

Use of natural draft cooling tower is practised, when the air has low (A) Humidity (B) Temperature (C) Both 'a' & 'b' (D) Neither 'a' nor 'b'

Description : Use of natural draft cooling tower is practised, when the air has low (A) Humidity (B) Temperature (C) Both 'a' & 'b' (D) Neither 'a' nor 'b'

Last Answer : (C) Both 'a' & 'b

The most efficient cooling tower out of the following is (A) Induced draft (B) Forced draft (C) Natural draft (D) Atmospheric

Description : The most efficient cooling tower out of the following is (A) Induced draft (B) Forced draft (C) Natural draft (D) Atmospheric

Last Answer : (A) Induced draft

Blowdown in a cooling tower (A) Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities (B) Increases the scale forming tendencies of water (C) Is undesirable (D) All (A), (B) & (C)

Description : Blowdown in a cooling tower (A) Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities (B) Increases the scale forming tendencies of water (C) Is undesirable (D) All (A), (B) & (C)

Last Answer : (A) Means discarding a small fraction of circulating water to prevent and limit the concentration of salt and impurities

A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height. (A) 10-15 (B) 30-40 (C) 70-80 (D) 90-100

Description : A natural draft cooling tower is filled with wooden grids, which covers about __________ percent of the tower height. (A) 10-15 (B) 30-40 (C) 70-80 (D) 90-100

Last Answer : (A) 10-15

In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat

Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat

Last Answer : (A) Loosing sensible heat

Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater number of blades (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)

Description : Noise produced by cooling fans (employed in air cooled heat exchangers or cooling tower) is mainly caused due to the turbulence created by blade passage through air. It can be reduced by use of a slower fan (A) With greater ... (B) Of increased diameter (C) Both (A) & (B) (D) Neither (A) nor (B)

Last Answer : (C) Both (A) & (B)