Prelab Report - Cooling Tower Experiment

PROBLEM B3EVAPORATIVE COOLING ANG HUMIDIFICATION

Che514L Friday5-ChEA Group 1San Juan, Jamie Ashley E.San Miguel, John AndreSingh, DaljitSilvester, Ces Angelin

OBJECTIVES• To apply the principles of humidification and

evaporative cooling in the shell-and-tube heat exchanger-cooling tower network in the laboratory.

• To study the parts of an induced draft, counter flow cooling tower and their uses.

• To estimate the number of transfer units and height of a transfer unit of the tower

ChE514L Friday 5A G1 2

COOLING TOWER


• equipment used to reduce the temperature of a water streamby extracting heat from water and emitting it to the atmosphere.

• makes use of evaporation whereby some of the water is evaporated into a moving air stream and subsequently discharged into the atmosphere.

• the purpose of a cooling tower is to conserve cooling water by allowing the cooled water to be reused many times

COOLING TOWER


SCHEMATIC DIAGRAM


PARTS OF COOLING TOWER


Frame and casing

Fill (Packings) Nozzles Fans

Drift eliminator Air Inlet (Louvers)

Cold Water Basin

ADVANTAGE AND DISADVANTAGE


ADVANTAGE- achieve water temperatures below the

temperature of the air used to cool it.- smaller and cheaper for the same cooling

load

DISADVANTAGE- risk of water fouling- risk of water-borne organisms

COOLING TOWER PERFORMANCE


PARAMETERS:1. Wet bulb temperature of air2. Dry bulb temperature of air3. Inlet water temperature4. Outlet water temperature5. Exhaust air temperature6. Electrical readings of pump and fan motors7. Water flow rate8. Air flow rate



• Range – difference between water inlet and outlet temperature.• Approach – difference between the water outlet

temperature and ambient wet bulb temperature.• Effectiveness – ratio between the actual range and

ideal range (Range / (Range + Approach).• Cooling Capacity – heat rejected (mCpΔT)• Evaporation loss – water quantity evaporated for

cooling duty.• Liquid/Gas ratio – ratio between the water and air

mass flow rates.



EQUIPMENT AND MATERIALS


Boiler



Cooling Tower



Heat Exchanger



Water Tank



Anemometer



Digital Thermometer



Tape Measure



Mercury Thermometerwith Cotton



1-L Beaker

PROCEDURE


• Safety and Preliminary• Star-Up• Experimental Proper• Shutdown

SAFETY AND PRELIMENARY


• Check the equipment to be used

– Operating parameters should be within operational specifications

– Should have prior knowledge with the system before operating

– Simultaneous operation with the shell-and-tube heat exchanger and boiler



• Be careful with the use of movable ladder. When climbing, there should always be a support at the bottom.

• Open the windows and exhaust fan to maintain proper ventilation



• Before starting up the Boiler, there must be coordination with the Tunnel Drier group

• Picture sana ng tunnel drier group HAHA



• Prepare the Data table for efficient data gathering

• Prepare all necessary measuring instruments to be used

• Special handling of the measuring instruments should be considered

START-UP


1. Check the Catch Basin before turning on the main switch, it should be at least ¾ full of water

2. Open the water inlet valve in the boiler and the main source of diesel fuel

START-UP


3. Switch on the main switches in the following order: 1, 2 then 3, 4

1 for Water Pump Boiler2 for Control Panel Boiler 3 for Water Pump Tank4 for Cooling Tower

START-UP


4. Turn on the Boiler-note: the safety button should be pressed down-run for 15 to 20 minutes to achieve steady state

START-UP


5. Open steam valve to start the experimental proper (don’t forget the tunnel drier group)

Be sure that everything is ready before starting the experimental procedure.

EXPERIMENTAL


Heat Exchanger must be in steady state before gathering data.

CONSTANT

EXPERIMENTAL


AIR CONDITIONS t1 t2 t3 t4 t5 t6

Entering

Dry-bulb Temperature

Wet-bulb Temperature

Exit

Dry-bulb Temperature


WATER CONDITIONS T1 T2 T3 T4 T5 T6

Entering Temperature

Exit Temperature

FLOW RATES

Water

Entering Volumetric Rate

Exit Mass Flowrate

Air

Entering Velocity

Exit Velocity

Measure every 10 minutes until steady state is attained ( ± 0.5 difference between any three consecutive data. )

EXPERIMENTAL


AIR CONDITIONS t1 t2 t3 t4 t5 t6

Entering Dry-bulb Temperature


Exit Dry-bulb Temperature


EXPERIMENTAL


WATER CONDITIONS T1 T2 T3 T4 T5 T6

Entering TemperatureExit Temperature

EXPERIMENTAL


FLOW RATESWater Entering Volumetric Rate Exit Mass FlowrateAir Entering Velocity Exit Velocity

SHUTDOWN


1) Switch off: - Boiler - Water pump in boiler - Diesel - Breaker 1 and 2

2) Wait for 15 – 20 minutes for all the steam to condense3) Switch off Breaker 3 and 4

RAW DATA


Diameter of tower 198 cm

Height of Packing, Z 134 cm

Ambient Room Temperature 280C

RAW DATA


AIR CONDITIONS t1 t2 t3 t4 t5 t6 t7 t8 t9 t10

Entering

Dry-bulb Temperature , 6C 30.7 33 30.2 31 31.1 30.1 31.2 31.6 31.2 31.2

Wet-bulb Temperature, 6C 28.5 24 26 28 28 29 28 28 28 28

Exit

Dry-bulb Temperature, 6C 29 29.8 28.8 30.3 30.6 30.3 30.4 30.5 30.6 30.6

Wet-bulb Temperature, 6C 24.5 23 24 28 28 28 28 28 28 28

WATER CONDITIONS T1 T2 T3 T4 T5 T6 T7 T8 T9 T10

Entering Temperature, 6C 36 39 40 41 42 43 43.5 43 43 43.5

Exit Temperature, 6C 30 33 34 35 36 36 36 36 36 36

FLOW RATES

Water

Entering Volumetric Rate 70 70 70 70 70 70 70 70 70 70

Time to fill 1000 L Beaker, s 1.43 0.59 1.28 1.43 1.61 1.51 1.55 1.56 1.69 1.53

Air

Entering Velocity 0.61 8.81 7.91 7.86 8.83 8.07 8.11 8.64 8.65 8.29

Exit Velocity

TREATED DATA


AIR CONDITIONS t1 t2 t3 t4 t5 t6 t7 t8 t9 t10

Entering

Dry-bulb Temperature 30.7 33 30.2 31 31.1 30.1 31.2 31.6 31.2 31.2

Relative Humidity

Exit

Dry-bulb Temperature 29 29.8 28.8 30.3 30.6 30.3 30.4 30.5 30.6 30.6

Relative Humidity

WATER CONDITIONS T1 T2 T3 T4 T5 T6 T7 T8 T9 T10

Entering Temperature, TL2 (oC) 36 39 40 41 42 43 43.5 43 43 43.5

Exit Temperature, TL1 (oC) 30 33 34 35 36 36 36 36 36 36

FLOW RATES

Water

Entering Volumetric Rate 70 70 70 70 70 70 70 70 70 70

Exit Mass Flowrate, L (kg/s) 699.307 1694.91 781.25 699.300 621.118 662.251 645.161 641.025 591.716 653.594

Air

Entering Velocity 0.61 8.81 7.91 7.86 8.83 8.07 8.11 8.64 8.65 8.29

Exit Velocity

SAMPLE CALCULATION


PROBLEMS ENCOUNTERED AND SUGGESTIONS


• Boiler shutdowns• Have a consistent pattern in recording data• Hot / bring extra clothes• Free sauna• Flashlight for flowrate• Don’t hesitate to ask.

SUMMARY


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Prelab Report - Cooling Tower Experiment

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