Prelab Report - Cooling Tower Experiment
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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
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COOLING TOWER
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• 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
PARTS OF COOLING TOWER
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Frame and casing
Fill (Packings) Nozzles Fans
Drift eliminator Air Inlet (Louvers)
Cold Water Basin
ADVANTAGE AND DISADVANTAGE
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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
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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
COOLING TOWER PERFORMANCE
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• 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.
SAFETY AND PRELIMENARY
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• 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
SAFETY AND PRELIMENARY
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• 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
SAFETY AND PRELIMENARY
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• Before starting up the Boiler, there must be coordination with the Tunnel Drier group
• Picture sana ng tunnel drier group HAHA
SAFETY AND PRELIMENARY
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• 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
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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
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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
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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
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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
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Heat Exchanger must be in steady state before gathering data.
CONSTANT
EXPERIMENTAL
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AIR CONDITIONS t1 t2 t3 t4 t5 t6
Entering
Dry-bulb Temperature
Wet-bulb Temperature
Exit
Dry-bulb Temperature
Wet-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
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AIR CONDITIONS t1 t2 t3 t4 t5 t6
Entering Dry-bulb Temperature
Wet-bulb Temperature
Exit Dry-bulb Temperature
Wet-bulb Temperature
EXPERIMENTAL
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WATER CONDITIONS T1 T2 T3 T4 T5 T6
Entering TemperatureExit Temperature
EXPERIMENTAL
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FLOW RATESWater Entering Volumetric Rate Exit Mass FlowrateAir Entering Velocity Exit Velocity
SHUTDOWN
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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
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Diameter of tower 198 cm
Height of Packing, Z 134 cm
Ambient Room Temperature 280C
RAW DATA
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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
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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
PROBLEMS ENCOUNTERED AND SUGGESTIONS
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• Boiler shutdowns• Have a consistent pattern in recording data• Hot / bring extra clothes• Free sauna• Flashlight for flowrate• Don’t hesitate to ask.
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