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    Experiment No #2: Objective

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    mjunaid
    Experiment no. 2 aimed to determine the height of packing and number of transfer units (NOG) in a cooling tower, and approach temperature range for cooling. The cooling tower uses convection and evaporation to transfer heat from water to air. Calculations determined the tower's effectiveness was 33.33%, NOG was 40, and approach temperature range was 4°F. Key applications of cooling towers include use in power plants, oil refineries, and other industrial processes to reject waste heat to the atmosphere.

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    Experiment No #2: Objective

    Uploaded by

    mjunaid
    27 views5 pages
    Experiment no. 2 aimed to determine the height of packing and number of transfer units (NOG) in a cooling tower, and approach temperature range for cooling. The cooling tower uses convection and evaporation to transfer heat from water to air. Calculations determined the tower's effectiveness was 33.33%, NOG was 40, and approach temperature range was 4°F. Key applications of cooling towers include use in power plants, oil refineries, and other industrial processes to reject waste heat to the atmosphere.

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    cooling

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    Experiment no. 2 aimed to determine the height of packing and number of transfer units (NOG) in a cooling tower, and approach temperature range for cooling. The cooling tower uses convection and evaporation to transfer heat from water to air. Calculations determined the tower's effectiveness was 33.33%, NOG was 40, and approach temperature range was 4°F. Key applications of cooling towers include use in power plants, oil refineries, and other industrial processes to reject waste heat to the atmosphere.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    27 views5 pages

    Experiment No #2: Objective

    Uploaded by

    mjunaid
    Experiment no. 2 aimed to determine the height of packing and number of transfer units (NOG) in a cooling tower, and approach temperature range for cooling. The cooling tower uses convection and evaporation to transfer heat from water to air. Calculations determined the tower's effectiveness was 33.33%, NOG was 40, and approach temperature range was 4°F. Key applications of cooling towers include use in power plants, oil refineries, and other industrial processes to reject waste heat to the atmosphere.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 5

    Experiment no #2:

    Objective:
    To determine height of packing and Nog & temperature range and
    approach for cooling tower

    Apparatus:
    Cooling tower apparatus & water

    Working principle:
    Dry cooling towers operate by heat the transfer through a surface that
    separate the working fluid from ambient air, such as in a tube to air heat
    exchanges utilizing convective heat transfer. They do not use evaporation
    Wet cooling towers operate on the principle o evaporation cooling.

    Theory:
    What is a cooling tower?
    A cooling tower is a heat rejection device that rejects waste heat to the
    atmosphere through the cooling of a water stream to a lower temperature.

    Industrial cooling towers:


    A large volume of air is constantly moving along the fill courtesy of large
    fans in the tower. As evaporation takes place, the water loses heat. It eventually
    enters the tower sump at the bottom. The cool water then goes back to cool the
    initial heat source and the cycle repeats. For the sake of system dilution, of
    portion of the system water goes to the drain through a bleed-off valve. The
    makeup line feeds the cooling tower with fresh water for replenishment.

    Types of Cooling Towers:


     Mechanical draft cooling tower
     Atmospheric cooling tower
     Hybrid draft cooling tower
     Air flow-characterised cooling tower
     Construction-characterised cooling tower

    Air flow generations:


     Natural draft
     Mechanical draft
     Fan assisted natural draft

    Air to water flow:


     Cross-flow
     Counter-flow
     Cross and counter flow with natural or mechanical draft

    Applications:
    The prime use of the cooling tower is to block out the heat absorbed in the
    moving cooling water system. The application of cooling tower is as follows,

     Natural gas processing plants


     Power plants
     Food processing plants
     Petrochemical plants
     Semiconductor plants
     Petroleum refineries

    Observations and calculations:


    Air calculations:

    Inlet Outlet
    T=85oF T=102oF
    Humidity=55% Humidity=75%
    Tsat=72oF Tsat=93oF
    Hsat=0.018lbH2O/lbAir Hsat=0.035lbH2O/lbAir
    H=0.015lbH2O/lbAir H=0.033lbH2O/lbAir

    Enthalpies:
    1.
    Tin=85oF hin=0.015
    H1=(1.005+1.88h)T+2501h
    H1=12.5 btu/lb
    2.
    Tout=102oF hout=0.0033
    H2=173btu/lb
    3.
    Tsat,in=72oF hsat,in=0.018
    H3=13.33 btu/lb

    4.
    Tsat,out=93oF hsat,in=1.035
    H3=18.7 btu/lb

    Water calculations:
    Inlet Outlet
    T=105oF T=99oF
    From Graph
    H1=64.5 H2=26.5 Hm=42
    f∆Hm= Hm/H2 – Hm/H1
    = 0.93

    NOG= (H2-H1)/(f∆Hm)
    = 40
    Hog= z/Nog = 0.772/40 = 0.103m
    K= G/M*P*Hog
    = 84/18*1*0.103
    K= 45
    Temp. Range= T1-T2=41-37=4OF
    Temp. approach= 37-29 = 8oF
    Effectiveness = range/range+ approach
    = 4/4+8 = 0.333= 33.33%

    Precautions:
     Don’t let packing over-flood
     Don’t heat water more than 100oC

    Results:
    Effectiveness of cooling tower is 33.33%.

    References:
     www.qoura.com
     www.wikipedia.com
    Line flow diagram: Water
    Temp.
    Out

    Container
    for Water
    desiccant storage
    with
    heater

    Pump

    Water
    Temp. Out
    Blower

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