Cooling towers transfer units

The section on Performance provides a handy nomograph for quick cooling tower evaluation. More detailed analysis requires the use of transfer units. The performance analysis then asks two questions ... [Pg.158]

How many transfer units can the actual cooling tower or proposed new cooling tower actually perform ... [Pg.158]

Equation 3 Is quite accurate for calculating the number of transfer units for the example cooling tower... [Pg.158]

Calculate N,og and Table 1, from Predict the number of Transfer Units for Cooling Towers, by Kamal Adham Khodaparast, Chemical Engineering Progress, Vol. 88, No. 4, pp. 67-68 (1992). Reproduced by permission of the American Institute of Chemical Engineers. 1992 AlChE. ... [Pg.159]

Ap = Final column inside net area, ft, or in. a = Surface area of an orifice, in. a = Effective interfacial area for contacting gas and liquid phases, ft /ft. Because this is very difficult to evaluate, it is usually retained as a part of the coefficient such as Kca or Kj a a = Area of transfer surface per unit of tower volume in water cooling towers, ft /ft, or, termed contact area... [Pg.408]

N = Number of transfer units N = Number of deck levels in cooling tower Nog = Number of transfer units, based on overall gas film coefficients... [Pg.410]

The information that is ultimately needed about a cooling tower design is the height of packing for a prescribed performance. This equals the product of the number of transfer units by the height of each one,... [Pg.279]

Sizing of a Cooling Tower Number of Transfer Units and Height of Tacking... [Pg.281]

A cooling tower operates in the countercurrent mode as illustrated by Figure 5.13. Entering air has a 5% wet-bulb temperature of 65°F. Hot process water enters the tower at 118°F and cold water leaves at a 15° approach to the wet-bulb (i.e., at 80°F). The cross-sectional area of the tower is 676 ft2. Determine the number of transfer units (Ntu ) required to meet the process requirements. Air is supplied to the tower by a blower having a capacity of 250,000 cfm and the water loading is 1500 lb/(hr)(ft2). [Pg.114]

A cooling tower 20 X 20 feet cross section was sized to cool 2300 gpm of water from 115 to 82°F, when the 5% wet-bulb temperature is 65°F. The maximum air rate that can be delivered is 400,000 cfm. Determine the number of transfer units needed to meet process conditions. [Pg.122]

An analysis of multi-unit cocurrent crossflow cooling towers is made. Towers were placed in series and the results obtained were compared with that of multi-unit countercurrent crossflow cooling towers. The experimental data on the multi-unit cocurrent crossflow cooling tower were, analyzed in terms of enthalpy efficiency of single-unit, heat capacity ratio and number of transfer units. An outline of design calculations of multi-unit cocurrent crossflow cooling towers is presented. 4 refs, cited. [Pg.282]

Cooling towers may be classified on the basis of the fluid used for heat transfer and on the basis of the power supplied to the unit. In wet cooling towers, the condenser cooling water and ambient air are intimately mixed. Cooling results from the evaporation of a portion of the water and to a lesser... [Pg.89]

Cooling water in process plants is most commonly and effectively obtained using a cooling tower. The principle of operation is the simultaneous transfer of mass and heat. Colburn (1939) introduced the idea of a unit of mass transfer which is a measure of the number of equilibrium changes to required to effect a given amount of diffusion. It is identical with the concept of a theoretical plate in distillation (Kern, 1950). [Pg.267]

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