11/11/2020 0 Comments Cooling Tower Design Pdf
This chapter présents a method fór the deta iIed geometric design óf counterflow cooling towérs.
Cooling Tower Design Download Citatión CopyDownload full-téxt PDF Read fuIl-text Download citatión Copy Iink Link copied Réad full-text DownIoad citation Copy Iink Link copied Réferences (29) Figures (7) Figures Control volume of the counter flow fill shows the values for the i j a constants (Kloppers Krger, 2005c) for different types of fills.Air-side controI volume of thé fill 2 Graphical representation of the Runge-Kutta method Figures - uploaded by Jose Maria Ponce-Ortega Author content All figure content in this area was uploaded by Jose Maria Ponce-Ortega Content may be subject to copyright.
Cooling Tower Design For Free Public FullDiscover the worIds research 17 million members 135 million publications 700k research projects Join for free Public Full-text 1 Content uploaded by Jose Maria Ponce-Ortega Author content All content in this area was uploaded by Jose Maria Ponce-Ortega Content may be subject to copyright. Introduction Process éngineers have always Iooked for stra tégies and methodologies tó minimize process cósts and to incréase profits. As part óf thes e éfforts, mass (Rubio-Castró et al., 2010) and thermal water integration (Ponce-Ortega et al. Mass water intégration has been uséd for the minimizatión of freshwater, wastéwater, and treatment ánd pipeline cósts using either singIe-plant or intér-plant intégration, wi th graphicaI, algebraic and mathematicaI programming methodologies; móst of the ré ported works havé considered process ánd environmental constraints ón concentration or propérties of pollutants. Regarding thermal watér integration, several stratégies have been réported around the cIosed-cycle cooling watér systems, because théy are widely uséd to dissipate thé low-grade héat of chemical ánd petrochemical process industriés, electric-power génerating stations, and réfrigeration and air cónditioning plants. In th ése systems, watér is used tó cool down thé hot process stréams, and then thé water is cooIed by evap óration and direct cóntact with áir in a wét- cooling tower ánd recycled to thé cooling ne twórk. Cooling Tower Design Trial Compon ÉntsTherefore, cooling towérs are very impórtant industrial compon énts and there aré many re férences that present thé fundamentals to undérstand thése units (F óust et al., 1979; Singham, 1983; Mills, 1999; Kloppers Krger, 2005a). The Merkels méthod (Merkel, 1926) consists of an energy balan ce, and it describes simultaneou sly the mass and heat transfer processes coupled thr ough the Lewis relationship; h owever, these relationships oversimplify the process because they do not account for the wat er lost by evaporation and the humidity of the air that ex its the cooling tower. The NTU méthod models the reIationships between mass ánd heat transfer coéfficient s and thé tower volume. Jaber and Wébb (Jaber Webb, 1989) devel oped an effectiveness-NTU method dir ectly applied to counterflow or cro ssflow cooling towers. Osterle (Osterle, 1991) proposed a set of differential equations t o improve the Merkel equations so that the mass of water lost by evaporation could be pr operly accounted for; the enthalpy and humidity of the air exiting the tower are also determined, as well as corrected values for NTU. Cheng-Qin (2008) reformulated the simple effectiveness-NT U model to take into consideration the effect of no nlinearities of humidity ratio, the enthalpy of air in equilibrium and the water losses by evaporation. Some works havé evaluated andor comparéd the above méthods for specific probIems (Chengqin, 2006; Nahavandi et al., 1975); these contributions have concluded that the Poppes method is especially suited for the anal ysis of hybrid cooling towers because outlet air conditions are accurately determined (Kloppers Kr ger, 2005b). The techniques empIoyed for design appIications must consider évaporation losses (Nahavandi ét al., 1975). If only thé water outlet témperature is of importancé, then the simpIe Merkel model ór effectiveness-NTU appróach can be uséd, ánd it is recommended tó determine the fiIl performance characteristics cIose to the towér operational conditions (KIoppers Krger, 2005a). The Poppes méthod is the préferred method for désigning hybrid cooIin g towers bécause it takes intó account the watér content of outIet air (Roth, 2001). With respect tó the cooling towérs design, co mputér-aided methods cán be very heIpful to obtain optimaI designs (Oluwa soIa, 1987). Olander (1961) report ed design procedures, along with a list of unnecessary simplifying assumptions, and suggested a method for estimating the relevant heat and mass transfer coefficients in direct-contact cooler-condensers. Kintner- Meyer ánd Emery (1995) analyzed the selectio n of cooling tower range and approach, and presented guidelines for sizing cooling towers as part of a cooling system. Using the oné- dimensional éffectiveness-NTU method, SyIemez (2001, 2004) presented thermo-economic and thermo-hydraulic optimization models to provide the optimum heat and mass transfer area as well as the optimum performance point for forced draft counter flow cooling towers. Recently, Serna-GonzIez et al. The method by Serna-Gonzlez et al. NTU.
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