Cooling Towers

Preface Acknowledgments Section A Cooling tower practice A.1 Fundamentals A.1.1 Evaporative cooling A.1.2 Main components A.1.3 Operating terms A.1.4 The physical mechanisms of cooling tower operation A.2 Types of cooling tower A.2.1 Natural draught A.2.2 Cross-flow forced draught designs A.2.3 Cross-flow induced draught designs A.2.4 Contra-flow forced draught designs A.2.5 Contra-flow induced draught designs A.2.6 Indirect evaporative cooling towers A.2.7 Evaporative condensers A.2.8 Some factors affecting the selection and performance of cooling towers A.3 Rating duty and physical size of cooling towers A.3.1 The problem of units A.3.2 The methods of specifying capacity A.3.3 Design factors which affect tower size A.3.4 The use of selection charts A.3.5 Effect on tower size of the variation of the main parameters A.4 Cooling tower components and construction materials A.4.1 Packing A.4.2 Drift eliminators A.4.3 Water distribution A.4.4 Cold water basin A.4.5 Fans and fan drives A.4.6 Materials used in cooling tower manufacture A.5 Practical aspects of tower selection A.5.1 Heat energy calculations A.5.2 Determination of water flow rate A.5.3 Determination of the re-cooled water temperature A.5.4 Choice of design air wet bulb temperature A.5.5 Effect of altitude A.5.6 Choice of Site A.5.7 Appearance A.5.8 Capital costs and operating costs A.5.9 Performance testing A.6 Noise and noise control A.6.1 The subjective nature of sound A.6.2 The basis of sound measurement A.6.3 The measurement of sound A.6.4 The effect of distance on sound power levels A.6.5 Subtraction and addition of noise levels A.6.6 Sources of noise from cooling towers A.6.7 Achieving low noise level in cooling towers A.6.8 Noise level reduction of an existing tower A.6.9 Calculations to meet noise level and of the attenuation necessary to meet various criteria A.6.10 Legislation and regulations relating to the enforcement of noise restrictions A.7 Industrial applications A.7.1 Refrigeration plant A.7.2 Air compressors A.7.3 Engines A.7.4 Metallurgical processes A.7.5 Chemical and refinery plants A.7.6 Turbine condenser cooling A.8 Water quality and treatment A.8.1 The constituents of 'pure' water A.8.2 Ionization of water A.8.3 Acidity, alkalinity and pH values A.8.4 Hardness A.8.5 Dissolved solids A.8.6 Suspended solids A.8.7 Dissolved gases A.8.8 Measurement of contaminant content of water by proportion A.8.9 Water softening by ion exchange A.8.10 Scale and its control A.8.11 Purging and purge rate calculations A.8.12 Corrosion A.8.13 Balancing the treatment for scaling and corrosion A.8.14 Deposits A.8.15 Fouling A.8.16 Microbiological fouling A.8.17 Water treatment system controls A.8.18 Electromagnetic and electrostatic water treatment A.8.19 Ultra-violet light biological control A.8.20 Filtration A.9 Legionnaires disease A.9.1 A brief history A.9.2 A perspective on risk A.9.3 The facts on cooling towers and legionella A.9.4 Alternatives to the use of cooling towers A.9.5 Reducing the risks of infection A.9.6 Health and Safety Commission proposals A.10 Maintenance A.10.1 General considerations A.10.2 Maintenance of the tower and its structure A.10.3 Water treatment A.10.4 Maintenance schedules Section B Cooling tower theory and calculations B.l Psychrometry B.1.1 The atmosphere B.1.2 Moisture in the atmosphere B.1.3 Atmospheric pressure and partial pressure B.l.4 Vapor pressure B.1.5 Saturated air B.1.6 The saturation curve B.l.7 Absolute humidity B.l.8 Relative humidity B.1.9 Dew point B.l.10 Dry bulb temperature B.l.11 Wet bulb temperature B.1.12 Measurement of wet bulb temperature B.l.13 Humidity calculations B.l.14 Total heat or enthalpy B.l.15 Psychrometriccharts B.1.16 Wet bulb temperature and system equilibrium B.2 Heat transfer theory B.2.1 Some general notes on heat transfer B.2.2 Heat transfer theory applied to cooling towers B.2.3 The approach to practical cooling tower calculations B.2.4 The use of overall heat transfer coefficients and volumetric coefficients B.3 Heat transfer calculations B.3.1 Merkel's theory and calculation of driving force B.3.2 The volume transfer coefficient B.4 Selection of tower size for a given duty B.4.1 Data requirements B.4.2 Sample calculation - diesel engine cooling B.4.3 Sample calculation - prediction of the performance of an existing tower B.5 Corrections for altitude B.6 The use of charts for calculation of cooling tower duties B.6.1 Data presentation B.6.2 Sample calculations B.7 Determination of water cooling duties B.8 Symbols used in calculations Section C Data and tables C.1 The basis of the SI system of units C.l.l Basic units C.1.2 Supplementary units C.1.3 Prefixes C.1.4 Derived units C.2 Definitions and relationships of relevant units C.3 Conversions into SI units C.4 Meteorological tables and data C.4.1 Screen dry bulb and wet bulb isotherms for the UK for temperatures exceeded for the stated percentage of hours during June to September: period 1964-1970 C.5 Variation with pressure/temperature of physical properties of steam, water and dry air C.6 Variation with temperature of the enthalpy of saturated air C.7 Relationship between pressure drop and volume flow in steel pipes C.7.1 Flow of water at 15°C in Schedule 40 steel pipe C.7.2 Equivalent length (m) of pipe fittings for resistance calculations C.8 Specific heat capacity of some common substances C.8.1 Effect of temperature variation on specific heat capacity of iron and steel C.9 Some common conversions to imperial units and Celsius/Fahrenheit tables Bibliography Index