Document bOYrQE3wmO7qMOg7aGLOvZ0jy

976 CHAPTER 44 installation of water economizing equipment since the cost for pumping and the fixed or ownership charges may be in excess of the annual cost for once through condensing operation. If operating costs are to be the basis for selection, then fixed charges should be determined when studying ap plication of this equipment which usually has a shorter life than the other components. ' , '.' Usually the primary factors influencing the installation of water con servation equipment are the lack of an adequate water supply or local regulations intended to conserve an existing water supply. Another factor influencing the installation of: such equipment' is the in creasing trend toward the .enactment of taxes and service charges: for con densing water wasted into city sewers. Certain municipalities"will remit the sewer taxes or service charge if the edndensing water is subinetered and discharged into a storm sewer or used for process purposes. Heating; The method of estimating fuel consumption to balance the building heat loss is given in Chapter.18, It is important to include the fuel required to heat ventilation air as used in ventilating and air conditioning systems.. In estimating fuel consumption for ventilation air, the tendency of the conventional control systems to use less than the estimated quantity of out side air in cold weather should be considered in its effect in lowering fuel consumption. In addition, the heat required to accomplish winter humid ifying must not be neglected, when this feature is included in the equip ment. ' V"' .. BIBLIOGRAPHY Modern Air Conditioning, Heating and Ventilating, by W. H. Carrier, R. E. Cherne, and W. A. Grant--Chapter IV (Pitman Publishing Carp., 1950). Predicting Operating Hours of Refrigeration Equipment Used in Air Condition ing, by W. A. Grant (Refrigerating Engineering, July, 1941). Cost of Operation of Refrigeration Used for Air Conditioning, by R. E. Cherne (Refrigerating Engineering, December, 1943). CHAPTER 45 INDUSTRIAL AIR CONDITIONING General Requirements for Manufacture; Processing and Preservation; Design Con?; ditions and Application Data; Classification of Problems; Moisture Content and; Regain;-Conditioning and Drying; Chemical and Biochemical Reactions;-, r! Crystallization; Control,for Machining, Polishing, and for Static Elec- , , tricity Elimination; Laboratory Conditions; Calculations; Safe guarding Health and Maintaining Safety; Contaminant Control; Dilution Systems for Contaminants; Heat Storage; Radiation; Local Relief and Spot Cooling; Odors INDUSTRIAL air conditioning is concerned with the design and ;ap-. plication of equipment for obtaining proper conditions for (1) the; manufacturing, processing, and preserving of material, equipment, and commodities; and (2) maintaining the health, safety and efficiency of workers. This chapter includes a general discussion of these conditions and also a comprehensive list of specific requirements for various types of products. ;;': GENERAL REQUIREMENTS FOR MANUFACTURE, PROCESSING AND PRESERVATION In order to apply air conditioning to industrial processes,-the air condi tioning engineer must have a thorough understanding of the processing problems involved; -Individual processes and machines'are changing rap idly, and air conditions must be revised constantly to meet the new conditions. Table 1 lists the temperatures and relative' humidities required for storage of certain commodities, and for manufacturing and processing of others. In some cases the temperatures and- relative humidities listed in Table. 1 have no .direct influence upon the product itself, but do affect the efficiency of employees, and in turn affect workmanship, uniformity and the cost of production.' Sometimes, a compromise between the known optimum condition for processing and that required for worker comfort is unavoidable. Air conditioning for industrial processes is so extensive and involved that a detailed treatment is beyond the scope of this chapter. It is possible to cover only a few salient points of the general subject. In many in dustries the exact conditions to be maintained are determined and known only by the manufacturer who specifies them. In other industries there rs a wide variance between manufacturers' requirements, depending on results desired, experience, and cost considerations. ....... CLASSIFICATION OF PROBLEMS In general, any industrial air conditioning problem in processing may ue classified under one or more of the following: 1- Control of regain. 2. Control of rate of chemical reactions. 3- Control of rate of biochemical reactions. 4. Control of rate of crystallisation. * Control of temperature for close tolerance machining and grinding. 977