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110 CHAPTER 5 1956 Guide the analogy of electrical resistance-capacitance networks to thermal systems.*4 For two dimensional problems in steady state conduction* additional techniques of solution are found in flux plotting,4,19 and in the use of a potential tank.4,19 These methods are of most direct use in problems in which the boundaries of the two dimensional shape are made up of isothermal and adiabatic surfaces; !& REFERENCES 1 Absorption and Extraction, by T. K. Sherwood (McGraw-Hill Book Co., Inc., 1937). 1 The Transmission of Heat by Radiation and Convection, by Griffith and Davis (Special Report No. 9, 1933, Department of Scientific and Industrial Research. His Majesty's Stationery Office, London, England). * A Method of Correlating Forced Convection Heat Transfer Data and a Compari son with Fluid Friction, by A. P. Colburn (American Institute of Chemical Engineers H:U:. Transactions, Vol. 29, 1933, p. 174). 4 Beat Transmission, by W. H. McAdams (McGraw-Hill Book Co., Inc.). I Beat Transfer Notes, by L. M. K. Boelter, V. H. Cherry, H. A. Johnson and R. C. Martinelh (University of California Press, 1946). Heat Transfer by Free Convection from Heated Vertical Surfaces, by V. S. Touloukian, G. A. Hawkins and M. Jakob (A.S.M.E: Transactions, 1948, p. 13). 7 Heat Insulation in Air Conditioning, by R. H. Heilman (Industrial and Engineer f 4.1-.. ing Chemistry, Vol. 28, July 1936, p, 782). 8 Photoelectric Photometer for Rapid Comparison of Two Light Sources, by L. M. >iV K. Boelter, J. T. Gier and F. A. Ryder (Illuminating Engineering Society Transac tions, 1939). " Scientific Basis of Illuminating Engineering, by Perry Moon (McGraw-Hill Book Co., Inc., 1936). 10 Beat Transfer, by Max Jakob (John Wiley and Sons, Inc., Vol. I, 1949). II Numerical Methods in Engineering, by L. E. Grinter (The MacMillan Co., 1949). " Numerical Analysis ofBeat Flow, by G. M. Dusinberre (McGraw-Hill Book Co., Inc., 1949). 11 Elements of Beat, Transfer and Insulation, by Max Jakob (John Wiley and Sons, ft |k 'fit- m All' Inc., 1942). 14 Periodic Heat Transfer at the Inner Surface of a Homogeneous Wall, by H. A. Johnson (A.S.H.V.E. Transactions, Vol. 54, 1948, p. 143) " Temperature Charts for Induction and Constant Temperature Heating, by M. P. Heisler (A.S.M.E. Transactions, Vol. 69, 1947, p. 227). ** Temperatures in Solids During Heating and Cooling, by F. C. W. Olsen (In dustrial and Engineering Chemistry, Vol. 34, 1942, p. 874). Hi 17 Applied Mathematics in Chemical Engineering, by T. K. Sherwood and Charles E. Reed (McGraw-Hill Book Co., Inc., 1939). 18 Introduction to the Mathematical Theory of the Conduction of Beat in Solids, by H. S. Carslaw (Dover, 1945). `ft' 17 Beat Conduction, by L. R. Ingersoll, A. C. Ingersoll and O. J. Zobel (McGraw- IHill Book Co., Inc., 1948, p. 209). " Charts for Estimating Temperature Distribution in Heating or Cooling Solid f.-t Shapes, by H. P. Gurney and J. Lurie (Industrial and Engineering Chemistry, Vol. 15,1923, p. 1170). 71 Applied Mathematics in Chemical Engineering, by T. K. Sherwood (McGraw-Hill Book Co., Inc., 1949, p. 241). * Methods graphiques pour l'etude des installations de Chauffage et de refrigera tion en regime discontinu, by A. Nessi and L. Nissolle (Dunod, Paris, 1949). u Transient Heat Conduction in Hollow Cylinders after Sudden Change of Inner- P |lSurface Temperature, by R. L. Perry, and W. P. Berggren (University of California Publications in Engineering 5, Vol. 59, 1944). 14 Method for Determining Unsteady-State Heat Transfer by Means of Electrical iAnalogy, by V. Paschkis (A.S.M.E. Transactions, Vol. 64, 1942, p. 105). CHAPTER 6 PHYSIOLOGICAL PRINCIPLES Chemical Vitiation of Air, Physical Impurities in Air, Thermal Interchanges Between the Body and Its Environment, High Temperature Hazards, Acclimati zation, Upper Limits of Heat for Men at Work, Application of Physiologic Principles .to Air Conditioning Problems, Effective Temperature Index and Comfort Zones VENTILATION is defined in part as the process of supplying air. to,, or removing air from, any space by natural or mechanical means. The word in itself implies quantity, but air must be of the proper quality also. The term air conditioning in its broadest sense implies control of any or all of the physical or chemical qualities of the air. The A.S.H.V.E. Code of Minimum Requirements for Comfort Air Conditioning1 defines it "as the process by which simultaneously the temperature, moisture content, movement and quality of the air in enclosed spaces intended for human occupancy may be -maintained within required limits. If an installation . cannot perform all of these functions, it shall be designated by a name that describes only the function or functions performed." CHEMICAL VITIATION OF AIR People living indoors bring about certain physical and chemical changes., in the air about them. The oxygen content of the air diminishes and the. carbon dioxide increases, but these changes are too slight to be significant, except in air tight spaces as in submarines. Organic matter which is usually perceived as odors, comes from the body or clothes. Moisture and heat are given off by the body. There is no evidence of any toxic volatile material given off by man to the ambient air. Stale air may be offensive because of odors and may induce loss of appetite and loss of energy. Objectionable body odors have the same effects. These reasons, whether esthetic or physiological, usually make it desirable in the design of air conditioning systems to provide for the elimination or control ofodors, arising, from occupancy, cooking, or other sources. This may be accomplished by introducing odor-free air in sufficient quantities to reduce odor concentrations by dilution to a level which is not objectionable. Odor-free air may be outdoor air or air which has been cleared of odors by sorption, washing, or other appropriate means. ; In the case of vitiation by a few hazardous gases such as carbon mon/ oxide from heating, cooking, and certain industrial processes, no satis factory chemical treatment for the elimination of the impurity has been ^ found. The only satisfactory solution is elimination at the source by local exhaust ventilation; or, if this is impossible, reduction to a safe concen tration by dilution. (See Chapter 8.) In the case of contamination by other matter, including volatile vapors and gases, chemical treatment for the removal or reduction of the impurities has been made available through air cleaning methods, which afe discussed in .Chapter 34. , When the only source of contamination is the human occupant, and over heating is not a problem, the minimum quantity of outdoor air needed ap pears to be that required to remove objectionable body odors, or tobacco smoke. The concentration of body odor in a room, in turn, depends ill