Document bapDLZOzZN3J7bDa72a0pyXKD

ire S' 296 CHAPTER IS J946.Guide I Heat FIow--Homogeneous Walls or Roofs, by-C. O.. Mackey and L. T. Wright Jr (A.S.H.V.E. Transactions, Vol. 60, 1944, p. 293). KJ 4`"A?S.H.V.E. Research Report No. 1157--Summer Cooling Load as Affected by Heat Gain Through Transactions ^/ol^46^1940^23i)f8` by F' C' Houghten' H- T- olson knd Carl Gutberiet (A.S.H.V.E. ,, fr^.S.H.VjE. Rkearch Report No 1195--Heat Gain Through-Walls and Roofs as Affected by Solar Radtarion. by F. C. Houghten, E. C. Hach. S. I. Taimuty and Carl Gutberiet (A.S.H.V.E. Transactions. Vol. 48,1942, p. 91). . ^The Transmission of Solar Radiation Through Flat Glass Under Summer Conditions, by G. V. Parmelee (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, October-November. 1945, p. 562). '-Proposed Standard Solar Radiation Curves for Engineering Use. by P. Moon (Journal of the Franklin Institute, November, 1940. Vol. 230, No. 5..p..583-617). .. .... `-A-S-U-V.E RnsKARCK Report No. 975--Studies of Solar Radiation-Through Bare and Shaded Window3, by F C. Houghten. Carl Gutberiet. and J. L. Blackshaw (A.S.H.V.E. Transactions. Vol. 40. "Si; p- -'M). . A.S.H-y.E. Research Report No. 1180--Heat Gain Through Western Windows With and Without Shading, by F. C. Houghten, and David Shore (A.S.H.V.E. Transactions, Vol. 47. 1941, p. 251). "A.S.H.V.E. Research Report No. 1002--Cooling Requirements of Single Rooms in a Modern Office Building, by F. C. Houghten. Carl Gutberiet, and. Albert J. Wahl (A.S.H.V.E. Transactions. Vol. 41, 1935, p. 53). . , `~Co?jer Footcandles for Air Conditioning, by W. G.- Dariey (A.S.H.V.E: Transactions, Vol. 46, 1940, p. 367). Ughring and Air Conditioning Design Factors, Report of A.S.H.V.E. Joint Com- mittee on Lighting m Air Conditioning (A.S.H.V.E; Journal Section, Heating, Piping and Air Con ditioning, September. 1941, p. 605). Lighting and Air Conditioning, by. Howard M. Sharp (Heating and Ventilating, November. 1942, p. 35). ,, "-Moisture Condensation in Building Walls, by Harold W. Woolley (U. S. Department of Commerce, National Bureau of Standards, Building Materials and Structures Report BMS63). I li \v I l CHAPTER 1 6 3ue(s and C^ombu&tion Combustion Principles, Heat and Flames; Air Required, Excess Air and Secondary Air; Draft Requirements, Classic Heation of Coal and Coke, Firing Methods, Classification and Combustion of Oil and Gas; Dustless Treatment of Coal THE data given in the first part of this chapter are of general appli cation to the various fuels used in domestic heating which are coal, coke, oil and gas. The choice of fuel is a question of dependability, cleanliness, fuel availability, economy, operating requirements and control. FUNDAMENTAL PRINCIPLES OF COMBUSTION Combustion may be defined as the chemical combination of a substance with oxygen with a resultant evolution of heat. The rate of combustion depends partly upon the specific rate of reaction of. the combustible substance with oxygen, partly upon the rate at which oxygen is supplied, and upon the temperature obtained due to surrounding conditions. Complete combustion is obtained when all of the combustible elements in the fuel are oxidized with all of the oxygen with which they can combine. All of the oxygen supplied may not be utilized. Perfect combustion is defined as the result of supplying the required amount of oxygen for combination with all of the combustible elements of the fuel and utilizing all of the oxygen so supplied. The oxygen required for the process of combustion is obtained from air which is a mechanical mixture of oxygen, nitrogen and small amounts of carbon dioxide, water vapor and inert gases. These inert gases are generally included with the nitrogen, and for engineering purposes the values given herewith may'be used. . Bt Volume, Per Cent Bt Weight, Pee Cent . 20.9 ' 79.1 23.15 76.85 The combination of oxygen with the combustible elements and com-, pounds of a fuel is in accordance with fixed laws. In the case of perfect combustion the reactions and resultant combinations are shown in Table 1. The most important condition governing the process of combustion, is temperature. It is necessary to bring a combustible substance to its ignition temperature before it will unite in chemical combination with, oxygen to produce combustion. The ignition temperatures for several of the combustible constituents of fuels are presented in Table 1. HEAT OF COMBUSTION As previously stated, the process of combustion results in the evolution of heat. The heat generated by the complete combustion of a unit of fuel is. constant for a given combination of combustible elements and com- . pounds, and is known as the heat of combustion, calorific value, or healing value of the fuel. . 297 :