(2) Heat Balance and Thermal Efficiency Heat balance is prepared to make an important guideline on a basis of which the degree of rationalization in the use of energy is judged, through investigation of the heat energy provided to the combustion equipment and of its state of use in order to clarify the relation between heat input and output. IV-2-4 To calculate the heat balance, Properties of the used fuel Fuel consumption Temperature of air Composition of combustion products Amount and temperature of heated matters Amount and composition of unburnt matters Temperature of flue gas Chemical reaction in heated matters, etc. on a basis of which the following calculations are made: + Heat input Heat content retained by fuel (Q x F) + (F x Cpf x At) Sensible heat of air V x Cpv x At Heat content carried in by heated matters M x Cpm x At Heat input due to chemical changes HxM

+ Heat output Heat content carried out by heated matters M x Cpm x At Heat content carried out by combustion exhaust gas (E x Cpe x At) + (S x Cps x At) + 600 S (when based on higher calorific value) Heat loss due to incomplete combustion (Ex (CO) 100 x 3,050 x F) + (8,100 x (amount of soot)) IV-2-5 Heat foss due to unburnt matters in combustion residue n Fx 8,100 x

Y (he + hr) (At) (A) For he, refer to item Basic Calculation of Heat Transfer as mentioned later. hr = 4.88 {(To/100)* ~ (Ta/100)*, e/At Aen Clarifying the heat balance in combustion equipment will tell how much of the given heat is used for the heating for which it is intended and how much is lost. How much of any given total heat is effectively used is expressed by Thermal Efficiency: that against total heat input is thermal efficiency against total heat input; and that against fuel calorific value is thermal efficiency against fuel calorific value. Since thermal efficiency varies depending on which item is regarded as effective heat capacity, it is necessary to define the effective heat of each combustion equipment beforehand. (Symbols) F : Fuel consumption [kg/h] Q : Fuel calorific value {keal/kg] H : Heat of reaction {kcal/kg} M : Amount of heated matters (input) [kg/h] WwW : Amount of heated matters (output) {kg/h]

E : Amount of dry exhaust gas {mh] Ss : Amount of water vapor in exhaust gas [kg/h] A : Radiating area {m?] Vv : Amount of air {m/h] Ti, To, Ta: Furnace temperature, furnace external wall temperature, ambient temperature {K] At : Temperature difference with ambient temperature [c] e : Thickness of furnace wall [m] Cp : Specific heat at constant pressure and the subscripts of f, v, m, w, e, and s indicate a value of fuel, air, heated matters (input), heated matters (output), dry exhaust gas, steam in exhaust gas respectively. (CO) : Vol.% of CO in exhaust gas h, : Radiation heat transfer coefficient [kcal/m?hC] h, : Convection heat transfer coefficient [kcal/m?hC] x : Thermal conductivity of furnace wall material [kcal/mhC] a : Ash content in | kg fuel [kg] n : Carbon content in 1 kg combustion residue {kg] : Emissivity of wall surface IV-2-6 (3) Rationalization in the Use of Thermal Energy in Combustion Equipment a.