APPENDIX. 



193 



HEAT BALANCE, OR DISTRIBUTION OF THE HEATING VALUE OF THE COM- 

 BUSTIBLE. 



Total Heat Value of i Ib. of Combustible B. T. U. 



B. T. U. Per Cent. 



1. Heat absorbed by the boiler = evaporation from and at 



212 degrees per pound of combustible X 965.7. 



2. Loss due to moisture in coal = per cent of moisture re- 



ferred to combustible -=- 100 X [(212 t) + 966 

 0.48(2" 2I2)](* = temperature of air in the boiler 

 room, 7' = that of the flue gases). 



3. Loss due to moisture formed by the burning of hydrogen 



= per cent of hydrogen to combustible -- 100 X 9 



X [(212 - /) -f- 966 -|- o.48( T - 212)]. 

 4.* Loss due to heat carried away in the dry chimney gases = 



weight of gas per pound of combustible X 0.24 X 



(T-t). 



CO 

 5.f Loss due to incomplete combustion of carbon = _L.rQ 



X 



per cent C in combustible 



100 



X- 10150. 



6. 



Loss due to unconsumed hydrogen and hydrocarbons, to 

 heating the moisture in the air, to radiation, anc 

 unaccounted for. 



Totals , 



IOO.OO 



* The weight of gas per pound of carbon burned may be calculated from the gas analyses 

 as follows : 



Dry gas per pound carbon = " C a 



. in which CO 2 , CO, O, and N are 



the percentages by volume of the several gases. As the sampling and analyses of the gases 

 in the present state of the art are liable to considerable errors, the result of this calculation is 

 usually only an approximate one. The heat-balance itself is also only approximate for this 

 reason, as well as for the fact that it is not possible to determine accurately the percentage 

 of unburned hydrogen or hydrocarbons in the flue gases. 



The weight of dry gas per pound of combustible is found by multiplying the dry gas per 

 pound of carbon by the percentage of carbon in the combustible, and dividing by 100. 



t CO 2 and CO are respectively the percentage by volume of carbonic acid and carbonic 

 oxide in the flue gases. The quantity 10150 = No. heat-units generated by burning to car- 

 bonic acid one pound of carbon contained in carbonic oxide. 



XXII. Report of the Trial. The data and results should 

 be reported in the manner given in the following table, omit- 

 ting lines where the tests have not been made as elaborately 

 as provided for in such table. Additional lines may be added 

 for data relating to the specific object of the test. The extra 

 lines should be classified under the headings provided in the 



