It is a positive fact, not very creditable d either to the genius of our age, or the econom- c cal habits of those who use steam, that at a east one half of all the useful duty which nay be obtained from fuel is lost or thrown i: iway. In scanning the surface of a manu- a 'acturing city or village, from a neighboring p elevation, volume after volume of steam is g seen rapidly shooting up in clouds from a I mndred sources, as if it cost nothing, and v was only fit to be thus "cast out." Those who c :hus waste steam do not seem to know that c jvery thousand pounds of water generated i nto vapor, and thus allowed to escape at fif- I ;een pounds pressure on the square inch, in- solves the loss of at least one hundred pounds Df coal, under the very best boilers in use. 1 Ihe loss incurred in this waste of steam in s working engines, taking into account the vast j lumber which are employed throughout the c country, must amount to several millions of i dollars annually. But there is another great 1 source of loss in steam boilers themselves, and s this is much greater than the other—we mean i the small quantity of steam generated in boil- i ers in proportion to the fuel used. If we en- quire into the quantity of water which one i pound of the best coal can evaporate into 1 steam, under the most favorable circumstan- i ces, we find that it amounts to from twelve to J fourteen pounds, whereas the quantity of ] water generated into steam under the very 1 best boilers in use, does not exceed ten pounds, 1 or nearly thirty per cent. less. But although 1 this is a great loss, it would, not excite so much surprise, if the majority of steam boilers work- ' ed up to this standard; the case, however, is : far otherwise. There are but few steam boil- '. ers which are thus economical—not one in a thousand perhaps-—the great majority of them do not evaporate seven pounds of water to one of coal consumed, and a vast number, we ! are assured, do not evaporate five pounds of water. Now here is a subject, not for speculation, but practical effort. When we take into consideration that many thousand engines are now employed, throughout the extent of our country, and reflect that at least fifty per cent, of the fuel used in them is wasted, or lost, surely, it requires little to be said in directing attention to this field, as one inviting to all those who would open a rich mine of wealth to active industry—every dollar saved in economising power, being just so much gain to the whole community. It is true that much has been done in introducing improvements j for saving fuel and steam, and it is not too j broad an assertion to make, that at least j twenty per cent, of fuel is now saved, in comparison with the amount consumed ten years ago, in most boilers ; this result has been accomplished, chiefly, by the extended use of j multitubular flues, and the more careful enclosing of the boiler, with good non-conducting covering to retain the heat, but for all this, greater improvements have yet to be made before the goal of perfection will be reached in economising steam fuel. It has been calculated by those who have devoted attention to this subject, that at least $40,000,000 are expended annually for the fuel of our steam-engines, one half of which sum is actually money lost or thrown away. The very consideration of this fact is somewhat astounding, and imparts a phase, almost akin to insanity, on the part of all those financially interested in fuel consumption. All kinds of coal will not evaporate fourteen pounds of water per pound, but Cumberland coal, which is equal to the best Newcastle, will; and if, in the best boilers, there is nearly thirty per cent, of loss with the best fuel, the conclusion at which any person must arrive, in view of this fact, is that, under all our steam boiler's, J burning all kinds of fuel—wood, coal, &c.— there is a monstrousloss continually going on, which ought to be, and no doubt will yet be, curtailed.
This article was originally published with the title "Loss of Heat in Steam Boilers" in Scientific American 13, 13, 101 (December 1857)