Radiator

“ With these the heating is accomplished entirely by convection, while with direct radiators the radiant heat rarely amounts to 40 per cent., generally not over 30, and often in practice considerably less. For a radiator in any particular location the radiant heat is constant for the same conditions of temperature of the radiator and surrounding objects, and is independent of currents of air. ”

“ The picture (Fig. 15, after Jacobs) shows the arrangement of the radiators in one of the buildings of the University of Pennsylvania. A is the opening in the wall [Pg 80] below the window; D is a valve which regulates the amount of air entering through the opening; R is the radiator; B is a tin-lined box which surrounds the radiator; T is a door in front of the box, which when raised allows the air of the room to be heated and to circulate through the radiator. By adjusting the two valves D and T, air of any desired temperature can usually be obtained. ”

“ Surface of radiators.—There are other considerations which alter the effectiveness of a radiator besides the design and setting, notably the condition of the surface. Radiators are rarely used with the natural iron surface, but are painted in all possible ways. The nature of the surface has practically no effect on the convected heat, but a very decided effect on the radiant heat; but as the latter is generally less than 35 per cent, of the whole, the effect on the total heat emitted is not so marked. Furthermore, usually only the top and outside surface of one side is painted at all. ”

“ But radiators are invariably built of clusters of pipes or surfaces, and as radiant heat travels only in straight lines and perpendicular to the surface of its source, a large proportion of the surface is wasted so far as radiant heat is concerned, due to what may be called the mutual interception of the rays. In the ordinary one-column cast-iron radiator, the proportion of surface from which no radiant heat takes place is nearly 20 per cent., in the two-column, 45 to 55 per cent. ”

“ But it is impracticable to have all the radiators of a system turned on at one time, and the difficulty with such a system is made evident the minute steam is turned into a cold radiator. When the steam comes in contact with a perfectly cold radiator a large amount is condensed at once in heating the cold iron, and as soon as the pressure becomes adjusted this bulk of water flows out of the radiator connection at one time and drops down the vertical pipe. ”

“ This means quick and positive venting for steam, vapor, or hot water installations and provides rapid circulation, causes radiator to heat up more rapidly.
Air Vent (Steam heating)
The air vent on each main, allows the air to escape so that the heat arrives more rapidly to radiator. This of course, saves fuel.
Heat Controls
To take the heating of your home out of the area of dreams and out of the expensive realm of “feeling,” some sort of heat regulating device is recommended. It is foolish to say “Do you think it is warm enough?” to a group in the room. For no two will think alike! ”

“ Where this kind of radiator is used in connection with an exhaust ventilating system very good results are obtained by using the author's formula for direct radiators, with an addition to the of , where is the cubic feet of air per hour required for ventilation. This gives additional surface necessary to heat cubic feet of air from the outside temperature to that of the room. The author figures on (in some cases 3⁄4) , as in extreme weather the degree of ventilation may be somewhat reduced. For these radiators also, the factor in the formula may be taken as 1.9 or 2. ”

“ The Full Radiator.—We have assumed that a lamp-blacked surface is a perfect absorber, and consequently a full radiator, but although it is a very near approach to the ideal it is not absolutely perfect. No actual surface is a perfectly full radiator, but the exact equivalent of one has been obtained by an ingenious device. A hollow vessel which is blackened on the inside has a small aperture through which the radiation from the interior of the vessel can escape. ”

“ Ordinarily, when steam is shut off from a radiator it fills with air at atmospheric pressure, through the air valve; and when steam is turned on, this air must in some way be allowed to escape before all of the surface can have full heating effect. The rapidity with which the air will be displaced by the steam depends on where the air valve is placed and on the design of the radiator. In some radiators the air will flow out the air valve and be followed up by the steam rapidly and uniformly; while in others the air will pocket in places, and it may be hours before it all works out. ”

“ As stated in a previous chapter, in the opinion of the author the use of the direct-indirect radiator, which has been, up to this time, and is now, very limited, will be materially increased in the immediate future, as in connection with exhaust fans they form an effective means of introducing adequate ventilation into buildings which are not very densely populated but in which there is a decided need of ventilation. ”

“ Another method, where steam or hot-water radiators are placed in the room, is to connect the outer air, either through the lower part of the window or through the wall of the room just below the window opening, with a space back of the radiator, so that the cold air entering will pass around and through the radiator and so be warmed as it enters. ”

“ A radiator with several swings is less violent at its first impulse than is a momentary emitter; but then the lessened emitting power of a radiator is to be compensated by a correspondingly prolonged duration of vibration on the part of the receiver or absorber, thus rendering the radiator susceptible of tuning to a special similarly-tuned receiver or resonator. ”

“ Radiators should not be fixed directly on to the main heating pipe, but always on branches of smaller diameter leading from the flow pipe to one end of the radiator and back to the main return pipe from the other end; they may then be easily controlled by a valve placed on the branch from the flow pipe. To each radiator should be fitted an air tap, which when opened will permit the escape of any air that has accumulated in the coil; otherwise free circulation is impossible, and the full benefit of the heat is not obtained. ”

“ Seemingly they use their pride to keep themselves warm. At any rate, whenever Edward Henry talked to them of radiators, they would sternly reply that a radiator did not and could not brighten a room. Edward Henry had made the great discovery that an efficient chandelier will brighten a room better even than a fire; and he had gilded his radiator. The notion of gilding the radiator was not his own; he had seen a gilded radiator in the newest hotel at Birmingham, and had rejoiced as some peculiar souls rejoice when they meet a fine line in a new poem. ”

“ In buildings of the second class, such as residences, office buildings and hotels, we have been, as a rule, satisfied with sufficient heat, and have relied upon such ventilation as is secured by the natural circulation methods. In such buildings, therefore, the system of heating most used is that known as "direct radiation," in which radiators, or some form of radiating surface, are located in each room, and connected by an arrangement of piping to a central source of steam or hot-water supply. ”

“ As the temperature of a full radiator rises it first gives out only invisible heat waves; as soon as its temperature exceeds about 500° C. it begins to emit some of the longest visible rays; and as the temperature rises further, more and more of the visible rays in the spectrum are emitted until, when the radiator is white hot, the whole of the visible spectrum. is produced. Thus the higher the temperature of the radiator the more of the shorter waves are produced. ”

“ It’s delightfully warm, now that we’ve got the radiators, though I don’t suppose anyone would want a radiator on in the summer, but still, there it is, and so I thought I’d simply make an inclusive charge for heating and lighting. ”

“ In laying out the floor plans for the heating system of a large office building it is a mistake to try to reduce the number of risers to a minimum. It is much better to put in risers enough so that a radiator can be placed under any window in the building without too long a connection from the riser, for in such buildings one can never know what changes in the arrangement of rooms or in the location of radiators may ultimately be desired. ”

“ Your hands would receive the heat readily by conduction, but the air does not.
“And the tea-kettle,” continued his father, “does not radiate the heat very fast, because it is a bad radiator. It is made so on purpose.”
“What do you mean by a bad radiator, father?” asked Rollo.
“Why, all white, and bright, and polished surfaces radiate very little,—and all dark, and dull, and rough surfaces radiate very fast. So the bright surfaces are called bad radiators, and those that are of dark color and dull, are called good radiators. ”

“ Having selected the system of heating to be employed according to the needs of the building in hand, and having proportioned the radiator surface according to the requirements of the various rooms, it then remains to lay out the system of piping and arrange the various details of construction. ”

“ The radiator is a complex affair and soldering it used to be a matter of skill. There are ninety-five tubes in a radiator. Fitting and soldering these tubes in place is by hand a long operation, requiring both skill and patience. Now it is all done by a machine which will make twelve hundred radiator cores in eight hours; then they are soldered in place by being carried through a furnace by a conveyor. No tinsmith work and so no skill are required. ”

“ A radiator for heating a room should therefore have a dull, dark surface, while a vessel which is designed to keep its contents from losing heat should have a highly polished exterior.
A perfectly transparent substance would radiate no energy, whatever the temperature to which it is {42} raised, for its absorbing power is zero and therefore its radiating power is also zero. No perfectly transparent substances exist, but some substances are a very near approach to it. ”

“ If the radiator is not kept free from oil the outside passages will very quickly collect dust, which will prevent a free flow of air and cut off radiating surface, which also occurs when the front of the radiator is smeared too thickly with paint. ”

“ In practice, a given radiator in a given setting, and with given temperatures of steam and outside air, condition of wind being constant, will deliver a definite amount of air heated to a definite degree and the velocity and final temperature adjust themselves until there is an equality between the temperature head acquired and the velocity head plus the head necessary to overcome the resistance. ”

“ We put alcohol in the radiator to be safe at about zero degrees. You couldn't put anymore than that because every time the car got warm it would boil over. On very cold nights we would drain the radiator into a large pan and take it into the cabin. One night it went down to 26 degrees below zero and I believe that is still the record for this area. We took the mattress off the other bed and put it over us and a big wooden chair on top of that to keep it from sliding off. Clarence always got up first in the morning and I still hear him crumpling newspapers to start the fire again if it was out. ”

“ The advantage of a large radiator is the comparative ease with which the receiver can be adjusted to respond to the waves, but this advantage is more than counterbalanced by the increased difficulty with the stray radiation and other disturbances. ”

“ This method is frequently adopted in combined schemes of heating and ventilating; the fresh air is warmed by being passed over their surfaces previously to being admitted through the gratings into the room. Direct radiators are a development of the early coil of pipe; they are made in various types and designs and are usually of cast iron. Ventilating radiators are similar, but have an inlet arrangement at the base to allow external air to pass over the heating surface before passing out through the perforations. ”

“ Consequently an air valve is almost a necessity on every radiator, and those which are now almost universally used are automatic; that is, they close as soon as the hot steam comes in contact with them, and open if air accumulates and they become cold. ”

“ ORBIT After orbiting for approximately 30 minutes, to allow the radiator to cool after being subject to launch heating, the coolant flow is directed through the space radiators by manual selection of the radiator switch located on the center panel. This by-passes the ground cooling heat exchanger. The evaporator selector valve is also positioned so that only the flow to the suit and cabin heat exchangers pass through the evaporator. ”

“ Radiator connections are frequently encased in the floor, but it is generally difficult to accomplish this in fireproof buildings, as the space between the floor level and the top of the iron beams is not generally sufficient to box in the connections and make proper allowance for the vertical movement of these connections due to riser expansion. ”

“ Keeping the radiator protected against freezing is not complicated. Nearly any filling station has the necessary hydrometer. To be sure the anti-freeze liquid has not evaporated unduly, have the radiator contents tested about once in two weeks, particularly after several days of abnormally warm weather. For real safety, it is wise to have any automobile radiator filled with enough of the compound so that its freezing point is fully ten degrees colder than the lowest temperature expected. ”