HEAT AND VENTILATION.--COMMON HEATING ARRANGEMENTS.--PRESENT
METHODS GENERALLY UNSATISFACTORY.--IDEAL CONDITIONS.--PROPER AMOUNT
OF MOISTURE RARELY ATTAINED.--A FURNACE DEFINED.--METHODS OF
REACHING BEST RESULTS.--SUPPLY OF PROPER AMOUNT OF
MOISTURE.--REMOVAL OF FOUL AIR.--SUPPLYING FRESH AIR WITH PROPER
MOISTURE FROM STOVES.--STEAM AND HOT WATER HEATING.--DIRECT AND
INDIRECT RADIATION.--LOW-COST HEATING APPARATUS.
It is only within a short time that the heating and ventilation of
buildings of any kind have been in any measure satisfactory. This
applies only to the largest buildings; the heating and ventilating of
smaller structures are still in an unsatisfactory condition. Most
dwelling-houses are heated with stoves, which, as now arranged, are not
successful. The same air is heated over and over again. Fresh air in the
proper quantities or from the proper source is not supplied to the
interior of the building. Grates are very well in their way in that they
take large quantities of air from the room. Thus far they ventilate. The
supply of air is necessarily irregular, unless special means are
provided.
Furnaces are used for heating a very large number of houses. While they
are satisfactory in some respects, they are deficient in others. The
same thing may be said of steam, hot-water, or other heating apparatus.
As the statement has been made that heating systems in general, as
applied to dwelling-houses, are unsatisfactory, it may be well to state
the fault, and what is to be desired. It is not the purpose to consider
this question chemically, or from a highly scientific standpoint; there
is no occasion for it. It is well to bear in mind that we are
considering the heating and ventilating of a house during cold weather,
and not its ventilation during the summer, when natural means are to be
relied upon. Then it may be asked, What is to be done? Primarily the air
should be at the proper temperature at all times; it should be in its
pure state, as found on the outside of the building, and not
contaminated with any of the gases of combustion. It should be supplied
with its proper equivalent of moisture at the temperature at which we
find it in the room. As it becomes impure from natural causes, there
should be some means of effecting its withdrawal.
These are the ideal conditions. How far do they exist in practice? The
temperature is ordinarily high enough. The air of the room is apt to be
contaminated by the gases of combustion, and vitiated by breathing and
otherwise. Rarely indeed does it contain its proper equivalent of
moisture; it is dry and parched. Now that we know the conditions in
their ideal state and as they exist in fact, we will consider in detail
what may be done to bring about more satisfactory results. If the
heating apparatus be a furnace, it should be constructed of steel or
wrought-iron plate, the joints thoroughly riveted and calked; or, if of
other material, it should certainly be gas-tight. Every precaution
should be taken to prevent the passage of the air of combustion from the
furnace to the warm-air chambers and from thence to the rooms above. The
furnace is nothing more or less than a large stove with various
radiating arrangements, surrounded by an iron or brick enclosure, with a
supply of fresh air from the outside, and with connecting tin pipes to
the rooms above. It is important that the inner parts, the fire-pot,
the radiating surface, etc., be thoroughly well built and gas-tight, to
prevent the heated air from becoming contaminated by the gases of
combustion. The supply of outer air should be ample. It should be so
arranged that it can never be entirely cut off. The furnace should be of
sufficient capacity so that means of reducing the outer air supply
should not be necessary. However, if such arrangements are made, they
should be limited.
The proper equivalent of moisture should be given to the air at the
temperature at which it reaches the room. It may be said that there is a
water-pan connected with every furnace, that will do everything
necessary in supplying moisture. This is a mistake. So far as I know,
the furnace or other heating apparatus for dwellings has not been
constructed which is provided with a proper evaporating apparatus. The
pan is set in the side of the furnace, with an opening to the outside
into which water may be poured. It is small, and has very little
evaporating surface on the inside. Oftentimes the joints at the outside
are so poorly made that the cold air from the cellar may be drawn in
over the water in the pan, and in that way prevent its proper
evaporation. Winter air heated to a summer temperature is dry and
parched, whereas natural summer air contains the proper amount of
moisture. The outer air during the winter time has its proper equivalent
of moisture for the winter temperature, which is a much smaller amount
than would belong to it at a higher temperature. Therefore when we take
winter air into the furnace or other heating apparatus, raise it to a
summer temperature, and carry it into a room, we have a very dry air,
which seeks its equivalent of moisture from the occupants of the room,
from the furniture, carpets, walls, ceiling, and everything in it. The
air will not take additional moisture unless that moisture be supplied
after it has reached a higher temperature. For instance, if a spray or
a series of wet blankets be arranged in the cold-air duct, before the
air gets to the furnace, the air will not take the moisture from that
spray or from the damp blankets. The moisture must be supplied after the
air is heated. Where the water-pan is set on the side of the furnace,
and where there is a supply of air through the pan from the cellar, as
there frequently is, evaporation is naturally retarded by the cold air,
as indicated. Again, if this pan be never so well protected, it is
small, the proper amount of evaporating surface is not presented. An
evaporating pan or other device should be placed above the fire-pot and
should occupy a large proportion of the area of the heating chamber. The
supply of water should not be dependent upon some one's attention. It
should be constant by means of a ball-cock or otherwise. It should run
into or drip into a shallow pan, or should be supplied to sheets of felt
or blanket so that the air will come in contact with the moist surfaces,
at the temperature at which it is to go into the room. Thus it has the
proper amount of moisture which belongs to it at that temperature. In
this way we have winter air from the outside going into the room at a
summer temperature and with a summer equivalent of moisture; that is, we
have summer air in the winter time. People sometimes undertake to get
around this by putting water-pans in the registers, but they are rarely
ample. They are neglected, or they interfere with the supply of warm
air, and are abandoned.
Where a furnace is already in a house, or where it is not possible to
make elaborate arrangements for providing the air with moisture, there
is a very simple makeshift which is quite effective. It consists in
suspending in the registers in the floor small water receptacles--a
quart bucket answers every purpose--in which is placed a broad strip of
linen. This cloth should go to the bottom of the receptacle and be long
enough to hang over and below it for several inches. When the bucket is
filled with water this piece of cloth acts as a siphon, and carries the
water, a drop at a time, into the furnace-pipe, where it is converted
into steam. A piece of old table-linen is the best material to use, for
the reason that it carries the water fast enough, that the heat from the
furnace does not dry it out before it can drop into the pipe; otherwise
the cloth becomes dry at the end, and the siphonage ceases. For the same
reason it should be broad,--about twelve inches. Where a moderate heat
is carried through the furnace-pipe, three quarts of water may be
evaporated in this way in twenty-four hours from each bucket. A bucket
of the size mentioned does not in any way interfere with the passage of
heat.
The next point for consideration is the means of getting the foul,
contaminated air to the outside. One way is through the use of grates.
Another is by means of ducts in the wall, opening near the floor, which
draw the foul air from the room to the outside. These should consist of
heated flues, with connecting registers in the ceiling and floor, which
may be open when necessary. Under any circumstances, the grate is best.
Sometimes the flue may be heated by a supply of warm air from the
furnace, or by a steam-pipe in case steam is used for heating the house.
In natural-gas regions, the supply of additional heat in a flue from a
furnace or by a jet would be a small matter.
We have mentioned heating by stoves, grates, and furnaces. The same
principles which apply to the furnishing of fresh air to a furnace may
be applied to a stove. The fact is, they never have been. A stove should
be made, and will be made some day, that is surrounded on the outside by
a second jacket, the space between being connected with the outer air by
means of a tin tube to the under side of the stove. The supply of cold
air could be so arranged as to be shut off when there was no heat in the
stove. The warm air would pass out at the top of the jacket. On top of
the stove could be placed an evaporating pan, and the supply of moisture
come therefrom. In connection with the stove-pipe, which should be
jacketed, a second ventilating flue, starting from the floor and having
an opening both above and below, could be arranged, and in that way the
supply of fresh air and withdrawal of impure air could be accomplished.
Next we may speak of steam and hot-water heating. So far as a change of
air and the ventilation of the room are concerned, heating by direct
radiation, that is, by radiators placed in the room, is no better than
stove heating. It may be that the air is not so severely parched by the
extreme heat, also the escape of steam may contribute somewhat to the
moisture of the air; but the escape of steam is not agreeable, and is
not allowed to exist to any great extent;--its odor is not always
pleasant. Certainly the addition of moisture to the air by this means
would be a mere makeshift and unsatisfactory.
Hot-water coils act the same as steam radiators in that they heat the
same air over and over again, and are no better than stoves, so far as
the provision for fresh air, at proper temperature and humidity, is
concerned.
A steam or hot-water apparatus, with indirect radiation, is superior to
furnace heat as ordinarily provided. The means of supplying moisture to
an indirect steam apparatus, as ordinarily constructed, are not
convenient. There is a radiator for each hot-air connection above, that
is, a radiator for each register, with a distinct and direct supply of
outer air thereto. Sometimes there are two registers connecting with a
single radiator. But under any circumstances the radiators are somewhat
separated, having steam or water connection with the boiler at the
proper point. Steam apparatus for public buildings has been constructed
where the radiators have been bunched, that is, put into a single
chamber, the air passing through the chamber containing the radiators,
where it is heated to the proper temperature, and the moisture
afterwards supplied before it enters the room. Where this arrangement is
used, there must be conductors, tin or otherwise, from the chamber to
the register, as in the case of a furnace. Again, it will be found that
the supply of air will not be uniform through all of the openings; for
instance, the register that is farthest removed from the warm-air
chamber may fail to act. In this event, auxiliary radiators may be
placed under that register, and the operation of the heating apparatus
greatly facilitated thereby. This plan is superior to a furnace, and can
be applied to hot-water or steam apparatus in dwellings. The reason that
it is superior to a furnace is that the supply of heat is more uniform.
It does not require the constant firing or attention that is necessary
in the case of a hot-air furnace. It may be known that the temperature
does not change with the pressure of steam or in the same proportion.
There are inexpensive automatic arrangements in connection with furnaces
and steam apparatus, which control the dampers and keep the steam
pressure measurably uniform, as long as there is fuel of sufficient
quantity in the fire-pot. The hot-water apparatus is more uniform in its
operation than steam, and for that reason more satisfactory.
A furnace plant is the most inexpensive apparatus that may be used for
general heating; the steam apparatus is next higher as to first cost,
though no more expensive in amount of fuel used. The hot-water apparatus
costs more than steam, and is somewhat more economical in the cost of
maintenance. It is probable that a house of moderate size can be warmed
all over at a less cost, as far as fuel is concerned, by a furnace or a
steam or hot-water heating apparatus than by stoves and grates. However,
grates are generally used in addition to these for the purpose of
comfort and appearance, and for ventilating. Under such circumstances,
they consume very little fuel.