2
THE BATTALION
Mrs. ParkhilPs
Across from Aggieland
Pharmacy
Good Coffee
And Sandwiches
anytime—
Day or Nig-ht
Pure Wool
Sweaters
$5*90
J. C. PENNEY CO.
42 out of 54
colleges choose
this FAVORITE
pipe tobacco
and Yale agrees
TOOK UP at the windows of
J j ITarkness to find out what
the Yale man smokes. In the spring
time you’ll see him sitting in his
window seat with a pipeful of
Edgeworth between his teeth.
On Chapel Street. .. out at the
Bowl. .. everywhere the Yale man
goes, his pipe and Edgeworth go
with him. And at 42 out of 54 of
the leading colleges and universities
Edgeworth is the favorite tobacco.
A tobacco must be good to win
the vote of so many discriminating
smokers. And Edgeworth is good.
T o convince y ourselftry Edgeworth.
You can get it wherever tobacco is
sold... ijf! a tin. Or, for a generous
free sample, write to Larus & Bro.
Co., 105 S. 2ad St., Richmond,
Virginia.
EDGEWORTH
SMOKING TOBACCO
Edgeworth is a blend
of fine old hurleys,
with its natural savor
enhanced by Edge
worth’s distinctive
eleventh process
Buy Edgeworth any
where i n two forms
— “ Ready-Rubbed ”
and “Plug Slice.” All
sizes, 15^ pocket
package to pound
humidor tin.
HOT WATER HEATING SYSTEMS
By
F. E. Gieseke, College Architect
The Estimated Cost Of Heating Hart
Hall
To determine the cost of heating a
building for a given period of time it
is necessary to know the quantity of
heat lost by the building during that
period and the cost of producing heat
and of delivering it to the building.
In determining the heat lost by a
given building, Hart Hall, for ex
ample, it is customary to assume that
the indoor temperature should be
maintained at 70 degrees, and that the
heat lost by the building is propor
tional to the differences of the indoor
and outdoor temperatures. For ex
ample, for indoor and outdoor tem
peratures of 70 degrees and 25 de
grees, and of 70 degrees and 55 de
grees, the respective temperature
differences are 45 degrees and 15 de
grees and it is assumed that the heat
loss of the building is three times as
large in the former as in the latter
case.
It is known from experiment and
from experience how much heat will
flow through various types of build
ing materials and it is therefore com
paratively easy to calculate the heat
losses of buildings under given condi
tions. For example, Hart Hall will
lose about 850,000 B. t. u. per hour
when the outdoor temperature is 25
degrees, the hall temperature 55 de
grees and the room temperature 70
degrees.
In addition to the heat lost by a
building through the walls, floors and
roof, heat is also lost with the air
which is used for ventilation, and
which flows through the building, en
tering at the outdoor temperature and
leaving at the indoor temperature.
At 70 degrees one B. t. u. will heat
about 55 cubic feet of air one degree.
If we assume for Hart Hall that ev
ery occupant should be provided with
1400 cubic feet of outdoor air per
hour, the heat loss for ventilation will
be about 350,000 B. t. u. per hour
when the outdoor temperature is 25
degrees; the total heat loss for the
building will, therefore, be about
1,200,000 B. t. u. per hour.
The most efficient method of se
curing the ventilation referred to is
to lower the upper sash and to raise
the lower sash. When that is done
outdoor air will flow ’ .0 the room
through the lowf" c of the window
and indoor air win flow out through
the upper j'art of the window, and the
outdoor atmospheric pressure will be
equal to the indoor atmospheric
pressure at an elevation at or near
the center of the height of the win
dow. The zone in which the two at
mospheric pressures are equal is the
neutral zone. The flow of the air
through the windows can be demon
strated by a simple calculation. Let
us assume that the windows are six
feet high, that the neutral zone is at
the center of the height of the win
dows, that 70 degrees air weighs 75
pounds and 25 degrees air 82 pounds
per 1,000 cubic feet. If the atmos
pheric pressure at the neutral zone is
W pounds per square foot, the out
door pressure three feet above the
neutral zone will be W—3 x .082 and
the indoor pressure will be W—3 x
.075. The indoor pressure is there
fore 0.007 pounds per square foot
greater than the outdoor pressure;
this excess pressure causes the air to
flow outward through the upper part
of the window. A similar calculation
will show that at the bottom of the
window the outdoor pressure is aboul
0.007 pounds per square foot greater
than the indoor pressure and will
cause the air to flow inward at the
bottom of the window.
Knowing that the heat loss of Hart
Hall under normal conditions is
1,200,000 B. t. u. when the outdoor
temperature is 25 degrees, the heat
loss for any other outdoor tempera
ture can be determined by proportion.
For example, when the outdoor tem
perature is 55 degrees, the heat loss
will be 400,000 B. t. u. per hour.
The next step in the calculation is
to determine the probable total heat
requirement for the heating season.
The period during which heating may
be required varies with the latitude.
For College Station we may assume it
to extend from October 1 to May 1, a
period of seven months. The average
mean temperature for this period at
College Station for the past 29 years
was 59 degrees, according to the U.
S. Weather Bureau records.
Assuming that the heat is to be
supplied to buildings only when the
outdoor temperature is 65 degrees or
lower, the mean indoor and outdoor
temperature difference is 65 - 59 or 6
degrees for the seven-month heating
period. If we apply the name “de
gree-day” to the quantity of heat
which must be supplied to a building
during a period of 24 hours when the
outdoor temperature is one degree
below 65 degrees the total quantity of
heat to be supplied to the building at
College Station will be 212 x 6, or 1272
degree-days.
The concept “degree-day” just de
scribed was first proposed by the
American Gas Association. It is now
in general use for calculating the heat
requirements for different localities.
According to a diagram published in
Heating and Ventilating, February,
1930, the number of degree-days
along the 98th meridian varies about
as follows: South Texas, 1,000, North
Texas, 2,500, Oklahoma, 3,000, Kan
sas, 5,000, Nebi’aska, 6,500, South Da
kota 7,500, North Dakota, 9,500.
I believe that the heating load, 1272
degree-days calculated above for Col
lege Station, is too small for two rea
sons. First, because I believe we
should reckon our degree-days with
70 degrees as the basis instead of
with 65 degrees, and second, because
the mean temperature cited above is
the mean of the daily maxima and
daily minima and this does not rep
resent the mean temperature for
which heat must be supplied. On
many days from October 1 to May 1
the maximum temperature at Col
lege Station is above 70 degrees. I
believe these high temperatures
should be replaced by 70 degrees be
fore the mean temperature for heat
ing purposes is calculated. For ex
ample, if we consider the heating sea
son October 1, 1928, to May 1, 1929,
and campare the actual mean tem
peratures with those found by sub
stituting 70 degrees for all maximum
temperatures higher than 70 degrees,
we secure the following monthly and
seasonal mean temperatures:
Oct.
73.8
56.5
Nov.
57.4
55.0
Dec.
49.8
49.1.
Jan.
50.7
49.8.
Feb.
44.8
44.4.
Mar.
63.3
57.4.
Apr.
71.0
60.0.
Season
59.7
53
And we find that the mean tempera
ture for heating purposes is 53.2 di-
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vided by 59.7, or 0.888 of the actual
mean temperature for this particular
period.
If the same percentage may be ap
plied to the 29-year period referred
to above, the desired mean tempera
ture is 0.888 x 59, or 52.4.
The number of degree-days which
should then be used for heat calcula
tions at College Station will be 212
times 65 minus 52.4, or 2671, instead
of 1272 as calculated above. However,
if the number of degree-days are cal
culated with 70 degrees instead of 65
degrees as the basis, the number will
be 212 times 70 minus 52.4, or 3731 in
stead of 2671.
It was shown above that the heat
loss of Hart Hall is 1,200,000 B. t. u.
per hour when the outdoor tempera
ture is 25 degrees. If the outdoor
temperature were to remain con
stant at 25 degrees for an entire day
(Continued on page 3)
AGGIELAND TAILOR SHOP
TAILOR MADE
Shirts and Breeches
Blouses and Slacks
Cleaning Pressing and Alterations a Specialty
WIN OR LOSE — THE AGGIES FOR US.
FRANK ZUBIK, Prop.
The Ideal Gift For Christmas
YOUR PHOTOGRAPH
Kodak Finishing Picture Frames
Aggieland Studio
JOE SOSOLIK, PROP.
SEVENTY
NNIVERSARY
pi% of the energy we
use demands VALVES
“ Eighty-seven per cent of the energy zve use in
our daily life . .. heat energy as well as mechan
ical energy, exclusive of that produced in our
own bodies and brains... is derived from the hy
drocarbon chain, coal, oil, and gas. Waterpower
yields 4.°/ 0 , firewood 6%, work animals J}%.”
George Otis Smith, U. S. Geological Survey
Take away the 87% of energy now ex
tracted from coal, oil, and gas . . . and we
would be back in the year 1855... the year
Crane Co. was founded. Take valves and
fittings away, and we would be deprived
not of 87 but of 91%. For from water
power as well as from coal, gas, and oil,
energy is almost never extracted in the
modern world but valves and fittings enter
into the process.
It is significant that the history of Crane
Co. and the history of modern utilization
of natural energy, cover almost exactly
the same period. Many years ago. Crane
metallurgists and engineers began the de
velopment of piping materials for each
new need as it appeared. The years since
have seen every Crane resource . . . re
search, engineering, production . . . de
voted to supplying materials that would
keep the road to progress open.
What Crane has learned and the materials
that it has developed will be of vital in
terest to you after you leave school.
Let us send you the story of research
in piping metals, “Pioneering in Science.”
l C RAN E
PIPING MATERIALS TO CONVEY AND CONTROL
STEAM. LIQUIDS. OIL, GAS, CHEMICALS
CRANE CO., GENERAL OFFICES: 836 S. MICHIGAN AVE., CHICAGO
NEW YORK OFFICES: 23 W. 44TH STREET
Branches and Sales Offices in One Hundred and Ninety-six Cities