January, 1920 
REFRIGERATION 
The Principles By ll hich Electrical Ice-Making and 
Refrigerating Machmes Work 
GRACE T. HADLEY 
59 
A T 
HOME 
A rtificial refrigeration, is not new, but 
. until recently it has not been practical to 
build ice-making machines of small capacity. 
Now there are several machines of a size suit¬ 
able to residences. These machines serve for 
cooling and to make ice in limited quantity. 
They are practically automatic in operation 
and while calling for a moderate investment at 
first they show practical economy over old 
methods of cooling. The small motor-driven 
refrigerating machine is, in fact, a modem 
household essential. The turn of a switch 
brings winter’s cold! 
Electricity has won another household tri¬ 
umph. Over the same wires that bring cur¬ 
rent to light your home, to heat your iron or 
your toaster, to run your range, now comes the 
same current to cool your ice box. It seems 
marvelous to frigerate without ice, yet it is only 
the application to the home of a principle made 
use of commercially for years—mechanical re¬ 
frigeration. 
Most of the artificial ice companies licjuefy 
ammonia gas under pressure. The different 
mechanical appliances used in handling the 
ammonia are connected in such a way as to 
form a complete cycle called the ammonia 
cycle, around which the ammonia travels con¬ 
stantly. Other refrigerants which can be used 
are sulphur dioxide and ethyl chloride. One 
process for producing intense cold depends 
upon the expansion of compressed air in hair¬ 
like tubes. Electric power is used for com¬ 
pression in each case. 
Laboratory methods of producing low tem¬ 
perature by means of the so-called frigorific 
mixtures by which a perceptible drop in tem¬ 
perature is jwoduced by certain chemical re- 
In several of the systems the 
machinery is placed in a com¬ 
partment at the bottom of the 
refrigerator with the coil box and 
ice making trays in a section 
above. Where the machinerv is 
so installed it must work silently. 
Courtesy of the Frigidaire Cor¬ 
poration 
Other systems call for an installa¬ 
tion of two sections—the con¬ 
densing machinery in the cellar, 
a pump motor and condenser coil 
which is connected with the brine 
tank in the freezing chamber of 
the refrigerator above. Courtesy 
of the Kelvinator Corporation 
The coil system is used in practically all 
the home refrigerating systems. These 
roils are set in a compartment of the ice 
box, and in addition to refrigerating, they 
make ice cubes. Courtesy Frigidaire Corp. 
actions and solu¬ 
tions, have been 
known for at least 
three centuries. The 
reduction of the 
temperature of wa¬ 
ter by the melting of 
saltjjeter is said to 
have been known in 
India at a very re¬ 
mote period. The 
Romans cooled wine 
by immersing the 
bottle containing it 
in a second vessel 
filled with cold wa¬ 
ter into which salt¬ 
peter was gradually 
thrown, while at the 
same time the bot¬ 
tle was rapidly ro¬ 
tated. Probably the 
most common ex¬ 
ample of a frigorific 
mixture is that of ice or snow and salt. The 
addition of a foreign substance to a liquid 
lowers its freezing point. 
Primitive Methods 
Prom earliest times man has recognized that 
perishable foods should be kept in a cool 
place, though he probably did not know at 
first that their decomposition was due to the 
development within the food of living organ¬ 
isms; had primitive man known this a solu¬ 
tion of the problem of food preservation might 
have been forthcoming before our day, but all 
that was understood was that food tasted bet¬ 
ter and it kept fresh longer when put in a 
cool place. Is it any wonder then that man¬ 
kind sought by every means to keep food cool 
and immune from molds and decomposition? 
Trees were hollowed and perishable foods 
stored within them. Caves were dug and bot¬ 
toms of streams were tried for the same pur¬ 
pose. In more modern times the cellar floor 
(Continued on page 66) 
