PART IV
Cooling Devices
CHAPTER XVI
Refrigerators
116. Principles of Refrigeration. Refrigerators (Fig. 56) are designed to prevent the rapid spoiling of food by keeping it too cool for the rapid growth of bacteria. They vary considerably in their efficiency, according to their construction and to the way in which they are managed. To preserve food and to save ice, the housewife must understand her refrigerator, and she must choose a good one. There is as much difference in the efficiency with which housewives manage their refrigerators as there are differences in refrigerators.
Fig. 56. Refrigerator.
A series of experiments were conducted with a number of different makes of refrigerators. When the outside temperature was between 80 and 90 degrees Fahrenheit, and when the refrigerators were kept full of ice, it was found that the temperatures in different refrigerators varied between 45 and 60 degrees Fahrenheit. When the refrigerators were only partly full of ice, their temperatures rose several degrees.
The refrigerators which held a temperature of 45 degrees when filled with ice, or with 100 pounds, used 25 pounds of ice each in three days, while in the same three days, the ones which could maintain only a temperature as low as 65 degrees, used 50 pounds each. The warmer the inside of a refrigerator, the faster the ice melts.