CHAPTER II ICE FOR REFRIGERATION PURPOSES (Part 1)

CHAPTER II ICE FOR REFRIGERATION PURPOSES Historical Data. — The practice of cooling bodies below the temperature of the atmosphere by the use of ice, has been fol- lowed for centuries. In the earlier times, the ice used for refrigeration purposes was natural ice, which formed on the rivers, lakes and ponds, during the cold winter months. The ice, after being harvested in the winter, was stored in caves in the ground, so that perishable foods could be preserved during the hot summer months. Coming up to modern times, we find, in the last half of the nineteenth century, due to im- proved methods of storing, harvesting, and distribution, that the use of natural ice for refrigeration purposes assumed a large proportion in the United States. Later, practically within the time of the present generation, means were devised whereby ice for refrigeration purposes could be procured by mechanical means in commercial quantities. Still later, within the last decade, attention has been directed to ways and means of producing refrigeration in the home by mechanical means directly. At present this subject is receiving the attention of many inventors, engineers, manufacturers, and others. New and improved devices and processes are being developed con- stantly. The National Association of Ice Industries has recently published a bulletin, entitled "The Romance of Ice," which contains an interesting review of the historical data on this subject. The following has been extracted from this bulletin : 17 18 HOUSEHOLD REFRIGERATION THE ROMANCE OF ICE Prologue. — Evt'iy i)ioducl, every industry, every modern develop- ment has its "story." Perhaps the pages have not been turned back to that he who runs may read and be interested, but the story is there. Some of our greatest untold romances concern those taken-for-granted commodities which the public sees, uses, enjoys, without giving a thought to their interesting origin or the struggles of men in their development. For example, ice is a necessity without which the public would really suffer. True the blasts of winter turn the waters of river, lake, and pond into ice; one long pufJ from Boreas' cheeks provides thous- ands of tons of ice each year, but twenty-six million American families cannot be supplied by Nature's manufactory alone. Let's turn back the pages of history for a moment and see what happened in the world of yesterday to make ice now as readily acces- sible as coal or wood. These pages reveal real romance. History. — The early Greek poet, Simonides, while at a banquet, observed that the liquor served to the other guests was cooled by snow. Whereupon he expressed his dissatisfaction in the following ode: "The cloak with which fierce Boreas clothed the brow Of high Olympus, pierced ill-clothed man While in its native Thrace; 'tis gentler now, Caught by the breeze of the Pierian plain. Let it be mine: for no one will commend The man who gives hot water to a friend." History's pages also show that the ancient Egyptians knew the secret of cooling by evaporation, as practiced by the native of India today — filling with water shallow trays of porous material placed on beds of straw, and leaving them exposed to the night winds, with the result that dawn finds a thin film of ice formed on the surface. On a very early page we find that the Emperor Nero had slaves bring snow down from the mountains to cool his wines. Alexander the Great had trenches dug for storing snow. Hundreds of kegs of wine were cooled there, with the result that his phalanxes entering battle the next day didn't care much what became of them, just so it was a good battle. Marco Polo, the great Italian navigator, brought recipes for water and milk ices from Japan and China in the thirteenth century. When Catherine d'Medici left Florence, Italy, to go to France, in the sixteenth century, she took with her the best of the chefs to make sure that she would be supplied with frozen creams and ices every day. ICE AND REFRIGERATION PURPOSES 19 Sir Walter Scott told how Saladin, leader of the Mohammedan armies, sent a frozen sherbet to Richard the Lion Hearted, much to the amazement of that doughty monarch. During the seventeenth century the French government made an unsuccessful attempt at government ownership when it licensed the business of farming snow and ice. The farmers who received govern- ment favor thereupon raised prices with such studious regularity that the people refused to buy and the Government was forced to relinquish its control of this commodity. Immediately thereafter supply and demand got into its stride and the business settled back into sanity. As Lord Bacon commented in his Sylva Sylvarum: "Heat and cold are Nature's two hands whereby she chiefly worketh, and heat we have in readiness in respect of the fire, but for cold we must stay till it cometh or seek it in deep caves or mountains, and when all is done, we cannot obtain it in any great degree, for furnaces of fire are far hotter than a summer's sun, but vaults and hills are not much colder than a winter's frost." Bacon knew what a useful thing it would be if man could have the same command of cold as of heat. Scientist that he was, he under- took experiments into its possibilities. This led to unfortunate re- sults, as he caught his death of cold by alighting from his carriage one winter day and stuffing snow into a chicken to see if it would keep. The Italians, Spaniards, and Frenchmen have always been devotees of better living, and history is filled with interesting side lights on their uses of snow and natural ice. Then we have the picture of the early fishmonger in England sell- ing ice from his wagon, a practice which is continued to the present day. The first record of American delivery of ice to the home is in 1802. The first commercial shipment of natural ice from America was ex- ported from Boston by Frederick Tudor in 180.S when a shipload was sent to Martinique in the West Indies to help stay the ravages of yellow fever. During this time all of the ice used was produced by Nature. Natural and Manufactured Ice. — One of the most interesting phe- nomena of Nature is the formation of ice. We all know that cold is the absence of heat and that the freezing point of water is 32° F. When the air above a pond, lake, or river is below 32° F., the top layer of water is cooled and will sink because it is heavier than the warmer layers underneath. This continues until all the water is cooled to 39.1° F., at which point water reaches its greatest density. The top layer will then be cooled still further but remains on top and eventually will be reduced to the freezing point and ice will form. 20 HOUSEHOLD REFRIGERATION If the water undearneath the ice is not in motion, opaque ice will form. On moving bodies of water, as rivers and large lakes, clear ice forms. This is because each drop of water in freezing sets free the air it contains. The bubbles of air adhere to the surface of the newly frozen ice crystal. As more ice encloses the bubbles, the product becomes opaque. But where the water is in motion, the bub- ble is washed ofiE the surface of the newly formed ice crystal and thus the ice forms, clear and hard. But how about the actual manufacture of ice? As Edwin F. Slosson of the Science Service, Washington, D. C, explains in his article, "Science Remaking Everyday Life:" "The chronicle of the century of effort to approach the farth- est north of temperature, absolute zero, is as fascinating as the contemporary struggle to reach the geographic pole and unlike the latter has proved profitable at every stage. When Fahrenheit in 1724 stuck his mercury thermometer into a mixture of salt and snow, he thought he had reached the lowest point possible and boldly scratched zero on the tube. But it was not long before scientists began to climb down the minus steps. In 1769 a Russian professor, taking advantage of a cold spell, froze mercury itself in a mixture of snow and nitric acid." A hundred years ago, Faraday, working in the Royal Institution of London, succeeded in condensing ammonia gas to a liquid by apply- ing pressure and then cooling it. When the pressure was removed, the liquid of course boiled off rapidly as a gas, absorbing heat in doing so. Any liquid absorbs heat when it turns into a gas. This discovery proved of the greatest importance, both practically and theoretically. A solution of ammonia and water was used by Carre in 1858 in his ice making machine. The first Carre machine to reach the United States was shipped through the blockade of New Orleans in 1863. In 1755 Dr. William Cullen invented the first machine which pro- duced ice by purely mechanical means, his achievement being followed by those of Vallance of France (1824) and Jacob Perkins, an Ameri- can then residing in England, who is given credit for the forerunner of the modern compression apparatus, his model being patented in England in 1834, with ether as the refrigerant employed. Other early workers in this field of science were Prof. A. C. Twining, of New Haven, Connecticut, and Dr. John Gorrie, of Appalachicola, Florida. In the rotunda of the capitol at Washington, where each of the states has set statues of its most distinguished citizens, Florida has chosen this same Dr. Gorrie instead of any of its pioneer politicians or military geniuses. Too many men of various countries have con- ICE AND REFRIGERATION PURPOSES 21 tributed to the gradual development of mechanical refrigeration for any one person to be entitled to exclusive credit for the invention, but Dr. Gorrie certainly deserves this place in our National Hall of Fame for the service rendered to the country when he took out the first American patent in 1850 for a practical process of manufacturing ice. In the years of 1873-75 the first successful ammonia compression machines were introduced by C. P. G. Linde of Germany, and David Boyle of the United States. From 1875 to 1890 many new forms of apparatus were produced and certain improvements were made. Until the year 1890 the practical utilization of the art of ice mak- ing and refrigeration had seemed to come to a standstill. But there occurred in the year 1890 an incident that awakened the general public to the possibilities of the use of mechanical refrigeration. This inci- dent was the greatest shortage in the crop of natural ice that has ever occurred in the United States. To this unusual shortage may be accredited the impetus that started the rapid development and utiliza- tion of mechanical refrigeration. Since 1890 the ice making and re- frigerating industry has grown by leaps and bounds. Thanks to the manufacturers of the refrigerating machine, ice can be had at any time and anywhere that power can be obtained. The ice machines give us ice in any quantity at any time. Manufactured ice is made in cans holding 300 to 400 pounds. The can is filled with pure water and is let down into a tank which is filled with brine. The brine is made of sufficient density to permit its freezing point to fall to zero Fahrenheit or below. The cans are ar- ranged in regular order, in rows; between these rows of cans are continuous coils of closed pipe through which passes the ammonia, it being the most commonly used refrigerant. The ammonia starts out as a liquid and expands, turning into a vapor and finally into a gas as it absorbs heat from the brine which surrounds the coils As the ammonia circulates through the pipes in the brine tank, it absorbs the heat from the brine and lowers its temperature to a point below the freezing point of water. As heat always travels from the higher to the lower temperature, the brine, in turn, absorbs heat from the water in the cans. When the temperature reaches a point low enough, the water begins to freeze and ice forms on the inside of the cans. As the freezing continues, the ice thickens until it finally closes to the center of the can and is a solid block. As the ice forms, any foreign matter in the water is forced to the center of the block. In order to manufacture clear ice, it must be made from distilled water or from "raw water," which is low in mineral content. The water must also be kept in motion just as Nature keeps the river water moving. By so doing, the particles of air and gases are liberated and 22 HOUSEHOLD REFRIGERATION come to the top, thus allowing clear ice to be frozen. This is accom- plished by conducting a stream of cold air into the can which keeps the water in motion. Frequently, in order to get a cake that is clear and clean all the way through, avoiding what is called a "core," the water is drawn from the center of the can before it is completely frozen and this cavity is refilled with distilled water. What Ice Can Do. — When ice melts, it absorbs heat. Each pound changing from solid ice to liquid water absorbs as much heat as would be required to raise the temperature of one pound of water 144 de- grees Fahrenheit. Indeed, the heat absorbing capacity of ice is so great that it has been made the standard of comparison and the units in which we measure this power are called British thermal units. Ice is greedy to absorb heat. Therefore, if it is to do specific work, it must be protected from those warm objects which we do not desire cooled. For instance, in our home refrigerators ice is placed inside of what we term insulated walls. A material which does not allow heat to pass through it is called an "insulator." To keep the ice from melting too rapidly, we build into the walls of the container some insulator which keeps away the atmospheric heat. The articles to be preserved for cooking or to be kept cold are put into the insulated space with the ice. Then the ice can absorb their heat, thereby cooling them, but turning into water in doing so. This is the principle of all ice refrigerators. The better the insulation, the less heat can get into the refrigera- tor or ice box, and therefore, the less the ice meltage due to heat leakage. The warmer the articles put into the box, the more ice they will melt before they reach the same temperature as the ice box itself. The temperature of ice is 32° F. If we had a perfect insulator — one which would not allow any heat from outside to go through the refrigerator walls, the temperature of the inside of the refrigerator would be 32° F. also. However, all insulators allow some heat to pass; the best ones permit little, while the poor ones let much heat pass through. The poorer the insulation in the refrigerator, the higher will be its temperature and the more ice will be melted when the air outside is warm. The question of proper air circulation in a refrigerator is one of vital importance. The heat enters the refrigerator in two ways; some through the walls of the box and some with the food to be cooled. The warm air travels to the ice, is cooled, drops down to the section directly under the ice and thence over the food, absorbing heat, mois- ture, and odors. The warmed air, being lighter, rises through the food chamber and again reaches the ice. Here the air is cooled, drops moisture because of its lowered temperature, and whatever odors may have been absorbed during its passage over the food are dissolved in ICE AND REFRIGERATION PURPOSES 23 the film of water on the surface of the melting ice and pass off in the meltage. Then the cooled, dried, and cleaned air is ready to make another trip through the food compartment. The intelligent housewife utilizes these facts to the advantage of her family and her pocketbook. She sees that the ice compartment of the refrigerator is ready to receive the ice when the ice man brings it. Every minute it stays outside the insulated space it is absorbing heat from the air and melting. Refrigeration is the ideal preservative and the housewife who really wants to economize on both food and ice keeps her refrigerator well filled at all times. This is a simple matter of household efficiency. When the ice gets low in the refrigerator, the walls naturally grow warm and just that much more ice is required to bring the tempera- ture down again to a safe point where the constant circulation of cold air across the top of the ice, down its sides, down the side of the small food compartment, across the floor of the refrigerator, up through the food compartment and over the ice again purifies, and preserves through every inch of its journey. Ice in Daily Living. — In a multitude of ways ice has entered into the daily life of the American people. It tinkles in the glass of water with which the master of the house quenches his thirst; it furnishes soft, clean water to shampoo milady's hair; and a small piece rubbed on her satiny cheek brings the blush of youth. In the laboratory the scientist depends upon it to chill his mixtures, and, in the hospital the physician prescribes it to cure and to comfort. But most important of all is the use of ice to maintain freshness, wholesomeness, and high quality in foods, and, directly or indirectly, most of