Artificial refrigeration is now assuming such an important place in the arts that, without entering into all the details of its history, it is nevertheless proper to review the principal and most important attempts made by inventors to bring it to its present state of perfection. The processes employed may be divided into three classes: Ast. Specific heat. 2d. Latent heat of fusion. 3d, Latent heat of volatilization. I—APPARATUS EMPLOYING SPECIFIC HEAT. These contrivances are generally very limited in power. They are founded on the fact that two bodies, liquid or gaseous, at different temperatures, when brought into communication with each other, whether at a distance or by contact, exchange their temperatures. The theory of this system of apparatus is very simple; it illustrates the fact that several units of heat given out by the hot liquid is equal to the same number of units absorbed by the cold liquid; and this gives the measure of their power. Compressed Air Apparatus.—Specific heat has likewise been employed in other more complicated machines, which have brought out several patents, the combinations of which are extremely ingenious while experiments have been numerous, but very costly. The inventions just alluded to employed either compressed atmospheric air or incondensible gases. They are founded on the well known laws of physics, that, compression producing heat, expansion must, by inversion, produce cold. M. Peclet estimates that one horse power would produce, theoretically, 75} English pounds of ice per hour. This would be a good result, though inferior to those since obtained. Atmospheric air and incondensible gases give out either heat or cold communicated to them with great difficulty ; it is almost impossible to take away from atmospheric air the high temperature communicated to it by compression, or to collect cold which it has obtained by expansion, One of the first and most complete arrangements of this kind was invented by Dr. John Gorrie, of Florida, who obtained a patent in England, in the name of his solicitor, Wm. E. Newton, in 1850. He collected heat by means of divided sprays of water injected by a pump; to collect the cold, he replaced the water by an uncongealable liquid, such as spirits, &e. Up to the present this system of apparatus has been unsatisfactory industrial results. Kirk, in 1862, invented machines on the same principle. The last inventor put his machine at the Bathgate Paraffin Works, in Scotland, where one ton of ice was produced by 600 lbs of compressed air. II—APPARATUS EMPLOYING LATENT HEAT OF FUSION. The employment of the properties of latent heat of fusion, which is greater than specific heat, for equal variations of temperature, has nearly always given more satisfactory results. Quite a number of machines have been invented and constructed for the purpose of rendering these properties useful, the most practical of which were patented. The first to which allusion is made are those which are based on the employment of latent heat, as a body passes from a solid to a liquid condition. Each body requires a given quantity of heat to melt it; it is therefore evident that if two solid bodies are mixed together, the reciprocal action of which makes them melt, it may happen that the required units of heat for melting may be more numerous than those supplied from the substances in contact, or from the surrounding bodies. The same phenomena occur between a solid body which is simply dissolved in a liquid. In this manner refrigerating mixtures are constantly used in apparatus of various shapes, generally comprising a reservoir containing the substance to be frozen, surrounded by another reservoir or vessel, inclosing the refrigerating mixture, which is covered by a non-conduet- ing substance, to protect it from the external heat. The most commonly employed refrigerating mixtures are the solution of nitrate of ammonia in water, which lowers the temperature from 48° to 7° above zero, Fahrenheit; the mixture of sulphate of soda and hydrochloric acid, which will reduce the temperature from 48° to 3° above zero, F., and the mixture of ice and salt, which are daily employed in domestic use. Although these systems of apparatus have been so frequently put into use, they have not yet developed into important industries. An attempt which should not pass by unnoticed, although it has shown no industrial results, was patented in England, in 1855, by Siemens. It had the merit of being presented in a most ingenious manner. He proposed the continuous manufacture of ice by means of a refrigerating mixture obtained by a body dissolving and concentrating continuously. For example, around a freezing cylinder of any convenient form water was placed, into which nitrate of ammonia was made to fall, thus causing a lowering of temperature to about 15° above zero, Fahrenheit. When the solution was made, and the effect produced by the cold exhausted, the liquor was run off, and was replaced by water and solid nitrate of ammonia. The nitrate of ammonia was re-obtained by evaporating the solution, which evaporation was continued until the material became perfectly solid and dry. This attempt likewise seems to have failed; it must have met with many serious difficulties in its practical execution. III—APPARATUS EMPLOYING LATENT HEAT OF VOLATILIZATION. The future art of artificial refrigeration seems to rest on the application of the properties of the latent heat of volatilization. The machines which are based on its application may be divided into two classes: Ast. Those founded on Leslie’s experiments. 2d. Those founded on Faraday’s experiments. To commence with the first class it is necessary to recall to memory Leslie’s two well known discoveries. Place upon the platform of the air pump a capsule, full of ether, into which a bottle containing water is plunged; then depress the plunger and in a very short time the bottle will be frozen. Replace the ether by acid, and above the capsules have a platform on which there may be a few drops of water; then obtain a vacuum, and the water will freeze very rapidly. These two experiments were so conclusive that they became the starting point of numerous attempts from which apparatus of various forms were constructed, differing from each other as they inclined toward either of the above mentioned experiments, Jacob Perkins, an American, patented in England, in 1834, an apparatus, the fundamental principle of which was based on Leslie’s first experiment. He described in his patent a freezing cistern, or inclosed vessel, containing liquid ether, or some other condensed gas, in combination with an exhausting and compressing pump, and a condenser or restorer. This pump in its alternate movements successively exhausts the vapor of ether, which volatilizes in the freezing cistern, and afterward compresses it into the condenser or restorer, where it is restored to its original liquid condition. It is perfectly well known that the change from a liquid to a gaseous state is only effected by absorbing from the surrounding objects a number of units of heat, which represent its latent heat. Therefore the ether in such a case is only in contact with itself and with the bodies which are to be acted on; not finding in its own substance sufficient calorie to absorb, it will borrow heat from the bodies surrounding it; of which it necessarily reduces the temperature. The apparatus of Perkins seems to have served as a basis for improvements made in the art of refrigeration by the following inventors: Bourgois, Kingsford, Harrison, Carré, Siebe, Tellier, Mort, Nicolle, Lowe, Vanderweyde, and others. Many ingenious physical and mechanical operations, based on Perkins’ patent, have been tried, but in most instances have failed to realize the sanguine expectations of the inventors. The ether, which was the material at first employed, since has been partially replaced by protoxide of nitrogen, sulphuric acid gases, carburet of hydrogen, gaso- lene, methylic ether, &c., &c. Inventors, employed ether as his freezing agent, in Europe and America from 1857 to 1860, but powerful steam machinery,” in combination with the same principle, was more successful. In 1862, he manufactured ice on a commercial scale, he was compelled to abandon his invention, after having expended large amounts of money on it, and resorted to his new system, with which he produced such wonderful results. Peclet describes an apparatus in which he employs simultaneously vacuum and the absorption of the vapors of water by chloride of calcium; its fundamental principles seem to have been taken from Leslie’s second experiment. Other machines have been constructed, which literally reproduce the last mentioned experiment. The air pump is employed to produce vacuum, and sulphuric acid as the absorber. These inventions present the same objections as those based on Leslie's first experiment, and taking everything into consideration they must be more complicated, because they employ the two agents of vacuum, namely the pump, and the powers of affinity. CARRE’S APPARATUS. The machine that up to the present day has attained the greatest industrial perfection, and from which the most useful results have been obtained, was invented by Carré, and is based on Faraday’s experiments. The idea which distinguishes it from all others is the “production of vacuum and of volatilization by the action of affinity alone.” It merely requires a few words to recall to our minds the experiment which served as a starting point. The illustrious Faraday studied the properties of various gases which were considered non-condensible, and succeeded in liquefying a few great number of them under the double influence of heat and cold. His process, which was very simple, is the employment of a very strong glass tube, one of the branches of this tube, he inclosed a small quantity of chloride of silver in his tube, which had already absorbed large quantities of ammoniacal gas. He heated the first limb of the tube, and in a short time obtained in the second branch a liquid, which was liquefied ammoniacal gas. By leaving the tube under its own influence, he observed that it gradually condensed off, and that while it was cooling the ammoniacal gas volatilized and went back to be reabsorbed by the chloride of silver; he merely remarked at the same time that as volatilization took place, the ammoniacal gas produced very intense cold. There are few examples which demonstrate in such a striking manner the slow progress of the human mind, for it required upward of thirty years before any inventor ever thought of applying this remarkable experiment to use. Probably it was because Faraday’s complete experiments are very seldom illustrated by lecturers; his tube is at times shown to students, but very seldom experimented with, because it must be handled with extreme care. Nevertheless, M. Carré founded on Faraday’s observations a most ingenious and remarkable apparatus, afterward improved upon by his associates, Messrs. Mignon and Rouart. Ammoniacal chloride of silver being considered too costly as a freezing agent, heat is applied to produce cold;’ ‘fire to make ice;’ and this is one of the claims of originality made by the patentee, who also claims ‘the application of the power of absorption due to mutual affinity asa means of producing vacuum, volatilization, the removal of heat, and the consequent production of cold.” It may be premised that the form of ammonia used is the concentrated aqua ammonium, containing 26 per cent: of gaseous ammonia, and that there is a constant pressure in the apparatus, when in full operation, varying from 8 to 13 atmospheres, equal to about 120 to 200 lbs to the square inch. The apparatus consists (1) of a cylindrical, dome-topped, vertical boiler, A, into which the aqua ammonium is introduced, part of which enters the exchanger, the complement and the absorption vase, to be described. A large tube B, issuing from the dome connects it with (2) the liquefactor, C, which is an extensive series of connected tubes, nearly horizontal, contained in a sheet-iron tank D, filled with cold running water. In this the gas, under the great pressure and the cold, is liquefied, its latent heat being carried off by the cold water, whilst the liquid ammonia passes out at the lowest end by a small tube E, into (3) the recipient, F, where it collects. This vessel is connected by a tube with (4) the distributing valve, G, which distributes the liquid ammonia, by means of four small tubes of 1-16 of an inch calibre, into four stacks of zig-zag tubes H, contained in the freezing cistern, I. The freezing cistern consists of a wooden tank lined with iron, in which are placed four lines of vertical zig-zag tubes, above noticed, into which the liquefied ammoniacal gas enters from the distributing valve. Between these tubes, twenty-four metallic cans, or freezers, filled with water, are placed, and the whole interior of the tank is filled with a bath of strong brine, or, preferably, solution of chloride of calcium, which is incapable of being frozen by the temperature produced, and is made to circulate between the tubes and freezing cans J, as a carrier of heat, by a stirring apparatus K. These stacks of zig-zags connect at bottom with a cylindrical tube called the collector, L. When now the distributing valve is partially opened,
Key Takeaways
- The processes of artificial refrigeration can be divided into three classes: specific heat, latent heat of fusion, and latent heat of volatilization.
- Early attempts at artificial refrigeration were limited in power but laid the groundwork for future innovations.
- M. Carré's apparatus based on Faraday’s experiments is considered the most industrially perfected method to date.
Practical Tips
- Understand that early refrigeration techniques, like those described by Peclet and Siemens, are complex and often impractical without modern equipment.
- Learn from the failures of inventors who relied solely on compressed air or ether, as these methods were too costly and inefficient for commercial use.
Warnings & Risks
- Be aware that early refrigeration techniques can be dangerous due to the use of flammable gases like ether and the potential for vacuum leaks.
- Recognize that the apparatus described by Carré requires precise control over pressure, temperature, and chemical reactions, which can pose significant risks if not handled properly.
Modern Application
While the specific techniques detailed in this chapter are no longer used due to advancements in technology, understanding the principles of artificial refrigeration remains crucial for modern survival preparedness. Techniques like those described by Faraday and Carré laid the foundation for today's more efficient refrigeration systems. Knowledge of these early methods can provide valuable insights into how to troubleshoot and maintain modern equipment.
Frequently Asked Questions
Q: What was M. Peclet’s contribution to artificial refrigeration?
M. Peclet estimated that one horse power would produce, theoretically, 75½ English pounds of ice per hour using compressed air apparatus. However, this method proved to be less efficient in practice.
Q: Why did the ether-based refrigeration methods fail?
Ether-based methods failed due to the difficulty in transferring heat and maintaining a vacuum, as well as the high cost of ether compared to other substances like ammonia chloride.
Q: What is unique about M. Carré's apparatus?
M. Carré’s apparatus was based on Faraday’s experiments and used the principle of producing vacuum and volatilization by the action of affinity alone, making it more industrially perfected than earlier methods.