4^ The Canadean Horticulturist. 



COLD STORAGE PLANT. 



HE experiments with cold storage were made in New York eigh- 

 teen years ago, and developed into a commercial industry thre^ 

 years later, says Garden and Forest. Since then the knowledge of 

 scientists and inventors has been combined with the practical 

 experience and capital of warehousemen, until now the business 

 of cold storage and freezing is a considerable factor in the market 

 supply of the world. At first cold air for refrigerators on the ground floor was 

 forced to storerooms above, but this plan was soon given up for the system, 

 still in limited use, of massing ice at the top of the building, so that a current 

 of cold air is drawn by gravity through shafts to the lower floors. By this 

 system only cold storage at 38 degrees and above is possible, while actual 

 freezing is necessary for many classes of goods. 



One of the nine large cold storage warehouses in New York uses a system 

 of metal pipes ten inches in diameter, which encircle storage rooms. These 

 begin below the " charging floor," the upper story of the building. Here ice is 

 broken by hand power, the sectional trap doors are lifted, and the pipes set close 

 beside each other and extending down on the floors below, are closely packed 

 with ice and salt. The drainage from these, which is collected on the second 

 floor, is utilized to cool rooms on the ground floor to a temperature of 40 

 degrees. This method of cold storage is especially adapted for holding com- 

 paratively small amounts of perishable goods, without the cost of expensive 

 machinery. 



The system most generally in use, however, is that of producing intense 

 cold by the evaporation of ammonia, and one of the largest and best-equipped 

 cold warehouses uses the so called " direct expansion " system, which it is not 

 necessary here to explain. In this immense establishment which comprises in 

 two warehouses 1,500,000 cubic feet of cold storage and freezing space, eight 

 boilers, each of 75 horse power, are used in the smaller building alone. 



The engines, compressors, and all parts of the machinery are in duplicate, so 

 that if one set is disabled the other set of machinery may be started and the 

 requisite temperature throughout the building steadily maintained. \\'hatever 

 method used, the effect aimed at is the reverse of steam heating, that is 

 to grasp and carry heat out of the rooms which it is desired to refrigerate. The 

 brine which is produced by the ammoniacal gas process, and conveyed through- 

 out the building in main pipes and smaller coils, leaves the manufacturing room 

 in the basement at zero and returns from the circuit only five degrees higher. All 

 this apparatus is especially constructed ; buildings cost money, and at the 

 present time more than $4,000,000 are invested in cold storage in New York 

 alone. 



The first floor of these great buildings is usually occupied by offices and 



