or 2200 / 53280 = 4.1 cent per ton [11] OVERHEAD CHARGES: 8 per cent interest on $220,000.00 investment equals $ 17,600.00 8 per cent interest on value of land ($10,000.00) $ 800.00 8 per cent interest on working capital ($7,500.00) $ 600.00 3 per cent depreciation on $220,000.00 $ 6,600.00 Insurance (estimated) $ 1,000.00 Taxes (estimated) $ 2,000.00 Total overhead charges $ 28,600.00 or 28600 / 53280 = 53.7 cent per ton Total Expense $ 75,069.60 or 75069.60 / 53280 = $ 1.409 per ton Divided as follows: Overhead charges $ 0.53.7 Manufacturing Cost (total) $ 0.87.2 [12] NUMBER FOUR Manufacturing Costs Per Ton of Ice Using Steam Power at Medium-Sized-Town Rates for Labor 100-ton capacity per day. 1,080--400-lb. cans. 333 days continuous full output. 7,600-ton Storage House. COST OF POWER: A modern, highly efficient and economical steam driven high speed compressor plant must be installed so as to get the maximum power out of coal. The boiler-room will contain two 200-H. P. water-tube boilers with automatic stokers and coal bin overhead holding two weeks' supply of coal. Steam pressure 175 lbs. As the firing of the boilers is automatic and requires practically no work on the part of the engineers, no firemen will be needed. Ashes will also be automatically removed. The engine room equipment will consist of two 100-ton high speed compressors, direct connected to two Simple Condensing Unaflow Engines; also two generators, two cooling tower pumps, two air compressors, switchboard, etc. All to be equipped with the latest labor and power-saving devices. Equipped as above, 25 tons of refrigeration can be easily obtained from one ton of ordinary 12500 B T U coal. 1.8 tons of refrigeration is required to produce one ton of ice, including the cooling of the storage house. Therefore, the power cost of making one ton of ice with coal at $5.00 per ton equals $5.00 divided by 25/1.8 = 37 cent. (One cent per ton of ice is added for heating of dipping-tank water.) Assuming one month's shut down for inspection and repairs, the total output of 100 tons of ice for 333 days amounts to 33,300 tons of ice. The total power cost of making 33,300 tons of ice is therefore, 33,300 x 37 cent, equals $ 12,321.00 [13] ENGINE ROOM AND ICE PLANT LABOR COST: 1 Chief Engineer per day $ 8.00 3 Engineers per day $ 6.00 2 Storage House Men per day $ 4.00 Total per day $ 34.00 Total 365 days at $34.00 per day $ 12,410.00 Additional labor cost for putting 7,500 tons into winter storage and taking out at $4.00 per day $ 750.00 Total labor cost $ 13,160.00 or 13160 / 33300 = 39.52 cent per ton