Document bBRpJOgw0YZNoaQaqedeNqjqD

Heating Ventilating Air Conditioning Guide 1938 Table 1. Pressure Losses in Dichlorodifluoromethane Discharge or Hot Gas Lines* Pressure Drop in Pounds peb Squabs Inch peb 100 Ft* Capacity BTU peb Hour Line Sizes, Inches . X X - H 1H lH lH 2H 2H IX IH, 10,000 15.000 20.000 2.3 1.0 0.6 4.9 2.0 1.0 8.5 3.4 1.7 0.6 25.000 30.000 40.000 5.3 2.6 7.5 3.6 6.4 0.9 1.2 0.5 2.1 0.7 50.000 60.000 70,000 9.8 3.1 1.0 0.5 4.4 1.3 0.7 6.0 1.9 0.9 80,000 90,000 100,000 8.0 2.5 1.1 10.2 3.1 1.4 3.8 1.7 0.5 125.000 150.000 175.000 200,000 250.000 300.000 400.000 500.000 600.000 800,000 1,000,000 1,250,000 . 1,500,000 2,000,000 6.0 2.6 0.7 8,5 3.8 1.0 11.6 5.1 1.3 6.7 10.4 1.7 0.6 2.6 0.9 3.7 1.2 0.5. 6.7 2.2 0.9 10.5 3.5 1.5 5.0 2.1 0.7 1.0 9.0 3.8 5.8 9.5 1.8 2.9 4.4 6.4. 11.3 ASoft annealed copper tubing up to and including & in. outside diameter. Hard copper pipe % in. outside diameter and larger. bLength of tubing includes the average number of fittings. Another method of providing for economy of operation is to have storage capacity which can be utilized during the peak period. The refrigerating system can be operated for a longer period at maximum efficiency with tanks to store cold water or brine for supplementing the actual output of the refrigerating equipment. However, storage tanks require space and extra apparatus, which increase the cost of the entire system, and further, it is difficult to determine the. exact size of the compressor because of the other variables which enter the problem. Depending upon the availability of storage space, the compressor may be designed for any reasonable percentage of the maximum load. On this basis of selection, the smaller the compressor, the larger the storage space, and vice versa. 486 Chapter 24. Cooling and Dehumiditication Methods Table 2. Pressure Losses in Dichlorodifluoromethane Liquid Refrigerant Lines Capacity BTU per Houb Pressure Drop in Pounds peb Squabs Inch peb 100 Ft* Pips Sizes, Inches 100,000 . 125,000 150,000 175,000 200,000 225,000 j 250,000 275,000 300,000 325,000 350,000 375,000 400,000 450,000 500,000 .550,000 600,000 700,000 800,000 900,000 1,000,000 1,200,000 X 0.6 ! 0.9 1.3 1.8 2.3 .2.9 3.6 4.3 5.1 5.9 6.9 7.9 9.0 IX 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.1 2.3 2.9 3.S 4.3 5.0 6.7 8.7 1,400,000 1,600,000 1,800,000 2,000,000 "7 2,200,000 Length of tubing includes the average number of fittings. IM 0.8 1.0 1.3 1.5 1.8 2.4 3.1 3.9 4.7 6.7 9.0 1H . 0.7 08 1i 1.4 17 21 3.0 40 6.3 9.2 There is a further method of controlling the compressor output which is particularly adaptable to the centrifugal type of machine. This is accomplished by varying the amount of condensing water used with the fluctuation in load demand. Because of the characteristics of the cen trifugal type of apparatus, as the condensing water quantity is reduced and the condensing temperature consequently raised, the discharge pressure of the centrifugal machine rises correspondingly and the horse power input to the machine drops proportionately. While this reduces the total power input'to the machine, it does not necessarily reduce the power input per ton of refrigeration developed, as the power input does not drop with a rising discharge pressure as fast as the refrigerating effect is reduced. 487