Document 4aY25ye9dakEyG8dxVrMmMyjp

838 CHAPTER 76 1962 Guide And Data 1 ^Melting Table 6.... Physical Properties of Antifreeze Solutions* FUd Ethylene Glycol 15.3% by vol. Ethylene Glycol 31.4% by vol. Ethylene Glycol 42.7% by vol. Fieeik# Temp, f +20 0 -20 F X 10* c to F x 10* c to F X 10* c to -20 _ -- -- -- -- -- -- -- -- Fluid reuipaiuAuu f\dumrf>afl ------- m 0 20 40 120 140 160 "200~~ -- -- 2.64 0.840 0.687 0.577 X -- -- 0.935 0.956 0.960 0.962 -- -- 64.0 62.8 62.5 62.1 58.8 l' 4 ^ _ 6.86 4.18 1.19 0.955 0.784 0.609 -- 0.833 0.850 0.895 0.905 0.910 -- 65.7 65.4 64.1 63.7 63.3 60.0 16.1 0.764 66.8 9.47 0.775 66.7 5.75 0.788 66.3 1.46 0.832 65.3 1.20 0.845 64.9 0.950 0.856 64.4 0.748 0.884 60.6 Ethylene Glycol 51.2% by vol. -40 F X 10* c to. 46.3 0.682 68.2 21.3 0.717 67.6 . 12.13 0.728 67.4 7.54 0.745 67.2 1.77 0.809 65.9 1.46 0.823 65.4 1.14 0.870 0.835 0.854 65.0 `61.1 Beat Transfer Oil -40 F X 10* c IB 105 0.382 62.9 43.1 0.390 62.5 29.7 0.400 62.0 14.0 0.408 61.6 3.13 0.444 59.1 2.51 0.452 58.6 2.06 0.462 57.6 1.48 0.480 55.3 Water +32 F X 10* _ _ _ 1.71 0.603 0.494 0.413 0.328 e -- -- -- 1.005 0.999 0.999 1.001 1.005 w -- -- -- 62.4 61.7 61.4 61.0 60.1 * H--d ob data gives in BafunmcB A * " Etanantie vieeoeity. (feet equated par eeacad) (m< lor ofl at 40 P, 0000140 ft* per eeej. e -- apeeifie beat, Btu per (pound) (Falaeabeit liegiee). w M anight, par nihtfi . 1 * the length of the pipe, in feet. V the velocity, in feet per second. g -- the acceleration due to gravity * 32.174 ft per (second) (second). D ** the internal diameter of the pipe in feet. / -- a dimensionless friction coefficient which can be de termined from Fig. 19, Chapter 7 of the 1961 Guide And Data Book. The Reynolds number can be computed from data in Table 6 of this chapter. Solutions for the pipe friction should be plotted for tem peratures at the starting condition (probably 0 F) and at the operating condition (use either 120 or 160 F). Then on the wa-me graph, the operating curve of the pump should be plotted (see Reference 4 for such a graph). The intersection of tiie fluid friction curve and pump operating curve will give the operating point for the system. Table 8 can be used to allow for the viscosity effect on the pump. The designer must decide on the tolerable viscosity limit. Generally it is between 300 and 500 SSU, although for com mercial or private systems (where Ar is 0.5 or 0) it may go to 750 SSU. Efficiency loss is not important, but head and capacity losses are. Reduced flow means a longer period of time for the system to become operative from a cold start. The viscosity limit is controlled by means of a low-limit thermostat. For example, if it is desired to hold the viscosity of the solution to less than 200 SSU (4(k3 X 10-* ft sq per sec), then for the oil shown in Table 6, the low-limit control would be set at about 10 F. For grrmTl installations, a quick method of determining the fluid friction for a 1-in. EPS pipe circuit is given in Fig. 2. The required pump capacity, in pounds of fluid per hour b given by the equation: A,#, C- (ID C -- pump capacity, pounds per hour. Ap -- area of slab, square feet. -- total heat requirement (slab output, q. , plus back and edge losses) Btu per (hour) (square foot). Cm specific heat at temperature tm , Btu per (pound) (Fahrenheit degree). At " temperature drop through circuit, Fahrenheit degrees. For a temperature drop ofAt = 20 F, Equation 11 becomes A 160u*e (12) G gallons per minute. b. " mean specific weight at temperature tm , pounds per cubie foot. : An approximate solution for systems using pipe sizes other than 1-in. IPS can be obtained by using Table 9 or Fig- 3Table 9 is for use when the flow is in the laminar zone. Fig. 3 `Table 7 - * - Conversion of Kinematic Viscosity Units* Bter~ tft*/Sd X 10* SSU* CeaWobi IFP/Sae) X 10* SSU* SHr*J2 3^2.5 83gS?3'- Sg%-'4:5 gggPV M 58$$-8. rt-9 W:W 2.15 2.69 3.23 3.77 4.30 4.84 5.38 6.46 7.53 8.61 9.68 10.8 32.6 36.0 36.0 37.6 39.1 40.8 42.4 45.6 48.8 52.1 55.5 58.9 31 32 33 34 35 36 37 38 39 40 33.4 34.4 35.5 36.6 37.7 145.7 150.2 154.7 159.2 163.7 38.7 39.8 40.9 42.0 43.0 168.2 172.7 177.3 181.8 186.3 fs :- 13 -|r15 %frl6 : 17 .18 ;*v 19 V 20 l'.. 21 |ii 22 ' 23 , 24 - 25 11.8 12.9 14.0 15.1 16.1 17.2 18.3 19.4 20.4 21.5 22.6 23.7 24.7 25.8 26.9 62.4 66.0 69.8 73.6 77.4 81.3 85.3 89.4 93.6 97.8 102.0 106.4 110.7 115.0 119.3 41 42 43 44 45 46 47 48 49 so 65 60 65 70 44.1 45.2 46.3 47.3 .48.4 49.5 50.6 51.6 52.7 53.8 59.2 64.6 69.9 75.3 190.8 195.3 199.8 204.4 209.1 213.7 218.3 222.9 227.5 232.1 255.2 278.3 301.4 324.4 .J 26 27 : . 28 T ' 29 ~ 30 28.0 29.1 30.1 31.2 32.3 123.7 128.1 132.5 136.9 141.3 ' Our TOC eeatietokee, SSU - 4.05 X ceatistokea. - * Kferratic nacoeitr in fU/eec - 1.07# X llT* X ecutletekm. Value* lifted fer SSU (Saybolt Second* 1 Uoiverml) are for fluid tempera. . toe* of U0 P. To obtain the Sayboit Uaivezaal vieeeaxty equivalent to a kioe- rwlie vbemity determined at a Fahrenheit temperature t, multiply the equive. but Sajbott Universal vbeoeity at [00 F by 1 -f (( - 100) O.OOOOS4; It* Umototokee at 210 F areequivalent to SSJ X 1X070 orOM me Sayboit Unirenal at 210 F. (Taken from ASTU D 440 - 6X) is for flow in the turbulent zone. For flows where Reynolds number falls between 2000 and 3000, no reliable prediction for pressure loss can be made. It is generally safe to a-ygimg the flow to be increased to a Reynolds number of 3000 with the pressure loss estimated at that flow rate. Ftg. 2 is based on a pipe size of 1 in. IPS. If another pipe size U used and the flow is laminar, the correction factor from Table 8 can be used. For example, samme a viscosity of 300 SSU, a flow of 5 gpm, and a -in. IPS pipe. Fig. 2 shows that for 1-in. IPS, friction loss would be 15.50 ft/100 ft. Table 9 gives K = 2.62 for $-in. pipe; therefore, friction loss would be 15.5 X 2.62 = 40.6 ft/100 ft If the flow is in the transition zone or is turbulent, than Fig- 5 of Chapter 8 can be used in conjunction with Fig. 3. 839 Table 8 .... Viscosity Effect on Centrifugal Pump Characteristics Kbeaufic VwcotSf SSI* C<uiwtiai fudmi Pump Hood Pump Copodty Pump Efficiency 0 to 30 60 100 200 1.00 1.00 0.98 0.96 1.00 1.00 1.00 0.98 1.00 0.94 0.88 0.79 300 0.95 0.97 0.73 400 0.93 0.96 0.68 500 0.92 0.96 0.65 600 0.91 0.95 0.62 700 800 900 1000 0.90 0.89 0.88 0.87 * SSU -- Seyfaolt Boccoda--UuvubL 0.94 0.94 0.93 0.92 0.59 0.57 0.55 0.53 For example, assume a viscosity of 0.0001 sq ft/sec (56.5 SSU), a flow rate of 14 gpm and a 1^-in. IPS pipe Fig. 5, Chapter 8, shows a head loss for water to be 190 milinches per foot or 1.58 ft/100 ft Fig. 3 gives a correction factor K of 1.75 for a viscosity of 0.0001 sq ft/sec; hence, the pressure loss is 1.58 X 1.75 = 2.77 ft/100 ft INSTALLATION There are certain precautions that must be taken during installation. They concern internal corrosion, flammability, toxicity, cleaning, joints, and hookup. A comprehensive discussion of these precautions may be found in Reference 5. Safety Since ethylene glycol and petroleum distillates are slightly toxic, the system should be installed and maintained in dependently. ' There should be no permanent connection Table 9 .... Correction Factors for Pipe Size (For Laminar Row Ns, <2000) ftp* Stze (and* i >fcuuater tedme Feet o,4 _ SJt4 X I0-* * D<* Ft* (So# fipore 2) H " 0.622 0.0518 7.18 X 10-* H 0.824 0.0687 2.23 X 10"* 1 1.049 0.0874 5.84 X 10-* iH 1.380 0.115 1.75 X 10-* 8.13 2.62 1.00 0.334 1.610 0.134 3.26 X 10-4 0.179 2 2.067 0.172 8.75 X 10-4 0.0667 2* 2.469 0.206 1.81 X 10-* 0.0322 3 3.068 0.256 4.30 X 10-* 0.0136 3X 3.548 0.296 7.68 X 10-* 0.00760 4 4.026 0.335 1.26 X 10-* 0.00462 6 5.047 0.421 3.14 X 1(T* 0.00186 6 6.065 0.505 6.50 X 10-* 0.000898 ) \ pi |