Document LpjrLGBmOq9XRG445R3vajqeb

American Society of Heating and Ventilating Engineers Guide, 1935 The results of tests conducted at the University of Illinois are shown in Figs. 1 and 2s. For the four types of radiators shown, the following con clusions are given: j ~ Cold Room 7emp m deg R -Z2 rammvvmmmmirTW SS2/6- TesS R-E2, J-Tobc Rbd- -22 uu^uimiiiiiutitimrzmn S*2/6 7esr R-6/,3-T<rte/Fad -2-7 342. /6-7esfR-E/O, /-Tdbe-Rbne/f&d. 9/ 2 3 4 S *7 & Ref /> ofSteam Condensed per Rrr Eee|ee5 = = Tesff?-'2c.{Bi,i223)Z/Sa '/dU-jt-S = = = Wall Rad- /4'c/Surfi f j L llA 1T == - Wrooped-^R'^ 1 \-7esfR-E/O. = = - \ yX A= - == Tubafar /2w/ /xb<d - -- -- - = 'iSSa&d-Tisf t?-EZ 6-Jee, J* = = = -vpl^ TZ/be = = = = = =|= = =g ifeS m==&s _____________ 1 -to / 23**1,739/0 Tie/ght Abote Rbar in Roe/ Fig. 1. Room Temperature Gradients and Steam Condensing Rates for Four Types of Cast-Iron Radiators with a Common Temperature at the 60-In. Level Note that the steam condensations are practically the same for all four radiators when the sam air temperature cf 69 F is maintained at the 60-in. level. ^ CoId Room Temp- in deg-E i t-tsu>,7eat R-CSZ.S-Tube Red640/6. Test R-E20,3-7t/be Red6S2/0- Teor R-5&J-Tut>e^Fbne/Rbd. SSO/b. Test R-2c. -&4 223)nbf/fxhd __ 4-3673 Ref /?. ofSteam Condensedper hr / 2.343*789 '/ie/ghf Abate R/oor r? /ratsv* Fig. 2. Room Temperature Gradients and Steam Condensing Rates for Four . Types of Cast-Iron Radiators with a Common Temperature at the 30-In. Level Note that the steam condensations are different for all four radiators when the same air temperature of 68 F is maintained at the 80-in. level. 1. The heating effect of a radiator cannot be judged solely by the amount of steam condensed within the radiator. 2. Smaller floor-to-ceiling temperature differentials can be maintained with long, low, thin, direct radiators, than is possible with high, direct radiators. Steam Condensation an Inverse Index of Heating Effect, by A. P. Kratx and M. K. Fahnestock (A.S.H.V.E. Transactions, VoI. 37. 1931). 494 Chapter 30--Radiators and Gravity Convectors 3. The larger portion of the floor-to-ceiling temperature differential in a room of 'average ceiling height heated with direct radiators occurs between the floor and the ^breathing level. y*4. The comfort level (approximately 2 ft-6 in. above floor) is below the breathing line - levei (approximately 5 ft-0 in. above floor), and temperatures taken at the breathing ic'jihe may not be indicative of the actual heating effect of a radiator in the room. The -'roinfort-indicating temperature should be taken below the breathing line level. High column radiators placed at the sides of window openings do not produce as ^comfortable heating effects as long, low, direct radiators placed beneath window jopenings*. ;; HEATING UP THE RADIATOR The maximum condensation occurs in a heating unit when the steam is first turned on. Fig. 3 shows a typical curve for the condensation rate in pounds pier hour for the time elapsing after steam is turned into a castiron radiator. The data are from tests on old style column type radiators. Time elapsing after Steam is turned into Radiator (rn Minutes) Fig. 3. Chart Showing the Steam Demand Rate for Heating Up a Cast-Iron Radiator with Free Air Venting and Ample Steam Supply . In practice the rate of steam supply to the heating unit while heating up ds frequently retarded by controlled elimination of air through air valves - or traps. Automatic control valves may also retard the supply of steam. ENCLOSED RADIATORS The general effect of an enclosure placed about a direct radiator is to restrict the air flow, diminish the radiation and, when properly designed, improve the heating effect. Recent investigations6 indicate that in the design of the enclosure three things should be considered: 1. There should be better distribution of the heat below the breathing line level to produce greater heating comfort and lowered ceiling temperatures. Effect of Two Types of Cast Iron Steam Radiators in Room Heating, by A. C. Willard and M. K. Fahnestock (Heating. Piping and Air Conditioning, March. 1930). University of Illinois Engineering Experiment Station Bulletins No. 192 and 223, and Investigation of Heating Rooms with Direct Steam Radiators Equipped with Enclosures and Shields, by A. C. Willard. A. P. Krat?, M. K. Fahnestock and S. Konzo (A.S.H.V.E. Transactions. Vol. 35. 1929). 495