Document XORe0LK1xqGZQmgmqzKb76orR

\ American Society of Heating and Ventilating Engineers Guide, 1934 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: 0* 234*6739/0 /ieigtrt Aixotte Ffaar in FaeT Fig. 1. Room Temperature Gradients and Steam Condensing Rates for Four Types of C. I. Radiators with a Common 60-in. Level Temperature Note that the steam condensations are practically the same Iot all (out radiators when the some air temperature of 69 F is maintained at the 60-in. lead. ^CokfRoom 7cmp. inadg-F -28 c LWft>. Tost 3-Tube Fb*. -22 ^48 Mx Tesf *9-220.3-Tube frtitf- ~Zt bJ2 M> Test R-'5&-l-Tubef=bne/tt>d *30Mx Tost R-2c. 223Jt\b//Fb* _ / 2 3 4- _ - 7 3 Mr2 Mx ofSteam Condense*per nr 0/2.3436789/0 tie/ght Abate Floor in Fe&f Fig. 2. Room Temperature Gradients and Steam Condensing Rates for Four Types of C. I. Radiators with a Common 30-in. Level Temperature Note that the steam condensations are different for all four radiators when the same vie temperature of 68 F is maintained at the SO-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, this, direct radiators, than is possible with high, direct radiators. *Steam Condensation an Inverse Index of Heating Effect, by A. P. Kratz and M. -K. Fahnestock (A.S.H.V.E. Transactions, Vol. 37. 1931). 410 v 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. 4. The comfort level (approximately 2 ft-6 in. above floor) is below the breathing line level (approximately 5 ft-0 in. above floor), and temperatures taken at the breathing line may hot be indicative of the actual heating effect of a radiator in the room. The comfort indicating temperature should be taken below the breathing line level. 5. 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 openings4. 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 per hour for the time elapsing after steam is turned into a cast-; iron radiator. The data are from tests on old style column type radiators. 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 is 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 investigations5 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. rahnestock (Heating, Piping and Air Conditioning, March, 1930). `University of Illinois Engineering Experiment Station Bulletins Nos. 192 and 223, and Investigation of a Rooms with Direct Steam Radiators Equipped with Enclosures and Shields, by A. C. Willard, A. P. Kratz, M. K. Fahnestock and S. Konzo (A.S.H.V.E. Transactions, Vol. 35, 1929). 411