Document 1ydVQ5OnZ1g26xKVVJXa7ENV5

526 CHAPTER 22 1951 Guide For a radiator, the finish coat of paint affects the heat output. Oil paints of any color will give about the same results as unpainted black or rusty surfaces, but an aluminum or a bronze paint will reduce the heat emitted by radiation. The net effect may be a reduction of 10 percent or more in the total heat output of the radiator.8-9-10 Radiator enclosures and convector cabinets of proper design may im prove the heat distribution within the room as compared to the heat dis tribution obtained with an unenclosed radiator.11 Heatmg Effect For several years the term heating effect has been used to designate the -relation between the useful output of a radiator, in the comfort zone of a room, and the total input as measured by steam condensation or water I I I I I i 11 Mi I .Cold room temp in deg F / -IB 5.60 (5 convector No. 1 16 564 lb convector No. 22 612 lb convector No. 6 , 6.32 ib 5-tube radiator Temperature in deg F Position No. 3 Position NO. 1 30'level Eauiv Otff 30" level Eauiv Diff 67.7 662 1.5 67.4 65.9 15 682 643 *3-9 68.0 66.6 1.4 68.0 65.1 2.9 67.9 67.9 0.0 68.2 66.4 15 <9 | Fio. 2. 56 HEIGHT ABOVE FLOOR IN FEET Temperature Gradients and Equivalent Temperatures toa Radiator and Convectors with Common 30 in. Level Temperature temperatures.15-13 The application of such a heating effect factor implies that some radiators and convectors use less steam than others for pro ducing equal comfort heating results in the room. All authorities do not agree that the use of heating effect factors are justified. No standard method for evaluating the heating effect of radia tors and convectors and correlating it with comfort has yet been accepted. One method, with test data14 on radiators and convectors, and making use of the eupatheoscope for evaluating the environment produced, has been sug gested by the University of Illinois. The principle underlying the eupatheo scope involves the measurement of the heat loss from a sizable body by radiation and convection, when the surface is maintained at some constant temperature. Through the use of this instrument and its calibration curve, non-uniform environments may be referred to uniform environments in which the air and all surrounding surfaces are at the . same temperature. The temperatures of the uniform environments are referred to as equivalent temperatures. The Kata thermometer,16 the thermo-integrator,16-17 and the globe18 thermometer are other instruments which have been used to measure the influence of air temperature, air movement and radiation in an environment. Radiators and Convectors ' 527 Data given in Fig. 2 show that while the air temperature at the 30-in, level is the same for the three convectors and the one large-tube cast-iron radiator, in position No. 3 in the test room, the equivalent temperature is 1.5 deg lower than the air temperature in the case of the three convectors, and the same as the air temperature in the case of the radiator. The' difference between the minimum and the maximum amount of heat re quired to maintain the common air temperature at the 30-in. level is of the order of 13 percent. In Fig. 3 are shown the results of tests made with the same three convec tors and the one large-tube cast-iron radiator, so adjusted in size that each gave approximately the same equivalent temperature in the No. 3 position in the test room. The difference between the minimum and the maximum TTT1 111 111 Cold rami temp in deg F III III 1 i i ITT XUt Tpr 5.9 Ib cohvwtor No. 1 6.17 (b convector No. 22 6.20 tb convector No. 6 632 Ib 5-tube radiator 5 6 7 8 9 10 Equivalent net steam condensed, Ib per hour Temperature in des F Position No. 3 Position No. 1 30* level tqurv 0<ft 30* level Equiv Diff 69.4 67.8 1.6 69.9 682 1.7 68.7 67.6 u 67.9 67.9 0.0 682 66.4 15 Convector No. 22 Copvector No. 1 non-ferrous heating unit cast iron heating unit >8% 51V "---- 5' ' 3 4 56 HEIGHT ABOVE FLOOR IN FEET 5-tube cast iron radiator Convector No. 6 non-ferrous heating unit Fiq. 3. Temperature Gradients and Equivalent Temperatures for Radiator and Convectors with Common Equivalent Temperature amount of heat required to maintain the common equivalent temperature is of the order of 7 percent. Figs. 2 and 3 show results obtained in cold room tests in which the radiators were continuously filled with steam at 215 F. Under these conditions of operation, air temperature gradients are likely to be exag gerated as compared with those encountered with the intermittent opera tion usually obtained in actual practice. The following statements applying to the use of radiators are based on experience and test results:18 1. The beating 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 Ions low, thin, direct radiators, than can be maintained with high, direct radiators. ' 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. i- * iu-v ui. aiwve 110017 is Deiow me Dreatmni line level (approximately 5 ft-0 m. above floor), and temperatures taken at the breath m