THE TABLES AND DIAGRAMS 99 



rlc done by the compressor. Since I horsepower-hour is equal to 254* 

 eat removed per horsepower-hour i 



2546 



e fnlluxKiiiK jiroMrins illustrate the uae of Table 6, Mixtures of Air 



and \\.it. i \., : 



Example 13. Ilnmidifyittt Ai> is to be maintained at 70* F. with 



humidity of 040, uh.n the outside air is at F. with a rrUtixr 



humidity of 0.70. Find tin- weight of u.iti-r v.i|.r |cr pound of dry air to be 



added >>\ .iir ua-h. i. thr t. UIJH r.iiut. .,i tin- saturated air leaving the latin, 



and tin- lu.it rr.juirrd t.. l.rin s tin- air to thi- fund it ion. 



ng to Table 6, i |*.und of air at 70 F., if ituratcd, contain* 0.01578 Ib. 

 vapor; hence with 40 per cent humidity it contain* 0.40 X o 



- 0.006312 Ib. i pound of air at o F. contains 0.0007 : vapor when satu- 

 rated and 0.70X0.000781 -0.000547 Ib- whin thr humidit> IH .. 70 Tbe 

 water vapor to be added per pound of dr> .iir is thrrefore 0.006312 - 0.000547 



- 0.005765 Ib. By ii it i- found that . s F. completely saturated 

 fontaiiiN thr same weight of vajxir. namely 0.00631 1., * *"" l 7OF. with 40 



nt humidity; hriuv tht- air should UMM- the washer at 45 F. The beat 

 nd 70 JH humidity is o + 0.70 X 0.964 - 0.675 



H.t.u . ami tin- heat contrnt of i II.. of air at 45 F. with th<- vapor required to 

 saturatr it i- i;.s> M.t.u. Thi- lu-at ntji. the process per pound of dry 



fore .ij>i)ro\iinatfl\ 17.59 ~ 0.675 - 16.92 H.t.u. 



Example 14. ( 'oolin^. . re a washer at 84 F. with a rrlati\-e humidity 



M> and i> to IK- rooK-d to 54 I Kind the dew-point, weight of vapor con- 

 densed and lu-.it rnnoxrd per pound of dry air. 



At v; I i pound of air contains 0.02547 Ib. of water vapor when saturated 

 and d 0.50 X 0.02547 - 0.01274 ll>. uith 50 per cent humidit 



contains the sanu u. : s ht of water vapor; hence the dew-point is 

 64 F. At 54 F. i pound of air, if saturated, contains 0.00887 Ib. of vapor. 

 Hrncc in cooling from 64 to 54 thr \sri^ht of vapor removed is 

 0.00887 ~ 0.00387 Ib. The heat content of the air in the initial state ($4* F.. 

 50 per cmt humidity) is 20.29 X 0.50 X 26.62 - 33.60 B.t.u.. and the heat con- 



>f I Ib. of dry air at 54, \vith \apor requirrtl to saturate it. is 2245 I 

 Thr diffrrrmr i- 33.60 - 22.45 " ' i-*5 B.t.u. A slight corrvctioo may be made 

 for thr h. ie water, due to condensation between 64 and 



54 F. At 64 fondrn-ation I *% ins, at 54 0.00387 Ib. has been condensed; hence 

 thr In at that mu-t 1> "in thr water is approximately ) X 0.00387 X 



10 0.019 B.t.u. Adding thi- to 11.15 B.t.u., the heat removed per pound of 

 iir during the process is 11.17 B.t.u. 



