Question

4. Moist air enters a chamber at 60°F dry-bulb and 46 °F wet-bulb temperature at a rate of 5000 cfm. In passing through the chamber, the air absorbs sensible heat at a rate of 20,000 Btu/h and picks up 63 lb/h of saturated steam at 200°F. Determine: (a) The dry-bulb and wet-bulb temperatures of the leaving air. (b) The sensible heat factor (25)

Answer 1

PROBLEMA Geiven data in Problem. Dry Bulb temperature of air inlet Tdi = 66°F Wet Bulb temperature of air inlet Twe= 46°F Volume flow rate ů 5000 ft3/min Senable Heat absorb = 20000 Btu/h mass flow rate of 200f staturated steam = 63 lb/h = 63* to = 1:05 Jblemin ms FIRST of all mork Condition 1 of 60'F DIST and 46°F WBT on psychometric chart specific humidity at t WE 24 grains of moisture / Pound of day ap= 241 0.0001420 =0.0034 27 onde enthalp at 1, h = 18.5 Ituleb of Mestur Pond of specfic volume at t, O= 13:25 ft 1 lb of day air dry air. Now, mass flow rate of air flowing ma- % - 5000 ft / min 13.25 ttleb Ima= 377.35 lb/min We know that wo- wit me = 0.003427+ 1.osas = 0.006209 Pound - 700DX0606209 43:46 Graine/pond From steam table corresponding to enthalpy of dry-saturated steam hs = 11480 Btuleb

We know that ha= hit ms xhs ma = 18.5+ los x 10 +377.*1146 The = 21.688 Bulbol In Peychrometre choot mook from Here we find Point 2 corresponding to ha and we Dry Bulb temperature of Leoving air = 63°F Wet Bulb tempecature of Leaving air = 51F sensible Heat - 20000 Btulho ra - 20000 20000 btulho 377.35 16/mm 377.35 800 - 0.8833 pul alb Total heat = ha-hi = 21.680-18.5 = 3.188 otuleb - sensible Heat factor - Sensible Heat Total Heate 0.083) 3.180 = 0.2770 I sensible Heat factor