Question

4 AAA 4 An 11111111111 water from condenser - =6000 gal/hr Ten=95°F water to condenser + air Tamb= 74°F Pamb=0.5 Ve=10,000 cfm makeup water T = 80°F Figure 1: Cooling tower. The cooling tower is designed to cool water from the condenser of a large air conditioning system that enters with a flow rate V =6,000 gallons per hour with temperature Twin = 95°F. Outdoor air at Tamb = 74°F and Pamb = 50% relative humidity is forced through the tower at a rate of V. = 10,000 cfm. Makeup water is provided at Tmuw = 80°F. The effectiveness of the cooling tower is ect = 0.7. a) Determine the load, range, approach, and makeup water flow rate.

Answer 1

Air inlet condition; Tamy = 24°F = 296.4834 damb = 0.5 =P Rat @ 74°F = 28.68x1013 barro 0. 02868 boro = 59.9 13/gt2 = Ps| So fra 0.5*59.9= 29.95 146442 -0.01434 bars Paris Parm - Py = 500p. 2115.69 13/142 - 29.9513/412 Pair = 2085.7415/J12 = 0.99866 bar po lentos a 0.99866 xio5_- = 1.173 kg/m3 0.287x10? Men x 296.483 Paris - 1.173 kg/m3 = 0.07 322 1/43 may flow rate of amento cooling tower - Pais V = 0.07322% 10,000 ft m - 732.2 l I maig = 12.203 is see 1 Hume dety ratio w, = 0.622 Pv 0 .622 x 0.01434 apo RT mer min 1.01308-0.01434 wrë 8430 Hyon? Kung 0.622 * 29.95 2115.69-29.95 1W, = 8:93 xio 3 lb vap / is dry air 7

Wet bulb temperature of ambient air. = 63°F ( from psy chrometric chart for $20., & ita = 741F Cafe effectwenes of cooling tower es (E) R=cold water outlet - Wetbulb temp. o fair Chlet Approacht Rand APPER OCH (A) = cold water outlet & hot water B einted difference so Ro tez-twaig , As tantes c- ta - twain to-twaid tart + Ws - twain te, mtwang Tot hot water en led temperature: 950 - Tez - 63 Los or Tg = (017) (95-63) 463 as-63 cold water outlet temperature = Tg = 85.40 Aito emit 6000 gal/mo -t sór. omir ,74°F, D=0.5 Hació V = 120w com makeupweter

so Range = tez-tware = 85.4'F - 63°F = 22.4°F Approach = tega teg = 95E 85-4°F = 9.6°F - heg hw, = enthalpy of eactor inlet chot) - pucator CTC) = 1.001 Btu x95°F F 95 Bts - 15°F 15 bus 13 x 4 + 5 x 1 = 3 x 62.92 8 I5 x Gooof herst as X 62.428 *6000 * 3.7133x10-5 143 hut I322 6 St. 143 * Googgy ho sec

may balance lively mingtas man m = miting & By energy balance mg = my mis minit maha tms hg = mihet mig hy enthalpy of make upweter. hg = 1001 BIS x 80 hg = so sto 52 = 85.4 BHD =28BHU ( from psychrometne table Botar e 50% RH & Pf.ctd), mg = 12.203 is see h, a hew, = as BID m, = 62.428x6000*3.733 2105= 13.9.15 کیا For rest Calculation, I need emit condition of air, ammy & hey can be obtained then make up water = my-mg amg once we know mig, hq = cpwatert t x C mg tris) cooling load a hirm.