It is planned to cool water from 43.3C to 29.4C in a packed counter-current water-cooling tower...

  

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It is planned to cool water from 43.3C to 29.4C in a packed counter-current water-cooling tower using air entering at 28C (dry bulb) and 13C (wet bulb). The water flow rate is 9764.9 Kg/h.m and the air flow is 4439.8 Kg/h.m. The overall mass transfer coefficient Kya is 2500 Kg/mh. Water heat capacity is 4200 J/KgC. A psychrometric chart is supplied overleaf that should be submitted with your test solutions. Calculate: (a) minimum air rate that can be used. (b) tower height needed if air flow of 6835.4 Kg/h.m is used. Enthalpies of saturated air-water vapor (base temperature 0C) Enthalpy of air H at Enthalpy of air H at Enthalpy of air Enthalpy of 100% Temperature Temperature (C) H (KJ/Kg dry saturation (C) air) dry air) air H (KJ/Kg saturation 100% (KJ/Kg dry (KJ/Kg dry air) air) 15.6 43.68 37.8 122.4 148.2 26.7 84.0 40.6 139.4 172.1 29.4 71.7 97.2 43.3 154.8 197.2 32.2 88.4 112.1 46.1 224.5 35 95.4 128.9 60 461.5 S 15 20 90% 40 45 50 55 60 65 70 75 Enthalpy At Saturation, kJ/kg Dry Air 80 85 90 85 95 100 105 110 15 Wet Bulb or Saturation Temperature, C 0 5 10 +0.2 +0.4 +0.6 +0.8 -0.05 -10 0.75 10 15 0.80 20 25 Dry Bulb Temperature, C Below 0C Properties and Enthalpy Deviation Lines Are For Ice Humid Volume, m/kg Dry Air 120 35 125 130 135 140 145 40 45 50 0.033 0.032 0.031 0.030 0.029 0.028 0.027 0.026 60% 70% 50% Relative Humidity 40% 0.025 0.024 0.023 0.022 0.021 0.020 0.019 0.018 0.017 0.95 0.016 30% 0.015 0.014 8 0.013 0.012 20% 0.011 0.010 0.009 0.008 0.007 10% 0.006 0.005 0.004 0.003 0.002 0.001 30 35 40 45 0.00 50 0.85 55 0.90 Moisture Content, kg/kg Dry Air It is planned to cool water from 43.3C to 29.4C in a packed counter-current water-cooling tower using air entering at 28C (dry bulb) and 13C (wet bulb). The water flow rate is 9764.9 Kg/h.m and the air flow is 4439.8 Kg/h.m. The overall mass transfer coefficient Kya is 2500 Kg/mh. Water heat capacity is 4200 J/KgC. A psychrometric chart is supplied overleaf that should be submitted with your test solutions. Calculate: (a) minimum air rate that can be used. (b) tower height needed if air flow of 6835.4 Kg/h.m is used. Enthalpies of saturated air-water vapor (base temperature 0C) Enthalpy of air H at Enthalpy of air H at Enthalpy of air Enthalpy of 100% Temperature Temperature (C) H (KJ/Kg dry saturation (C) air) dry air) air H (KJ/Kg saturation 100% (KJ/Kg dry (KJ/Kg dry air) air) 15.6 43.68 37.8 122.4 148.2 26.7 84.0 40.6 139.4 172.1 29.4 71.7 97.2 43.3 154.8 197.2 32.2 88.4 112.1 46.1 224.5 35 95.4 128.9 60 461.5 S 15 20 90% 40 45 50 55 60 65 70 75 Enthalpy At Saturation, kJ/kg Dry Air 80 85 90 85 95 100 105 110 15 Wet Bulb or Saturation Temperature, C 0 5 10 +0.2 +0.4 +0.6 +0.8 -0.05 -10 0.75 10 15 0.80 20 25 Dry Bulb Temperature, C Below 0C Properties and Enthalpy Deviation Lines Are For Ice Humid Volume, m/kg Dry Air 120 35 125 130 135 140 145 40 45 50 0.033 0.032 0.031 0.030 0.029 0.028 0.027 0.026 60% 70% 50% Relative Humidity 40% 0.025 0.024 0.023 0.022 0.021 0.020 0.019 0.018 0.017 0.95 0.016 30% 0.015 0.014 8 0.013 0.012 20% 0.011 0.010 0.009 0.008 0.007 10% 0.006 0.005 0.004 0.003 0.002 0.001 30 35 40 45 0.00 50 0.85 55 0.90 Moisture Content, kg/kg Dry Air