Question 3 1) A counter-flow cooling tower is to be installed for cooling the condenser water in a chiller plant. The wa

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Question 3 1 A Counter Flow Cooling Tower Is To Be Installed For Cooling The Condenser Water In A Chiller Plant The Wa 1 (111.81 KiB) Viewed 61 times

Question 3 1) A counter-flow cooling tower is to be installed for cooling the condenser water in a chiller plant. The water leaves at 31 °C, and the water flow rate of 60 kg/s. The corresponding airflow rate through the cooling tower is 48 kg/s and the inlet air wet bulb temperature is 27°C. A supplier of cooling towers offered a model and the NTU of this cooling tower is shown as below. dT NTU-hav Where he is the total heat transfer coefficient; a the heat and mass transfer area per unit volume; V the volume of the cooling tower, TW the water temperature; how the saturation air enthalpy corresponding to Tw; ha the enthalpy of air, and Cw the specific heat capacity of fresh water (Cw = 4.2 kJ/kg-K). Using the saturated moist air properties as given in Table Q4, determine the NTU of the cooling tower for the cooling range of 7 °C. (20 marks) 2) Two cooling towers are working at the same outdoor environmental conditions for the same chiller plant. The approach of cooling tower A is larger than that of B. Which cooling tower has the higher capacity? (5 marks) Table Q3 Properties of saturated air Temperature T (°C) (K) Sat, vap. press. Pys (kPa) Sat. hum. ratio Ws (kg/kg) Sat. air enthalpy hws (kJ/kg) 38 37 36 35 34 33 32 31 30 29 28 27 311.15 310.15 309.15 308.15 307.15 306.15 305.15 304.15 303.15 302.15 301.15 300.15 6.63147 6.28099 5.94664 5.62782 5.32391 5.03434 4.75853 4.49594 4.24603 4.00829 3.78221 3.56731 0.04356 0.04110 0.03878 0.03658 0.03449 0.03252 0.03065 0.02888 0.02720 0.02562 0.02412 0.02270 150.2 141.5 134.9 128.5 122.4 116.5 110.8 105.1 99.7 94.6 90.1 85.0