Question

Air enters a 30-cm-diameter cooling section of an air-conditioning unit at 95 kPa, 35°C, and 60% relative humidity at 120 m/min. The air is cooled by passing it over a

cooling coil through which cold water flows. The cooling water (CW) experiences a temperature rise of 8°C. The air leaves the cooling section of the air conditioning unitsaturuted at 20°C. a) Draw a schematic diagram of the air-conditioning unit and illustrate the process on a psychometric chart. b) Construct a property table giving the pressure, temperatures, relative humidity, specific humidity ratio, specific volume and enthalpy for each of the state points identifiedin the process and hence determine the mass flow rates of the air and the cooling water, the rates of heat transfer and moisture removal from the air, and the exit velocity ofthe air stream from the cooling section of the air conditioning unit.(6 marks)

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