3 2 3. (12 marks total) The atrium of a building with a glass wall receives...

Transcribed Image Text:

3 2 3. (12 marks total) The atrium of a building with a glass wall receives s = 70 kW of heat from the sun. An air-conditioning system cools the air entering the space and either adds or removes moisture as required. Outside air enters the air-conditioning system (point 1) at a dry-bulb temperature of 25C and a wet-bulb temperature of 20C, and it is to leave the atrium at T, = 30C and a relative humidity 3 = 30%. The volume flow rate of the air at point 1 is 200 m/minute, and the total pressure is 100 kPa. Qc mw (a) (5 marks) Determine the state of the air required at point 2 - i.e. T and the relative humidity $2. (b) (3 marks) Determine how much water m in kg/min must be added or removed. Note: the diagram shows water being removed, but this is not necessarily correct. (c) (4 marks) Determine the cooling & required in kW. The temperature of the water stream m may be taken as 10C. Use the psychrometric chart provided at the end of this paper for your calculations. The specific gas constant for air R = 0.287 kJ/kg K 3 2 3. (12 marks total) The atrium of a building with a glass wall receives s = 70 kW of heat from the sun. An air-conditioning system cools the air entering the space and either adds or removes moisture as required. Outside air enters the air-conditioning system (point 1) at a dry-bulb temperature of 25C and a wet-bulb temperature of 20C, and it is to leave the atrium at T, = 30C and a relative humidity 3 = 30%. The volume flow rate of the air at point 1 is 200 m/minute, and the total pressure is 100 kPa. Qc mw (a) (5 marks) Determine the state of the air required at point 2 - i.e. T and the relative humidity $2. (b) (3 marks) Determine how much water m in kg/min must be added or removed. Note: the diagram shows water being removed, but this is not necessarily correct. (c) (4 marks) Determine the cooling & required in kW. The temperature of the water stream m may be taken as 10C. Use the psychrometric chart provided at the end of this paper for your calculations. The specific gas constant for air R = 0.287 kJ/kg K