. In a water cooling tower air enters at a height of 1 m above the ground level with velocity of 20 m/s and leaves the tower at a height of 7 m above the ground level with a velocity of 30 m/s. Water enters the tower at a height of 8 m above the ground level with a velocity of 3 m/s and leaves the tower at a height of 0.8 m with a velocity of 1 m/s. Water temperatures at inlet and exit are 800C and 500C respectively, while the inlet and exit temperatures of air are 300C and 700C respectively. The cooling tower is well insulated and a of 2.25 kW drives the air through the cooling tower. Determine the mass flow rate of air required if the mass flow rate of water is 1.5 kg/s.