In a steam-heating system, air is heated by being passed over some tubes through which steam flows steadily. Steam enters the heat exchanger at 30 psia and 400°F at a rate of 15 lbm/min and leaves at 25 psia and 212°F. Air enters at 14.7 psia and 80°F and leaves at 130°F. Determine the volume flow rate of air at the inlet.

answer in an analytical way

Water is stored in a large, well-insulated storage tank at 21.0°C open to atmosphere. It is pumped at a rate of 40 m3/h to another tank 25 m above, which is also open to atmosphere. The motor driving the pump supplies energy at the rate of 9.5 kW. The water passes through a heat exchanger where 255 kW of heat is added to the water. The total friction loss (ΣF) in the system is 90.25 J/kg. Determine the final temperature of the water at the second tank

5-84 Air (Cp=1.005 kJ/kg°C) is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. Air enters the heat exchanger at 95 kPa and 20°Ct at rate of 0.6 m³/s. The combustion gases (Cp=1.10 kJ/kg°C) that enter at 160°C at a rate of 0.95 kg/s and leave at 95°C. Determine the rate of heat transfer to the air and its outlet temperature. Air 95 kPa 20°C 0.6 m³/s Exhaust gases 0.95 kg/s 95°C