Nitrogen gas is compressed at steady state from a pressure of 14.2 psi and a temperature 60°F to a pressure of 120 psi and a temperature of 500°F. The gas enters a compressor with a volumetric flow rate of 1200 ft^3 /min. The magnitude of the heat transfer rate from the compressor to its surroundings is 5% of the compressor power input. Using the ideal gas model and neglecting kinetic and potential energy effects, determine: a. The compressor power input (in horsepower). b. The volumetric flow rate at the exit (in ft3 /min)

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?