A mild steel steam pipe (k=54 W/mK) has an outside diameter of 15 cm and a wall thickness of 0.7 cm. It is insulated with a 5.3 cm-thick layer of 85% magnesia insulation(k=0.073 W/mK). Superheated steam at 500 K flows through the pipe, and the inside heat transfer coefficient is 35 W/m2K. Heat is lost by convection and radiation to surroundings at 300K, and the sum of outside convection and radiation coefficients is estimated to be 8 W/m2K. Find the rate of heat loss for a 20 m length of pipe.

Ahouse has the following electrical appliance usage (1) single 40w lamp used for 4 hours per day (2) single 60w fan used for 12 hours per day (3) single 200w refrigerator that runs 24 hours per day with compressor run 12 hours and off 12 hours find the solar power inverter size in watt with correction factor of 1.25.

Aflywheel accelerates for 5 seconds at 2 rad/s2 from a speed of 20 rpm. determine the total number of revolutions of the flywheel during the period of its acceleration. a.5.65 b.8.43 c. 723 d.6.86

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?