Consider a flat plate that is 25 mm long, 30 mm wide, and 1 mm thick and a 50 mm long cylinder with the same volume as the plate. Compare the heat transfer of the plate in parallel air flow to the heat transfer of the cylinder in cross flow under the same conditions. Both the plate and cylinder have a surface temperature of 80°C. The air is at 25°C with a velocity of 3 m/s. Note: Use the Churchill and Bernstein correlation to determine the Nusselt number for the cylinder case.

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.