Consider a piston-cylinder assembly located in a room at 100 kpa and in which a saturated liquid+vapor mixture of h20 exists with a quality of 0.5. heat is added until the specific volume is tripled. neglect changes in potential and kinetic energy. neglect the mass of the piston. a. draw the process and label the states on a t-v diagram. b. draw the process and label the states on a p-v diagram. c. determine the boundary work per unit mass. d. determine the heat transfer per unit mass. e. determine the entropy produced per unit mass if the boundary temperature is 200°c.

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?