Air enters a heat exchanger at a volumetric flow rate of 50 m3/min at 305 k and 100 kpa. air exits at 295 k and 95 kpa (this means that the air stream of the heat exchanger is not ideal, as there is a drop in pressure). r-134a enters the heat exchanger at 0.5 mpa at a quality of 0.2. r-134a exits at 20°c. a. draw the t-v diagram for air. b. draw the p-v diagram for air. c. draw the t-v diagram for r-134a. d. draw the p-v diagram for r-134a. e. determine the mass flow rate of r-134a. f. determine the heat transfer from the air stream in units of kj/min. g. clearly outline every assumption that must be made to determine the mass flow rate and heat transfer.

Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w