The food compartment of a refrigerator is maintained at 4 c by moving heat from it at a rate of 360 kj/min. if the required power input to the refrigerator is 2 kw, determine:

(a) the coefficient of performance of the refrigerator and
(b) the rate of heat rejection to the room that houses the refrigerator.

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3