Refrigerant 134a enters an air-cooled condenser at 12 bars and 60°C, and leaves as a saturated liquid at 12 bars. Atmospheric air at 35°C is blown over the condenser tubes and leaves at 45°C. The heat transfer between the two flfluid streams equals 25 MJ/h. Changes in kinetic and potential energy are negligible. Make any reasonable assumptions if necessary. Determine (a) the mass flow rates for the R-134a and the air, in kg/h, Hint: Use the energy conservation on each of the ⁅ uid streams separately. (b) the entropy production rate in the condenser, in kJ h-1K-1, Hint: Use the entropy balance over the whole condenser. (c) the change in kinetic energy for R-134a if the pipe dia
Refrigerant 134a enters an air-cooled condenser at 12 bars and 60°C, and leaves as a saturated liquid at 12 bars. Atmospheric air at 35°C is blown over the condenser tubes and leaves at 45°C. The heat transfer between the two flfluid streams equals 25 MJ/h. Changes in kinetic and potential energy are negligible. Make any reasonable assumptions if necessary. Determine
(a) the mass flow rates for the R-134a and the air, in kg/h,
Hint: Use the energy conservation on each of the ⁅ uid streams separately.
(b) the entropy production rate in the condenser, in kJ h-1K-1,
Hint: Use the entropy balance over the whole condenser.
(c) the change in kinetic energy for R-134a if the pipe diameter is 2.0 cm, in kJ/h
(d) Draw the T-s diagram for the process for R-134a.
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