Question

Refrigerant-134a is to be cooled by water in a condenser. The refrigerant enters
the condenser with a mass flow rate of 6 kg/min at 1 MPa and 708C and leaves
at 358C. The cooling water enters at 300 kPa and 158C and leaves at 258C.
Neglecting any pressure drops, determine (a) the mass flow rate of the cooling
water required and (b) the heat transfer rate from the refrigerant to water

Answer 1

Answer:

Refrigerant R-134a is to be cooled by waterin a condenser.The refrigerant enters thecondenser with a mass flow rate of 6 kg/minat 1 MPa and 70 C and exits at 35 C. The cool-ing water enters at 300 kPa and 15 C andleaves at 25 C. Neglecting pressure drops,determine a) the required mass flow rate ofthe cooling water, and b) the heat transferrate from the refrigerant to the water.SolutionFirst consider the condenser as the control volume. The process is steady,adiabatic and no work is done. Thus over any time intervalΔt,ΔEΔt=0and thusXin˙E=Xout˙Ewhere˙E=˙m h+12V2+gz650:351 Thermodynamics·Prof. Doyle Knight37

Background image

I only know this

sorry for errors