Question

In: Mechanical Engineering

The isentropic efficiency of an ammonia, NH3, refrigeration plant is 0.88. The ammonia enters the compressor...

The isentropic efficiency of an ammonia, NH3, refrigeration plant is 0.88. The ammonia enters the compressor as dry saturated vapour at -16 ? and leaves the compressor in a superheated state at 11.67 bar. The refrigerant is then condensed and undercooled by 4K at constant pressure before being expanded at -16 ?.

(NEED TO USE STEAM TABLES FOR NH3, PLEASE ONLY ANSWER IF YOU HAVE A GOOD UNDERSTANDING OF REFRIGERTION)

a)Draw a schematic of the plant and the cycle on T-s and P-h coordinates.

Calculate:

b (i) the superheat temperature at the exit of the compressor

b (ii) the compressor work

b(iii) the refrigeration effect

b(iv) the coefficient of performance of the plant

b(v) the volume flow rate of the refrigerant measured at the compressor inlet for a plant refrigeration capacity of 500kW.

DATA Assume that the cp of ammonia at 11.67 bar is 4.86 kJ/kg

PLEASE DON'T JUST MAKE UP THE ANSWERS.

ANSWERS;

bi)118.1 oC

b(ii) 278.9 kJ/kg

b (iii) 1121.6 kJ/kg

b(iv) 4.02

b (v) 0.0493 m3 /s

Expert Solution

samet mamat answered 2 years ago

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