The isentropic efficiency of an ammonia, NH3, refrigerationplant is 0.88. The ammonia enters the compressor as dry saturatedvapour at -16 ? and leaves the compressor in a superheated state at11.67 bar. The refrigerant is then condensed and undercooled by 4Kat constant pressure before being expanded at -16 ?.
(NEED TO USE STEAM TABLES FOR NH3, PLEASE ONLY ANSWER IFYOU HAVE A GOOD UNDERSTANDING OF REFRIGERTION)
a)Draw a schematic of the plant and the cycle on T-s and P-hcoordinates.
Calculate:
b (i) the superheat temperature at the exit of thecompressor
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 thecompressor inlet for a plant refrigeration capacity of 500kW.
DATA Assume that the cp of ammonia at 11.67 bar is 4.86kJ/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
