(1) A chiller plant uses Refrigerant-134a as the working fluid and operates on the vapor- compression refrigeration cycle between and evaporating pressure of 0.3 MPa and a condensing temperature of 60C. The compressor has an isentropic efficiency of 80%. The refrigerant leaving the condenser is saturated and the refrigerant entering the compressor is superheated by 10 C. You can use the R134a p-h diagram to find the properties. a) Sketch the cycle on the R134a p-h diagram attached at the end of this exam paper, and mark all the enthalpy values. Show your procedure for obtaining the values; (10 marks) b) Sketch the T-s diagram of the cycle; (5 marks) c) Calculate the power consumption of the compressor. Refer to the R134a p-h diagram. (3 marks) (2) A single-stage reciprocating compressor intakes? the air at 1 bar and 15 C and delivers it at 6 bar. Assuming the law of compression is pVr=constant, and n is 1.4, calculate the air temperature after compression and the work done per unit mass of intake air. Gas constant of air is 287 J/kgK. PRESSURE, MPa 100 0.02 0.04 0.2 N A o 100 8 0.70 60 Properties computed with: NIST REFPROP - 2000 kJ/kg bes doud. 50 1450 150 0.80 -40C R-134a -301400 0.90 20 1350 1.00 200 1.10 - 1300 1.20 - 0.4 1250 250 8 8-1.30- 8 0.5 1200 -1.40 0.6 1150 300 1.50 0,7 1100 .60 - 1050 0.8 06 1.70 100 1000 ENTHALPY, kJ/kg 350 400 0.9 80 900 06 -0 8 8 00 10 - 20 30 40 50 60 70 80 450 8 450 220 06 500 100 110 120 130 400 500 kg/m S = 2.30 kJ/(kg) 140 150 T 160C 170 8 500 Based on formulation of Tillner-Roth and Baehr (1994) 550 550 90 180 0.60 1.5 14.0 1.0 10 6.0 009 LOO 009 G 0.02 0.04 0.06 0.08 0.1 0.2 10