MEE20001 Thermodynamics Assignment 2 2025 | SUT

MEE20001 Thermodynamics 

1. Refrigerant -134a enters a compressor as a saturated vapour at 160 kPa at a rate of 0.04 m3/s and leaves at 750 kPa. The input to the compressor is 11 kW. If the surroundings at 250C °C experience an entropy increase of 0.01 kW/K, determine 
(a) The rate of heat loss from the compressor, 
(b) the exit temperature of the refrigerant, and 
(c) The rate of entropy generation (10 marks) 

2. An air-standard Diesel cycle has a compression ratio of 18 and a cutoff ratio of 3. At the beginning of the compression process, air is at 100 kPa and 270 °C. Assuming the variation of specific heats with temperature, determine 
(a)The temperature after the heat-addition process 
(b)The thermal efficiency and 
(c)The mean effective pressure (10 marks) 

3. Consider a steam power plant that operates on the ideal reheat Rankine cycle. The plant maintains the boiler at 20 MPa, the reheater at 4 MPa, and the condenser at 100 kPa. The temperature is 6000 at the entrance of the high-pressure turbine, and 3000 °C at the entrance of the low-pressure turbine. Determine the thermal efficiency of this system. (10 marks)