Chapter 5, Problem 5.21P

During January, at a location in Alaska winds at -30°C can be observed, However, several meters below ground the temperature remains at 15°C.An inventor claims to have devised a power cycle working between these temperatures having a thermal efficiency of 10%. Investigate this claim. What is the maximum thermal efficiency for these conditions? Is the inventor's claim possible?

A diesel engine produces 500 kW at 3800 rpm while consuming 0.02975 kg/s of fuel. During operation, data shows that its mechanical energy loses 17%, the actual volume of air going into each cylinder is 90% (The volumetric efficiency has a negligible variation) and the actual fuel to air ratio is 0.05. If the ambient temperature at this location is 18 0C and the standard atmospheric condition is 14 0C hotter with pressure of 100 kPa, what are the standard parameters of the engine:                                     a. Brake Power, kW b. Indicated Specific Fuel Consumption, kg/kW-hr c. Mass of air, kg/s d. Indicated Mean Effective Pressure, kPa WRONG ANSWERSSSSSS a. 415 b. 0.2147 c. 0.595 d. 35.31 THESE ARE THE WRONG ANSWERS. SHOW CORRECT ANSWER

A 3L, 4-cylinder gasoline engine produces 150 kW at 4,500 rpm when the operating standard condition are 1 bar and 30 °C. The compression ratio of the engine is 9, the heating value of the fuel is 44,400 kJ/kg and the mechanical efficiency is 73%. The engine is brought to an Industrial Plant 3,500 ft above sea level which presented a volumetric efficiency of 70 % at 10.3 kgair/kgfuel. At this condition, find: a) brake power, kW b) brake engine efficiency, % c) PmB kPa d) Mechanical Efficiency, %