1. A 110-hp car engine burns fuel with an energy content of 37 MJ/kg at a rate of 4.5

g/s. Find the thermal efficiency of the engine and the rate of heat transfer rejected to

the ambient.

2. Refrigerant R-410a enters the evaporator in an A/C unit (COP = 1.6) at a temperature

of -22°C, and quality of 0.35, and leaves at -15°C as saturated vapor. The mass flow

rate is 0.0022 kg/s. Find the work input.

3. A heat engine develops 55 kW of power and rejects heat to a low-temperature reservoir

(T = 0°C) at a rate of 1150 kJ/min. Determine the minimum theoretical value for the

temperature of the high-temperature reservoir.

4. A Carnot cycle with an efficiency 52% uses H₂ as the working fluid. The low-temperature

reservoir is at 282 K. During the heat rejection the pressure changes from 95 kPa to

110 kPa. Find all heat transfer quantities and the (specific) net cycle work.

5. A Carnot refrigeration cycle uses ideal gas with R=0.202 kJ/kg. K as the working fluid.

Heat is transferred from the freezer at 257 K to the ambient at 320 K. During the heat

rejection, the pressure changes from 1100 kPa to 2200 kPa. Find the COP and the

specific heat transfer from the freezer to the cycle.