(a) A reversible heat engine operates between a reservoir at 444°C and an environment at 36.3°C. 71% of the power output of the heat engine is used to drive the compressor of a reversible refrigeration system. The refrigeration system removes heat from the cooled space of -15°C at a rate of 8.94 kW. The system rejects the waste heat to the same environment of 36.3°C. (i) Determine the rate of heat supply to the heat engine, in kW. (ii) Determine the total rate of heat rejection to the environment. (7 marks) (3 marks) (b) The steel plate of a device in a room is being cooled at the upper surface (Figure 3). The room has the air temperature of 21°C. The convection heat transfer coefficient over the upper surface of the plate is 23.4 W/m²K. The plate upper surface is maintained at a constant temperature, Ts, of 240°C. The plate has the diameter of 70 cm, the thickness, t, of (2.54+0.1 × B)* cm, the heat conductivity of 41.9 W/m-K and the emissivity of its surfaces of 0.74. An associate engineer disregards any heat transfer from the steel plate to the device. The engineer claims that the inside plate temperature, Ti, is less than 251°C. Do you agree with the engineer? Give your answer and support with evidence. *, B is the last digit of your student number, e.g. if your student number is 19123456A, B = 6, (2.54+0.1 × B)=(2.54+0.1 x 6) = 3.14 cm. Air Device Steel Plate Figure 3 Ts Ti (10 marks)