Engineering Thermodynamics Engineering Essay Research (Essay Sample)

Theoretical Cycles
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Question a: 100% Heat Engine Efficiency
Heat engine’s efficiency can be computed thrugh the following equation:
N= 1- Q2/ Q1 Where; Q1 is the rejected heat at the sink.
Q2 I the heat absorbed at the source.
n is either 1 or 100% once the value of Q2 is 0.
A heat engine consists of 3 elements which include a heat source, working object, as well as a heat sink. The whole amount of energy is said to be conserved if the system is isolated. In order to have a flow of heat, temperature difference must be present. Transferring temperature from a substance to the other also leads to equalization in the level of temperature for the two substances, and this means that heat sink increases in temperature as the heat source reduces in the level of temperature (Xiao & Gong, 2016). This flow continues until a level when the transfer can’t continue regardless of the presence of heat in the two objects. The temperature of a substance keeps of increasing from 0. However, there is a stage at which the temperature of the source becomes equal to that of the working substance. At this point, the transfer of heat is absent meaning that the output cannot be obtained. Moreover, the work done by the engine is used to overcome friction and this leads to a higher input compared to output. In order to have 100% efficiency, the Q2 should equal to 0meaning that there is no work done. According to Kelvin, however, the second law of thermodynamics argues that producing heat in a complete cycle by a heat engine is impossible if the heat is only exchanged with bodies along a single fixed temperature.