Second Law - Quality of Energy

Practice flashcards related to the second law of thermodynamics, focusing on heat engines, refrigerators, and performance measurements.

The second law of thermodynamics is needed for __________ processes.

real

The specific statement of the second law of thermodynamics pertains to __________.

energy quality and direction of processes

Reservoirs and working fluids are key concepts in __________.

thermodynamics

Characteristics of heat engines include receiving heat from a __________ source.

high temperature

The difference between thermodynamic heat engines and __________ heat engines is significant in thermodynamics.

mechanical

An energy-flow diagram indicates the flow of energy, and must label all __________ and reservoirs.

energies

The desired output for a steam power plant is __________.

work produced

To determine performance, you must obtain the performance of a steam power plant in terms of __________.

heat exchange

The Kelvin-Planck statement relates to the __________ of a steam power plant.

efficiency and heat conversion

For a refrigerator, desired output refers to __________.

cooling effect

In terms of the heat exchange, the performance of a refrigerator is obtained by calculating its __________.

coefficient of performance (COP)

The Clausius statement pertains to the operation of __________.

refrigerators and heat pumps

Energy entering a system minus energy leaving it equals the change of __________.

system's energy

For mass and energy balance in a control volume, if the system reaches a steady state, then __________ = 0.

change in mass and energy

The first law of thermodynamics states that energy must be __________ in processes.

conserved

Natural processes flow from high temperature to __________.

low temperature

The major uses of the second law include identifying the direction of processes and asserting __________.

that energy has quality as well as quantity

Heat engines operate in a __________.

cycle

The thermal efficiency of a steam power plant measures the fraction of heat input that is converted to __________.

net work output

The coefficient of performance for a refrigerator is defined as the ratio of __________ over required input.

desired output

Work done by the shaft in a heat engine is usually converted from __________.

internal energy