Applications of Thermodynamic Cycles: Power Plants, Refrigeration, and More

Question 1

In a power plant, the Rankine cycle is commonly used to:

Accepted Answer

Convert heat energy into mechanical energy

Answer

Extract heat from a low-temperature source

Answer

Power internal combustion engines

Answer

Operate heat pumps

Question 2

The primary function of the evaporator in a refrigeration system is to:

Accepted Answer

Absorb heat from the refrigerated space

Answer

Reject heat to the surroundings

Answer

Compress the refrigerant

Answer

Control the refrigerant flow

Question 3

Heat pumps are versatile devices that can:

Accepted Answer

Both heat and cool a space

Answer

Only heat a space

Answer

Only cool a space

Answer

Generate electricity

Question 4

In an internal combustion engine, the spark plug:

Accepted Answer

Initiates combustion of the fuel-air mixture

Answer

Controls the compression ratio

Answer

Exhausts gases from the cylinder

Answer

Lubricates moving parts

Question 5

The condenser in a refrigeration system:

Accepted Answer

Releases heat to the surroundings

Answer

Absorbs heat from the surroundings

Answer

Compresses the refrigerant

Answer

Expands the refrigerant

Question 6

The Otto cycle is commonly used in:

Accepted Answer

Gasoline-fueled internal combustion engines

Answer

Diesel engines

Answer

Refrigeration systems

Answer

Steam turbines

Question 7

In a Rankine cycle, which component is responsible for the isentropic compression process?

Accepted Answer

Pump

Answer

Turbine

Answer

Condenser

Answer

Boiler

Question 8

Which of the following devices is NOT classified as a heat pump?

Accepted Answer

Jet engine

Answer

Air-source heat pump

Answer

Ground-source heat pump

Answer

Absorption heat pump

Question 9

What is the primary purpose of a regenerator in a gas turbine cycle?

Accepted Answer

Preheat the air entering the combustor

Answer

Increase the compression ratio

Answer

Reduce the heat loss

Answer

Cool the gases exiting the turbine

Question 10

How is the thermal efficiency of a power plant mathematically defined?

Accepted Answer

Ratio of work output to heat input

Answer

Ratio of heat output to work input

Answer

Ratio of heat rejected to work output

Answer

Ratio of work output to heat rejected

Question 11

What is the maximum theoretical efficiency of a heat engine operating between two fixed temperatures?

Accepted Answer

Carnot efficiency

Answer

Otto efficiency

Answer

Diesel efficiency

Answer

Rankine efficiency

Question 12

Which thermodynamic cycle is typically used in spark-ignition internal combustion engines?

Accepted Answer

Otto cycle

Answer

Carnot cycle

Answer

Diesel cycle

Answer

Rankine cycle

Question 13

In a Rankine cycle, what is the primary function of the condenser?

Accepted Answer

To convert steam into water

Answer

To increase the pressure of steam

Answer

To decrease the temperature of steam

Answer

To expand steam

Question 14

What is the primary purpose of a regenerative heat exchanger in a gas turbine engine?

Accepted Answer

To increase thermal efficiency

Answer

To reduce emissions

Answer

To improve performance of the refrigeration system

Answer

To increase power output

Question 15

What is the theoretical maximum efficiency of an ideal Stirling engine?

Accepted Answer

Carnot efficiency

Answer

Otto efficiency

Answer

Diesel efficiency

Answer

Rankine efficiency

Question 16

Which process is NOT involved in a Rankine cycle?

Accepted Answer

Adiabatic expansion

Answer

Heat rejection

Answer

Heat addition

Answer

Condensation

Question 17

The maximum possible efficiency of a heat engine operating between two fixed temperatures is:

Accepted Answer

Carnot efficiency

Answer

Brayton efficiency

Answer

Rankine efficiency

Answer

Otto efficiency

Question 18

In a heat pump, the transfer of heat from the cold reservoir to the refrigerant takes place in the:

Accepted Answer

Evaporator

Answer

Expansion valve

Answer

Compressor

Answer

Condenser

Question 19

Which process in a Stirling cycle results in the transfer of heat to the working fluid?

Accepted Answer

Regenerator heating

Answer

Isothermal expansion

Answer

Isochoric compression

Answer

Adiabatic compression

Question 20

The efficiency of an internal combustion engine is fundamentally limited by:

Accepted Answer

The Carnot efficiency between the combustion and exhaust temperatures

Answer

The type of fuel used

Answer

The design of the engine components

Answer

The compression ratio of the engine

Question 21

One of the key advantages of a combined cycle power plant is:

Accepted Answer

Improved overall efficiency

Answer

Increased fuel flexibility

Answer

Reduced maintenance requirements

Answer

Lower capital costs

Question 22

In the condenser of a refrigeration system, the refrigerant:

Accepted Answer

Rejects heat to the surroundings

Answer

Absorbs heat from the surroundings

Answer

Expands isentropically

Answer

Is compressed adiabatically

Question 23

During an isentropic process in a closed thermodynamic system, the:

Accepted Answer

Entropy remains constant

Answer

Entropy increases

Answer

Entropy decreases

Answer

Temperature remains constant