Cyclic processes and their efficiency, Carnot cycle Worksheet

Worksheet

Circular processes and their efficiency. Carnot Cycle.

Lesson objectives:

- describe the principle of operation of the heat engine;

- describe the Carnot cycle for an ideal heat engine;

- apply the efficiency formula of a heat engine for solving problems.

(I/G) Task 1. Match text and technical device.

(G) Task 2. Discuss the following questions in pairs.

1. Investigate the practical effectiveness of the transducers proposed in the pictures and suggest discussing the causes of the "loss" of energy.
2. List the negative effects of using heat engines.
3. Offer your solutions to the problem.

(G) Task 3. Watch the video: https://www.youtube.com/watch?v=GTPKShjBqmg

1.      What is the name of the cycle described in the video?

2.      What processes does the cycle consist of?

3.      Why is the engine working on this cycle called ideal?

4.      What is the efficiency of this engine?

(I) Task 4.

Solve problems on your own and make a Sankey diagram for each.

Level А

1. The heat engine for the cycle receives from the heater the amount of heat 100 J and gives the refrigerator 60 J. The efficiency of the machine is equal to …

A.    67 %

B.     60 %

C.     40 %

D.    25 %

E.     15 %

2. Efficiency of the heat engine is 30%. The working fluid received from the heater 5 kJ of heat. What is the work done by the working body?

A.    150 000 J

B.     1 500 J

C.     150 J

D.    ≈ 67 J

E.     0,15 J

3. Efficiency of an ideal heat engine, with heater temperature 327⁰С and the temperature of the refrigerator 127 ⁰С    

A.    100 %

B.     61 %

C.     33 %

D.    50 %

E.     40 %

4. What is the efficiency value of an ideal heat engine using a heater with a temperature of 427 ⁰С and a fridge with temperature 27 ⁰С?

A.    70 %

B.     43 %

C.     94 %

D.    6 %

E.     57 %

Level В

1.      The heater temperature of an ideal heat engine is 117 °C, and that of a refrigerator is 270 K. The amount of heat received by the machine from the heater in one second is 60 kJ. Calculate the efficiency of the machine and the amount of heat given to the refrigerator in 1 second.

2.      The temperature of the heater is 227⁰С. Determine the efficiency of the ideal engine and the temperature of the refrigerator, if at the expense of each kilojoule of heat received from the heater, the engine performs 350 J of mechanical work.

3.      In an ideal heat engine, the absolute temperature of the heater is 3 times higher than the temperature of the refrigerator. Determine the efficiency of the engine.

4.