Fundamentals of Mechanical Engineering Unit 3 – Introduction to Refrigeration and Air-Conditioning: AKTU previous year questions
36 AKTU questions from Unit 3 (Introduction to Refrigeration and Air-Conditioning) asked in 2021–2026, tagged by marks, year and topic. In short: about 22 marks of every paper come from this unit; the most asked topic is Refrigeration Fundamentals (17 times); 30 questions came back in a later year. The latest ones are listed below; on the page you can filter them by 2-mark or long questions, topic and repeats.
Unit 3 previous year questions
- Write down any two differences between efficiency and COP. (2 marks, 2026, Refrigeration Fundamentals)
- What are the factors affecting the performance of a domestic refrigerator? Discuss methods to improve or optimize its performance. (7 marks, 2026, Domestic Refrigerator and Heat Pump)
- A Carnot refrigerator operates between temperatures of –5°C and 35°C. If the refrigerator requires 3 kW of power input, determine: (i) Coefficient of Performance (COP) (ii) Refrigeration capacity in tons (7 marks, 2026, Refrigeration Fundamentals)
- It is proposed to heat a house using a heat pump outside air at 0°C is used as the heat source. Inside temperature of house is maintained at 30°C. The heating load estimated as 205600 KJ/hrs. Calculate the minimum power to drive the heat pump. (7 marks, 2026, Domestic Refrigerator and Heat Pump)
- Drive the expression for the coefficient of performance in refrigeration? (2 marks, 2025, Refrigeration Fundamentals)
- A refrigerator extracts 10,000 kJ of heat per hour. Calculate its Ton of Refrigeration. (2 marks, 2025, Refrigeration Fundamentals)
- Differentiate between dry bulb and wet bulb temperatures. (2 marks, 2025, Air Conditioning Fundamentals)
- Explain the construction & working of a domestic refrigerator with a suitable diagram. Also, show all the components. (7 marks, 2025, Domestic Refrigerator and Heat Pump)
- Describe the psychrometric properties of air such as DBT, WBT, DPT, and humidity. (7 marks, 2025, Air Conditioning Fundamentals)
- Define the Heat pump. It is proposed to heat a house using a heat pump outside air at 0°C is used as the heat source. Inside temperature of house is maintained at 25°C. The heating load estimated as 104500KJ/hrs. Calculate the minimum power to drive the heat pump. (7 marks, 2025, Domestic Refrigerator and Heat Pump)
- Discuss the factors affecting air-conditioning performance and how they can be optimized. (7 marks, 2025, Air Conditioning Fundamentals)
- Write the short notes on the followings: (i) Dew point temperature (ii) Comfort air conditioning (7 marks, 2025, Air Conditioning Fundamentals)
Most asked Unit 3 topics
- Refrigeration Fundamentals – asked 17 times
- Air Conditioning Fundamentals – asked 9 times
- Domestic Refrigerator and Heat Pump – asked 6 times
Unit 3 question pattern
- 2-mark questions: 10 asked in 2021–2026
- 7-mark questions: 21 asked in 2021–2026
- 10-mark questions: 5 asked in 2021–2026
- About 22 marks from Unit 3 in every paper
- 30 questions were asked again in a later year
Unit 3 questions year by year
- 2026: 4 Unit 3 questions asked (23 marks across that year's papers)
- 2025: 9 Unit 3 questions asked (48 marks across that year's papers)
- 2024: 7 Unit 3 questions asked (44 marks across that year's papers)
- 2023: 9 Unit 3 questions asked (48 marks across that year's papers)
- 2022: 4 Unit 3 questions asked (32 marks across that year's papers)
- 2021: 3 Unit 3 questions asked (22 marks across that year's papers)