Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
The fluids used in electrolux refrigerator are
Options- A. water and hydrogen
- B. ammonia and hydrogen
- C. ammonia, water and hydrogen
- D. none of these
- Correct Answer
- ammonia, water and hydrogen
- 1. The overall coefficient of heat transfer is used in problems of
Options- A. conduction
- B. convection
- C. radiation
- D. conduction and convection Discuss
- 2. During heating and humidification, the final relative humidity of air
Options- A. is higher than that of the entering air
- B. is lower than that of the entering air
- C. can be lower or higher than that of the entering air
- D. none of the above Discuss
- 3. A human body feels comfortable when the heat produced by the metabolism of human body is equal to the
Options- A. heat dissipated to the surroundings
- B. heat stored in the human body
- C. sum of (a) and (b)
- D. difference of (a) and (b) Discuss
- 4. The specific humidity during cooling and dehumidification
Options- A. remains constant
- B. increases
- C. decreases Discuss
- 5. During sensible cooling,
Options- A. relative humidity remains constant
- B. wet bulb temperature increases
- C. specific humidity increases
- D. partial pressure of vapour remains constant Discuss
- 6. The refrigerant after condensation process is cooled below the saturation temperature before throttling. Such a process is called
Options- A. sub-cooling or under-cooling
- B. super-cooling
- C. normal cooling
- D. none of these Discuss
- 7. In a parallel flow heat exchanger, the rate of flow of heat and the rate of decrease of temperature are maximum.
Options- A. Yes
- B. No Discuss
- 8. The boiling point of R-12 is about - 30°C.
Options- A. True
- B. False Discuss
- 9. It is desired to condition the outside air from 70% relative humidity and 45° C dry bulb temperature to 50% relative humidity and 25° C dry bulb temperature (room condition). The practical arrangement will be
Options- A. dehumidification
- B. cooling and humidification
- C. cooling and dehumidification
- D. dehumidification and pure sensible cooling Discuss
- 10. The heat transfer from a hot body to a cold body is directly proportional to the surface area and difference of temperatures between the two bodies. This statement is called
Options- A. First law of thermodynamics
- B. Newton's law of cooling
- C. Newton's law of heating
- D. Stefan's law Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: conduction and convection
Correct Answer: can be lower or higher than that of the entering air
Correct Answer: sum of (a) and (b)
Correct Answer: decreases
Correct Answer: partial pressure of vapour remains constant
Correct Answer: sub-cooling or under-cooling
Correct Answer: Yes
Correct Answer: True
Correct Answer: cooling and dehumidification
Correct Answer: Newton's law of cooling
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