Discussion
Home ‣ Mechanical Engineering ‣ Heat Transfer, Refrigeration and Air Conditioning Comments
- Question
The sensible heat factor during cooling and dehumidification process is given by (where h1 = Enthalpy of air entering the cooling coil, h2 = Enthalpy of air leaving the cooling coil, and hA = Enthalpy of air at the end of dehumidification process)
Options- A.
- B.
- C.
- D.
- Correct Answer
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- 1. The formation of frost on cooling coils in a refrigerator
Options- A. increases heat transfer
- B. improves C.O.P. of the system
- C. increases power consumption
- D. reduces power consumption Discuss
- 2. The by-pass factor for a cooling coil
Options- A. increases with increase in velocity of air passing through it
- B. decreases with increase in velocity of air passing through it
- C. remains unchanged with increase in velocity of air passing through it
- D. may increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering Discuss
- 3. The process of heat transfer from a hot body to a cold body, in a straight line, without affecting the intervening medium, is called radiation.
Options- A. True
- B. False Discuss
- 4. Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)
Options- A.
- B.
- C.
- D.
Discuss
- 5. The subcooling in a refrigeration cycle
Options- A. does not alter C.O.P.
- B. increases C.O.P.
- C. decreases C.O.P.
- D. none of these Discuss
- 6. The optimum effective temperature for human comfort is
Options- A. higher in winter than in summer
- B. lower in winter than in summer
- C. same in winter and summer
- D. not dependent on season Discuss
- 7. Defrosting of a refrigerator may be done by stopping the compressor for a short period.
Options- A. Correct
- B. Incorrect Discuss
- 8. A water cooled condenser operates at a __________ condensing temperature than an air-cooled condenser.
Options- A. higher
- B. lower Discuss
- 9. For ammonia refrigerating systems, the tubes of a shell and tube condenser are made of
Options- A. copper
- B. aluminium
- C. steel
- D. brass Discuss
- 10. In a psychrometric process, the sensible heat added is 30 kJ/s and the latent heat added is 20 kJ/s. The sensible heat factor for the process will be
Options- A. 0.3
- B. 0.6
- C. 0.67
- D. 1.5 Discuss
Heat Transfer, Refrigeration and Air Conditioning problems
Search Results
Correct Answer: increases power consumption
Correct Answer: increases with increase in velocity of air passing through it
Correct Answer: True
Correct Answer:
Correct Answer: increases C.O.P.
Correct Answer: lower in winter than in summer
Correct Answer: Correct
Correct Answer: lower
Correct Answer: steel
Correct Answer: 0.6
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